DIY SUSTAINER...hear for yourself

[psw]

that's right...look at some of my hex designs...I pushed thin aluminium (flashing) over a shape to make it...aluminium is non-magnetic...but a tele pickup cover might work...

[psw]

Actually, i've built my sustainer (called Dizzy Feedback Machine)
about a year ago.

Great...now the details...maybe a pic...amp, driver style, the works...cough up... :wink:

pete

[Paul Marossy]

psw-

I haven't been keeping up on the sustainer thing too much lately, but I just listened to those soundclips - nice work. Good on you mate!  

[Dizzy_One]

psw:

The driver is a much like Sustainiac bilateral driver.

Signal from pickups goes to buffer with a very
high impedance, then to a complicated phase
and amplitude correction scheme, to
a AGC circuit and finally to the power amp (lm386, heh).

No a fundamental/harnonic mode because of
placement of driver. Just a some mixed mode -
harmonics on most bass strings and fund. on
high strings. Varying picking style and switching
to different pickup combintation, i got a different
harmnonics.

Picture of pickup in da place: http://home.planetahost.ru/~firewood/driver.jpg

Sound sample (a theme from some great comp game of the
past): http://home.planetahost.ru/~firewood/diablo_theme.mp3 (1.44 Mb). Almost all notes of the lead were picked with left hand only.

[psw]

Thanks Dizzy...great stuff...

BTW...it didn't take two years to do the DIY sustainer...it was those darn ultraminiture hex drivers...

I tried the mid position and it worked...mess' with the harmonics but I'm not quite sure why...you can see why I wonder in the sustainer thread on my last post. Basically, I've had very focused hex drivers operating within a cm from the pickups, and at the bridge....!!!

I just don't have what it takes to all that phase correction stuff. Instead, I've been developing the driver side of things to work with a very simple amplifier circuit. I know it looks simple...and it is...but it's getting the right kind of simple that's the key. Just check out the posts of all the"look I got a coil of wire, why doesn't it work" posts...it's a simple formula, but a formula nonetheless... :roll:

cheers...I'll have to check the sounds later...psw

[Dizzy_One]

psw, ok. i'll check thread you mentioned later.

What about a current consumption and parasitic
feedback in your design ? All the notes
could be sustaned - even most high ones ?
And the driving force - is it virtually same for all
strings ?

If you wanna make a high efficiency device, I sure
there is now way to go without amplitude and
PHASE corrections.

Heh. My first attemp sustainer was working after
week - 150 ma current draw, two 9-volt batteries
and rewinded single very hungry for parasitic
feedback  :-)

And it took two years to smooth thing out :-)

[JimRayden]

Wow, you've smoothened it out alright... amazing sound clip you have there. Very balanced sustain and feedback.

It looks like we have two ways to approach this: either all electronic and digital, or extra careful driver design.

I'm not saying anything against digital, I actually love to hear it working. Any schenatic, or at least a block diagram of your device, Dizzy? What did you use for phase control?

----------
Jimbo

[Dizzy_One]

Both driver and electronic are equally important, I would say.
To have a working system one must design a proper driver.
And to have an _efficient_ system, goos electronic part is a must.

Sorry, I can't post schematic now - it has a
some potential commercial value :-)

About block diagram: the signal from pickup generic pickup
switch goes to high impedance buffer, then to the amplitude/phase
correction stage, to AGC and to the lm386 power amp.

Now phase correction. You have to compensate
phase shifts (lags) intruduced by pickup, circuit and driver - then
strings will be driven almost in-phase. The lesser overall
phase shift, the better performance on the whole system.

You have to make an amplitude correction also - to make
sure the higher strings accept more driving force.

My phase correction circuit is based on plain active
filters. Emphasis should be put on 'phase shift vs frequency' characteristics, not 'amplitude vs frequency' as usual.

[psw]

psw:

The driver is a much like Sustainiac bilateral driver...

No a fundamental/harnonic mode because of
placement of driver. Just a some mixed mode -
harmonics on most bass strings and fund. on
high strings. Varying picking style and switching
to different pickup combintation, i got a different
harmnonics.

Picture of pickup in da place: http://home.planetahost.ru/~firewood/driver.jpg

Sound sample (a theme from some great comp game of the
past): http://home.planetahost.ru/~firewood/diablo_theme.mp3 (1.44 Mb). Almost all notes of the lead were picked with left hand only.

