TILLMAN: HOW TO INCREASE OUTPUT LEVEL?

[wampcat1]

wow... someone has some issues sounds like...

Yup - with those that hinder any sort of advancement in this field by espousing an 'it's so simple' point of view. That view only serves to continue the long dry road of 'yet another TS/Dist+/FF with cap changes' we have been seeing. I mean, I have zero repect for Mike Fuller as a designer, but damn, at least he tried something NEW with the boost function on his fulldrive. He TRIED to progress.

I didn't mean offense to gus or anyone else either, but ummm... yep it pretty much is simple for the OP's purpose. If you are clipping, reduce the signal going in, i.e. volume control before the jfet.

Ummm... Simple does NOT mean that it is RIGHT.

Forget the added noise and sub-optimal S/N ratio aftermath of reducing the signal BEFORE the amplifier with a pot. (to avoid that you would probably say, 'just use a lower value pot' and neglect to mention the effect of that pot's loading of the previous stage, the fact that if it is too low it would actually INCREASE the noise of a JFET stage... but then, that wouldn't be a 'simple' answer would it?)

It just means it's simple. To quote Einstein 'Make everything as simple as possible, but not simpler.' - who, I'm going to go out on a limb here and say, was smarter than either of us, combined - unfortunately, you've made the answer 'simpler', and therefore WRONG.

Did you even understand my point? It could end up that your drain trim is a LOWER value than that in the schematic - and you have REDUCED the volume. ESPECIALLY if the OP couldn't find a J201. Or his J201 was actually a missorted J202?

What would you do then? Find another trim and hope for the best???

Seriously, what would be YOUR answer in that case? Be sure to keep it as simple as you say...

you are forgetting one important thing though, the same as alot of the "old timers" feel... not everyone wants to learn this stuff. They just want a working circuit, and if they are having a problem they just want it fixed. like some guitarists, they may have no desire to learn theory. believe it or not, there actually are a ton of guitar players who would smoke me or you on a good day and don't know the difference between a mixolidian and a penatonic blues. Or at least, they don't know it by name, but they know it when they hear it.

So we are supposed to aim for the lowest common denominator? We never challenge the existing myths? We never strive for anything new? To understand anything?

So you are saying that it is better to stagnate and get it done than to actually learn anything and progress?

Bullsh!t.

I may be alone in believing this, but THERE IS SO MUCH UNTAPPED POTENTIAL IN THIS FIELD - ESPECIALLY IN THE AREA OF DISTORTION.

But as long as there is a 'simple' answer, few will strive to find out the 'right' answer, and in the process discover something new.

The reason for all the byoc type sites is simple... it's profitable! It's profitable because there are ALOT more people that don't want the theory and details compared to the ones that DO want the theory and details.

I agree wholeheartedly. But in that case stick to another paint-by-numbers BBS for your questions and know that when someone takes the time to explain to you the process of CORRECTLY doing something, it is EXTREMELY rude to dismiss it outright, and only serves to shine a light on the 'dismissers' ignorance when they post the WRONG answer - no matter how simple it is.

Sorta like cooking... if i like to cook a good hamburger on the grill, i don't necessarily care about how my grill works, how heat is produced from it, or what part of the cow my hamburger comes from. I just want a hamburger.

No. It isn't even 'sorta' like cooking. Your analogy would be right on if all you had when you wanted that hamburger was a schematic and parts for the grill and a live, chewing cud, cow standing before you. Remember, the OP is building from scratch.

If I was building a gas grill from scratch (which I would NEVER do, by the way, I'm a charcoal man all the way) with nothing but a schematic, I would certainly want the CORRECT answer to any questions I had, not the SIMPLEST. Simply for self preservation reasons.

In this case someone found a schematic and was pretty much building something from scratch and wanted to know how to get 'more volume' WHILE KEEPING THE SAME OVERALL RESPONSE. You told them how to get more volume (maybe, if the Gods were in a good mood and let the OP pick a high Idss J201, OOPS! I used some math!!!) while most definitley screwing up every other variable in the process. To me - that doesn't answer the OP's questions, and certainly NOT CORRECTLY, no matter HOW SIMPLE your answer is.

