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Sustainer Ideas


psw

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Hey All,

img_2032.jpg

It's been almost a year, but I finally got my sustainer guitar done. I stopped working on it for a while because I was so frustrated, and just picked it up again recently. I used MRJ's layout for the circuit, and had to wind the coil two more times before I got one that works. The only thing that isn't working is the harmonic mode. It actually just mutes the strings (and makes a lot of noise) regardless of how I have it set. I hardwired it in regular sustain mode for now, but I hope to fix it so I can put in the switch. Any ideas on what might help? I ended up going with the 220uf cap instead if the 100uf because it worked better. Thanks so much to PSW, and everyone else that contributed. I couldn't have built it without you.

The sustainer is completely stealth (except for the driver looking a little strange, I plan on dealing with that eventually). Both of the pots are mounted where the neck pickups volume and tone would be, and the pickup selector switch controls on/off for the sustainer. I also plan on eventually coil tapping the bridge pickup, and adding a harmonic switch once I get that worked out (both will be push/pulls).

ps. there will be a white knob on the pot without a knob. I just need to get another knurled shaft pot.

-jftl

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Something's still not right...hmmmm

i suspect that a magnet under the driver with one pole facing directly up under it might be something to try...and move the driver up by the neck instead of the middle of the pickup cavity (further from the pickup)

But is sounds like there is some feedback between the driver and pickup perhaps...so, do you get clean sustain with a clean amp or is there some distortion in the signal? Also, have you the ability to adjust the gain? This could be a symptom of too much power or something...while if might be short of squealing, it may well be trying too hard...

remember what I was saying about this project being a balance of forces...more force is not a solution, it only exasperates problems...

otherwise well done for coming back to it, many have found they need to do the same thing...but it definitely has the potential to work more or better.

The dampening symptom is interesting for those interested in the moog thing...maybe some clues in there...i have some experience of this effect, but not consistently...it is more a symptom of things not working right.

A diagram of how it is wired may also help...perhaps...

pete

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Hey Pete,

Well I ended up wiring another driver. I was dis-assembling this guitar's old neck pickup (it has a silver cover I was going to use), and found that it was actually a single coil, so I decided to wire it up as a driver to make it even more stealthy. This put the driver a little bit closer to the neck as well. I don't want to do the surface mount thing if I can get away with it just cause I'm liking the stealth thing (if you haven't noticed =) ).

There is some distortion in the signal with everything cranked. I can back the controls off and get rid of some, but then of course it doesn't work as well. As I think you've stated before there is a lot of factors to it, and it takes some twiddling to get it to work just so. I probably won't be able to use it completely clean all the time, but it sounds heavenly with a bit of distortion and some delay or reverb.

I'll admit I didn't tinker with getting the harmonic part working a lot. I was just happy to have a functional unit. I played with bias on the jfet some, and got rid of the noise, and damping, but still not harmonics.

I followed MRJ's schemo to the letter. The input is wired directly to the pickups hot lead, and the circuit shares ground with the guitar.

Here's how it looks now

img_2057.jpg

I plan on eventually getting another bridge pickup that has a metal cover also.

-jftl

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OK...

well looks good...not sure if the metal cover would be affecting it...but it looks ok. I wasn't thinking you need to do a surface mount thing but just replacing the typical HB magnet with something under the coil with the poles facing up instead of to the side as in an HB.

Otherwise it sounds like it is wired ok...typically you need to wire it direct to the pickup and to turn it on, switch on the battery power...so much easier to do with just the one pickup.

However, it still leaves some room for improvement and it may be something in the circuit. I am not that familiar with the F/R and not sure how tested the MRJ version is but it looks ok and the extra caps helps with stability.

(perhaps when i finally get my finger out and solder up my circuits you could be interested in swaping out yours for mine :D )

pete

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I'm not sure which way the magnet faces on this one because like I said, it's actually a single coil. Considering the adjustable poles I'm assuming it's flat like you said.

Yeah, I wired this (as far as I know) how you've been saying to for the last 286 pages (wow!). The pickup switch controls the battery on/off rather then haveing a stereo jack that turns in on when the guitar is plugged in, and there is only the bridge pickup. Another thing I've found that you've said before is that it sucks juice, my battery is already going flat! Have you tried one of these with a coil shunted pickup? I tried it, and it made the sustainer squeal big time.

I would love to have one of your circuits. Hopeful by the time you "pull the finger out" I will be in better financial shape. I was laid off, and un-employed for 2 months, I'm just getting back on my feet again this coming week.

-jftl

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I would love to have one of your circuits. Hopeful by the time you "pull the finger out" I will be in better financial shape. I was laid off, and un-employed for 2 months, I'm just getting back on my feet again this coming week.

Me too...my commiserations...you are not alone! However...good to keep yourself occupied, something like his is a distraction. Also, the F/R has shown to work ok. I am wondering whether that cover isn't making things worse, however you have tried the same setup with a different driver and no cover. There definitely seems to be some EMI between the driver and the pickup especially at high frequencies. The 220uF cap is filtering out a lot of that which is raising the threshold, but I found the high strings struggled with this value although the low strings were stronger....the 100uF is my compromise. I have had it work better with HB's (fernandes even sells their kit with a bridge HB)...but then I have also used it on a strat with single coils to good effect...so there is not necessarily a reason why a split pickup will be worse...except perhaps...

If you split the HB, it will become a single of a particular polarity...as a result you can end up reversing the phase between the pickup and the driver..reversing the phase of the pickup is the same as reversing the phase of the driver and as a result produce the harmonic effect...this is possibly the reason for your problems here I suspect.

What needs to be done is to address the EMI problem so that it works in either mode and coil splitting should work...

Ahhh...it depends also how you split the pickup...potentially if you split the pickup, you are getting current running through the HB's coil right next to the pickup coil and this will feedback badly. Again, it comes down to this multiple pickup problem where you need to lift the ground and hots of unused pickups...hmmm

I wonder if you shunted the coil through a capacitor to ground this might help and produce a decent split...just a thought...

pete

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Hey Pete,

Sorry for the tardiness of my reply, I've been training this week.

I'm not sure when I'll have the parts to do the coil shunt, but when I do I'll make sure to shunt the coil closest to the driver to try and avoid any issues.

When you spoke of moving that magnet so that the polarity would be point up. Would all I have to do is pull it off the bottom (I think it's just lightly glued on), and point one of the thinner ends upward toward the strings? I believe it's mounted flat right now.

-jftl

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I'm not sure about this new pickup design if it is only single coil anyway....but generally an HB has a magnet where the poles are the two outer edges and the alternate coils touch the sides of the magnet. It was just a thought, but having a clear polarity might have helped a bit...so a different magnet might be in order...an hb one on it's side is not ideal as it's going to be pretty thick.

