Sustainer Ideas

[psw]

COMBINATION PICKUP / DRIVER PROJECT...Part 1

Ok...here's what I'm working on at the moment. Basically, it's a conventional single coil passive neck pickup. On top, I'm winding a driver (pretty much identical to the one I'm using at the moment) around a steel blade core that's shared between the driver and the pickup.

After taking apart a cheap pickup (about 4k ohms by the way, pretty low...I could rewind it but it doesn't sound too bad actually) I found it had a slotted coil despite it appearing to have separate pole pieces:

Here is a picture of the components taken apart:

In the above picture you'll also be able to see some Rare earth magnets stuck to the piece of steel with holes in it that formerly held the pole pieces (they look like cut off nails) next to the coil of wire I'll be using to wind the driver. I've assembled the new pickup/driver here.

The following picture shows the parts for the device taken apart:

Next to the coil of wire, to the right, is the pickups ceramic magnet. To the left two neodymium magnets that could be used as an alternative more powerful magnetic source (six would be required). Below that, with holes in it is the pickups base plate. Leaning against it on the right is the blade with a very thin plastic bobbin top tapped to it. I simply traced the bobbin onto some plastic (cut from a folder), slotted it for the blade and stuck it on with electricians tape and a bit of glue. The tape also serves to isnsulate the blade from the windings of the driver coil...very important. The pickup's coil is at the bottom...see top picture.

Ok...so this picture is of the device assembled, as it appears without the bits we dont need:

And the final picture is probably the most important one so I tried to get it in focus for you. The assembled device, pre winding of the driver:

From the bottom you've got the base plate, a ceramic magnet, the pickup coil, space for the driving coil and on top, the DIY bobbin piece taped to the internal blade.

You can see that the size of the coil is much smaller than that required by the pickup. In fact, with the original pole pieces (and the steel plate that held them in place) removed it is no larger than the original pickup. It would fit back perfectly into it's cover if it weren't for the blade!

So, next time I do some work on this I'll show how the coil looks when wound and report on wheather the thing actually works!

till then

pete

[psw]

COMBINATION PICKUP / DRIVER PROJECT...Part 2

oK...Lets start winding...here we are with some stuff we'll be needing:

You'll notice I've already stripped and soldered the lead (green and blue) wire. To do this you will need to scrape off the enamel on the winding wire...a little light sandpaper does the trick. The PVA is used to pot the coil as you wind...as you'll see.

This picture shows some initial windings. Notice I've left a bit of the wire thats soldered on free. We dont want to wind the solder joint under the coil and make a big lump! Time now to squeeze on a little glue to both sides of the coil.

Also...forgot to mention...I've double sided taped on a bit of cardboard to the top of the driver bobbin. This will help keep the thin plastic piece on and stable...it will be removed later. You don't want to be hand winding anything too fragile.

In this next shot, you can see some of the white glue in the windings. As you wind on the bobbin, excess glue will seep up through the windings. Everynow and then gently smooth the side windings down (pushing with a stick) this will keep the coil more compact on the sides where it will be looser and access more glue.

I tested the coil at this point. Used the sandpaper to gently scrape off a bit of the winding on measured the ohms with the multimeter between that point and the soldered end. It was about 2 ohms here so still quite a bit more to go!

The next one is particularly out of focus but we're up to about 5 ohms now. As the coil gets bigger the ohmage rises more rapidly so you need to check a little more often...we're aiming for 8 ohms by the way.

Well, we finally reached 8 ohms so I cut and soldered on the other end of the wire. Unfortunately, it now reads between 6-7 ohms...should have checked twice. Anyhow, this will still work fine so I'm going to leave it as is...not rocket science!

Plenty of white glue here...this has squeezed up through the windings by gently pushing down on the sides. The ends of the coils tend to be rather tight and can push up on the bobbin making a banana, so I've gently clamped these down. Checking all the time that I haven't created a short or broken a wire.

Alright, now I've cut electricians tape into thin strips. First I made a little groove for the wires to exit to the bottom (pickup) coil area. Then I taped one (the blue wire, under the first layer of tape.

Here I've put on a second layer of tape. This time the green wire and the rest of the lead is secured and the trailing end comes down in it's groove on the pickup bobbin's end.

You want to make these tape bindings really tight. Smooth them down so excess glue comes out. Make the final layer even tighter! Electricians tape is stretchy. Basically you want to be sure that that hand wound coil is fairly compact and becomes well potted.

Potting in some way is pretty much essential because...when you send the signal through it, if it can it will physically vibrate....you want the strings to vibrate, not the driver...plus you'll get a fair amount of squeel!

