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Help With My Sustainer


Joghurtgumi

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"efficiency" relates to the effectiveness of the driver, not the current draw on the battery. The limits of a battery can itself serve as an AGC. The more efficient the driver is at driving all the strings and frequencies required, the less "power" is required and usually this leads to less power consumption.

Adding AGC will typically save power...unless you use a complex compression circuit which will draw even more. Use a powerful amp or needing it means your driver lacks the efficiency and you have to go multi-coil like FF and others to reduce EMI so this added power can be harnessed. More power, more battery drain generally and more problems...or a requireement for separate mains derived power to get the headroom and power for the circuit and any reasonable battery life. If that creates the effect after and fits the individuals criteria, then it's valid.

Of course, most DIY sustainers also only work when the sustainer is in use while a commercial system uses power to simply work at all...when the battery dies, the whole guitar dies. As this is a specialized effect, the amount of use is less and so my tele has had the same battery in it for months and still going strong. The "ultimate' sustainer is a myth...it all depends upon the criteria one places on all aspects of the system and how you want it to sound and respond.

Comparisons with sustainiac are completely irrelevant really. Something like my design is a completely different beast and approach. The designed a bi-lateral driver and compensations circuits for it and optimized it to work as both a driver or an active pickup. There is no 'ultimate' spec other than that which works within the criteria of the individual. Setting the criteria is the only way to judge success and everyone's ideas are different beyond the basic sustaining of all strings. Battery life may not be a factor at all.

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No I don't recall any tests on current draw.

That's a shame - I guess nobody is as tight as me wrt shelling out for 9V batteries! lol.

Col, one of the guys over here, has come up with an agc that utilizes a feedforward sidechain.

Using a feedforward compression variant makes sense - particularly with something like a sustainer, because such an arrangement monitors the input (vs the output of the circuit of a feedback compressor) - and it's the input from the string that needs to monitored wrt how the string levels are doing. As it goes, feedforward is the preferred technique used with a lot of 'dynamic range' handling audio devices nowadays, I found a reasonable explanation & diagram here....

http://en.wikipedia.org/wiki/Dynamic_range_compression (listed under the 'design' heading)

Ok, so in the absence of any documented driver coil efficiency data, it looks like I have some experimenting ahead :D

(after making a few pickups over the years, I eventually got my backside in gear built myself a gaussmeter last night, so will be able to take some measurements wrt RMS current into the driver coil vs gauss output presented at the string).

I want to be sure that I've the most efficient coil before moving on to the associated circuit.

Edited by Wasp
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sooo guys, i have a working amp(thanks for the tips on that ), the driver coil is wound, potted, the magnet is only on one side of the coil and not inside it(therefore the coil is around only one pole of the magnet), i have connected it all up, but no sustain. what can be causing this? can it be the trim pot? does it matter wich side of the strings the driver is on? (i haven't installed it on the guitar, only seperately and held it above the strings) is there anything else that might be causing this? please, i'm soooo close to getting it to work

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sooo guys, i have a working amp(thanks for the tips on that ), the driver coil is wound, potted, the magnet is only on one side of the coil and not inside it(therefore the coil is around only one pole of the magnet), i have connected it all up, but no sustain. what can be causing this? can it be the trim pot? does it matter wich side of the strings the driver is on? (i haven't installed it on the guitar, only seperately and held it above the strings) is there anything else that might be causing this? please, i'm soooo close to getting it to work

I'm glad that your glass is halve full, that's the spirit. :D

Some questions:

But inside the coil there is an iron core, right?

You didn't burn out the driver coil? Does it still measure 8 ohms?

There is no wrong side for the driver, from above works even better. (Sustain more balanced from open string up to highest fretting positions.)

Do you have enough gain? Does your guitar overdrive the lm386?

FF

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I'm glad that your glass is halve full, that's the spirit. :D

Some questions:

But inside the coil there is an iron core, right?

You didn't burn out the driver coil? Does it still measure 8 ohms?

There is no wrong side for the driver, from above works even better. (Sustain more balanced from open string up to highest fretting positions.)