The driver has shown to work with converted HB bobbins and setup with fake coils next to it and such though...so this will not explain your difficulties...

as for the coil splitting, there may well be a need to use different techniques in achieving this aim that I had not previously thought of...it could be that this is not possible with the sustainer on and require the same kind of bypass switching of a multipickup guitar to control...the HB being treated as two independent single coils...tricky...lifting the coil instead of shorting it to ground may be another way of tackling the split. A series parralel switch can give a similar effect as splitting and retain humbucking. The sustianer though will not work as well in the parallel mode as it will have less power.

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Hello again Pete and Michael and others.....I am sorry to hear that you are still suffering from ill health Pete, and wish you a speedy and full recovery.

I have been out of the circuit for some time, partially due to embarrassment for the way some of my threads wound up provoking arguments, particularly with Col - but most of all because I was pursuing another line of interest, i.e. the Roland VG-99. This has not prevented me following the progress of the project however.

Well the renewed interest in the hex approach to the sustainer is really why I am posting now, because the idea of the Variax transplant was something I tried and failed miserably - it turned out to also be an expensive mistake although it did not involve butchering the original host instrument.

In any case, what I was going to mention was whether anyone has considered using an existing hex p/up solution such as the GK type p/ups as a basis for sustainer coil experimentation? This might be more feasible and practical than trying to build one's own from scratch, particularly as the old GK-2As can now be aquired reasonably cheaply on e-Bay, so it might be a good start....the idea of converting a piezo type hex p/up for individual drivers seems impossible to me because of the strings actually being in contact with the strings. There is also the additional problem of the strings momentarily losing contact with the strings when using a tremolo bridge, and this is even a problem with VG type systems (as well as with trem equipped Variaxes)...

Aside from that however, I am no longer so interested in that approach, although my question also relates to the use of a guitar fitted with a GK system; however what I now want to do is fit a single mono sustainer to a guitar that is using no mag p/ups whatsoever (because the physical modeling on the VG-99 has meant that I never need to use anything else and already have the separate hex output from each string).

Is this possible? I imagine that it would cause less problems than mounting the system on a guitar with multiple mag p/ups, but as you know my knowledge is very limited in this field, but growing considerably in the field of physical modeling. I might add that having owned both the Variax and the VG-99 as well as the VG-8EX, it's previous incarnation, I would without hesitation say that there is absolutely no comparison, the VG-99 is in a totally different ball-park, both in terms of versatility and sound quality. The Variax software looks nice but in fact does not offer anything like the range of programmability that the VG-99 offers, and moreover it works excellently with the GK range of p/ups, which means you can use it on whichever guitar you like, including acoustics.....

So my intention is simply to a add physical sustainer to the guitar which drives my VG-99 via the GK p/up - can it be done, and if so how?

P.S. Although it might seem that I am plugging the VG-99, it is really an attempt to draw people's attention to the advantages offered by such a system over the Variax, especially to those considering a Vax transplant. I am more than willing to discuss what those advantages are, as well as to provide recorded samples to prove my point, but I do not intend doing so here, although I could not avoid mentioning what I have already written here, so apologies if it seems way off topic :D

David L

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I have been out of the circuit for some time, partially due to embarrassment for the way some of my threads wound up provoking arguments

I can certainly relate to that...I'm new on the thread, but even this early on, there's been at best a dismissive (bordering on patronising) response to initial posts. I'm sure there are a lot of folks who pass through this thread that haven't got the faintest idea about electronics or the technology & just want to build a cheap sustainer - but that doesn't mean everyone is clueless.

For what it's worth (& *without* wanting to sound dismissive myself!), I think the basic design promoted here is a fantastic starter sustainer - & cheap as chips, but I'd imagine it's not where most want to end up. (even though it seems to yield decent results).

An earlyish observation - it seems most attempts have been to use a driver based loosely on a pickup format ...I'll be taking a different tack based on some related info gleaned from totally unrelated sites (& in the best tradition upheld on this very thread...I'll keep that particular tack to myself for now!)

I haven't got all the way through the 280 odd pages, but as of yet, I've seen no indication/data as to how much electrical power each string needs to get it to 'excite' satisfactorily (ie open string through highest fret per string). This is a little surprising....without such info, the resulting circuit proposals would seem to be very much 'hit & hope'! (sure, I'm aware that there are variables...driver efficiency, core type used etc - but I've not not even seen a general ballpark figure)

In any case, what I was going to mention was whether anyone has considered using an existing hex p/up solution such as the GK type p/ups as a basis for sustainer coil experimentation? This might be more feasible and practical than trying to build one's own from scratch, particularly as the old GK-2As can now be aquired reasonably cheaply on e-Bay,

I'd pondered this myself (even posted the coil resistance a couple of pages back), but even though I have an old GK2A lying around & could readily experiment - I doubt I ever will, because 1. I just can't see those six small coils (with the limited amount of copper & tiniest of magnet) ever being able to handle enough current to drive a string! And 2. Once again, it's a pickup design...& at this stage, I don't think that's the best way to go (design wise).

Re Variaxes... very current, I have several related mini projects relating to Variaxes pending (once the weather warms up here in London & I can venture into my workshop without freezing my Nads off). He's my Variax carcass, which I knocked up some circuitry to drive midi synths...

(I also added a magnetic pickup to the guitar ...the aformentioned bespoke circuit allowed a mix of piezo & magnetic pickups). I intend installing the original removed Variax guts in a standalone floorboard & ultimately driving these guts from a midi guitar (no need to carve up the intended guitar then) Anyway, we're veering off!

Re your VG-99, fed via a GK2A. Hmm....the GK-2A is a tradtitional magnetic pickup design (albeit six mini ones!) -& therefore it's going to suffer from the same problems that traditional magnetic guitar pickups have by being placed in too close in proximity to the sustainer. You might have a bit of a win here, because a GK pickup being so narrow & placed so close to the bridge, puts more physical distance between the driver & the GK2 - distance is good!

Edited by Hank McSpank
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I have been out of the circuit for some time, partially due to embarrassment for the way some of my threads wound up provoking arguments

I can certainly relate to that...I'm new on the thread, but even this early on, there's been at best a dismissive (bordering on patronising) response to initial posts. I'm sure there are a lot of folks who pass through this thread that haven't got the faintest idea about electronics or the technology & just want to build a cheap sustainer - but that doesn't mean everyone is clueless.

Hi Hank, I think that attitude would be understandable, given that most of those who have been following this thread over the years will be seeing a repetition of many themes, and no doubt many newcomers will tend to approach this with what they believe is new information, new ideas etc., when in fact in all probability many these will have already been relegated to the list of impractical or overly complicated projects; and I know that many of my own previous posts fell into that category. Not only that, but there is a great deal of ignorance about modeling technology and the sort of processing power one is able to access once on has a 13 pin hex p/up interface. Fair enough if all you are interested in is done to death run of the mill guitar sounds, but I would guess that anyone interested in sustainer technology would be open to more innovative approaches anyway....

For what it's worth (& *without* wanting to sound dismissive myself!), I think the basic design promoted here is a fantastic starter sustainer - & cheap as chips, but I'd imagine it's not where most want to end up. (even though it seems to yield decent results).