However, if you had an answer to the simplest way to slaughter the cow, as long as the first step was actually killing it, I'd probably go with you on that...

But, unfortunately, building something using semiconductors from scratch, isn't as easy as slaughtering an animal (if step one is killing it, if it's not, it can be CONSIDERABLY more difficult. )

And again, nothing like a vested interest to solidify an opinion,

Regards,

Jay Doyle

whatever makes you happy jay... I don't have the extra time today to keep debating your point of view so we'll just have to agree to disagree.
vested interest or not, I have 10,000 members that would probably disagree with you.


bw

[puretube]

If former Marston linx won`t work, go: "Discrete Tubeless"

[Renegadrian]

Would you then suggest this 8-year-old to try different j201s??? Shall I find big differences amongst them???

I think it's time you need to open a textbook and do some math...

Or - build a Minibooster over at AMZ, about as much gain from one JFET stage as you can get, it will bias up right, and you'll never have to worry about it again... Unless you want something changed...

For the record, way way way back in the 'old site' archives are several posts by R.G. trying to help an ignorant me build a common source JFET stage from scratch. In the end, he quit answering my 'problem de jeur', as he put it, and just laid out the way to do it for me and anyone else reading.

Simply the best advice I have ever gotten from this board - this stuff ISN'T easy and it takes knowledge to get a result that you want.

However, if you just want to 'build and go' with good volume/tone, I think the Minibooster might be the route for you...

Regards,

Jay Doyle

Jay, I am following this discussion with a lot of interest, "listening to both bells" as we say here (is it the same there?)
I understand your point of view, still I am more on Brian side...
Let me also tell you that given as correct what you wrote, you didn't give the correct solution, as the question that started my topic is that without a multimeter and complicated math theories I'd like to get some more volume from a good working and already built and boxed FX - I don't want to learn math, I don't want to build another circuit. So I read carefully what you wrote but let me tell you I didn't find it useful as it exceeds my needs...While maybe Brian suggestion is not a rule of thumb but could surely be an easy thing to try to achieve some improvements...

[Dragonfly]

There are 2 sides to every story....

It comes down to :

A) Would you like THIS PARTICULAR Tillman Booster to have a bit more output of possibly perform better (with the J201 thats already in it) ?

OR....

B) Would you like to know how to make ANY Jfet booster perform properly, so that you don't run into this problem in the future.


For each question the answer MAY be different.

Certainly the way to solve Question B will also solve Question A.... BUT...The inverse is not necessarily true.

Throwing a trimmer on the Drain may make this particular J201 bias up better and give more voltage swing... might not...I didnt see the voltage readings (I didnt look either...they might be in the thread somewhere).

Adding a bypass cap on the source should increase the output....but it will introduce a greater amount of distortion...this might be desirable, might not.

The reality is that...and hindsight is flawless... if you want to have a Jfet based amplifier with more gain than the Tillman, then the BEST solution is to build a Jfet booster thats DESIGNED to have more output than the Tillman.

I digress....

personal opinion....and what I would do....if the guy is in a hurry to get this, then do what you need to do to make it work...toss a pot across the SOURCE, set the DRAIN bias at about 1/2 the supply voltage, measure the value and stick a resistor in there.

However...

If he's NOT in a hurry, either spend the time (which, BTW, is probably about the same amount of time that it takes to read this thread...all bickering included) to read App Notes or the Marston article so that you can modify it "properly"....or....build a different circuit that is "designed" to do what the person needs.

A few years back I came up with the Sparkle Boost...it works great, and most people like it. Knowing what I know NOW, I would have designed it differently.

[DougH]

vested interest or not, I have 10,000 members that would probably disagree with you.

50000000 Elvis Fans Can't Be Wrong. Maybe the OP should join your forum and/or byoc where he can get fast-food electronics then. Would you like fries with that?





"For every complex problem there is a simple, easy to understand, wrong answer."

