Sustainer Ideas

[spazzyone]

most all will be clean like the tremolo wich i never like distorted

the whammy is distorted but way cool ill post soon

[onelastgoodbye]

I think I just understood - instead of one clamp with jaws pressing on the top and bottom bobbin ends, each bobbin end IS a clamp that bites the 1 or 2 mm of the core that sticks out (of course, you can't then have the coil flush with the core), Then when you're done and the glue is dry, you just remove the clamps and hey presto... is that about right onelastgoodbye?

that's right, you explain it better than me

What about a jig where even the core is part of the jig, so a bobbinless, coreless potted coil can be constructed, this could then be tried with a veriety of different cores...

i've got a few coreless bobbins lying around (see page 103). If you've used epoxy, you can gently tap the core out with a hammer without damaging the coil itself. Just be careful you don't break any windings. Don't know if the core material would make an audible difference though. throughout this thread, there have been quite a few working drivers, all quite different too. tall coil, flat coil, wide core, narrow core, rare erth magnets, neodymium, ceramic, internal magnet, magnet shared with pickup,...the only things that always come back are the 8 ohm coil and 0.2mm wire. Same recipe, different cakes; and anyone who wants to know which is best, better do a lot of baking!

right now I'd (personally) like to focus on, in the following order

(1) getting rid of any EMI

(2) getting the thing as small as possible

(3) implementation/setup

(4) battery drain

because I believe those are the biggest obstacles if you'd actually want to market and sell the thing. Not that we're actually going to do that, just an old dream of mine and, i'm sure, Pete as well. We're getting pretty close to solving some of these issues (thanks, col ) and the dual driver might just be a breakthrough.

Let's not forget this thing already has some features that improve a lot on the current commercial systems (no routing, no loss of the neck pickup, simpler and smaller circuit,..).

Give it another...50 pages or so

[spazzyone]

considering i have not recorded much yet how about some suggestions

like should i make individual links for each sound

any song ideas? maybe with all your suggestions i can come up with something new

as i have yet to learn anything useing this system. give some feedback

and ill try whatever you can come up with that is just better than sustaining jibberish

in the meantime.....sustain on my brothers of infinity

[axe_2_grind]

Well, other than the afore mentioned U2 song "with or without you", I don't really know too many sustainer-ish songs. It would definitely have to be something with some long drawn out notes.

As i'm typing this it dawns on me (duh), Carlos Santana's version of "Europa" would be a good one!

Also, just as a progress report:

I've rewound my recycled single coil using the 6 pole-pieces which are themselves magnets, and am happy to report no wild fluctuations in the resistance this time. I realized my problem. I was attatching alligator clips to the leads, and the other end of those clips to the contacts of my multimeter, and I believe those were somehow adding extra resistance depending on how I had them positioned. So i took them off and pressed the wires directly to the multimeter and was able to get a more acurate (and stable, and consistent) reading.

7.6 ohms. Not too far off the mark for my 1st driver.

I also found some PVA wood glue (which definitely has a different quality to it than the regular carpenter's glue I was using) to pot the windings with. Once all was said & done I wrapped up the coils with some cloth tape I pulled off of another junk pickup that I had, then used 2 small spring clamps to compress the coils. I've got it setting up to dry overnight. I'll be posting some pics soon.

[psw]

right now I'd (personally) like to focus on, in the following order

(1) getting rid of any EMI

(2) getting the thing as small as possible

(3) implementation/setup

(4) battery drain

because I believe those are the biggest obstacles if you'd actually want to market and sell the thing. Not that we're actually going to do that, just an old dream of mine and, i'm sure, Pete as well. We're getting pretty close to solving some of these issues (thanks, col ) and the dual driver might just be a breakthrough.

Let's not forget this thing already has some features that improve a lot on the current commercial systems (no routing, no loss of the neck pickup, simpler and smaller circuit,..).

Give it another...50 pages or so

Well, I don't know if I have the same priorities anymore. There will always be an EMI problem, but it can be significantly reduced. Even with the current design, I can get clean sounds and I really am only unhappy with the "pop" on switching off as far as performance goes...

But these are the main things. A lot of threads like this continue as a talk fest, but this thread is alive with both ideas and practical experience. I am really happy that it has turned from effectively a blog about my work (with considerable input of others), to active participation and progress. And let us not forget a viable working DIY sustainer design.

There have been many people attempt to do this with various degrees of success, but together we have not only achieved it but, I believe, considerably extended the technology and created interest in the device.

There is so much to explore yet and this thread could easily go another 50 pages of development, and more...

Of the things I would like to see developed (and it will in time) is...

=> a standard circuit that is small and easily built or supplied so more can be involved.

=> more certainty in the driver construction and design

=> consideration of remote power to address battery drain (as I believe this will always require a reasonable amount of power consumption compared to other onboard active electronics like preamps, etc)

=> improvement in polyphonic performance (perhaps a stereo driven, dual core design, for instance).

And of course...there is the musical side of things...

Well, other than the afore mentioned U2 song "with or without you", I don't really know too many sustainer-ish songs. It would definitely have to be something with some long drawn out notes.

As i'm typing this it dawns on me (duh), Carlos Santana's version of "Europa" would be a good one!

Yes...Santana is the most obvious exponent of those long crying notes (satriani too sometimes) and Hendrix experimented a lot with feedback too. In a blues format, Albert King's style leads a little to the use of this device. Speaking of "Europa" there is a little bit of the main theme I think from me over here...

Soundclick page for sustainer sounds

One of the things that interests me is that it offers a way to expand the vocabulary of the guitar in interesting ways. Look at the way the electric guitar, amplification and distortion changed the way we think of guitar. This device allows all that to continue, yet adds the ability to sustain notes and play tones well outside the normal range of the instrument with control. It allows for the "alive" feel of a very loud guitar but without having the loud amplification or distortion associated with it...

I still have a feeling that some of the interesting things that will come from this device may not be it's ability to create infinite sustain, but the way in which it allows for different types of articulation and expression despite it. Musically, infinite sustain has it's place (the infinite note in "don't fear the reaper" by BOC and some stuff by bands like Boston, for instance...as a gimmick) but would be boring in of itself. Music needs to form phrases, it needs to breath, to speak! Santana is a great example, he effectively has infinite sustain with the volume and signiture tone he plays with, but he still uses it with emaculate phrasing and quite quick passages.

We discuss clean sounds a bit because this is something that can't be done without such a device. Another artist that comes to mind is the enigmatic Allan Holdsworth. There is a guy with a crystaline chordal tone. But his lead tone is very distorted to achieve the kind of articulation he desires and requires for his technique. He is known for his incredibly fast, complex lines and stretchy fingerings. I have often heard him say he is trying to imitate the abilities of horn players (though to me he sounds more like a violinist, check out his early work with jean luc ponty) yet bemoans the inability to achieve this with out the distortion.