I agree, it is a very good place to start, but with the power of the VG-99, I hardly think I would need anything more. After all, basing the sustainer on interacting with the GK-2A or GK-3 would mean applying the sustainer technology to the VG-99, so there is really no need for me to consider having a polyphonic sustainer - that is what I will effectively have anyway, since the VG-99 itself relies upon receiving separate information from each string for individual processing, and those strings would already be vibrating as I need them to be, and that would then be processed by the VG-99....this is where this system also scores over the Variax.

I realize that it would then lack the ability via the sustainer to individually atenuate or reverse the sustainer effect upon each string, which is effectively what the Moog Guitar is capable of doing, but I really don't feel that is such a necessity for me, and much of that could probably be simulated via physical string muting. The reverse or damped sustain possible on the Moog Guitar is another kettle of fish altogether....

An earlyish observation - it seems most attempts have been to use a driver based loosely on a pickup format ...I'll be taking a different tack based on some related info gleaned from totally unrelated sites (& in the best tradition upheld on this very thread...I'll keep that particular tack to myself for now!)

That sounds very interesting, I'd like you to keep me posted once you feel the time is ripe to reveal your sources..... :D

In any case, what I was going to mention was whether anyone has considered using an existing hex p/up solution such as the GK type p/ups as a basis for sustainer coil experimentation? This might be more feasible and practical than trying to build one's own from scratch, particularly as the old GK-2As can now be acquired reasonably cheaply on e-Bay,

I'd pondered this myself (even posted the coil resistance a couple of pages back), but even though I have an old GK2A lying around & could readily experiment - I doubt I ever will, because 1. I just can't see those six small coils (with the limited amount of copper & tiniest of magnet) ever being able to handle enough current to drive a string! And 2. Once again, it's a pickup design...& at this stage, I don't think that's the best way to go (design wise).

I would not be able to comment on that, but doubtless someone else will......

Re Variaxes... very current, I have several related mini projects relating to Variaxes pending (once the weather warms up here in London & I can venture into my workshop without freezing my Nads off). He's my Variax carcass, which I knocked up some circuitry to drive midi synths...
(I also added a magnetic pickup to the guitar ...the aformentioned bespoke circuit allowed a mix of piezo & magnetic pickups). I intend installing the original removed Variax guts in a standalone floorboard & ultimately driving these guts from a midi guitar (no need to carve up the intended guitar then) Anyway, we're veering off!

Some time ago I had an RMC conversion done on a Strat, and that also allowed a mix between the 13 pin hex output and midi, but was never happy with the way the saddles were fitted to the bridge, and eventually I removed the entire system from my guitar (originally with the intention of refitting it to another project guitar) but I have since found that as the GK actually performs far better as a mag p/up than the piezo equivalent, there are many who agree that the results when using modeling are far better, especially for electric guitar type sounds. It is really uncanny how similar your ideas are to mine, if you look back through my posts, you will see that I actually also intended fitting the Variax guts into a standalone floorboard, but believe me, once I realized what the VG-99 was capable of, and did some calculations, I realized that it would be far better to invest my money in the VG technology, and now I am soooooooooo glad I did :D !!!!!

Re your VG-99, fed via a GK2A. Hmm....the GK-2A is a tradtitional magnetic pickup design (albeit six mini ones!) -& therefore it's going to suffer from the same problems that traditional magnetic guitar pickups have by being placed in too close in proximity to the sustainer. You might have a bit of a win here, because a GK pickup being so narrow & placed so close to the bridge, puts more physical distance between the driver & the GK2 - distance is good!

Yes, it is based on a multiple mag p/up, but the proximity should not be a problem because in fact I would like to fit this to a guitar with only the GK system and no mag p/ups whatsoever connected - because as I said, I simply do not need to use them. So potentially the driver could be mounted anywhere on the body between the bridge and the neck, which also means that one could make the decision based upon where one could achieve the best harmonic response, or where the strongest nodes are. However, even if I were to fit it to my Strat, given that I am not using the mags, there is still the potential to mount it anywhere it can physically fit.

There has also been talk of a Variax version 2. Personally I would wait and see whether that offers any direct competition with the VG-99, because presently the mere fact that the VG-99 is capable of producing two simultaneous models each with individual effects and amp/speaker modeling and individual virtual tuning for each model makes it a hands down winner. Plus the fact that one does not have to worry about fitting the circuitry into the guitar....just my two penneth worth.

David L

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For what it's worth (& *without* wanting to sound dismissive myself!), I think the basic design promoted here is a fantastic starter sustainer - & cheap as chips, but I'd imagine it's not where most want to end up. (even though it seems to yield decent results).

...continuing the 'not wanting to sound dismissive' theme...

Many folks have a different ideas about what would make the ideal sustainer. Unfortunately, most of the folks with their own ultimate plan have ideas that either are not feasable, or won't give the expected/intended results.

I've done a lot of studying and research, some practical and some theoretical. I don't claim to be an expert, but I often spot big problems with peoples 'great' ideas (often because I've already had that idea and worked out why it's not going to work).

The main thing for anyone buying into this project to remember is that they will not be able to build their dream sustainer - it is never going to be that good! (unless they dream small :D)

There are practical limits to what can be achieved without industrial processes that mean it will never be possible for a cheap diy sustainer to be as good as the ultimate commercial unit could be - there are always going to be compromises and issues.

An earlyish observation - it seems most attempts have been to use a driver based loosely on a pickup format ...I'll be taking a different tack based on some related info gleaned from totally unrelated sites (& in the best tradition upheld on this very thread...I'll keep that particular tack to myself for now!)

The best tradition of this thread is to share ideas freely and openly, it is a shame that some (a minority!) have not approached it this way.

I haven't got all the way through the 280 odd pages, but as of yet, I've seen no indication/data as to how much electrical power each string needs to get it to 'excite' satisfactorily (ie open string through highest fret per string). This is a little surprising....without such info, the resulting circuit proposals would seem to be very much 'hit & hope'! (sure, I'm aware that there are variables...driver efficiency, core type used etc - but I've not not even seen a general ballpark figure)

You said it yourself: "there are variables"!.

here are some of the variables I can think of:

Amplifier class; amplifier phase response; amplifier frequency response; string gauge; guitar scale length; bridge type (hard tail, trem etc.); driver position; frequency of note being played; pickup frequency response; inductance factor of driver core; driver topology; wire guage; number of turns; density of windings; 'quality' of windings; dimensions of coil; distance between driver and string; core losses due to eddy currents; losses due to hysteresis; magnetic properties of the particular strings being used...

Maybe the most significant variable is the subjective idea of what constitutes satisfactory exitation - is this enough vibration to get _any_ sound? if so then only very low power is required as long as AGC is used. If on the other hand the strings must shake until they are bouncing off the frets, you'll need to fry your amp and suck your battery dry in a few minutes to keep things at the level you want!

With all these variables considered, I wonder if a 'general ballpark figure' is desirable or even useful?