Anyway...time to let this thing dry. Next time...I'll try hooking it up and seeing if the thing works...

psw

[Biohazard]

Jesus christ havent been on this forum (or any of the other ones im a member of) for ages. Took a big break due to college work loads becoming stupidly high. Good too see all the hard work and enthusiasm is still in you guys. Its all incredible stuff.

[psw]

Good to hear from you Bio...I thought you might have had your priorities right!

Well, I've done some initial testing and the driver is working fine. Very similar response to the one I've been using but perhaps I'll try some different mags to get the power up. Compared to the design I've been using the ohms are a little lower but the main difference is the magnet being significantly further away from both the coil and the strings. I believe a more powerful magnet should be fine as it will be buried quite deep in the guitar (away from the strings).

So, a little trouble driving the high e and takes a bit more juice I think so it's not quite the range of the last one...but all looks fine so far. Next will be to check the pickup and see how that responds...that will be in the next installment

psw

[Bonfire]

Great job Pete!

Well, I have some little neodimium magnets and I tried to round a coil in it, but I think I need a little amp, don't I? Is there a way to try it without doing an amp or whithout conecting it to the pickup's?

[psw]

Hi Bonfire...

Well, you have to get a signal out of the guitar, and you do have to amplify it...so the short answer is no...you need to connect to the pickup (bridge) and amplify it!...However...

Transient/Emre built a simple coil around a little magnet (I think he only had about 1 ohm on it) to experiment sustaining just one string .

If you set the guitar's selector to the bridge pickup you can take the signal directly from the guitar lead. This saves you opening up the guitar. All my very early experiments were done this way...make a plug that has a separate line out.

Now emre used a powered computer speaker. You could connect the driver to the headphone socket or the speaker and the guitar to the input (the bit that plugs into your sound card.

You could also do it with a gettho blaster tape deck. Plug your guitar in and take a line from the speaker to the driver.

You don't need a lot of power, so don't try plugging into a marshall stack speaker out or anything. The poweramp (LM386) is rated at a max of 1/2 a watt.

Try not to blow anything up! You should be ok with anything low powered.

Good Luck

psw

[transient]

Hi guys,

I'm still around, checking the thread -almost- daily Good job with the tutorials Pete, teaching us to hunt fish for ourselves And good luck Tim I still am busy with a few things, so i can't experiment - yet.

Now about the single-string thing, yes i used a cheap pc speaker as a power amp. I didn't use the hedphone-out though, it might not be loud enough. I connected the driver to the speaker wires, removing the speaker of course. I had around 30 turns of wire around a very small screw, with a small magnet taped to the end of the screw. It worked really good, maybe as effective as an ebow, even the high-E string could be easily driven. And in fact i had taped the driver under the high-E string, right next to where the fingerboard ends. Here's a short mp3 file recorded a few months ago with that setup:

single-string driver sample

I'm playing fretless there (but not a glass-fingerboard one, i have the glass on my fretless classical), sorry for the intonation

A single-string driver works so well that it fools you into thinking that it really shouldn't be *that* hard to build a sustainer. But then you find out that it gets a lot harder and complicated as you try to get the same effect with a 6-string driver.

Anyway, good luck with your experiments, i will join you soon

...

emre

Edited May 11, 2005 by transient

[ansil]

Wow Ansil...so what you're saying is that with this box you can send phantom power to the guitar through a standard lead. Excuse my electronics knowledge...it's full of holes. Sot these caps block the DC signal but allow the AC guitar signal to be sent through to the amp...is that the idea?

I'll need to study it a little further to get the gist.

So, other applications could include powering any active electronics within the guitar...EMG's, effects, LED's, etc...not just a sustainer. I can just see with the price of digital modelling getting cheaper, that you could have something like your amp and effects sims right on board...if that were your thing.

I may have to ask you for more details when I get a chance to try this out as it may open yet a few more doors....hmmmm

Bonfire...I almost missed your little post. Where can you buy magnets...or are you talking winding wire and everything. I'm in Australia so I just shop around. You can often find winding wire and magnets at places like radio shack. Even craft shops sometimes have suitable ceramic magnets for making things to stick to your fridge. You can use a few if you cant find one big one...some of the other guy's here may be able to offer some more suggestions. There are magnet shops on the internet. I even found some suitable mags at a local hardware shop once!