I hadn't got a chance to hear the sound clip till now...well done, a few too many overdubs to hear what the raw effect is like...but excellent!

I'd be interested to know how you went building the bilateral driver (I'm familiar with the patent) and whether there's any negative effects from the crossover between coils (say bending the g string into d string territory) and whether the bi-lateral design causes some inconsistancy of harmonic/fundumental response (ie high strings opposite low, etc).

Do you have a harmonic switch?

How does it go with chords?

Do you run the circuitry direct from the selector (ie using whatever pickup is on at the time) or a direct line from the bridge pickup?

Do you get any "pops" or other noise from the system (eg EMI signals being picked up by the other pickups?

Sound's great and looks really neat. If people are interested in the "schematic" approach to phase problems and such you may wish to look at the patents by Hoover (sustainiac) and Floyd Rose (similar but easier, earlier approach.

As for my DIY sustainer...there's some more designs and pics from some others and there seems to be quite a few people coming forward with this project.

The advantages of the DIY sustainer is it's simplicity. There are aspects of the "slim" driver idea that make it a more practical DIY project. It's very compact, single easy to wind coil, very simple circuitry...

I really cant say what the battery consumption is like but it will go for a fairly long time...some say theirs go for a real long time...The circuitry would certainly be on a par...pickup power has quite an influence on it I seem to have found...

My idea has certainly been to concentrate on the driver and while it is very simple,  when you mess with the design principles, as people have found lately, it does not respond or work as it should.

My simple driver design really was born out of a desire to address the problems of phase difference, etc without having to deal with corrective circuitry. To that end, it works and is vastly different from the patented designs which seem to be modelled after conventionally sized pickups and complicated circuitry...which is understandably, secret  :wink:

Anyway, thanks for showing of the dizzy machine...tre cool... You wouldn't want to post the clip and pic over there by chance?

Check out the Sustainer thread for more people's sustainer attempts..

sustain on...psw

[JimRayden]

Laright, I got myself a roll of 0.2mm wire, it seems to be a pretty good one to drive all the strings equally but it still doesn't drive the strings hard enough to pass the infinite feedback limit. Could it be that my too long connection wires cause a too long delay and mess with the phasing. I can't seem to track the problem.

----------
Jimbo

[JimRayden]

Anyone?  :?

----------
Jimbo

[NaBo]

I feel out of place asking this...  its quite nubby amidst all this talk... but...

How in the hell do you measure the resistance of your wrapping wire as you go???    Seriously... how do i know when i've got about 8 ohms?  do you strip measure and tape/heatshrink every so often or wha?   :?

[JimRayden]

I just scrape the stuff off, measure and wind on. There is very little chance of your "checking points" touch each other if you don't check with every winding. Go for about 100 turns, check, then go on for as much as you need (by using simple maths).

----------
Jimbo

[psw]

Laright, I got myself a roll of 0.2mm wire, it seems to be a pretty good one to drive all the strings equally but it still doesn't drive the strings hard enough to pass the infinite feedback limit. Could it be that my too long connection wires cause a too long delay and mess with the phasing. I can't seem to track the problem.

----------
Jimbo

I had a really good, and typically long answer but the remote service I was using dropped out and I lost everything...oh well...

You seem to have progressed anyway...but...

Keep the leads short and the driver leads should be ideally twisted to help with EMI. You should also keep them away from pickups and wiring (even if shielded) as much as you can.

Think of the driver leads as simply extensions of the driver coil, which in fact they are! Short and twisted is best. Wires from the circuits to pots and switches etc also carry signals and if they are of any significant length should be shielded and kept as clear as possible from the driver leads...

I don't think that they would really have much effect on phasing. A very thin wire may not be able to carry the current required...but that would be a very thin wire...

The whole phasing issue is real and Dizzy and the two manufacturers have dealt with it by compensation circuitry. My approach has been fundumentally different in that I have throughout the hex designs and others tried to approach the phasing issue from a electro-mechanical perspective.

That is, that it is in the design of the drivers that minimises the phasing issues. The design of this one is deceptively simple...but I believe elegant and unique in it's approach.

So, NaBo...you use a multimeter to test from the start point of the coil to a position you've wound to by lightly sanding off the enamel coating. At first the resistance will build slowly but as you go on the coil will become bigger and other factors will lead to the resistance rapidly rising.

So, Jim's right...wrap to about 100 turns but someone said they had to wind approximately 200 turns. It depends on your winding style, tightness, potting method but particularly the bobbin and core size and material. The wire is very easy to handle, it's thin but wont break (unlike pickup wire) and 200 turns is easily done (a is easlier done) by hand.