It's probably more sensible to decide on what type of power supply to use and then try to get the best out of it. If it's a battery, get the best efficiency you can while still having acceptable sustain performance... if it's mains transformer via phantom power, try to get the best sustainer performance while keeping the thing controllable.

If you want figures, each of us could maybe give some figures for our own systems...

Here's a rough idea of what mine will do:

(this is for a six string driver in series bi-longitudinal configuration; class AB amp with AGC; 25.5'' scale; trem; seymour duncan JB pickup...)

My system will max out at about 1.3 watts (probably enough to damage the LM386 over time.). An earlier revision could produce an even responsive sustain with average power at roughly 0.5watts, but I wasn't happy with the volume of the sustain.

If you want to get more of an understanding of how the driver works, this site is a fantastic resource, I've learned a huge amount from it. Its heavy going to start with, but there's a huge wealth of information, and it's very concise.

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You said it yourself: "there are variables"!.

here are some of the variables I can think of:

Amplifier class; amplifier phase response; amplifier frequency response; string gauge; guitar scale length; bridge type (hard tail, trem etc.); driver position; frequency of note being played; pickup frequency response; inductance factor of driver core; driver topology; wire guage; number of turns; density of windings; 'quality' of windings; dimensions of coil; distance between driver and string; core losses due to eddy currents; losses due to hysteresis; magnetic properties of the particular strings being used...

Most of those - whilst obviously being variables - are arguably sufficiently within certain real life 'givens', so shouldn't impact the power figure *that* much ...but I guess I'm coming at it on a per string basis (ie hex vs the mono solution pursued by the majority on here). It'd have been great to see info along the lines of...

'Individual string' coil - 400 hundred turns of 0.15mm wire totalling 24 ohms, driver handheld approx 5-7mm above an open E string (10 gauge) immediately adjacent to the neck....this scenario needs an output signal of 8V peak to peak (measured across the driver) to excite the string sufficiently.

Once we have such data on a per string basis (open string thru top fret), then we have something to shoot for ...and can design a circuit to suit (whether mono or hex). What I'm reading often throughout the thread is "tried driver design MK27...the open G string was fine, but couldn't get E to sustain" Without wanting to belittle the research that's gone on hitherto, I'd say to get even results, the driver circuit is *very* important ...certainly as important as the driver itself IMHO.

With all these variables considered, I wonder if a 'general ballpark figure' is desirable or even useful?

I'd say certainly, just so long as the power figures are quoted with all the associated pertinent info....else it means anyone wanting a stab at taking this further, either has to fall into line & adopt the same mono driver as everyone else (with perhaps some of their own tweaking of the circuit to suit) - & where's the progress in that? Or else start from scratch!

That said, I guess not everyone has access to a scope or Sig Gen (fwiw, I'll be using a sig gen set the same at each string's frequency extremeties to see what input/output the LM386 power amp needs for the driver to get each string rocking)

If you want figures, each of us could maybe give some figures for our own systems...

Here's a rough idea of what mine will do:

(this is for a six string driver in series bi-longitudinal configuration; class AB amp with AGC; 25.5'' scale; trem; seymour duncan JB pickup...)

My system will max out at about 1.3 watts (probably enough to damage the LM386 over time.). An earlier revision could produce an even responsive sustain with average power at roughly 0.5watts, but I wasn't happy with the volume of the sustain.

If you want to get more of an understanding of how the driver works, this site is a fantastic resource, I've learned a huge amount from it. Its heavy going to start with, but there's a huge wealth of information, and it's very concise.

Thanks for the info (but I do relent that info for a mono driver perhaps has too many variables, ie wider frequency range, wider variation of string thicknesses & construction, material etc) - & thanks for the link.

Anyway, my parts are arriving bit by bit...I reckon I have all the components to crack on ... the breadboard, the wire (not 0.2mm - but finer at .15mm), the coil core (in various diameter mild steel bars), some magnets...I've even got a custom cheapskate pickup winder in the offing (parts needed being a 48VDC fan, a 10mm keyless chuck, an old wah wah pedal & a variable bench power supply!)...just need the weather now!

Edited by Hank McSpank
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chromesustainer2r.jpg

Hex miniture sustainer

CP9x.jpg

Single string sustainer

CONCOIL1.jpgCP6X2.jpg

Unique "non-pickup based" technology!

...

Obviously people are welcome to discuss and build what they like...within some limitations...

Obviously length of post isn't one of them... :D ...you guys are going to rival mine...

And, my apologies again if I have clashed some more in these discussions..."C'est la vie"

There are so many factors as col has pointed towards. One that immediately comes to mind in terms of "power" required to move a string type of questions is that we are talking more about mechanical forces as much as anything...therefore, the efficiency of the driver design to utilize power is vital to the success of these things.

There is only so much info that can be given. I don't have any way of measuring things, nor would these figures mean a whole lot I suspect. It would be nice, but the figures of phase response of various drivers at different frequencies for instance would be very interesting...and shed a lot more light on the "thin coil theory" of my most popular design.

On the other hand...and in many ways ironically due to my perceived attitude...I would have appear to have done more in terms of thinking and actually building many of these hex devices...as far as I can tell, more than any other, anywhere!

So, more power to you all if you are going to take up this challenge and work in that direction. I can only speak from my experience...and my limitations (as col points out, we can only work to a certain level and each of our skill sets will be quite different) are clearly...ummm...limited!

In fact, I have left this kind of work in the last year (or so) while maintaining an interest and input precisely so that others will have a forum to continue the discussion. The thread was titled "sustainer ideas" specifically to discuss all and any related thoughts and projects. Much of it has focused on my work for a lot of the time, either in me sharing it, or others seeking to replicate it.

At a certain point, the gauntlet was thrown down to me while working on the hex designs that much of my work was a fake...my ability to post pictures and sound was extremely limited...

On this point, the two pictures above were taken using a flat bed scanner and a baby nappy over it from my son...I sent one of the lower ones to LK to be verified independently and explained how it worked...

However...this incident (and the ensuing private and public personal abuse (most of which the member has chosen to delete from this thread)) did goad me into reacting and rethinking things. In particular, I was getting perhaps a little too clever and, I was creating things that I was struggling to build and I couldn't expect anyone really to follow in my footsteps. Obviously there were some things (although I have given away enough clues like the diagrams above) that I wanted to keep under my hat in detail because they were such original ideas.

Be aware, that this thread has always had a lot of interest...both here at PG and on other forums...many read it for entertainment value alone. However, over the years there have been many attempts to exploit that or to co-opt the work of myself and others who post information to there own threads and forums elsewhere. It is not unreasonable then to feel a little precious about ones ideas...especially in their infancy.

...

Interestingly...this comes to something that I am dealing with privately, but that is related here. I am in desperate need to clear house and I am making inroads. One of the things I am tackling with is the huge bulk of information and notes related to this project. I was in the habit of always having an A4 notebook with me...watching TV or wherever (rarely while driving) I would make little sketches of ideas and designs...much of which were perhaps impractical or foolhardy...many are kind of interesting in the way I was thinking about things at various times. I can unfortunately no longer really afford to keep these so these things will be lost I suppose. The nest thing may well be some of the original prototypes of many of these ideas...most only work in their limited ways or are monuments to failures in my attempts at various approaches...these too are likely to have to go.