Do you have enough gain? Does your guitar overdrive the lm386?

FF

Thanks for the quick response.

the answes to your questions:

Well, there is a sort of iron core. For this driver i used what was left of an old pickup bobbin, wich has 6 iron poles going halfway through the bobbin, and having a bar magnet in the other half like so:

http://www.myimg.de/?img=IMG20101129001e05a4.jpg

http://www.myimg.de/?img=IMG20101129002fef1f.jpg

http://www.myimg.de/?img=IMG201011290035de20.jpg

http://www.myimg.de/?img=IMG201011290042ddbd.jpg

http://www.myimg.de/?img=IMG201011290054fa31.jpg

http://www.myimg.de/?img=IMG201011290064bac4.jpg

the wire is only wrapped around the side with the poles, so it's only around a single magnetic pole. I have a simple jack plug connected to it for the time of the testing.

The coil still measures a little over 8 ohms (8.3 to be more-or-less exact)

I don't understand your last question. Why does the LM386 have to be overdriven?, how can i check if it is? if it isn't, how can i overdrive it, or get enough gain?

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"Col, one of the guys over here, has come up with an agc that utilizes a feedforward sidechain. The agc regulates the signal level right at the guitar pickup. This way the swing amplitude of the string is being controlled. This will save energy. How to save more energy? Like you already said, more windings on the driver coil (it might well be that the sustainiac's spec is the optimal performance). It depends on whether the agc can deal with the behaviour in the high freqencies region, but it certainly would make your system more energy efficient for low frequencies.

Depending on how 'quiet' your driver and pickup are (humbucking?/shielding?) you can increase the gain in the pickup-amp-driver-string-pickup positive feedback loop and limit the swing amplitude even more. "

hey,can you draw me a very simple schematic of what agc appear to be? (not something from col's circuit design,but some simple implication of that post) it is enought to add some filter or ldr (with another stage of amp) from the output to the input?

thnx.

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Well, there is a sort of iron core. For this driver i used what was left of an old pickup bobbin, wich has 6 iron poles going halfway through the bobbin, and having a bar magnet in the other half like so:

'---'

The coil still measures a little over 8 ohms (8.3 to be more-or-less exact)

This driver was approved by the Habsburg dynasty lol

looks nice, i see no reason why this driver shouldn't work.

I don't understand your last question. Why does the LM386 have to be overdriven?, how can i check if it is? if it isn't, how can i overdrive it, or get enough gain?

I thought maybe you tested the lm386 with a a little loudspeaker.

Never mind, can you tell what you got between lm386' pinout 1 & 8? Is there some gain pot (or resistor) like in the ruby?

FF

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Ok, so in the absence of any documented driver coil efficiency data, it looks like I have some experimenting ahead :D

(after making a few pickups over the years, I eventually got my backside in gear built myself a gaussmeter last night, so will be able to take some measurements wrt RMS current into the driver coil vs gauss output presented at the string).

I want to be sure that I've the most efficient coil before moving on to the associated circuit.

Yes, but most efficient only according to some arbitrary criterion. You have to settle on a frequency range. Maximizing gauss output at 2 kHz or at 500 Hz ?

FF

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Ok, so in the absence of any documented driver coil efficiency data, it looks like I have some experimenting ahead :D

(after making a few pickups over the years, I eventually got my backside in gear built myself a gaussmeter last night, so will be able to take some measurements wrt RMS current into the driver coil vs gauss output presented at the string).

I want to be sure that I've the most efficient coil before moving on to the associated circuit.

Yes, but most efficient only according to some arbitrary criterion. You have to settle on a frequency range. Maximizing gauss output at 2 kHz or at 500 Hz ?

FF

Really it's all about balance. You need a driver that will drive all the strings evenly and "efficiently"...this generally allows you to save on "power" if that is a major concern for your 'criteria'...clearly it isn't for everyone. My tele has had the same battery for months now, the sustainer in a DIY version unlike commercial versions only draws power when the sustainer is on. Other options include rechargeable 9volt batteries...