Great stuff Ansil...my next post will I hope give people a better idea of what I'm up to for all those sustainoholics...plenty of pics!

psw

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in a nutshell you got it.

ac passes trhough capacitors the smaller ones don't let as much bass freq through. a cap to ground will act as a filter. but they do block dc. so if we look at tube amps. we have high voltage dc and coupling caps. so that our guitar's ac signal can make it through.

the biggest problem with this. is if you need high current you need to check the length of the cord you are using vs the guage. to make sure you dont' fry any cords along the way. but yeah its basically diy phantom power for 9-12v power instead of 48v. thats how i am powering my sustainor in my stratocaster.

it rests in the lower bass bout. i actually just used the idea someone posted here a link for removing part of a speaker. worked nicely. then i found a micro driver in an old set of computer speakers. i am unsure of the freq response of it. cause it was originally the low end part of the sound system for a cheap set of computer speakers. but it wasn't the sub it had its own sub system its one of those 2:1 systems. with the two speakers in each speaker box [plastic box].

but it works great. i used that with one of my new pedals as the gain circuit. and into a lm380n-8 as the driver for it. its way to much. i never have the output past the second level. the nice part is since it never comes in contact with the audio signal [ie output] i can get really clean sustain from my main amp. and then flip it to high gain on the amp for sick sustain. also the tone control helps shift the harmonics of it. so i can pretty much switch octaves via the tone control.. another thing is i mounted this two ways. the first way was direct mount and the second was a floating mount so that the speaker magnet is connected to a pin that sits in two holes in the wood of the guitar so it can pivet when you move so you can help simulate the moving the angle of the guitar to the speaker for more or less drive and or harmonics. this tends to just adjust the sensativity not really drive.

[psw]

...thats how i am powering my sustainor in my stratocaster. 

it rests in the lower bass bout. i actually just used the idea someone posted here a link for removing part of a speaker.  worked nicely.

I got a similar result in a similar place. In fact, I was trying to find a way of putting it in the strats jack socket hole! Actually, it worked better for me if the cone of the speaker was left on and the rim held against the guitar around that position.

then i found a micro driver in an old set of computer speakers. i am unsure of the freq response of it.  cause it was originally the low end part of the sound system for a cheap set of computer speakers.

I'd imagine that this "midrange" kind of driver is what you'd want to get all the strings humming.

...the nice part is since it never comes in contact with the audio signal [ie  output] i can get really clean sustain from my main amp.  and then flip it to high gain on the amp for sick sustain.

This has been the point of aiming for clean sustain...you can do what you want with the signal with processing...with enough distortion and/or gain you'll get sustain...but it's not at all like this sound. There's also a delicacy and power to the sound of clean sustain... With the driver gain up, those strings are really being driver hard...they leap into harmonics and are really attentive to the touch and dynamics of your playing...yet the sound is clean and rich and multi-dymensional...it never turns to compressed mush!

...also the tone control helps shift the harmonics of it. so i can pretty much switch octaves via the tone control..

I had considered putting a tone control into the sustainer circuit and got some similar results...Perhaps I should reconsider adding a tone control to my drive circuit for similar effects...it might even help drive that high e more, if it had an active treble boost in there...

My concern was, and still is, that the guitar is sprouting a lot of extra controls and mods. My initial aim was to get as low mod as I could...hence the surface mounted ideas. Perhaps you could try to get your "acoustic" sustainer into a package like we were looking at that is mounted behind the bridge. I was working on something like that but then went back to my electromagnetic systems. Sometimes it helps to do a detour to get closer to where your trying to get.

On the "acoustic" system that you're describing you can change pickups as well without a problem...where with mine, it's out of the signal chain because I have to wire all but the one pickup to bypass...so it's not an option (at least at this stage).

... another thing is i mounted this two ways.  the first way was direct mount and the second was a floating mount so that the speaker magnet is connected to a pin that sits in two holes in the wood of the guitar so it can pivet when you move so you can help simulate the moving the angle of the guitar to the speaker for more or less drive and or harmonics.  this tends to just adjust the sensativity not really drive.

←

Doesn't it rattle around in there if it's allowed to swivel about? Anyway, interesting idea.

Obviously, there are more ways to skin a cat! Emre/Transient also did some work on this with good results but has returned to experimenting with the electromagnetic systems. Whatever gets a result is ok by me. In the end I found it easier and had better results with my electromagnetic devices...but then I'd already put a bit of time into it...so perhaps I was just a little more committed.

Anyhow...good stuff ansil

sustain on!

psw

[onelastgoodbye]

Sounding good, transient!

I've found this: scroll down a bit for the schematic I think I'll build this (well atleast half of the circuit ) to replace the little gem amp I'm using now. It's really a toss up between this and the ruby or the ebow circuit. But since the headbanger is designed to produce little to no distortion, and I need a CLEAN amp this might be the way to go. I'm worried about it not being powerful enough though...It says 375 mW output...probably enough, but can someone confirm?