Other forms of inspiration are other instruments...the violin is an obvious one. The bow not only provides the ability to play infinite sustain, but to play incredibly fast legato phrases and to intersperse long and short notes. You need not be limited to a machine gun shred approach. There are a lot of "ethnic" instruments that use bows or wind to produce amazing expression, especially in asian countries...this could provide a wealth of inspiration. Then there is the possibilty that totally new forms of musical expression could arise form this device...I haven't even hinted at the harmonic function in this for instance.

A properly working sustainer should allow for the articulation of notes in many ways. You should have control over both the attack and delay of a given note. You can start a note from nothing, simply by fretting it, damping controls the manner in which it decays and perhaps improved circuit designs could add more functions here. Notes could be articualted effectively without picking, freeing up the right hand even more. It is not necessary that the sustainer lends itself simply to long drawn out notes, but could/can be used to articulate extremely rapid legato and tapped passages (as EVH shoed with his style and "loud" guitar style).

When all is said and done, what we are working on here, is an instrument of expression. I think that many feel an innate attraction to the possibilities of the device and what it has to offer. Our work on the technology is important, but it is the music and joy in making it that really counts in the long run. I really do believe that the sustainer will become a commonly accepted part of the guitar's vocabulary and may play a major role in it's continued popularity.

So...I watch with interest and not a small amount of frustraion the current developments taking place here. I look forward to seeing how the dual coil drivers pan out, definitely the next step...and some more input and experiment on the circuit is always welcome, and some interesting angles to consider have come up.

There were elements of the hex designs that were interesting, and still may have some place as a small driver with low EMI due to it's multi-coil design (six) and could be adapted perhaps for even more coils to address the alignment issue perhaps. One of the attractions of the technology that I developed there is that I (secretly) eliminated the coil winding process. Unfortunately it does not at all lend itself to integration with conventional pickups (like my combo idea) but could form the basis of a totally new kind of pickup using similar technology. I have some ideas recently of a completely different multi coil (up to 12 electromagnetic "elements") that could be used to produce a magnetic wave along a string and have lots of EMI reduction strategies built into the design. It could also be, for instance, even with the current technology, that you could have multiple pickup/driver's on a guitar and that the drivers not in use could be used to help sheild a pickup from stray EMI and allow for selection of different sounds and driver positions for interesting effects...off the top of my head...

...the only things that always come back are the 8 ohm coil and 0.2mm wire. Same recipe, different cakes; and anyone who wants to know which is best, better do a lot of baking!

Fantastic post as always Tim...one day soon I hope to get back into this, maybe develop and supply a circuit and even more will be able to get something into their ovens...errr....guitars! pete

Cool, looking forward to these clips, are any of them using a nice crystal clean tone ?

I will see what I can put together at some point, at least it will demonstrate that it is possible and you can hear the shortcomings. Distortion brings out a masking compression, but for clean sounds, the compression there to even things out, brings forward some of the driver's artifacts. I do get a cool surf sound working ok, but most of the time I play with a mild overdrive. The driver's action on the string does have a kind of physical distortion on the way the string vibrates you understand. Your more regulated power approach may hold the key to better clean sounds by avoiding the over violent vibration of the strings that can occur.

[col]

right now I'd (personally) like to focus on, in the following order

(1) getting rid of any EMI

(2) getting the thing as small as possible

(3) implementation/setup

(4) battery drain

because I believe those are the biggest obstacles if you'd actually want to market and sell the thing. Not that we're actually going to do that, just an old dream of mine and, i'm sure, Pete as well. We're getting pretty close to solving some of these issues (thanks, col ) and the dual driver might just be a breakthrough.

Let's not forget this thing already has some features that improve a lot on the current commercial systems (no routing, no loss of the neck pickup, simpler and smaller circuit,..).

Give it another...50 pages or so

Well, I don't know if I have the same priorities anymore. There will always be an EMI problem, but it can be significantly reduced. Even with the current design, I can get clean sounds and I really am only unhappy with the "pop" on switching off as far as performance goes...

I reckon successfully controlling EMI (1) is probably the most difficult of these particularly if the aim is a design that will work as is on a range of different setups.

(2) and (4) and the 'Pop' can all to some extent be improved with the same solution - which of course brings its own problems. That is switching to surface mount technology for the ciruit. The ICs that are available would allow us to have class D amplification and/or built in pop-reduction, AGC etc. And even with a considerably more complex circuit, the footprint would be much smaller. I have read a number of accounts of using this tech for DIY, and instructions on how to solder the components. The only real hassle for me I think is that you can't use perf board, you have to manufacture your own pcbs. So I want to steer clear, at least until the EMI issue has been stomped.

Its possible to build a class D amp with standard ICs and discrete parts, but its not easy, the component values are critical, as is the board layout, and ironically, EMI can be a big problem.

There is so much to explore yet and this thread could easily go another 50 pages of development, and more...

Of the things I would like to see developed (and it will in time) is...

=> a standard circuit that is small and easily built or supplied so more can be involved.

=> more certainty in the driver construction and design

Yep, this is a major issue. When/If the EMI bugs are dealt with, and we have converged on a working and simple to build design, it would be good to write a definitive 'How To' with specific parts - e.g. wire, glue etc. and where they(or equivalents) can be purchased in different countries. Also included would be printable templates for cutting bobbin parts, core etc. Basically remove much of the 'design it yourself' crafty element.

=> consideration of remote power to address battery drain (as I believe this will always require a reasonable amount of power consumption compared to other onboard active electronics like preamps, etc)

Not sure how attractive this will be to the majority of users - its bad enough having to carry spare batteries for your axe - having to carry special leads, and an outboard box around that are _required_ for the thing to work would kinda suck IMO. I hope the battery drain can be reduced to an acceptable level. Then folks who want to and can afford to can go buy lithium 9v batteries.

The final circuit must have tight tolerances for any gain/level control, even just setting this a little too high can have a major impact on power drain. Also the distance of the driver from the strings is crucial. guitars with higher actions (mine is medium) are going to struggle, particularly with the lower notes on the E and B strings.

=> improvement in polyphonic performance (perhaps a stereo driven, dual core design, for instance).

One thought I had along these lines was using a stereo amp with filters and a dual driver to set up woofer and tweeter drivers. Maybe drivers customised for high and low frequencies could be more efficient... who knows.