[JDoyle]

whatever makes you happy jay... I don't have the extra time today to keep debating your point of view so we'll just have to agree to disagree.
vested interest or not, I have 10,000 members that would probably disagree with you.


bw

Typical. Come in and criticize a correct answer for being too complex, though right, and then when the facts come out, duck and run...

But there is no debate: your answer was wrong.

Also, you should give your simple answers to your members who expect that type of response, at your own site.

The fact that this site still exists 10 years on, and didn't fade out after all of the simple answers were written, means that as a whole, this site is striving for the RIGHT answer, not the most simple.

10,000? Great for you! Good job. I am sure your book has helped many find the tone they were looking for, kudos.

Although that is a mighty depressing number to those of us who actually want to see PROGRESS. How many of your members could have come up with something new had they actually worked through the equations? (do you even provide them?) We'll never know because they were satisfied with your simple, albeit in this case, wrong, answer.

Regards,

Jay Doyle

[frequencycentral]

This thread makes me afraid to post a question unless I already know the answer.

[Renegadrian]

quote author=Dragonfly
A) Would you like THIS PARTICULAR Tillman Booster to have a bit more output of possibly perform better (with the J201 thats already in it) ?
OR....
B) Would you like to know how to make ANY Jfet booster perform properly, so that you don't run into this problem in the future.
Definitely A

Throwing a trimmer on the Drain may make this particular J201 bias up better and give more voltage swing... might not...I didnt see the voltage readings (I didnt look either...they might be in the thread somewhere).
I could try with a trimmer...You won't find any readings on this topic as I don't go by readings (I haven't got a multimeter, go figure...)

Adding a bypass cap on the source should increase the output....but it will introduce a greater amount of distortion...this might be desirable, might not.
No, it's not what I look for...

The reality is that...and hindsight is flawless... if you want to have a Jfet based amplifier with more gain than the Tillman, then the BEST solution is to build a Jfet booster thats DESIGNED to have more output than the Tillman.
That can surely be a obvious truth...but maybe my friend won't like another circuit as the Tillman, I made him try various boosters, Sparkle Drive included

personal opinion....and what I would do....if the guy is in a hurry to get this, then do what you need to do to make it work...toss a pot across the SOURCE, set the DRAIN bias at about 1/2 the supply voltage, measure the value and stick a resistor in there.
I could try it easily

If he's NOT in a hurry, either spend the time (which, BTW, is probably about the same amount of time that it takes to read this thread...all bickering included) to read App Notes or the Marston article so that you can modify it "properly"....or....build a different circuit that is "designed" to do what the person needs.
No please, I know that those files are important but I don't want to learn those technical stuff, at least for now...
Build a different circuit you say...well,that could be done, but maybe he won't like its characteristics...

A few years back I came up with the Sparkle Boost...it works great, and most people like it. Knowing what I know NOW, I would have designed it differently.
ME!!! I like it very much!!!

Thanks for your reply, Andy! 

[puretube]

...next question: ?

[Dragonfly]

It's interesting to note that while everyone is trying to "prove their point", I don't think anyone has bothered to ask Renegadrian....

"Do you want the "easy way", or the "right way" to solve your problem.

People are making assumptions left and right, and really its of no help to anyone. The info is all contained earlier in this thread... whats left now is just peoples "ego's" talking.

Seriously...Jay...for HIS clients, Brians way works fine. Brian knows his customers FAR BETTER than we could ever assume to. And Brian, for the people that want to LEARN the technical side of things in an effort to grow in the hobby, then Jay KNOWS what he's talking about.

What it comes down to is "Does Renegadrian want to solve the problem, or does he want to LEARN HOW to solve the problem?"

Plenty of people are just fine in knowing that if the shove Bosch Platinum Spark Plugs in their car engine they'll probably increase their engine's efficiency by a bit. Others want to know that, if they take the time to find the optimal spark plug "gap" for their particular automobile, then they increase their efficiency even more.

Two different types of people that "occasionally" have some overlap between them.