Also, up to now I've been using the y-cord trick to connect the driver to the pickup. How would i go and make a permanent connection to the pickup. I know ... just splice of the output, but since this is an active emg; aren't the batteries of the pickup (18v) going to act funny with the driver battery (9v)? Like, ummm when i connect them both to the same ground? So if anybody can help with that it'd be greaty appreciated.

It's a single emg 81 going directly to the vol en tone pots , into the jack btw: first schematic.

Greetz,

Tim

[GregP]

Any reason to not consider using normal phantom power along a balanced cable? 48v too much juice?

Greg

[psw]

No particular reason...although it's probably the current that's more of an issue.

I guess it's the same reason it's not used for active guitar electronics...guitar players have a hard time with putting a battery in a guitar...even a stereo cable is daunting...but a powered cable...oh no, it's the work of the devil (or perhaps the angels, for our death metal friends ).

But things are changing...your seeing powered piezo systems...even the variax modeling...it's only a matter of time before we see on board guitar modeling and effects as a semi standard feature. Once that occurs, I'm sure remote powered guitars will seem common place.

Just one more thing....50 pages....12,718 visits....and 735 posts! (some of them really, really, really, long!)

I'd just like to say how much I've appreciated all the support and suggestions and I hope you all have enjoyed this thread, so far...thanks...who would have thunk!

cheers buddies

psw

[GregP]

I don't know that I'll ever be one for on-board special effects (ie. flanger, chorus, octaver), but bread and butter things like EQ and compression I could go for on-board. I have no fear of powered cables.

I doubt it'd catch on beyond the studio, though. No phantom power with a wireless connection.

Or is there?

Greg

[Mr.Churchyard]

Just one more thing....50 pages....12,718 visits....and 735 posts! (some of them really, really, really, long!)

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I think this *really* qualifies for a pinned topic...

[lovekraft]

..since the headbanger is designed to produce little to no distortion, and I need a CLEAN amp this might be the way to go...

You need to read the fine print - the Headbanger is designed to be very clean with an input level of 80mV rms - unfortunately, an EMG 85 has an output level around 1 volt rms (that's 1000mv, or over 10x the level designed for) and an 81 is up to about 1.25 volts, so it's going to clip (just like what you've already got). The 12 volt supply will give you a little more headroom, but you still can't swing farther than your supply, and boosting a 1 volt rms signal 21dB is going to make the output try to swing over 13 volts, making distortion inevitable. To lower distortion (and overall noise), you'll need to match the amp's gain to the expected input level (and amp headroom) and limit the bandwidth as much as possible - sorry, no free lunch!

[lovekraft]

<EDIT> Double post!

Edited May 14, 2005 by lovekraft

[psw]

Sounding good, transient!

I've found this: scroll down a bit for the schematic I think I'll build this (well atleast half of the circuit  ) to replace the little gem amp I'm using now. It's really a toss up between this and the ruby or the ebow circuit. But since the headbanger is designed to produce little to no distortion, and I need a CLEAN amp this might be the way to go. I'm worried about it not being powerful enough though...It says 375 mW output...probably enough, but can someone confirm?

Also, up to now I've been using the y-cord trick to connect the driver to the pickup. How would i go and make a permanent connection to the pickup. I know ... just splice of the output, but since this is an active emg; aren't the batteries of the pickup (18v) going to act funny with the driver battery (9v)? Like, ummm when i connect them both to the same ground? So if anybody can help with that it'd be greaty appreciated.

It's a single emg 81 going directly to the vol en tone pots , into the jack btw: first schematic.

Greetz,

Tim

←

Hey Tim...don't you hate it when your post is the last on the page and gets bounced back and missed by everyone! I repeated it cause there are a few questions that need to be answered.

If you look at that headbanger circuit it's just two LM386 circuits like the dutch ebow one with the gain between pins one and eight of the chip limited by a resistor. As, I've said, this is also pretty much what I'm using and all of these, including the Ruby circuit, are pretty much lifted directly from the LM386 application notes...see the National Semiconductor wesite for details on the PDF file.

Now Lovecraft has pointed out (twice,LK...this moderating is taking it's toll I see!):

an EMG 85 has an output level around 1 volt rms (that's 1000mv, or over 10x the level designed for) and an 81 is up to about 1.25 volts, so it's going to clip (just like what you've already got).

What I think you've got with your EMG's are a distinct advantage...you already have the preamp section. All you need is the LM386 section...just like in the ebow circuit or the Ruby (which also has a stripboard layout) without it's transistor buffer circuit.