A properly working sustainer should allow for the articulation of notes in many ways. You should have control over both the attack and delay of a given note. You can start a note from nothing, simply by fretting it, damping controls the manner in which it decays and perhaps improved circuit designs could add more functions here. Notes could be articualted effectively without picking, freeing up the right hand even more. It is not necessary that the sustainer lends itself simply to long drawn out notes, but could/can be used to articulate extremely rapid legato and tapped passages (as EVH shoed with his style and "loud" guitar style).

Not so sure about this. There is always going to be some time lag between playing a note and the sustainer kicking in - unless it is turned up so high that it dominates the natural guitar resonance (I'd rather avoid that). My favorite setup so far allowed me to play normally with no noticable difference in tone, attack, response or feel, untill i held notes or chords, only then would you start to notice the sustain effect come to life.

What it does help with is slow tapping . you can tap notes or chords with your right hand and they will sing even if your right hand technique isn't quite up to it - you can get a nice strong singing tone this way.

When all is said and done, what we are working on here, is an instrument of expression. I think that many feel an innate attraction to the possibilities of the device and what it has to offer. Our work on the technology is important, but it is the music and joy in making it that really counts in the long run. I really do believe that the sustainer will become a commonly accepted part of the guitar's vocabulary and may play a major role in it's continued popularity.

Thats a nice idea, but I'm dubious. (I'm a terrible cynic )

IMO the electric guitars success is to do with in order if significance:

1 (by far) The way it looks. You can stand at the front of the stage and jump around with it (pretending its a huge spam if you so wish)

2 It's subversive / ani-establishment - not used in classical music - creates atonal noise.

3 Its accessible - comaratively cheap, portable and you can very quickly learn enough to play chord accompaniment to lots of songs.

4 It is percussive melodic and harmonic in equal parts simultaneously.

I think that a sustainer effect is most attractive to recording engineers (including home studio peeps), and also to gadget geeks like us . So I love the idea. But it's never going to be 'significant' in the history of guitar.

...It could also be, for instance, even with the current technology, that you could have multiple pickup/driver's on a guitar and that the drivers not in use could be used to help sheild a pickup from stray EMI and allow for selection of different sounds and driver positions for interesting effects...off the top of my head...

Or simply that both bridge and neck positions have a combo pickup/driver, so you can use neck driver with bridge pickup, or bridge driver with neck pickup....

Lots of cool stuff to mull over

cheers

Col

[onelastgoodbye]

Bit of a problem here..

The pva didn't work out, so today I got me some 5 min epoxy and wound a new coil. Now here's the catch... I figured about 7.3 metres of 0.2mm wire would get me to 4 ohms. So I cut 7m off the reel, measured it, turns out it only takes 6metres. Cool. I then proceed to wind the coil, pot it, wait for it to cure, comes out pretty good, but when I measure the resistance of the wound coil, I only get 1.8 ohms?

[col]

Bit of a problem here..

The pva didn't work out, so today I got me some 5 min epoxy and wound a new coil. Now here's the catch... I figured about 7.3 metres of 0.2mm wire would get me to 4 ohms. So I cut 7m off the reel, measured it, turns out it only takes 6metres. Cool. I then proceed to wind the coil, pot it, wait for it to cure, comes out pretty good, but when I measure the resistance of the wound coil, I only get 1.8 ohms?

Damn this coil construction.. it's like the playin' blues, you want it ? you gotta pay your dues man...

Must be a short somewhere ?

Are the ends of your core rounded or square?

col

[psw]

Damn this coil construction.. it's like the playin' blues, you want it ? you gotta pay your dues man...

Maybe, time to start again...

I reckon successfully controlling EMI (1) is probably the most difficult of these particularly if the aim is a design that will work as is on a range of different setups.

(2) and (4) and the 'Pop' can all to some extent be improved with the same solution - which of course brings its own problems. That is switching to surface mount technology for the ciruit. The ICs that are available would allow us to have class D amplification and/or built in pop-reduction, AGC etc. And even with a considerably more complex circuit, the footprint would be much smaller. I have read a number of accounts of using this tech for DIY, and instructions on how to solder the components. The only real hassle for me I think is that you can't use perf board, you have to manufacture your own pcbs. So I want to steer clear, at least until the EMI issue has been stomped.

Its possible to build a class D amp with standard ICs and discrete parts, but its not easy, the component values are critical, as is the board layout, and ironically, EMI can be a big problem.

I looked into this type of thing and even tried using surface mount components (the lm386 for instance) but it is really very hard to do. I too am steering away from PCB's but if a "standard", foolproof circuit were to be developed, it could be tempting. For now, basic DIY techniques are the order of the day and I think a lot more can be achieved with this in this way...

Yep, this is a major issue. When/If the EMI bugs are dealt with, and we have converged on a working and simple to build design, it would be good to write a definitive 'How To' with specific parts - e.g. wire, glue etc. and where they(or equivalents) can be purchased in different countries. Also included would be printable templates for cutting bobbin parts, core etc. Basically remove much of the 'design it yourself' crafty element.

Yes...and that is what a lot of visitors and emailer's want...but this is something still being developed. That said, it does work and is adaptable. Everybody seems to want something a little different or have their own hurdles to overcome, especially in installation, fitting a circuit and finding room for batteries...there also seems to be a wide range of understanding and skill in making this device, even from those with a lot of skill and understanding with building the instrument itself. That is where I think the "standard" circuit and even the supply of parts to make the device may further things considerably. It really isn't a hard project, it does take a little commitment (especially in the modifying of the instrument) but it is the sourcing of materials and working with unfamiliar techniques that are holding a lot of people back...or so it seems...

My favorite setup so far allowed me to play normally with no noticable difference in tone, attack, response or feel, untill i held notes or chords, only then would you start to notice the sustain effect come to life.

Yes...this is where it is at, and the aim of the device. There should be no change in the tone of the instrument but that the notes played continue to sound if held for long enough. My guitar does seem to have achieved that. What opens up are different ways to articulate a note...you can play a note very softly, and the sustain will "well up", so that the decay increases in volume...kind of like a volume swell, and if you cut the notes short, like a reverse tape effect. The lag is different depending on where you are fretting (higher up on my guitar will produce an almost immediate "effect" as with the bass strings) and this inconsistancy is something that needs to be learn't and compensated for, or used in some musical way.

The stereo thing is what I was getting at...it was one of the reasons I liked the bi-lateral design. The compensation for high and low strings could be built into the driver construction itself, and or the circuit driving it. I intended my hex designs to provide individual compensation through driver design and filtering (given the guitar signal is monophonic).