So...I don't know if there is an interest in me posting any oddball ideas that passed through my mind at various points along the way...I thought I might scan a few things before the books hit the bin.

I guess there is perhaps a lot less imperative to keep some of the things that were "secret" back in 2004 under wraps...much of it was tested and then dismissed I suppose...but what anyone really wants to know, I don't know!

...

Anyway...continue with your discussions and your ideas...keep things civil and respect each others views and modes of expression (remember to hear each other with a mind to our different cultural and language/expressive differences, experiences and limitations)...try not to get too carried away with the theoretical, some experimentation is always a better and impressive teacher...and do try to understand criticism and input of people like col and myself (as well as many others)...

In the case of col and me, both of us have worked on this for a while now and have had many practical experiences. Both of us have approached things in different ways and had our own clashes of ideas...both of us have contributed in significant ways through this to further the overall "project". Vigorous discussion is to be encouraged, many are not familiar with this kind of debate and can take offense...or be dismissed as dismissive or ignorant. I don't want to see the discussion move into this off topic bickering...ideally I'd like to see some ideas being put into practice, or at least some more of an understanding of what is being aimed for in the approach...

As for the "thin coil" designs that I tend to promote...this was developed to prove that in fact I could make a sustainer and one that could be replicated without secrecy and that the thread and the idea of the DIY sustainer was a possibility and within the limitations of many. I think it does that and provides a basis to take it or alternatives further and I am glad to see after all this time, and possibly after I am gone, the debates will continue!

continue...

pete

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You said it yourself: "there are variables"!.

here are some of the variables I can think of:

Amplifier class; amplifier phase response; amplifier frequency response; string gauge; guitar scale length; bridge type (hard tail, trem etc.); driver position; frequency of note being played; pickup frequency response; inductance factor of driver core; driver topology; wire guage; number of turns; density of windings; 'quality' of windings; dimensions of coil; distance between driver and string; core losses due to eddy currents; losses due to hysteresis; magnetic properties of the particular strings being used...

Most of those - whilst obviously being variables - are arguably sufficiently within certain real life 'givens', so shouldn't impact the power figure *that* much ...but I guess I'm coming at it on a per string basis (ie hex vs the mono solution pursued by the majority on here). It'd have been great to see info along the lines of...

'Individual string' coil - 400 hundred turns of 0.15mm wire totalling 24 ohms, driver handheld approx 5-7mm above an open E string (10 gauge) immediately adjacent to the neck....this scenario needs an output signal of 8V peak to peak (measured across the driver) to excite the string sufficiently.

Once we have such data on a per string basis (open string thru top fret), then we have something to shoot for ...and can design a circuit to suit (whether mono or hex). What I'm reading often throughout the thread is "tried driver design MK27...the open G string was fine, but couldn't get E to sustain" Without wanting to belittle the research that's gone on hitherto, I'd say to get even results, the driver circuit is *very* important ...certainly as important as the driver itself IMHO.

The DC resistance value (24 ohms in this case) is not as useful as you might think. The important value is the impedance which is a combination of dc resistance and inductive reactance. The DC resistance is only useful if you reduce the inductance enough that reactance is having much less effect than the DC resistance (this is what Pete ended up with by trial and error).

400 turns around one of our standard (to this project) cores would have a dramatic negative impact on the higher frequencies.

With a much smaller core for a single string, it might be OK - just have to suck it and see - remember to measure or calculate the inductance not the resistance if you want to get it right with out building lots of drivers.

As far as keeping the 'variables' within given ranges:

A driver 7mm from the string will need twice as much magnetic force to excite the string as much as a driver 5mm from the string (7mm would need 4 times as much as a 3.5mm !).

(You see, even one of those "arguably sufficiently within certain real life 'givens'" is enough to start making a 'ballpark figure' useless.)

If you specify distance to string exactly and get a figure for each string, then your still nowhere. Everything changes when you line 6 drivers up next to each other. The interaction between the magnetic fields of these drivers when placed together will dramatically change the inductance, and therefor their frequency response, phase response and the strength of magnetic field they produce.

The core dimensions and magnetic properties of the core material is also significant in deciding the inductance of the driver, this is a problem because with this DIY project we don't all have access to the same stuff to make cores out of - any old iron you can lay your hands on is what gets used. This means that the 400 turn 24ohm coil you make could be 25% (or more) more powerful than the 400 turn 24ohm coil I make.

Imagine what happens when you multiply (yes multiply!) the possible variance there with that of all the other possible variables, the differences in results can be orders of magnitude apart.

With all these variables considered, I wonder if a 'general ballpark figure' is desirable or even useful?

I'd say certainly, just so long as the power figures are quoted with all the associated pertinent info....else it means anyone wanting a stab at taking this further, either has to fall into line & adopt the same mono driver as everyone else (with perhaps some of their own tweaking of the circuit to suit) - & where's the progress in that? Or else start from scratch!

The 'associated pertinent info' is not easily available and to get it ourselves would require specialized and very expensive equipment.

If you want to 'take things further' go read up on how this stuff works, do some basic experiments with the materials YOU have access to and then use a combination of the available theory and a little experimentation to get a pretty good result.

You don't need 'ballpark figures', you need a better understanding, and a good chunk of time and effort.

That said, I guess not everyone has access to a scope or Sig Gen (fwiw, I'll be using a sig gen set the same at each string's frequency extremeties to see what input/output the LM386 power amp needs for the driver to get each string rocking)

If you want figures, each of us could maybe give some figures for our own systems...

Here's a rough idea of what mine will do:

(this is for a six string driver in series bi-longitudinal configuration; class AB amp with AGC; 25.5'' scale; trem; seymour duncan JB pickup...)

My system will max out at about 1.3 watts (probably enough to damage the LM386 over time.). An earlier revision could produce an even responsive sustain with average power at roughly 0.5watts, but I wasn't happy with the volume of the sustain.

If you want to get more of an understanding of how the driver works, this site is a fantastic resource, I've learned a huge amount from it. Its heavy going to start with, but there's a huge wealth of information, and it's very concise.

Thanks for the info (but I do relent that info for a mono driver perhaps has too many variables, ie wider frequency range, wider variation of string thicknesses & construction, material etc) - & thanks for the link.

The frequency range for a single string will be similar to that for all six. To keep some of the characteristic tone of the guitar, the sustainer needs to be able to drive the harmonics (else you will damp them quick and kill some of your tone), so we are talking maybe 5 or six octaves for six strings and something like 3 or 4 for 1 string. So you will need to take all the same things into consideration. And additionally, you need to understand how your 6 mini coils are interacting with each other (not a simple task). E.g. a single string driver that has had its inductance tweaked carefully to drive the g string might have a completely different response when it's jammed between two other single string drivers.