The LM386 is a standard amplifier circuit for a reason. It's an all in one (I originally ran it with just a 100uf cap on the output as Ansil suggested in his Sustainer Mod thread!) and very forgiving and runs well from batteries...plus it's really cheap. My kit circuit for it...including circuit board and everything from the ebow circuit...only costs only A$5.95. (from Dick Smith or Jaycar for you Auzzies! ) You could make it smaller, but the size of this circuit is exactly that of a single 9 volt battery (but much thinner).

So Tim...what I think you need is this circuit but instead of the link or a resistor between pins 1 and 8 (with the 10uf cap), replace it with a 1K trim pot. This will give you an ajustable max gain between 20x and 200x. 18v may be a bit much...a resistor may need to be added to bring this down (LK?) to say 12v but it might work fine without it at full voltage...the chip is pretty sturdy.

Use a 10k pot on the input as the sensitivity control. Feed that with the output from the bridge EMG's preamp. What you'll have is something really compact...more compact than what I'm using where I have to have a preamp almost twice the size of the poweramp circuit to get the power up from my POS single coils.

Now, Lovecraft sent me something by email on this:

Also, up to now I've been using the y-cord trick to connect the driver to the pickup. How would i go and make a permanent connection to the pickup. I know ... just splice of the output

Perhaps he could contribute it again for everyone. It's the stage I'm up to as well.

What you're getting at, I think, is... how do we actually implement the system into the guitar...well at least that's what I need to do. Basically, you need the switch to activate the system, not only connect power to the driver circuit, but to bypass the other pickups selecting only the bridge pickup...no matter what pickup was in use prior to activation. If I recall, LK proposed a DPDT switch...one side connects the power to the drive circuit. The other side switched the guitar's circuitry....hmmm...I've forgotten how....help, LK!

There may be something special that needs to be done with your active system, but I don't think so. In the end I think you'll find you can make something really neat and compact. You already have onboard power and preamplification.

I'll try to post my actual circuit in the near future...but it's pretty much identical to the ebow and like circuits. Limiting the max gain with that trim pot should help with stability (internal feedback) and distortion. I'm not quite sure of your concerns with distortion....I imagine you're trying to get a better response.

I think the driver is going to be more of a key to achieving improved response. Just the right combination of coil size, wire guage and shape will probably make all the difference. I suspect that we may get a better response on the high e, for instance, with a coil of lower resistance (say 4ohms) and or a material such as ferrite as the core as the electromagnet will be able to change states faster and keep up with the higher speeds.

Part of the problem here though will always be the amount of steel that the driver has to work on. I think that's why the low E very quickly drives to the octave harmonic...more magnetic material in the string (err...it's thicker).

I've done a few experiments with using my Rare Earth Magnets to try to compensate for string thickness by adding more magnetism under the thinner strings. I haven't done enough to reach a conclusion on this yet, but I'm thinking of replacing my large, broad ceramic with 11 or 12 of these tiny mags along the bottom of the blade. With the pickup / driver combination the magnet is a fair way from the strings and a lot of the field never reaches the strings. Smaller, more powerfull mags will be able to have a greater effect on the blade. It also allows for the use of more of them on the treble side to give a stronger pull on those thinner strings...at least that's the idea.

For now...I'm actually trying to find time to put together a guitar, purpose built for the sustainer...this will feature my neck pickup / driver combination and a single humbucker in the bridge position. It's interesting....with on board infinite sustain at my disposal, I'm actually thinking of a light weight percussive sounding guitar. I might even add my neck pocket piezo. It kind of turns some things around as far as guitar sound goes.

Anyway, time to go!

psw

[ansil]

...the nice part is since it never comes in contact with the audio signal [ie  output] i can get really clean sustain from my main amp.  and then flip it to high gain on the amp for sick sustain.

This has been the point of aiming for clean sustain...you can do what you want with the signal with processing...with enough distortion and/or gain you'll get sustain...but it's not at all like this sound. There's also a delicacy and power to the sound of clean sustain... With the driver gain up, those strings are really being driver hard...they leap into harmonics and are really attentive to the touch and dynamics of your playing...yet the sound is clean and rich and multi-dymensional...it never turns to compressed mush!

of course you see i am using a insanely compressed and distorted sound into a driver to make it respond like a great cranked up distorted amp. but this only goes to the driver and the guitar's actual signal is not combined with this, only the driver see's this. the rest is dumped through the blocking cap and into the amp so effectivly its like the old trick of having your normal amp set up for stage volume on clean, but having some little ratty amp sitting off to the side with a volume pedal and its cranked wide open so though its small it still makes the guitar feedback like a larger amp..