I think that a sustainer effect is most attractive to recording engineers (including home studio peeps), and also to gadget geeks like us . So I love the idea. But it's never going to be 'significant' in the history of guitar.

Well...not as significant as the guitar itself...the organ didn't replace the piano! But, although I can get a little overboard , a futuristic ideal device in the right hands could produce some influential sounds that adds to, and is desirable to, a broad range of musicians and musics in the way it provides for an extention to the goodness already offered by the instrument. On the otherhand, it could be the guitarists theramin...hmmm gadget geeks unite, errr

For now...tackling the EMI seems to be a big problem. My guitar seems to have successfully worked. The installation of the device actually improved things and the bypass wiring was essential to aleviate noise, so for me the EMI level seems to be controled enough for a working instrument with the simple design...on this guitar. For me, I think that tackling the EMI problem could extend what I have already achieved. I'd like to see a Mid driver like Dizzy's to allow for independant pickup selection and combination...this could also address the bypass complexity and switching involved in guitars like a strat. Otherwise, although it is possible that you could make neck and bridge driver/pickups...you probably couldn't use them in combination. The placement of the driver relative to the driving pickup and the distance along the string is important in the effect the device produces and could yeild some interesting results.

So, although happy that my guitar works, I too will be tackling a dual coil driver I suspect and trying these things out. I am still thinking about a circuit design...a simple opamp preamp and lm386 circuit with guitar buffer would seem like a good place to start...and if on a par with the fetzer ruby option, make clear instructions available to encourage more involvement. The more involvement, the more the device will progress...once the tool is available, the music will follow... pete

[col]

I looked into this type of thing and even tried using surface mount components (the lm386 for instance) but it is really very hard to do. I too am steering away from PCB's but if a "standard", foolproof circuit were to be developed, it could be tempting. For now, basic DIY techniques are the order of the day and I think a lot more can be achieved with this in this way...

The description of how to work with SMD components that I read was intriguing. And not having a pcb home production setup isn't the only thing holding me back - the other is the lack of a high power soldering iron with a half inch chisel tip - yep, you read that right :-o

(from memory) What the guy does is coat the pads on the board with flux, then put the chip in place, and while using gentle pressure to hold the chip down and make a good mechanical contact, he 'wipes' all the pins on one side with the huge (tinned) soldering iron - the iron is _very_ hot, so it only takes a very short time - not long enough for the heat to transfer up the pins, and the flux stops the solder from bridging the pins or the board traces... anyway, two swipes and the whole chip is done...

He reckons that given the choice, he would never go back to standard through hole components, and that even for prototyping, surface components are so much quicker and easier that the productivity gain outweighs the extra hassle of making pcbs !!!!!

I always thought is was a case of really fiddly work with a magnifying lense, very fine soldering iron and tweasers ..

...The lag is different depending on where you are fretting (higher up on my guitar will produce an almost immediate "effect" as with the bass strings) and this inconsistancy is something that needs to be learn't and compensated for, or used in some musical way.

In my first trials with the fetzer/ruby circuit, when the gain was high enough to work the B string and (most of) the top E string, playing the strings above about the 14th fret caused them to vibrate so hard the were rattling against the frets. With my current setup, they are more responsive, but not much louder - the balance is a LOT better. Having said that, the upper frets will probably always be somewhat more responsive because even with a low action, fretting a string high on the neck will push it closer to the driver than fretting near the nut.

Well...not as significant as the guitar itself...the organ didn't replace the piano! But, although I can get a little overboard , a futuristic ideal device in the right hands could produce some influential sounds that adds to, and is desirable to, a broad range of musicians and musics in the way it provides for an extention to the goodness already offered by the instrument. On the otherhand, it could be the guitarists theramin...hmmm gadget geeks unite, errr

lol

For now...tackling the EMI seems to be a big problem.....

Does anyone know anything about the parasitic eddy currents caused by using a solid steel or iron core. I know they generate heat and cause loss of efficiency, but to what extent is that a problem in a low power application such as this, and how much of an impact might they have on the levels of EMI in the system ?

I wonder if a laminated core, or one using ferrite powder (where do you get that stuff ?) and epoxy might help ?

Also, any tips on a (purely graphical) schematic layout program I could use to pretty up my circuit ? One that outputs to some sort of bitmap format.

cheers

Col

[spazzyone]

Hey COL im not sure but i think this is what your looking for

http://www.storm-software.co.yu/diy/index....roject=software

[col]

Hey COL im not sure but i think this is what your looking for

http://www.storm-software.co.yu/diy/index....roject=software

Thanks, that looks like a cool app.

What I really need right now is something I can use to make my circuit schematic readable so I can post it. Layout is a bit further down the line when the design has settled down a bit.

cheers, Col

[axe_2_grind]

Well, it seems like I take two steps forward, one step back. So I got my "driver" coil to just below 8 ohms, tested it with the circiut (before mounting it) just to see if anything heated up. So far so good, nothing seems to be malfunctioning with the circuit itself. My driver on the other hand, doesn't seem to want to...well...drive.

For this driver I am using a recycled single coil with 6 magnetic pole pieces. I slid the top part of the bobbin down, so there is about a good 1/4 of an inch exposed on top. The other problem I am having is that these pole pieces don't seem very strong. I'm wondering if I need to cut them down to size closer to the coil. Though, if the magnets are weak, then maybe I'm not generating enough of a magnetic field or something.

As a side note, with a little compression on my clean channel, I get some funky background noise when the circuit is on.

So it seems, at the very least, I have made myself a fancy noise maker thingy.

Any thoughts/suggestions?

Edited September 20, 2006 by axe_2_grind

[psw]

Wow...there is a lot of posting and reading to and fro...notice how quickly we are getting towards 60,000 visits!!! Seems like when ever I come and check out what others are checking out, there is at least someone having a look at this thread or one of the related ones on here, usually guests. This forum is free and open to one and all, including this thread. Feel free to join up and join in....

My driver on the other hand, doesn't seem to want to...well...drive.

I'm sorry that your driver doesn't seem to be driving...something amiss I fear. I wouldn't cut down the magnets for a start and a normal pickup magnet seems to be plenty strong enough...it's the coil that is at work. I think my guitar's driver is close to 7 ohms while the prototype was exactly 8, not really any difference between them that I can tell, both work fine. Back to the magnets...my blade on the pickup/driver is 10mm deep with the driver on the top 3mm and the magnet on the bottom (big ceramic) and works fine. The prototype had a 3mm deep core and worked with various magnets, so the distance of the magnet to the strings is not really an issue.