Anyway, my parts are arriving bit by bit...I reckon I have all the components to crack on ... the breadboard, the wire (not 0.2mm - but finer at .15mm), the coil core (in various diameter mild steel bars), some magnets...I've even got a custom cheapskate pickup winder in the offing (parts needed being a 48VDC fan, a 10mm keyless chuck, an old wah wah pedal & a variable bench power supply!)...just need the weather now!

That's good news. Good luck, and don't get discouraged if it doesn't all work first time - most of us who have had success with this have made a few drivers and/or circuits.

Just please don't get hung up on having data about other peoples drivers, it's not as useful as you might think.

cheers

Col

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Thanks col for a wonderful reply...

These are all very important points that become apparent once you start doing practical experiments I feel. This is not at all like circuit designs and such, far more complicated and subtle with not a lot of "hard evidence" to go by and much of the science difficult at best. Similarly, we are dealing with forces that are invisible and if working properly/ideally (as in no fizz, etc) not make any 'sound' evidence other than sustain or harmonic generation...

I see much of myself in the past in recent posts, I pursued the hex thing with a fervor for at least a year...obviously I felt there was some merit in the idea and it did lend a great deal to the "thin coil" design that has stood the test of time.

People should not necessarily be discouraged in pursuing these things, but the more you try and understand it, particularly through practical experiments, the more you realize there are limitation and interactions that you had not fully realized. However, this may force you to be ever more creative in solutions...and if you like that kind of challenge, this is a reward of sorts. Kind of like pursuing a perpetual motion machine or unified theory in many ways.

Of particular note is the interaction between coils and magnetic fields that col discusses above...whether the pickup and driver resulting in EMI or distortions...or the interactions between multiple drivers linked by their magnetic fields...there is no getting around this.

In my Hex drivers, illustrated by the last diagram...the CP series within the thread...I used what I termed a "balanced magnetic field". This consisted of 6 pairs of high powered miniture neodymium magnets specially arranged and aligned to attempt to create a balance field around the string. This field was such that it was neither north or south but vibrated within the balance of these fields (so there was no string pull despite the high power of the magnets themselves). I may have described, and certainly thought of the string vibrating within the sway of this permanent magnetic field.

Now, to this carefully aligned and powerful balanced field of about 10mm across (the only available space between strings) I added a means to which the field could be caused to "unbalance"...that is become more or less north or south...the result is that the permanent magnets dragged the string in relation to this unbalancing.

Unlike the pushing and pulling of conventional coils, it was this that created the "drive"...mainly exploiting the permanent magnet power over the electromagnet power...or so I hoped.

Along with this, I had to develop a lot of other radically new approaches to the alignment of the balancing elements and magnetic shielding as well as numerous other ideas to make this at all possible. The designs became more and more elegant, and most did work in a fashion, but not better than the "thin coil" designs once they had been developed. I had invested so much time, money and emotional attachment to these ideas and had achieved some positive results by stepping into radical and original designs, I felt I was really getting somewhere...in short, I was feeling very clever! And, indeed these things are clever, perhaps too clever!

Now, one reason that I didn't/don't divulge too much about this thing is that, although these ideas have major drawbacks as drivers...there is some potential in other areas. Given the more recent audience interests...an obvious one would be a very radical, miniture hex pickup system. As I have not come across any electromagnetic designs that use this kind of arrangement, I see it as my own and am a little precious about it. But, it is also extremely difficult to construct and expensive and in the end not the breakthrough in this application that I had hoped...so I see no point in others following this particular road for this particular application.

What was derived from the Hex experiences was that for all my desires to miniaturize things (out of necessity with hex drivers due to the string spread) and to use novel orientations of magnetic fields and driver orientation, shielding materials and such...it was this very small profile and the condensing of the forces into a small area that seemed to have the most impact...for all my clever strategies!

So, when it came to prove that I could make a sustainer of not so "clever" design and then continue with my private experimentation (as I fully intended to do with the hex things)...and to prove my critics wrong (being overly sensitive as I am)...I used what I could from these experiments (including the testing circuits) and such factors as the thin coil. The other motivation is that we were trying to develop a low mod and easy application of this device...this led the way to making a surface mounted device...and very soon thereafter the pickup/driver.

My telecaster driver of last year (see thread linked below) actually achieved much of what was aimed for back in the pages 30-40 (if I recall correctly)...and the pickup/driver similar things way, way back with the sustainer strat. Plus, it fulfilled the desire to make something that was truly DIY...none of my hex designs could easily be replicated and for various reasons remained secret and so subject to skepticism (probably quite rightly...but not so extremely as was displayed at the time).

Anyway...yes, i did do a lot (in fact from the very start, see page 2) of experimentation with single string drivers...there is photo of one above for instance. However, it is very easy to get false results from such things for the reasons col has expressed. The one pictured for instance was tested within 2cm of the bridge pickup, between the middle and the bridge pickup...surface mounted to a strat with conventional single coils.

The aim was to eventually build these kinds of things into or just forward of the bridge in fact and to overcome the need for special bypass switching. But...although I had some success there...6 of them many more times multiplied the problems and was clearly going to emit far more EMI...and as col points out, completely change the characteristics of the drivers and link them magnetically, despite my clever isolation strategies.

Many of these things were born out by intensive experimentation...I was churning out some of these things every couple of days. Sure, I have countless notebooks of noodling of ideas and fancies...but it has been shown that only in actually trying to build such things do the problems become manifest.

However...it is interesting stuff...there is a lot to learn...and the challenge is enormous and frustrating...so if you have a mind to do that, do the required research, practical work and not a little expense...it can be quite a rewarding diversion of sorts...

I do have to report that it is my feeling that the "thin coil" designs have ultimately proven to be at least as versatile for what I was aiming for with the hex things and certainly cheaper and easier to implement as a DIY project. They are not the last word...col for instance took it to the next obvious step with dual coil designs to limit EMI and extensively opened debate and practical work on circuitry...many others including me have experimented with dual coil concepts. In fact, there is a case for hex drivers in the reduction of EMI through multiple chained coils...a strategy that most of my designs used to enable less EMI with the pickups...why stop at two!

So...a suggestion to get a feel for this technology is to attempt to recreate what does work and then try to improve upon it...or at least learn what that has to offer before moving to more radical strategies. I so much wish that I had done this and learned what I know now from doing it. In fact, there are so many times I have come across solutions and understandings from working with the more simple approaches that illustrate what went wrong with some of the hex designs. There have been many times I have considered, or even tentatively rekindled these things in light of those things...but in the end I have to acknowledge it is my personal amore for the ideas over practicalities and I have not learned enough, nor may there ever be, ways to overcome all of the problems of the designs I have explored...

Anyway...

Perhaps this is of interest, perhaps it is seen as discouraging or dismissive...col comes from perhaps a deeper understanding, where mine is perhaps more intuitive based on my own experiences...perhaps those who do work on this in a practical way will have more luck...but wishful thinking is not enough to overcome the physics involved!

pete

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Hmmm...