If you need a lot of power to drive the strings, then you may expect a fair few EMI problems. This kind of thing may be addressed with multi coil drivers like FF's or the comerical systems. If you have been looking at the commercial systems a large component is frequency dependent phase compensation. The DIY designs I have pioneered work towards drivers that do not require that complexity of circuit.

I have the feeling that much of the AGC and other suggestions of performance are based on supposition...it really depends a lot on what kind of performance you want. Something like Col's is extremely controlled and even where as mine are far more dynamic...but both produce sustain and harmonics on all strings. For me, too much AGC tames things down far too much.

The original idea for the DIY project, encouraged by LoveKraft, was to concentrate on the driver design to avoid circuit complexity and to that end several designs were successful. One might also want to understand that the battery itself is a "limit" on the circuit and as such an AGC in itself...along with small amps...and should be considered an integral part of the circuitry and not simply a power supply.

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Yes, but most efficient only according to some arbitrary criterion. You have to settle on a frequency range. Maximizing gauss output at 2 kHz or at 500 Hz ?

The 'criterion' is solid sustain (for me at least) across the fretboard for the *least* battery consumption - so, while you may wish to call such related 'efficiency critereon' as arbitary ..I just interpret it as meaning the lowest battery running costs (or being a cheapskate for short) :D

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Yes, but most efficient only according to some arbitrary criterion. You have to settle on a frequency range. Maximizing gauss output at 2 kHz or at 500 Hz ?

The 'criterion' is solid sustain (for me at least) across the fretboard for the *least* battery consumption - so, while you may wish to call such related 'efficiency critereon' as arbitary ..I just interpret it as meaning the lowest battery running costs (or being a cheapskate for short) :D

So you're going to work by ear. Build a driver coil do a soundcheck and if the behaviour for the high notes is still acceptable take thicker wire and use more turns of windings. You don't know beforehand how much highs you can afford to lose. Depends on the guitar, guitar pickup, applied eq , all-pass filters as well. Only afterwards you can measure what it means for the gauss output per frequency.

But it's interesting to see how close you get towards the 256 turns of the sustainiac.

Cheers

FF

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You guys do realize that the sustainiac river is a completely different animal? It is a bi-lateral dual coil, broad laminated core pair that functions as an active neck pickup as well. Each coil is less than half the length of the standard pickup or single coil driver. FF uses a full dual coil driver where as the basic and tested DIY formula is again different and designed to avoid phase cancellation circuitry intrinsic to the sustainiac and other commercial systems.

Basically the "work" to produce a formula for the most basic design that can do the job with the lowest power, mainly to avoid noise and EMI problems, is what is presented and can be heard to produce harmonics and even polyphonic sustain and harmonics throughout the entire range of the instrument.

If you change things, such as to a thicker wire, you will require more turns and radically alter the resonance and response characteristics and slowing down the alternating EM action...so it will have phase problems and have to be corrected with circuitry. If you use big amps with unlimited power, then AGC will be more crucial as the battery is no longer a limiting factor as to how far the thing will go...these are all intrinsic elements of the basic design.

Also remember that you have to factor in the mass of each string into the calculations...the low strings are easier to drive because they are slower and have a lot of metal to work with...high strings fast and hardly any by comparison. The driver needs to accentuate those frequencies and perhaps to the circuit biased to create a good balance...

In the end there is no "ultimate" driver or solution, it's all a balance between response desired and criteria that few are prepared to set out a the outset. Your minimal criteria would it seems already have been met surely?

You are running a power amp from a battery, there is no getting around the fact that you are going to be drawing a lot of power from a small power source...you will never get the kind of draw that you might expect say from a fuzz box that is only modifying a signal, that amps clearly state that it alone is drawing perhaps 1/2 a watt of power..plus powering any other gadgets, filters, AGC's and such on there. FF has an entire stompbox compressor running in that thing, so it alone would kill a battery reasonably quickly before we even get to a power stage. Battery power is clearly not a criteria for FF and others and is designed with this in mind, fair enough too. Everyone has different criteria and many have alternate designs that are not comparable. The best one can do is to listen to the results and balance them with your own criteria.