For this driver I am using a recycled single coil with 6 magnetic pole pieces. I slid the top part of the bobbin down, so there is about a good 1/4 of an inch exposed on top. The other problem I am having is that these pole pieces don't seem very strong. I'm wondering if I need to cut them down to size closer to the coil. Though, if the magnets are weak, then maybe I'm not generating enough of a magnetic field or something.

Umm...does this mean that the coil is on the lower half of the pickup, away from the strings...if so test it upside down. I think the coil being close to the strings is critical. I did hope, at one point, that you could mount the driver under a conventional pickup but this did not work at all (rats). Test the circuit with a speaker...it is an amp remember...just to be sure. Otherwise, if you were to direct the driver at the pickup you should get very loud screeching feedback...not just a "noise".

The Layout Creator Software that I linked (I think that is the same as Spazzy's link) is fantastic...for layouts, not schematics. If you have Microsoft Office, you can do simple stuff with Viso. There are programs I'm sure that are free, but they often have otherstuff or are difficult to learn. The PCB creation software like eagle for instance...too much of a learning curve for me. I have a program called Stripboard Magic that crates layouts for Vero from a schematic...a bit buggy and the layouts aren't always ideal. If you find something simple, or anyone has any suggestions, let us know!

I always thought is was a case of really fiddly work with a magnifying lense, very fine soldering iron and tweasers ..

Well, there are other ways too but you do have to watch the heat. One way is to solder the whole thing down with a blob of solder and then "solder wick" off the excess. You really need to know that the circuit is worth the board to even test it, SMD means no breadboarding. But, so much good stuff is only SMD and often supplied in bulk...D class amps for instance. While the savings in space and power are ideal for this project, it is outside the experimenter and the DIYer I fear. If all the problems were ironed out a SMD circuit pre-made in even small quantities would probably be as cheap to get made as the circuit board for through hole components...but then we come back to the manufacturing side again...at the moment this is a project under development, not a product (wishful thinking aside )

In my first trials with the fetzer/ruby circuit, when the gain was high enough to work the B string and (most of) the top E string, playing the strings above about the 14th fret caused them to vibrate so hard the were rattling against the frets. With my current setup, they are more responsive, but not much louder - the balance is a LOT better. Having said that, the upper frets will probably always be somewhat more responsive because even with a low action, fretting a string high on the neck will push it closer to the driver than fretting near the nut.

Exactly...so it does sound as if your circuit is an improvement. Without giving too much away, my last generation of Hex drivers had a bias to push the string from side to side instead of bouncing them up and down as with this type of set up.

We could also open up the ideas of long ago of half wave driving...simply pushing on the string and letting them return by themselves. Could cause problems with the magnetics, but it is still a valid idea to debate and not one fully explored. I tried a few simple things (diode on the output to kill off the half wave) but nothing too serious...this conditioning should really be done in the preamp stage and I bought an "effect kit" that used a transistor to create this effect for the purpose, but it was never built.

Does anyone know anything about the parasitic eddy currents caused by using a solid steel or iron core. I know they generate heat and cause loss of efficiency, but to what extent is that a problem in a low power application such as this, and how much of an impact might they have on the levels of EMI in the system ?

I wonder if a laminated core, or one using ferrite powder (where do you get that stuff ?) and epoxy might help ?

Well...I read about them...ummm . I once made a simple miniture coil that was entirely encapsulated in iron epoxy...it seemed to work really well, yet it shouldn't really...go figure. Likewise, the hex drivers were essentiall like this...but they are not a good comparison. I messed around with this type of material as it is supposed to be better and my ferrite coils, including the first one built for this thread, were fabulous. The speed (that it could charge and lose a magnetic field) was the attraction. But this stuff is impossible to find in suitable shapes and sizes...or to cut (I tried, but it shatters and is impervious to saws and grinding...grrr). The powdered core was more promising...this could be made into any shape and I modeled some interesting hourglass profiled cores in FEMM that looked promising. But then you are looking at epoxies and iron which is not cheap and needs a whole new skill set, and molds etc.

The most promising for the DIYer is the laminated core. For people having trouble finding a suitable core material, or want to create something with the minimum of tools, this is an ideal way to go. Think of the way a transformer coil is typically construced...for this very reason. A suitable material is the thin galvanised iron used to make corners and such in plasterboard and available in hardware stores. It can be cut with scissors at a pinch and laminated with doublesided tape. You can usuall find some at building sites and renovation skips as cut offs for free!

I don't think that it is quite as critical given the technology we are working with (hand winding coils, etc) and probably influences efficiency more than the EMI that is put out. I think the design of the driver, keeping it relatively simple is more appropriate, at least at this stage, and as a DIY project.

Col...does your guitar have a neck pickup...or is it a single pickup guitar? Even if it is not selected, this could transmit some noise into the guitar's earth perhaps.

Otherwise, it sounds like you have a very good thing going with the circuit and the driver. I think if you were to get it off the breadboard, the noise would improve a lot, as would the EMI perhaps that may be related to it. Getting the driver under the strings would perhaps help it some more. You may already have something operable if given the best chance. It certainly sounds like you are close...

Meanwhile...out looking for a house for rent, I dropped into an electronics store and found a cheap little kit amp that I couldn't ignore. It is based on an 8 pin DIP TFK (TDA) 2822 1 watt D class amplifier. Very small, low parts count (board is 54mmx15mm). Still looking for the right data sheet for it, but the instructions state that "the small 9 V block container batteries will become to easily run-down!" The amplifier has a current consumption of "max 380 mA" with full power "2 W music power" at 9 volts and less for lower voltages (down to 3v I think) Heat sink required if using at high power....hmmm.

So, a class D amplifier on an 8pin DIP (like the LM386) at minimum cost...but hang on, I know this thing is more powerful than the lm386, but I thought the whole idea of class D was the low power consumption...what gives. Still, an interesting circuit for future experimentation perhaps. Still would require a non-loading preamp too I suspect.

Onwards and upwards...perhaps we are stuck with the good old LM386 and need to come up with a good simple circuit, small in size and layout. Perhaps col has come across something, i'd like to see a few more filters to ditch unwanted noise...but that's just me. The fact that col has got the thing operating so as the strings bounce the frets at a low power draw is significant. I don't know my power draw however, and it may not be that different, it will run for a very long time with intermitent use (weeks) but it will not last as long as most simple stompboxes would.

I wonder about other ways of manipulating the LM386. Is there an easy way for the pins 1-8 power control to be tweaked inversely to the signal in? So, with a strong signal (perhaps a threshold set by a pot) it would go to minimum gain, and with a small signal go to max gain (no resistance). Seems to be a similar effect to that of the AGC preamp proposed. But am I barking up the wrong tree? I really am out of my depth as to how the "Aussie Compressor is working, the LM386 (being a power amp) seems like a very odd choice for such a signal processing device.