Potting is crucial. I have used common PVA while winding mine as it's very safe and will insulate the test points then finally covering this with electrical tape very tightly. There's a pictorial of the process on the thread. As you wind you will find that the ends where it turns are very tight...beware...but the longer sides can become loose and have a lot of air.

Push these sides in gently into the PVA as you go and make sure the sides are compacted and held in place while it dries. You do not want vibration in the driver coil as theres will create there own signals of interferance. PVA was chosen because it's safe and can be used while winding and allow this compaction as it dries.

Anyway...good luck anyone trying this...it's not hard, it just needs care and attention to these detail. The actual construction of the bobbin and the core is harder (although not difficult) than the winding and potting. It's the idea that's off putting, not the process...it's actually rather fun !

psw

[Dizzy_One]

I agree, too many overdubs - 'couse I'm loving it :-)
I could post raw sample, not a problem.

My first attempt was to built a single coil driver. But the
problem of parasitic feedback between pickups
and driver force me to try a different design.

I wanted to have a driver in middle position,
and it made a parasitic feedback problem much worse.
I've tried a different geometry of coils, configuration
of poles and so on. It worked for neck position,
not middle. So I decided to make a patented bilateral
driver :-)

Bending G-string in D-string position decrease driving force
slightly. A known drawback of bilateral design.

I have no harmonic switch. Harmonic/fundamental mode
depends heavily on picking style and pickup selector.
Say, then I get signal from neck pickup, strings excited
mostly in fundamental mode. And in harmonic mode
then using bridge pickup.

My system increase the sustain of chords, but after
a some time bass notes tend to dominate.
After a more time only one note will sound.
Mostly because my AGC system seem to prefer
bass notes.

Yes, I run circuit directly from selector, and feeding
it with signal from any pickup combination.

I have no noise, no pops - thanks to
the bilateral driver and big input
impedance. Dead quiet.

A small tip about phase response. There is a good
PC spectrum analyzer program called Spektralab.
Hook your sustainer to audiocard and Spektralab will plot
transfer function of you system - amplitude vs freq and phase
vs freq.  Take a note which notes sustain good, which
bad and which not sustain at all, calculate their
frequences and find them on transfer function plot.
You will find some correlations for sure :-)

BTW, I'm fan of you slim pickup idea. Keep on
going ! :-)

[Yun]

Does anyone have a link to the actual Tautorial eh?  i've searched for 2 days, and it all leads back to the sound clip thread....

If youse guys can help us blind ones out- i/we would be much obliged....

[transient]

Does anyone have a link to the actual Tautorial eh?  i've searched for 2 days, and it all leads back to the sound clip thread....

It is here:
http://projectguitar.ibforums.com/index.php?showtopic=16984

...
emre

[Yun]

Does anyone have a link to the actual Tautorial eh?  i've searched for 2 days, and it all leads back to the sound clip thread....

It is here:
http://projectguitar.ibforums.com/index.php?showtopic=16984

...
emre

Much obliged, my friend

[psw]

Thanks Dizzy...great info...

The bi-lateral design is better in many respects...especially the parasitic feedback.

I believe that my driver's could be refined even further, based on the work I did on this with my hex drivers...to address the problem without going bi-lateral...

It's all a little ironic since I committed a year to stubbonly exploring the Hex (driver for each string) idea. The string bending was the real killer. I even had it developed to the point that it was supper small and could be constructed using modified off the shelf (cheap) miniture components...ie, no coil winding.

I believe that I will be able to improve the design without much trouble to work in the mid position. The thin design has many advantages but at it's heart it was trying to address the phase differences. I've posted some more thoughts over there today, but there really hasn't been a lot of work (besides my own screwing around) on alternative cores or the whole issue of EMI containment (or shunting) at least in practical (ie not theorising about it) experimentation. Such techniques however are common place in say transformer tecnology whth fantastic results so there's still plenty of room for future development!!!!

Cheers all...p

[psw]

Hi to Dizzy_One and all diy stompers...

Just thought I'd say I've posted Dizzy's fabulous soundclip over at Project Guitar site...hope you don't mind Diz :wink:

Also, it came to mind because people seem to still be working on their own systems, the latest an attempt at a mid driver sustainer on an SG based on my concepts, so dizzy's mid driver came to mind...

cheers...psw