My $.02...

errr, wait...I think I'm up to $.06 in this thread so far.

[JDoyle]

Let me also tell you that given as correct what you wrote, you didn't give the correct solution, as the question that started my topic is that without a multimeter and complicated math theories I'd like to get some more volume from a good working and already built and boxed FX - I don't want to learn math, I don't want to build another circuit. So I read carefully what you wrote but let me tell you I didn't find it useful as it exceeds my needs...While maybe Brian suggestion is not a rule of thumb but could surely be an easy thing to try to achieve some improvements...

And I was trying to write, without explictly saying it, that you were wanting something for nothing.

You were basically asking people to help you learn to fish without you having a fishing rod, hook, line, or bait, or even the desire to get them.

Yet you still expected to learn how to fish.

I basically said, well you actually DO need those things, and Brian's answer was: no you don't, just toss a stick of dynamite into the lake and you will get just what you want.

Problem being, if you come back and want to fish JUST FOR TROUT, you will have no idea how and only by happenstance will one float to the surface using Brian's method.

I used to love answering beginner questions because it seemed there were so many people wanting to LEARN. And then, from that, would come new ideas.

Now? Very very few are like that. Most of them want something for nothing and to have someone else do the work for them! As if all of FX design is about cap changes and diode swaps...

Thanks for proving to me that I need to avoid beginner questions as my answers are always too complex and therefore dismissed outright.

You absolutely need to buy a multimeter. I own four (two cheapies and two nice ones) and often use them all at once.

Regards,

Jay Doyle

[Renegadrian]

...

My .02...

errr, wait...I think I'm up to .06 in this thread so far.

[DougH]

What it comes down to is "Does Renegadrian want to solve the problem, or does he want to LEARN HOW to solve the problem?"

Given that he doesn't even have a DVM I'd guess he's looking for the quick fix.

But the lie behind all of this is that there is a quick fix. There isn't.

[Renegadrian]

I used to love answering beginner questions because it seemed there were so many people wanting to LEARN. And then, from that, would come new ideas.
.......................................
Thanks for proving to me that I need to avoid beginner questions as my answers are always too complex and therefore dismissed outright.

Jay Doyle

Well,  Jay, it seems that what you say in the second sentence is the opposite from the first...So as long as there are people wnating to learn, your contribution is important - I am telling you that (for now) I just want to walk the easy road (if there's one)...Altough I won't follow your kind suggestions, I thank you so much. 

[Dragonfly]

quote author=Dragonfly
A) Would you like THIS PARTICULAR Tillman Booster to have a bit more output of possibly perform better (with the J201 thats already in it) ?
OR....
B) Would you like to know how to make ANY Jfet booster perform properly, so that you don't run into this problem in the future.
Definitely A

OK...NOW we're getting somewhere !   

Throwing a trimmer on the Drain may make this particular J201 bias up better and give more voltage swing... might not...I didnt see the voltage readings (I didnt look either...they might be in the thread somewhere).
I could try with a trimmer...You won't find any readings on this topic as I don't go by readings (I haven't got a multimeter, go figure...)

First suggestion...buy a multi-meter...you're around here enough to justify one, and even a cheap one will help out. OK...now thats cleared up...ultimately your EARS are the best device you have for telling you when something is "right" top you.

Adding a bypass cap on the source should increase the output....but it will introduce a greater amount of distortion...this might be desirable, might not.
No, it's not what I look for...

The reality is that...and hindsight is flawless... if you want to have a Jfet based amplifier with more gain than the Tillman, then the BEST solution is to build a Jfet booster thats DESIGNED to have more output than the Tillman.
That can surely be a obvious truth...but maybe my friend won't like another circuit as the Tillman, I made him try various boosters, Sparkle Drive included

In a way you're trying to fit a "square peg" into a "round hole. Why, you ask ? Well...here's the reason...My guess is that a BIG part of why he LIKES the Tillman is that the Jfet isn't working too hard...its designed to put out only about 3dB's of gain. Once you start trying to get more gain from it, you push the Jfet harder, which makes the Jfet "sound" different

personal opinion....and what I would do....if the guy is in a hurry to get this, then do what you need to do to make it work...toss a pot across the SOURCE, set the DRAIN bias at about 1/2 the supply voltage, measure the value and stick a resistor in there.
I could try it easily