Anyway...I might leave the circuitry to the back of my mind while I set about finding a home and getting back my soldering and parts paraphenalia and while away the wee hours with some practical work after you guys do the experimental stuff Hope there's more joy to you all, especially axe2grind...so close... pete

[psw]

One quick addition...I see that there is an improved version of the "aussie Compressor" posted...this time featuring a buffer stage. While not itself being suitable for a sustainer circuit, I think there are some interesting simple ideas that could be worth considering, with those withenough electronic theory to consider such things!!!

I dropped the designer Brett Robbinson a line and maybe he can enlighten us on the scematic program he is using so that Col can post up his circuit for evaluation and improvement... pete

[col]

The Layout Creator Software that I linked (I think that is the same as Spazzy's link) is fantastic...for layouts, not schematics. If you have Microsoft Office, you can do simple stuff with Viso. There are programs I'm sure that are free, but they often have otherstuff or are difficult to learn. The PCB creation software like eagle for instance...too much of a learning curve for me. I have a program called Stripboard Magic that crates layouts for Vero from a schematic...a bit buggy and the layouts aren't always ideal. If you find something simple, or anyone has any suggestions, let us know!

I'll take a look at open office - i have that on my system, and its drawing package allows lines to be linked so that if parts are relocated, the wires stay attached... maybe I can find some component symbols on the web ready made...

We could also open up the ideas of long ago of half wave driving...simply pushing on the string and letting them return by themselves. Could cause problems with the magnetics, but it is still a valid idea to debate and not one fully explored. I tried a few simple things (diode on the output to kill off the half wave) but nothing too serious...this conditioning should really be done in the preamp stage and I bought an "effect kit" that used a transistor to create this effect for the purpose, but it was never built.

Might sound more natural - or maybe less so...

It maybe more like a bowed sound... when a violin string is bowed, it repeatedly pulls then releases the string - although theres a lot more than that going on with a bowed string.

I would still be worried about long term effects on the magnet though.

One possible solution would be to use a digital circuit

In the digital domain we would have much more control over the signal - the dynamic inversion i'm trying to achieve would be much easier to tailor, and we could more easily do fun stuff like: only the negative side of the signal for 100 cycles, then only the positive half for 100 cycles.... maybe that would save the magnet, use much less power and give a more natural sound.... or be crap - who knows

Does anyone know anything about the parasitic eddy currents caused by using a solid steel or iron core. I know they generate heat and cause loss of efficiency, but to what extent is that a problem in a low power application such as this, and how much of an impact might they have on the levels of EMI in the system ?

I wonder if a laminated core, or one using ferrite powder (where do you get that stuff ?) and epoxy might help ?

Well...I read about them...ummm . I once made a simple miniture coil that was entirely encapsulated in iron epoxy...it seemed to work really well, yet it shouldn't really...go figure. Likewise, the hex drivers were essentiall like this...but they are not a good comparison. I messed around with this type of material as it is supposed to be better and my ferrite coils, including the first one built for this thread, were fabulous. The speed (that it could charge and lose a magnetic field) was the attraction. But this stuff is impossible to find in suitable shapes and sizes...or to cut (I tried, but it shatters and is impervious to saws and grinding...grrr). The powdered core was more promising...this could be made into any shape and I modeled some interesting hourglass profiled cores in FEMM that looked promising. But then you are looking at epoxies and iron which is not cheap and needs a whole new skill set, and molds etc.

Where do you get the iron - what form does it come in, and roughly how much does it cost ?

The most promising for the DIYer is the laminated core. For people having trouble finding a suitable core material, or want to create something with the minimum of tools, this is an ideal way to go. Think of the way a transformer coil is typically construced...for this very reason. A suitable material is the thin galvanised iron used to make corners and such in plasterboard and available in hardware stores. It can be cut with scissors at a pinch and laminated with doublesided tape. You can usuall find some at building sites and renovation skips as cut offs for free!

I don't think that it is quite as critical given the technology we are working with (hand winding coils, etc) and probably influences efficiency more than the EMI that is put out...

Thats also my gut feeling, but for an electronics know-nothing like me intuition and gut feeling are quite likely to be completely wrong !

Col...does your guitar have a neck pickup...or is it a single pickup guitar? Even if it is not selected, this could transmit some noise into the guitar's earth perhaps.

Otherwise, it sounds like you have a very good thing going with the circuit and the driver. I think if you were to get it off the breadboard, the noise would improve a lot, as would the EMI perhaps that may be related to it. Getting the driver under the strings would perhaps help it some more. You may already have something operable if given the best chance. It certainly sounds like you are close...

Sorry I didn't explain that - right at the start of my experiments with the Fetzer ruby version, after I had made sure the thing was working, I removed the neck pickup from my guitar completely, and put in some wooden blocks to build up the cavity. The driver goes under the strings in the neck position - the only difference with a complete installation will be the length and proximity of the driver and pickup cables, and the circuit being compact and on perfboard instead of spidery wires everywhere and no shielding...

Meanwhile...out looking for a house for rent, I dropped into an electronics store and found a cheap little kit amp that I couldn't ignore. It is based on an 8 pin DIP TFK (TDA) 2822 1 watt D class amplifier. Very small, low parts count (board is 54mmx15mm). Still looking for the right data sheet for it, but the instructions state that "the small 9 V block container batteries will become to easily run-down!" The amplifier has a current consumption of "max 380 mA" with full power "2 W music power" at 9 volts and less for lower voltages (down to 3v I think) Heat sink required if using at high power....hmmm.

So, a class D amplifier on an 8pin DIP (like the LM386) at minimum cost...but hang on, I know this thing is more powerful than the lm386, but I thought the whole idea of class D was the low power consumption...what gives. Still, an interesting circuit for future experimentation perhaps. Still would require a non-loading preamp too I suspect.

That chip is stereo, and seems to be intended to drive 4ohm loads - each of which increase the power draw.

The same tech in mono driving an 8ohm load at just over 1 watt instead of 2 should be more efficient than the LM386.

e.g. My circuit when everything is setup just right - driver near the strings, input gain correct etc. draws between 22 and 50 mA. Thats MUCH lower than the LM386 is capable of... My guess is that with a similar specced class D amp, I could get the same results with a 12 - 30 mA draw, possibly lower, not sure.

(class B and class AB are about 50% efficient, whereas a well designed class D amp is supposed to be up to 90% efficient !)