It's not that other formulas can't work...but hours of testing and independent confirmation over some years has indicated for the simple design (and that design alone) there is an optimum formula that provides the capacity for efficient driving of all strings with very low and basic amplification.

There is maths to work it out as FF and others have quoted...but as yet no one has really run the figures (if even possible without a given criteria) to find that balance or compared apples with apples...that sustainiac uses windings on a unique and novel dual coil design that works in two functions has no bearing on what might be optimal for another completely different design, I would have thought was obvious. It is should in no way be seen to be some kind of "gold standard" and the windings are only relevant in conjunction with the core size and length (less than half of the DIY model or a pickup) and how it is wired (I assume parallel, i forget for the sustainiac) and the wire gauge specified...

If you are generating a lot of heat out of an LM386 that indicates you are wasting a lot of power and having to drive it far too hard to get the effect...

Of course the pickup signal going in radically changes things as FF points out also, so many variable that there is no way to determine some kind of "universal rule" anymore than one can say there is an "ultimate' pickup...

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hey,can you draw me a very simple schematic of what agc appear to be? (not something from col's circuit design,but some simple implication of that post) it is enought to add some filter or ldr (with another stage of amp) from the output to the input?

Hey man without quote button, :D

The whole agc thing is nothing more than some kind of compressor/limiter that has to be transplanted into your sustainer circuitry. So best to take a look first at the tangerine peeler which has feedforward as well as a feedback sidechain.

Filters, no! Ldrs are used in compressors like the flatline compressor (not feedforward). So ldrs yes if you know how to do it!

I can't offer anything from col's circuit design. Even if I had it, there's ownership rights that have to be respected. :aureole:

Cheers

FF

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I did test it with a little loudspeaker, and it was a little distorted at max volume. Is distortion what i'm supposed to be aiming for, or am i misusnderstanding what overdrive means?

pinout 1 and 8 do have a pot between them

i built the amp according to this schematic:

4107858712_4483e71933_o.jpg

No, you don't need distortion, you need sufficient gain.

I don't see what's the problem.

You have an amp that works and should have enough gain. The driver seems to be all right.

You don't notice anything when you switch on/off your sustainer?

Do you manage to get some sustain (even very weak) or is there no sustain at all? The driver coil above the 12th fret should sustain your open strings in fundamental mode. If you move the driver towards your guitar pickup do you get screaming feedback, squeal? If you move your driver towards your guitar pickup you should get noise out of your guitar amp, period!

Cheers

FF

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When i turn the sustainer on, there's a barely audible pop, but i don't think that's what's causing it.

I didn't notice any sustain at all, if there was any, it was too litle to be noticeable, even with the coil at the 12th fret.

At least one thing seems to fit: i did get the screaming feedback when i held the driver over the pickups.

Another interesting thing(even though i didn't manage to reproduce it just now):

about a week ago i was trying to get it to work as usual, and i accidentally put my thumb across all 3 connections of the gain pot, and i somehow started hearing some oreign radio station from my guitar amp O.o (probably croatian, since i live quite close to the border in Hungary)

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When i turn the sustainer on, there's a barely audible pop, but i don't think that's what's causing it.

I didn't notice any sustain at all, if there was any, it was too litle to be noticeable, even with the coil at the 12th fret.

At least one thing seems to fit: i did get the screaming feedback when i held the driver over the pickups.

Another interesting thing(even though i didn't manage to reproduce it just now):

about a week ago i was trying to get it to work as usual, and i accidentally put my thumb across all 3 connections of the gain pot, and i somehow started hearing some oreign radio station from my guitar amp O.o (probably croatian, since i live quite close to the border in Hungary)

ok Jogi,

One thing you could do is reverse the leads of the driver (reverse the phase - but I doubt an inefficient driver in harmonics mode is the problem)

You probably get radio Zagreb because of the high gain of the lm386, some 200 x.