since the input is split into the two amps but the output is two seperate amps and the expression control is the fx loop of the smaller amp so it controls how much drive the power section see's without changin the gain this is our controler. since the little amp is pusihing the guiitar into sustain/feedback, the larger amp will reap the benefits without having to be distorted via the coupling

as far as my tone control mine is in the guitar it is actually the guitar's tone control since i am going about this a little different using the guitar to start the actuall feedback loop it acts just like anormal guitar plugged into a cranked up amp so all the controls fucntion like you are just standing there so theres no extra controls wired in. i have a trim pot installed for the gain. but its internally adjustable.

i use the voltage drop on the pedal to control the sensativity of it

... another thing is i mounted this two ways.  the first way was direct mount and the second was a floating mount so that the speaker magnet is connected to a pin that sits in two holes in the wood of the guitar so it can pivet when you move so you can help simulate the moving the angle of the guitar to the speaker for more or less drive and or harmonics.  this tends to just adjust the sensativity not really drive.

←

Doesn't it rattle around in there if it's allowed to swivel about? Anyway, interesting idea.

nope it only moves a little bit but i have decided to go back to the original mounted idea. but right now i am busy winding output transformers and building jungle kats and moving into the new shop, and laying down studio tracks for this metal band from NCarolina. we get alot of buisiness in the studio from NC metal bands

psw

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[ansil]

hey psw and all of us lm386 fans that i am sure LK has pointed out before.

when using parrallel resistance there is that lovely formula {which i dont' remember off the top of my head thats wh;y GOD created multimeters lol } but riddle me this there batman, if you put two 1k resistors in parrallel you get what.

for only two resuistors of aprox equal value you get half the resistance. so using a 1k trim will not yield the 20x-200x gain factor the datasheet speaks off. as at max resistance you only get around 560ohms there. try a larger trim. i liked my gain set at around 790 ohms. and found my 1.5k resistor [acutally measured around 1.875k] gave me that reading when parralleled on m;y circuit boards. so in a nutshell you won't have the 20x gain on the down swing it will be a little closer to 85 or so

[psw]

So, Ansil

for only two resuistors of aprox equal value you get half the resistance. so using a 1k trim will not yield the 20x-200x gain factor the datasheet speaks off. as at max resistance you only get around 560ohms there. try a larger trim. i liked my gain set at around 790 ohms. and found my 1.5k resistor [acutally measured around 1.875k] gave me that reading when parralleled on m;y circuit boards. so in a nutshell you won't have the 20x gain on the down swing it will be a little closer to 85 or so

...what you're saying is that you'll get a better control down into the lower gain with a bigger trim...OK! I run the thing flat out with no resistor at all...just a wire link between 1-8 and control the input.

of course you see i am using a insanely compressed and distorted sound into a driver to make it respond like a great cranked up distorted amp. but this only goes to the driver and the guitar's actual signal is not combined with this,

Yep...it follows that, no matter what kind of signal you send the driver (electromagnetic or acoustic) they are not combined in the guitar's output.

An exception was shown in my last generation of Hex driver experiments...and is possible with this new one...where the pickup can pickup the signal of the driver through mutual inductance (i.e. by sharing the magnetic field). Whether some use can be made of this phenomenon I'm still not sure!

It may be faulty intuition on mine and Tim's part....but I think there is some merit in seeking a relatively clean sound in the drive chain... Firstly though, let's look at these driver's realistically...we're not talking hi-fi here (coneless speakers and hand-wound stationary coils driving resonant wires)!

There's going to be distortion and compression. LK also suggested that a more square wave signal would actually be benificial. There is no way that you can get the strings themselves to actually physically vibrate in a square wave, therefore the guitar, no matter the drive signal, will be essentially, as clean as you like.

Hooking a speaker on instead of the driver gives some idea of what kind of a signal you're generating. With my set up it's reasonably distorted...more of a heavy overdrive than fuzz.

I'm thinking the clean signal idea is that there is less "mush" and so the system works a little more dynamically. That is, the system's more responsive to technique, allowing the picking hand dynamics to be able to detirmine the type of effects (harmonics, swells, etc.) you can create. The other thing is that the driver will be able to perform better polyphonically. Also, I sense that a less subtle signal may actually be aiding in cancelling out the drive of less dominant notes within chords...speeding the tendancy for one to predominate.

That is not to say that I've got a truely polyphonic sustainer. Sustainer's are always going to have trouble with chords (unless you use a hex pickup and driver system...6 ebows!...and even then the closeness of the pulsing magnetic fields creates a lot of cross talk between them!).