Onwards and upwards...perhaps we are stuck with the good old LM386 and need to come up with a good simple circuit, small in size and layout. Perhaps col has come across something, i'd like to see a few more filters to ditch unwanted noise...but that's just me. The fact that col has got the thing operating so as the strings bounce the frets at a low power draw is significant. I don't know my power draw however, and it may not be that different, it will run for a very long time with intermitent use (weeks) but it will not last as long as most simple stompboxes would.

I haven't got it so the strings are bouncing off the frets at lower power draw

I've got it so that you can get the difficult strings (high B & E) and quieter notes going without the others bouncing off the frets !

Another thing I've noticed is that using the fetzer ruby with enough gain to work my B & E strings, the sustainer was dominating the guitars natural resonance - when I played harmonics at 12th, 7th and 5th frets, they would be quickly choked by the effect - pinch harmonics were also destroyed. Now they mostly ring true and are sustained.

I wonder about other ways of manipulating the LM386. Is there an easy way for the pins 1-8 power control to be tweaked inversely to the signal in? So, with a strong signal (perhaps a threshold set by a pot) it would go to minimum gain, and with a small signal go to max gain (no resistance). Seems to be a similar effect to that of the AGC preamp proposed. But am I barking up the wrong tree? I really am out of my depth as to how the "Aussie Compressor is working, the LM386 (being a power amp) seems like a very odd choice for such a signal processing device.

Theres no really easy way to do what you are suggesting - I've tried all sorts of stuff with the LM386 gain control options - you can vary the resistance between pins 1 & 8. Alternatively you can use a capacitor and resistor between pin 1 and ground for an alternative gain control method. I've messed around with both of these with no success.

I think the aussie compressor is using the MOSFET as a voltage controlled resistor - there are a lot of agc circuits that use JFETs in this way, but I don't have enough knowledge to design one from scratch, and none of the schematics I have found are right - or I couldn't find the parts.

One option that I have still to explore and that I think could be fruitful is using vactrols or LED/LDR combinations as variable resistors - a lot of good compressors use this tech, and I could set it up simpilarly to the way I have set up the LM13700. The main reason I'm using the LM13700 at the moment is because I had one in my parts box, and I found a promising circuit diagram in the datasheet to experiment with...

The ideal would be to be able to tailor a input/output gain curve that goes up sharply from 0 to max output at between 15 and 60 mA input (controlable with a trimmer) then tails off to 0 again between this point and about 200 (again controllable with a trimmer).

If the shape of this curve could be easily tweaked for testing, it would make finding the ideal response so much easier.... I don't have the test equipment or the electronics chops to really do it well.

We would also want to have control over the attack and release (although i guess these would be much faster than for a guitar compressor ?)

I think My circuit is getting close to the first part of those requirements. Unfortunately, the tail off is too long - and doesn't go down to zero, so its not as efficient as it could be. And the control of the low input part of the curve is a bit haphazard - done by amplifying the input signal before it gets to the agc... more precise control over that would be very good.

So still some work to do

For now, I'm taking a break from the circuit to build a twin driver.... have the cores ready now - 56mm x 3mm x 12mm cold steel rounded ends... ready to deal with those damn bobbins

If I can get the schematic polished up, I will post my circuit so that other folks can take a look at it - and ideally point out any obvious errors or problems with the design.

cheers, Col

[psw]

Where do you get the iron - what form does it come in, and roughly how much does it cost ?

I found that the "magnet Shop" sold pure iron filings (very fine powder) for educational purposes to demonstrate to students magnetic fields. I comes in a small vial. Forget how much, down here I was getting magnets from "Aussie Magnets" but I am sure you could find similar if you are keen. I don't think it is really cost effective, but you could mold iron cores with appropriate glue...I discovered a few techniques of interest...

Ok...well that is ideal then for testing, no neck pickup and under the strings...still got an EMI problem eh? Are your driver wires twisted, reasonably short but well clear of the pickup? Not sure what to suggest, I am running much higher gains with success...hmmm

I haven't got it so the strings are bouncing off the frets at lower power draw

I've got it so that you can get the difficult strings (high B & E) and quieter notes going without the others bouncing off the frets !

Ah...I see...well that is an excellent development, perhaps it will address the low string dominance of chords, or at least make damping the strings a little less critical in technique...more control...great!

Theres no really easy way to do what you are suggesting - I've tried all sorts of stuff with the LM386 gain control options - you can vary the resistance between pins 1 & 8.

Just thinking off the top of my head...some kind of auto variable resistance...perhaps not...

So still some work to do

For now, I'm taking a break from the circuit to build a twin driver.... have the cores ready now - 56mm x 3mm x 12mm cold steel rounded ends... ready to deal with those damn bobbins

If I can get the schematic polished up, I will post my circuit so that other folks can take a look at it - and ideally point out any obvious errors or problems with the design.

Can't wait for both those things...I'd be aiming to get the two cores as close as practical...I still hold dear to the thin core theory, and although your cores are thin, they are spaced apart. Actually, it is more a hunch than a theory as no one has definitively proved it, and a twin core rail driver may be a different beast...just a hunch is all!

From the archives of my mind I recalled a couple of other amp chips. At one stage, and still have a mind to, I was looking at alternatives to the LM386...figure the old IC is getting a little long in the tooth, and more modern, efficient alternatives with "pop" protection must be available. Plenty in SMD of course...but there are still a few in DIP. I have at "home" a TDA7052 class D amp and another of interest is a TDA 8551 BTL amp. Both use very few external components with the TDA8551 having on board digital volume control and mute+standby functions...on an 8 pin DIL. Could address some of the switching complexity perhaps...a little tricky to get, but they are out there. I suspect a preamp will still be necessary, or some kind of conditioning as you are suggesting, but both use less components than even the LM386. Just a thought... pete

[col]

I've found an app for creating schematics - ExpressPCB includes a thing called ExpressSCH.

I think this is the one Brett used for his Aussie Comp

cheers, Col

[onelastgoodbye]

humbucking sustainer succes!! sort of..

I managed to break both my coils (hardware store 5 min epoxy crap) but they're still somewhat useable. One coil is 1.8 ohms, the other, reverse wound is 3.3 ohms. figured If this thing still works, the next ones can only get better. So I hooked it up to a 10 watt practice amp (I know, I know, but it's all I have since the little gem is fried) and it seems to work. Efficiency is pretty bad, can't get any high notes, thing gets hot (gee wonder why ) but...drum roll... NO EMI. It only starts squealing if I hold it right above the emg (closer than 6-7mm). It's so quiet you start wondering if it's actually on. proof-of-concept I guess.

I hear some distortion on the clean signal , but I'm *pretty* sure this is from the practice amp, so the background distortion problem might be solved.