A short note on the synth thing. I attended a demo of the latest roland systems and they seem to have a very good sampling sustaining system built into the product. This is not a feedback effect, but a sample and hold kind of thing...but in many ways this is more like what I presume a lot of people are hankering for in terms of polyphonic sustain. It is much akin to keyboard technology but is able to use quite novel triggering strategies like infrared triggering instead of crude switching. In many ways, the synth technologies make the sustainer technologies obsolete...unless it is in fact the feedback effect that you really are after.

There is no real reason (as long as EMI does not get into the hex system for the synth tracking) not to include sustainer technologies into a synth guitar...or a variax for that matter...in fact there are a few examples of this kind of thing already created with the commercial systems.

pete

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Hmmm...

A short note on the synth thing. I attended a demo of the latest roland systems and they seem to have a very good sampling sustaining system built into the product. This is not a feedback effect, but a sample and hold kind of thing...but in many ways this is more like what I presume a lot of people are hankering for in terms of polyphonic sustain. It is much akin to keyboard technology but is able to use quite novel triggering strategies like infrared triggering instead of crude switching. In many ways, the synth technologies make the sustainer technologies obsolete...unless it is in fact the feedback effect that you really are after.

There is no real reason (as long as EMI does not get into the hex system for the synth tracking) not to include sustainer technologies into a synth guitar...or a variax for that matter...in fact there are a few examples of this kind of thing already created with the commercial systems.

pete

Hi Pete, I take it that you are in fact talking about the VG-99, which is not actually a guitar synth, although it does include a guitar synth interface. That is why I was asking what was needed in order to use the sustainer in such a GK based system. It is a modeling processor with two distinct channels, as well as two separate effects processing chains. The synthlike sounds are also modeling instruments, but unlike a synthesizer there are no sounds to be triggered, the sounds are all derived from the vibration of the guitar strings themselves, and thus react to every nuance of normal and not so usual guitar technique, which a guitar synth cannot do.

You are also quite correct that it does have a very similar 'freeze' function which can be assigned to whatever controller one might desire, it being actually more practical to assign to an expression pedal than the D-Beam controller or the Ribbon Controller. However it is more of a sample and hold function than a sustainer, although believe me many programmers are going all out to make it do the Moog Guitar thing.....in terms of sound it is getting there, but as you say, there is something organic about having the strings actually vibrate beneath your fingers that the VG-99's feedbacker just doesn't quite manage. That said it can sound very similar and can be combined with the 'freeze' function, and this on two channels simultaneously, so it is really an awesome device compared to the Variax.

I have no doubt that a sustainer or e-bow simulation could eventually be implemented, but it is not there yet. The sampler is also severely limited in terms of sample time, but we are expecting something to be done about that whenever Roland decide to provide us with a Version 2 firmware update.

Personally I feel that the combination of a physical sustainer and the polyphonic twin channel functionality of the VG-99 would be creative heaven, and unless I am mistaken, we would also have polyphonic output from the sustainer as the signal would be processed post sustainer via the hex p/up to the VG-99, which will process each string separately before eventually summing everything into stereo at the output....

Incidentally, VG-99 users who have tried the Moog Guitar say that it is not as awe inspiring as they would have hoped, because the actual quality of the sustainer seems to be tonally weak, and it is not immediately possible to find a good strong sustain that will pick up and get the strings vibrating straight away. When one takes into account the price Moog are charging for the instrument, this is just not acceptable. I know many players with sufficient funds to purchase the instrument who have been put off by what others have reported, but then again the same could be said for the stock sounds loaded into the VG-99. We have all had to erase all the factory patches and start from scratch in order to really find the unit's capabilities, which are truly awesome, so it might be that the Moog Guitar would require considerable experimentation in order to find its true capabilities.

David L

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Incidentally, VG-99 users who have tried the Moog Guitar say that it is not as awe inspiring as they would have hoped, because the actual quality of the sustainer seems to be tonally weak, and it is not immediately possible to find a good strong sustain that will pick up and get the strings vibrating straight away.

The moog people certainly have put out a lot of hype and there has been some discussion of what the thing is actually capable of...however, other than some small and very selective and non-informative company demo clips...very little is known about it and I remain a little skeptical still. Much of my skeptisisim is based on my experiences of similar experimentation and the apparent limitations on what can be done. However, nothing put out by moog suggests they have overcome these things.

Also...I have not heard anything from owners or uses of the moog guitar...i'd be interested in seeing some links perhaps...but even then, the lack of any technical information and a lot of mis-information is remarkable...even if it has caught the imagination of not just a few people.

Still...it is not all that much more expensive than the roland systems...all things considered.

Sample and hold things are a different effect, but just as valid musically as feedback, which tends to be more organic. However, in the bigger scheme of things, this technology is only a tiny part of the creative arsenal and shouldn't be seen as a magic bullet to creation and invention in music or guitar technique. Guitar synths have been around in various forms for a long time, yet they have never really been taken up or used to any real extent. Even things like sample and hold delay effects and other things have been available without much creative or commercial use. The eBow has been around much longer, yet very little prominent use has been made of this remarkable device...so that says something I think for the expressive nature of the guitar without these devices!

pete

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Hello guys,

I've been skulking around these forums for a few weeks, thought it was about time I actually registered and started posting.

I saw a post, on around page 80 (i think. this is a big thread :D ), which showed a driver design. Top and bottom of the bobbin were made out of a CD case, with a steel core and a magnet underneath. Seems like the generic driver design around here. Well anyways, I'm looking to build a driver, but I was thinking, is it really just an electromagnet? Surely you dont need the magnets underneath the driver, just a steel or iron core and a coil around it?

I'm certain I've misunderstood something vital here, but I thought I'd post anyways, hopefully somebody can set me on the right tracks. Thanks.

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Hello guys,

I've been skulking around these forums for a few weeks, thought it was about time I actually registered and started posting.

I saw a post, on around page 80 (i think. this is a big thread :D ), which showed a driver design. Top and bottom of the bobbin were made out of a CD case, with a steel core and a magnet underneath. Seems like the generic driver design around here. Well anyways, I'm looking to build a driver, but I was thinking, is it really just an electromagnet? Surely you dont need the magnets underneath the driver, just a steel or iron core and a coil around it?

I'm certain I've misunderstood something vital here, but I thought I'd post anyways, hopefully somebody can set me on the right tracks. Thanks.

Many of us have had that thought at some point, but it isn't as simple as that.

My (limited) understanding is that in the process of magnetic attraction, a 'soft magnetic' material like iron is only pulled towards a magnet after the field from the magnet has aligned the 'magnetic domains' in the iron. The weak field from our drivers small electromagnet cannot align enough of them, and would not be able to re-align them quickly enough once each wave cycle at the frequencies we are interested in.

The big old permanent magnet strongly aligns most of the magnetic domains in the string above the driver allowing the string to be effected as efficiently as possible by the relatively weak field from the electromagnet.