That said...you can play chords just as normal, and there will be some polyphonic drive, but you will get some notes that will pop out and predominate. It's not like an organ is to the piano, but you can use it with chords. It's not like sticking a fuzz on, so compressed and distorted that the guitar becomes monophonic in effect, is what I'm saying.

In general, I'm just promoting the sustainer device(s) as really adding some thing new to the instrument itself. The clean sound really shows this off as it has a power and grace to it that is similar to the "effect" that distortion and high volume had to the guitar but is, at the same time, fundumentaly different and new.

My purpose then, really is to promote the sustainer cause because it is not only really fun to play around with (enough of a reason in of itself) but, that I think there's some great music to be made with it.

The type of players who are prepared to DIY, like those guys in the sixties that experimented with effects boxes, are probably most likely to be the ones to get a head start. This is an approachable DIY project and eventually, pretty soon I suspect, we'll have a practical receipe or cookbook for creating the system. Once that happens, there will be all kinds of variations and evolutions and then we will see something really special come of it, in guitar playing and in the music created with it.

As far as my work has been going on this, I have'nt had much time, but my pickup driver seems to be working well and I'm looking at ideas for a guitar to put it in.

Anyway, enough preaching from me....

psw

[onelastgoodbye]

Yep...it follows that, no matter what kind of signal you send the driver (electromagnetic or acoustic) they are not combined in the guitar's output.

←

Errrr..seriously? because that's exactly what I'm hearing and the whole reason why I'm looking for a cleaner driver amp: I can hear the distortion of the driver amp when I'm using the sustainer on clean presets... Maybe I wired the Y-cable wrong . I'm use the 'semi' balanced type cables; which are essentially stereo cables, where red and blue carry the positive and negative part of the signal and the shield is only there for well..shielding. The jack also fuctions as a switch for the emg, so the wiring is a bit different there. Maybe the pickup IS sharing the magnetic field with the driver. Contrary to your designs psw, my driver only works in this one position: 25-th something fret for harmonic mode, 24-th something fret for fundamental mode. Anything else is just screaming feedback, so either yhe signal is to strong or the pickup is to sensitive or..

lol... I just found out I wired pins 1 and 8 on the lm386 with a 10 ohms resistor...should have been more like 10K guess that might explain the massive gain.

Apart from that, you'd think the strings would be driven more efficiently if the driver signal resembled the natural 'movement', of the strings. As in a clean amplification of what the pickup senses. of course, the pickup colours the sound plus it's also located in a different place from the driver, so the harmonics are different and whatnot, but still.

thanks LK for pointing out the headbanger won't work. No free ride indeed

Off for some further headscratching and testing when I find the time,

Tim

[lovekraft]

thanks LK for pointing out the headbanger won't work. No free ride indeed

That's not what I said - I simply said that it would distort with unattenuated pickup signals as an input, just like the Ruby (or for that matter, any >20dB gain stage with a 9 volt supply). Since you're using active pickups, you could just attenuate the signal coming into the 386 to keep clipping from happening, or you could go ahead and clip the signal up front (to limit the dynamic range), and then steeply lowpass it to remove most of the clipping harmonics before the power amp. All I was trying to point out was that there's nothing much about the Headbanger that's intrinsically cleaner than the Ruby - it's just very closely matched to the expected input level. A simple volume pot (or trimmer) in front of either circuit would allow you to dial in maximum output without distortion. HTH

[psw]

So Tim...you are only taking the signal from the bridge pickup and running it only with the bridge pickup selected...is that right?

Unless the driver is close to the source pickup you shouldn't get too much squeel. If you have the neck pickup sending any signal through to the output, it will pickup the driver's signal and amplify it, probably at enormous gain (=distortion) as in my mutual inductance experiments.

I gather that at the 24th/25th fret locations you are driving directly over the top of the neck pickup...yes? Remember that the magnetic field of the pickup will be adding or subtracting from the drivers magnetic field.

Just as you can get the harmonic mode by switching the wires on the coil, you can get it also by reversing the input phase and by reversing the magnet polarity (turning the magnet upside down). It may be that the EMG humbucker is effecting the drivers magnetic field as one side of a humbucker is N and the other S (unlike a single coil which is one polarity on top).

Well, I'd be putting a trimmer on the 1-8 pins. As I say, I just have them linked (with a straight 10uf cap), getting a max gain out of it. You might not want/need that much gain with your setup. Try it anyway if you like, just replace the resistor with a wire link! (Still, if there was only 10ohms on there you were probably pretty close to maxing the thing anyway, I guess).