What I really need at the moment is a better circuit so I can draw better conclusions. In particular, I'm having problems splitting the pickup signal.

Some sort of active splitter/buffer would be nice...right now my guitar out goes to the practice amp, which has the headphone out signal going to the big amp, and the speaker signal to the driver. I'm holding the speaker leads in one hand, the driver in the other....Not exactly practical or safe.

Another thought..the ceramic magnet I'm using (standard cheap pickup magnet) is way to powerful. It could easily be 3-4 times smaller. There's so much string pull it might actually be working aginst the driver.

[onelastgoodbye]

I should note that I've been using laminated cores in most of my drivers, doesnt make a big difference. there's probably a rule somewhere for x number of laminations for y core width, but as the cores are so thin, you can only use 3-4 laminates maximum, so I think there's little benefit in that (EMI wise).

I should also note, now the EMI is gone, there seems to be a lot less interference between strings; you can keep one note going without the constant dampening of the other strings.

[col]

I should note that I've been using laminated cores in most of my drivers, doesnt make a big difference. there's probably a rule somewhere for x number of laminations for y core width, but as the cores are so thin, you can only use 3-4 laminates maximum, so I think there's little benefit in that (EMI wise).

I should also note, now the EMI is gone, there seems to be a lot less interference between strings; you can keep one note going without the constant dampening of the other strings.

This is great news

You have officially tripled my energy to complete my own EMIBucker!

I hope the EMI is still gone with a 2x4ohm driver fed by an LM386, and that the loss of high frequency response is not related to petes worries about a 'wide' driver. Time will tell

Heres a version of my circuit.

(edited to fix an error and update the circuit)

Things to watch out for:

There may be errors - if anything seems odd, post a question.

If two wires are supposed to join, there will be a small 'blob' - if theres no blob where wires cross in the diagram, there should be no connection.

This is probably not exactly what I currently have on my bread board, but it is a working version.

Things to tweak:

The 9.1k resistor from pins 1&16 or the LM13700 try values from 6.8k to 15k - or others if you feel lucky - this effects the gain of the chip, I think getting this set correctly will be importand in having the circuit work well with a partially drained battery...

The 56k and 220k that connect to pin 2 of the LF358N that feeds the circuit - these control the gain - more gain means a lower threshold for the AGC... look ap an introduction on op-amps for details on how to correctly set the gain - the 51k resistor is also involved... to much to go into here, but not difficult at all to get stuck in.

The 4.7uf cap connected to pins 2 and 15 of the LM13700 - this has an impact on both the frequency response and the attack of the circuit (probably other things as well). right now I have a 47n in place of it on my board. The 100 ohm resistor from pin 8 interacts with this cap and is also ripe for tweaking.

(i've updated the cap and resistor in the diagram to 47n and 10ohm which are the values currently on my bread board. these change often though)

Other stuff - if you know how to make this better, don't keep quiet about it...

One thing I would like to know is if the values I've chose for the resistors in the voltage dividers for the LF358(33k) and LM13700(3.9k) chips are good bad or ugly. And if the caps to ground are good values (and are they all necessary? )

ok - please help with this, and enjoy it if it works.

cheers, Col

Edited September 20, 2006 by col

[col]

Oops, I've spotted one error in that schem already:

the 220k resistor connected to pin 12 of the LM13700 should be a 22k !!!

(now fixed)

Col

Edited September 20, 2006 by col

[psw]

humbucking sustainer succes!! sort of..

I managed to break both my coils (hardware store 5 min epoxy crap) but they're still somewhat useable. One coil is 1.8 ohms, the other, reverse wound is 3.3 ohms. figured If this thing still works, the next ones can only get better. So I hooked it up to a 10 watt practice amp (I know, I know, but it's all I have since the little gem is fried) and it seems to work. Efficiency is pretty bad, can't get any high notes, thing gets hot (gee wonder why ) but...drum roll... NO EMI. It only starts squealing if I hold it right above the emg (closer than 6-7mm). It's so quiet you start wondering if it's actually on. proof-of-concept I guess.

ALRIGHT!!!

Thanks to Spazzy for connecting up a rail pickup with surprising results too...everthing is encouraging...

Still...a bit more to do with the proof of concept...EMI may be low, but so may be drive force, necessitating heavy amplification...10 watts!!

Still the coils are way mismatched (interesting....as I thought mismatched coils could be purposely used for the woofer/tweeter concept) and it does work.

So frustrating, perhaps I could make a rail driver and stick it into the mid position of the strat without complications and be able to use both neck and bridge pickups at the same time!!!!

Great work getting the circuit up col...I'm sure it will work a lot better layed out nicely on a circuitboard...it could be that you are picking up RF noise that is interfering with the drive signal...that wouldn't help. At one stage I included a ferrite bead on the drive cables to help stop interferance from the driver getting into the circuit, just a thought!

Oh...and the other thing I wanted to try a EMIbucker driver is that I have a theory that it may reduce or eliminate the "pop". I did try a few "pop" solving problems suggested at Aron's Stompbox Forum for it, but to no avail. Some very well respected people over there suggested that it was a backlash from the driver coil...stored energy returning into the circuit. A dual coil design could help in this regard. Otherwise, it could be from the number of filter caps in my circuitry (primal did not have so much "pop" remember) releasing their energy when the power is turned off (the signal in is hardwired to the circuit, only the positive battery is disconected by the bypass switch).

I am interested in some of these other chips with ways in which the circuit can be left in an idle mode. I'd even like to see a return of the momentary driver switch, and such chips could simplify the switching allowing this (especially on a guitar with a mid driver).

HAahaha...that reminds me...I don't think I ever mentioned it here, but I was working on a new kind of tremolo for quite a bit...and I was working on a twist grip (like a motorcycle throttle) that went on the end of the trem arm for such a purpose...I should get more sleep...

Great stuff..."I'm excited" (as Big Kev says in the advertising down here)... keep up the flo and another 50 pages will be gone in no time!!! pete

[col]

Glad you are exited pete

I would suggest that folks don't try to build my circuit yet, unless they have a bread board or simulation software...

There are just so many things that need to be stabilised and finalised

ITS NOT READY YET

My reason for posting it at this stage it so any folks out there with the know-how and desire to help finish it can do so.

cheers

Col

[custom22]

First of all, thanks to everyone who contributes, especially Pete. After 108 pages many people have been helped because of you.

Secondly, what is the output on one of those amplifiers you make (ruby etc)? I was thinking i could use one of these http://store.guitarfetish.com/on25waguamdr.html in place of wiring it. What you you think? You say that this amplifier is able to drive a small speaker, so how about this?

Thanks in advance

-Ryan