In addition to this, due to the strength of the permanent field, the polarity of the magnetic field doesn't ever change, so the domains in the string never need to be broken down and re-aligned, the electromagnet just causes the field to become a little weaker or a little stronger as our input signal to the driver alternates.

Its simple to verify this effect - once you have a working driver based on the standard design from this thread, try it without the magnet attached :D

Of course, this means that the magnet used can have a significant impact on the functionality of the driver and is yet another of those variables that we cannot standardize. Too weak a permanent magnet and the string won't be properly magnetized, too strong and it will start to choke the natural vibration of the string. It's also possible that an overly powerful permanent magnet could cause core saturation problems, but I don't know enough about the subject to know for certain.

cheers

Col

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Okay, thanks. So would it be a good idea to buy a few dozen neodymium disk magnets, and stack them underneath my driver, increasing the number of magnets until i hit the "sweet spot" where it works best? Oh and what works well as a core, just a block of ferrite magnet, or a bar of iron or steel?

Sorry with all the questions, hopefully I'll soon learn enough to be able to start answering questions instead of asking them all, lol.

- Akula

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Welcome akula

a question that has been asked many times before...

the magnet is what couples the string to the driver without touching it is one way to look at it...it provides some grip in order to shake it about! It is much like a pickup in reverse...one might ask why a pickup needs a magnet as this too is only an electro magnet. With driver designs though, the specifications can be crucial...not just any coil of wire and magnet will do the job efficiently enough for this to work.

Much of this project is a balancing act, and efficiency is the key really. You need a device which can react as fast as the strings can move without delays in charging and recharging this electromagnet, and you need to be able to provide adequate force without generating so much electromagnetic interference EMI that the whole system doesn't just squeal...

So another common assumption is that a less than efficient (enough) driver can be compensated for, or more sustain generated if more power is supplied...not so, likely you will just generate excessive EMI and it won't work at all.

In relation to the magnet...too strong and it will be attracting the strings to the driver (and applies to pickups too) resulting in a dampening of vibration (as well as intonation problems and harmonic anomalies) too week and their will be insufficient coupling of the driver to the string resulting in less EMF and so inefficiencies.

With a conventional design, there is not that much of a science to it....a magnet of similar strength to that of a pickup is good enough. Taking this a little further, mounting the driver on the pickup makes for a good concept where no more magnetic pull is applied to the strings than is already present in the pickups themselves.

For a more condensed overview of some of these things...it is worth taking a look at the tutorials and pictorials and my telecaster sustainer linked at the bottom of my posts...

pete

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Okay, thanks. So would it be a good idea to buy a few dozen neodymium disk magnets, and stack them underneath my driver, increasing the number of magnets until i hit the "sweet spot" where it works best? Oh and what works well as a core, just a block of ferrite magnet, or a bar of iron or steel?

hahaha...posting at the same time...

No...neodyminium magnets are probably not the best idea at all...generally people underestimate the power of these things and the properties. Also NEVER attempt to cat or shape these things.

Neomags are fascinating things but they have unusual properties...i have attempted a lot of things with them...however...

In this application I have found them to be less than ideal. Mainly, although they have tremendous power for their size, this very fact holds against them. Consider the way the "magnetic lines" are in a magnet. The north pole is attracted to the south and they tend to travel more readily through ferrous materials like iron and steel. However, the lines are inevitably drawn to their opposite pole and will take the shortest route to this destination without crossing.

So...a very small, powerful magnet will have very little distance to travel to the opposite pole...so while powerful, the field is very condensed and has very little throw. To compensate, you may think to try and move the thing closer...but when you do (or add more)...you will find that the field is so powerful as to stick the string actually to the driver...hehehe

Tempting little things I know, and with some exotic designs there may be an application (like my hex designs, but in the balanced field thing, they were not pointing at the strings and operated in pairs :D)

In the tutorial, G-Mike used some neomags from disc drives...however, like much of his attempt, the project was never fully realized and his magnets were a part of the problem. He used two which created hot spots.

Generally I have found ceramic magnets to be quite a good solution...and cheap! One reason is that they are non conductive and may have less problems with eddy currents and demagnetizing effects from the AC signal going through it. Alnico has worked ok though regardless.

You can use multiple magnets...the ceramic magnet in the tele driver (which is transparent so you can see exactly what is in it) is actually four in a row stuck together. Finding suitable magnets can be tricky...the easiest solution is to use an old pickup magnet for the purpose...even easier, wind the driver into an old pickup itself (but only the top 3mm of the bobbin) if you have one around.

Also...it is possible to use the magnet as the core...but some tings work better than others in this regard. A big problem there is finding a suitable magnet of the right size for the design and yet has the qualities that we desire. The only real reason to do this is to cut down on size. On the tele driver, the core is a 3mm wide steel blade (a common feature of many of my drivers) sitting on top of the magnet(s)...this provides a very narrow aperture for the magnetic field in line with my "thin core" theory debated a long time ago.

Now...if I were to use the magnets as the core in this case, the core would be 3x wider and the resulting coil around it bigger and of a different quality in terms of resonance and EMF capability. It could work...but the depth that might be saved will be sacrificed in the number of terms for resistance on a wider coil and the resulting driver being considerably wider. With a good technique, I was able to reduce the depth of the entire drive sufficiently to surface mount it with a steel core anyway...so not much would really have been gained in compromising this approach.

Interestingly...I did try and make a neodymium version before this for the tele with remarkable failures for all the reasons and more noted above. Readers should note that much of what I have tried is not reported when it all goes wrong!

There may also be some problem with high powered super condensed fields in terms of driver speed and efficiency. The stronger the field and the qualities of the core (permanency, etc) may mean it is slow to respond making phase problems more striking. My feeling has been that cores of ferrite have been superior to other cores I have tried...but the inability to cut it or buy anything like the required shape rules it out. Similarly, laminated cores and powdered epoxy cores have some validity...but in general they require a lot of work to make with very little difference compared to ordinary steel for the core.

As people often need to make a few drivers, especially if they have the need to "improve the design" (in other words, go their own way and prove to themselves what I have found (or not)) I would suggest that you start with common easily obtainable and workable stuff before you attempt anything too "clever"

Anyway...a few further thoughts of the neomag and other questions related to that....

pete

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Well the guitar I'm using as the "testbed" is a cheap strat copy, y'know, the kind you can buy almost anywhere. Has the worst sustain I've ever seen, hence why I'm trying to sustainerize it. I might take out the bridge pickup and turn it into a driver (obviously, in the neck position), I'll look into this tommorow.

I see a few problems with my situation. Firstly, I have .315mm wire, not the .2mm that I read seems to work best. I'll order some more wire from ebay sometime, along with some magnets for future drivers. But for the time being I may as well wire it up into that pickup, see if I can get any kind of result.

Secondly, I've built a Ruby circuit, not a Fetzer-Ruby. Is this usable, I mean, whats the difference, just a different amount of gain or output power?

- Akula

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