You should not hear the drive signal at all. With all of the three drivers (and my pre-hex early experiments) I'm getting a pristinely clear and undistorted signal. The only distortion is that the strings can be driven hard. This is similar to picking hard. The cumulative effect of the sustain effect means that it will eventually work it's way (depending on the sensitivity control/gain max) to driving the strings so hard that they'll be slapping the fretboard on a low action guitar.

This is what I'm (errr...poetically) calling the power and grace of the clean driven sound. The strings can be driven hard with the kind of effect and intensity of a really loud and distorted amplifier but without that sound, more that it has that kind of intensity to the note.

The other thing is that some players will need to tighten up their technique a bit. Muting is essential as the guitar becomes very much alive (not as bad as you might think though...it doesn't go beserk) and it responds better to a varying pick strength. A lighter hand will definitely yield more rewarding results.

We really need to get this sorted for you, if this is a problem Tim, as you don't want to "hear" the driver at all.

Also, so is this likely to be installed on this guitar. If so, where? I imagine it will need to go on the bridge side of the neck pickup, on a two humbucker equiped guitar. There would be an option to have the thing driven down at the bridge and using the neck pickup as the source and active pickup during sustainer operation...it certainly looks better on my LP and there is room between the bridge and the pickup (and room between guitar top and strings for the driver. This arrangement gives max separation of driver to pickup (neck), is probably a little harder to drive (string tension at the bridge), and will have a mellower neck pickup sound in operation.

Keep mucking around with it...perhaps another, thinner blade driver or putting steel fins like I experimented with, will keep stray magnetic fields away from the pickups, if their sensitivity is going to be the issue. My fins worked and appeared no better or worse for me, so I left them off, but perhaps with your setup they'd be of benefit...

Now...has anyone worked out the switching of the device so only the one pickup is selected when the device is activated?

psw

PS...LK's right. (posted while I was posting )

My point about the headbanger (and most similar circuits) is, when you look carefully, the headbanger, the dutch ebow, the ruby, the LM386 app notes...they are all pretty much the same. There is often a variance in the resistor between 1-8 to limit the gain, but otherwise, everything is built into the chip. Look at the headbanger and you'll see it's just two ruby circuits...one for left, one for right!

I think there is a different problem here for you and it's not with the drive circuit. The drive circuit should not enter the signal chain at all. You may want to bring the power of the amp down a bit, but the input/sensitivity gain control should be doing this as LK points out.

Think about the above things in this post and let us know how it's going...

Edited May 14, 2005 by psw

[onelastgoodbye]

The thing is I don't even have a neck pickup. It's a one pickup guitar, only a bridge pickup.

I originally had pins 1 and 8 jumpered and it seemed a bit strong. pins 1 and 8 open was too weak.

I can hear a distortion buzz on clean sounds, yeah. It's not overly dominant, but definitely there. It's there on distortion patches too btw (well evidently, since the driver circuit's response doesn't change anyway).

Come to think of it; this guitar has an aluminium pickguard. You said somewhere aluminium was sort of 'anti-magnetic'. Maybe that's a factor too.

There's no real point in me making more assumptions before I can test it further though, so I'll check back later.

I think we can get it wrapped up before the thread hits page 100

Tim

[psw]

Well, it's the perfect guitar for it then isn't it...none of that fussy switching...just turn it on.

I was having trouble with the signal getting through the earth. This isn't a problem with the input, but having the wires to the driver too long or too near earthed parts of the guitar or the pickups seemed to be a problem at one stage.

Aluminium is slightly anti-magnetic...but really such materials are very rare (i.e. there are plenty of non-magnetic materials) and the effect is practically immeasurable. What is more important is that it is conductive and may be acting as an antenna to the drive signal and that's how it's getting into the drive chain.

I mean, the only way it should be able to cross over is if the signal somehow leaps (magnetically) over and is picked up by the pickup (say by travelling down the strings, or through the air). It's not actually wired in anyway to the output, except as an input...is it? (eg, your not sharing the input ground with the driver ground are you?) You have been trying this with a battery completely separate from the inbuilt EMG ones...that would be a test to see if the interaction is in the power supply / negitive earthing...or something...help!

Anyway, to illustrate what I was saying earlier...here is the circuit I'm using for my driver poweramp. If you look closely, it's the same (pretty much) as all those other LM386 circuits:

I've connected the cap between 1-8...ie no resistor for max gain. I have used a 1k trimpot (or 1.5 as Ansil would suggest) instead of the 1k resistor there to vary from 200x down and this is what I'd suggest. The pot on the input is the sensitivity control. A DPDT switch to reverse the phase of the driver should be placed on the output wires going to the driver.

Hope that helps some people who want more details regarding what kind of circuit to use.

good luck Tim

psw