To me it makes most sense to test the fet Q1 now. If you don't have a scope disconnect the volume pot from pinout 2 and connect it up to your guitar amp. So you need a 2 wire cable to your amp, ground and signal (= taper of volume pot). The fet should amplify the signal by some 10 - 20 times. If you compare fet inserted with guitar straight to amp there should be a noticeable difference in volume.

I also see 2 ways to improve stability:

A. add a zobel network at pinout 5.

B. swap the inputs of the 386, pinout 3 to signal, pinout 2 to ground.

FF

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Just wonderin' if there an agreed decent circuit for a DIY Sustainer out there?

Everwhere I look on the net, is littered with those going on about how to make a driver (from things like cut up CD cases & old PVA) ...but what about the circuit?

Is there a tutorial that 'completes the circle' so to speak...cos a driver ain't much use without a decent circuit.

Scoop 'n Daddy.

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Most of the debate is about this-or-that circuit, and I think that at least a degree of the issue is factoring out variables which affect the suitability or effectiveness of X circuit. Pretty much like banging a haulin' V8 through a mismatched box or drivetrain and wondering why the system as a whole doesn't work. Sustainers aren't my field though really.

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Pretty much like banging a haulin' V8 through a mismatched box or drivetrain and wondering why the system as a whole doesn't work. Sustainers aren't my field though really.

But - using your analogy - there are tutorials aplenty wrt the drivetrain (driver) ...in fact I'm fingering my CD collection to see which one must die & yield its case for a 'distressed' looking bobbin ...just scant info about the engine to marry it up with....isn't there one that folks can agree on?

Who are da' main eggheads wrt sustainer circuits? Surely they can bash a sustainer schem out to marry up with the driver tutorial?

It feels like McCartney is still trying to find Lennon here .....goo goo goo jooob.

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Who are da' main eggheads wrt sustainer circuits? Surely they can bash a sustainer schem out to marry up with the driver tutorial?

It feels like McCartney is still trying to find Lennon here .....goo goo goo jooob.

Some of the eggheads could use some feedback by you guys.

Build a driver together with a bare bones sustainer amp (no agc) as suggested by psw. And if you're not entirely happy with the performance report it back in the forum. Don't expect a free ride.

If there's enough demand for a more sophisticated sustainer, who knows what will happen. I could come up with something or perhaps col could repost his design.

cheers

FF

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The net is littered with all manner of "How to" tutorials.....the majority of them cover off all the aspects needed to achieve the intended purpose.

So, when looking up "Sustainer Tutorial" .....I guess most would expect a similar format, ie...

1. Here's how you make the driver.

2. Here's how you make the circuit.

Tutorial ends.

Don't expect a free ride.

Actually isn't that the purpose of an internet tutorial? ie someone else has gone through the nausea & pulled together all the various elements - it's a fair exchange - they get the kudos of saying "Here's how you do it, aren't I clever", & everyone else gets a free ride & feign "yes, you're extremely clever"

...so sure, yep, it's a fair cop - I'm paying nada & therefore can't demand anything, but in this rich internet age where we're all spoilt with the likes of instructables, most would have come to expect the full picture, but I'm now getting a vibe that anyone wanting to build a DIY sustainer, has to interpret the word tutorial as meaning half a tutorial......and then spend a good amount of time arguing the toss which circuit to go with to complete the other half of the equation.

Build a driver together with a bare bones sustainer amp (no agc) as suggested by psw.

Does anyone have some general linkage to his bare bones sustainer amp (no agc) ...??? (I promise to say it's clever)

Scoop 'n Daddy.

Edited by big_boleros
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There have been multiple threads contaminated by this "circuit" thing but few have offered anything practical. I've given all the mods required, although they are available in the data sheet, to keep an LM386 happy at high power including the zobel network and cap between pins 1&8 and for biasing the circuit for better high string response and balance by using a lower output cap...and there have been a few other circuits offered as well. The internet is full of non-loading guitar buffers and preamps to feed such a power amplifier.

Perhaps Mr Bolero would like to join his geographical cousin in debating the issue...

MajorWoody

There is no "one way" or best way to do this, I have shown many successful variations and ideas that could run of low powered generic circuits like those presented.