If he's NOT in a hurry, either spend the time (which, BTW, is probably about the same amount of time that it takes to read this thread...all bickering included) to read App Notes or the Marston article so that you can modify it "properly"....or....build a different circuit that is "designed" to do what the person needs.
No please, I know that those files are important but I don't want to learn those technical stuff, at least for now...
Build a different circuit you say...well,that could be done, but maybe he won't like its characteristics...

A few years back I came up with the Sparkle Boost...it works great, and most people like it. Knowing what I know NOW, I would have designed it differently.
ME!!! I like it very much!!!

Thanks for your reply, Andy! 

Now get to work ! You have the answers in this thread. But do yourself a favor... you have a "curious mind"...you're smart and seem to enjoy learning...SAVE those files that have been suggested, because it's very likely that you'll WANT to learn this stuff ...and probably "sooner" than "later".  Best of luck

[JDoyle]

What it comes down to is "Does Renegadrian want to solve the problem, or does he want to LEARN HOW to solve the problem?"

I completely understand your point, and do agree. However, I think you are missing the bit in the original post (admittedly, I ignored the whole sans-math/theory bit) that said:

"He asked me if it is possible to have a little more output without changing its tonal characteristics" emphasis added by me

Brian's answer may give more output, but it sure as hell will change the tonal characteristics, for EVERY JFET USED in that circuit.

In hindsight, I should have said:

"Yeah, follow it with a non-inverting opamp stage with an adjustable gain."

But I didn't.

Actually, building another one and putting them in series would probably make a quite nice circuit that went from the boost his customer wants to a distortion he doesn't even know he wants!

[Dragonfly]

What it comes down to is "Does Renegadrian want to solve the problem, or does he want to LEARN HOW to solve the problem?"

Given that he doesn't even have a DVM I'd guess he's looking for the quick fix.

But the lie behind all of this is that there is a quick fix. There isn't.

I don't know Doug... "quick fix" to me is different than a "permanent fix"...kind of like the guy who puts duct tape around his radiator hose so that he can get back and forth to work a little while longer, instead of replacing the holey radiator hose.

[DougH]

But there is no quick fix that will give him more gain without changing the sound of it. That's the point.

[puretube]

FETs don`t like me...

FETs - at least JFETs - don't like anyone. They're like precocious but intractibly ill-tempered children. They not only have great promise, but they also have quirks and the quirks vary so you can't easily compensate for them.

[Dragonfly]

What it comes down to is "Does Renegadrian want to solve the problem, or does he want to LEARN HOW to solve the problem?"

I completely understand your point, and do agree. However, I think you are missing the bit in the original post (admittedly, I ignored the whole sans-math/theory bit) that said:

"He asked me if it is possible to have a little more output without changing its tonal characteristics" emphasis added by me

Brian's answer may give more output, but it sure as hell will change the tonal characteristics, for EVERY JFET USED in that circuit.

In hindsight, I should have said:

"Yeah, follow it with a non-inverting opamp stage with an adjustable gain."

But I didn't.

Actually, building another one and putting them in series would probably make a quite nice circuit that went from the boost his customer wants to a distortion he doesn't even know he wants!

Yep... I mentioned that in a post above...what the guy seems to like about the Tillman is that the jfet isn't "driven hard". Reality is that just about anything you do to increase the output is going to drive the jfet harder, thus changing the sound.

I guess he could try putting a couple Tillmans in series, but even that is gonna change the sound.

Best thing...and not necessarily what Renegadrian wants to do...is design a jfet circuit thats similar to the Tillman that boosts somewhere from 6-9dBs, that way the jfet isn't working itself into overload, but has a bit more output.. (Still gonna sound a little different...just not AS different as driving the jfet hard). Of course that either involves "math", a "breadboard", or "both".