The 'sustainer project' was not ever intended to be some 'tutorial' but a general thread on the kinds of things I was working on and to encourage ideas...not tell anyone how it was to be done. However, I was asked to present something that could work with simple amplification and possible for DIY and presented those ideas, Galaga Mike took it upon himself to show his implementation of those ideas.

I have shown a tutorial on how to make a driver to this design, full step by step photos...that is the only tutorial presented by me of that nature. Perhaps you might consider taking the issues you have with tutorials up with him, or perhaps other prominent members here who have been successful and have yet to offer similar in terms of circuits or drivers or installations or sound clips in order to compare.

But then, there is no obligation and if people are not capable of working these things out without having things presented in 'storybook form' then perhaps they don't have the gumption to complete the project successfully. There are so many variables that some personal ingenuity is required...looking up a suitable preamp and data sheet should be the least of the problems. This was never presented as a basic project for novices.

Every time someone does present things, such as col's circuit or mine or Gmikes or any other...some clown comes along in short order with the EXACT same complaints and criticisms such as "he is piss" as with MajorWoody who spammed the other forum the day after this thread was spammed and offensive remarks deleted. That thread does contain one version of cols 'pre-amp' for instance and all the mods and implementations of his and my work are presented over the years.

The Driver is the key, making a driver that will effectively drive all the strings without phase compensation and complex circuit designs is the purpose of this simple design suitable for DIY construction. You might want to look into such areas but a low powered amp running from a battery is itself an "automatic gain control" in that the gain is intrinsically 'limited' and while all this may seem to 'simple' often the better ideas are.

As for wanting to be seen as "clever"...I think you misunderstand the psychology or projecting your own. I sought to share the things I was working on and there was interest in it, now it seems to only attract abuse. I don't need the approval of others, people can take or leave this project...and my time attempting to help those that may need it is only out of generosity on my part.

These kinds of posts offer nothing, there's not even a hint that the project is being attempted, just more 'noise'...much of it from people professing to know better but fail to come up with the most basic of amplifier solutions, only complaints.

Most of this leads to misunderstandings over very basic ideas and what would be "ultimate". Power consumption...mine still works and the battery last changed in february! Criteria is lambasted but it is so important to judge the success of anything on it's own terms or in relation to others. My criteria for my own projects are wide ranging and extensive...FF has different criteria...col had yet other criteria....it simply can not be compared on the same level. One is not better than another, each is simply a different solution.

For me aspects like battery power and the non-reliance on a battery for the guitar to work, low mods (meaning tiny circuits and driver solutions), ease of construction, dynamic performance, neck pickup and passive switching solutions...all these and others continue to inform the solution that I came up with. If battery power isn't important, there are plenty of suitable power-amp solutions and you can go to town with compressors and limiters, similarly if you don't mind digging enough room into your guitar to install it...same with the neck pickup, perhaps that is not important and that has been a trend generally.

In the end, dozens of these things have been built successfully and examples of them working well on all strings and frets and modes are available to hear. Want a super controlled even sustain, try something like col's approach...what a more dynamic effect, perhaps more like mine...but what point is there to log on for the sole purpose of asking over and over about circuits and tutorials and suggesting that there is some obligation on anyone to hand feed the internet or that the motivation be assumed to be for self gratification. If that was want it was about, then surely i or others would do what Gmike did and do a tutorial for you...or if you have a better idea might contribute something with your first posts instead of regurgitating years of the same under various names...just a thought

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Most of the debate is about this-or-that circuit, and I think that at least a degree of the issue is factoring out variables which affect the suitability or effectiveness of X circuit.

A debate is only possible between open-minded people who share an interest in improving a product.

Telling other people not to look any further because I build this or that product is not debating. It's marketing, promoting your own stuff.

Down with the marketing! Let us debate.

Why would anyone who is interested in building sustainers not prefer circuitry designed specifically for sustainers over a general purpose mini power amp?

Pretty much like banging a haulin' V8 through a mismatched box or drivetrain and wondering why the system as a whole doesn't work.

Yes indeed, those wicked Fetzer-Rubys.

cheers

FF

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