simple 2 knob hi gain distortion..collaboration?

[deadastronaut]

just out of curiosity, isn't the gate isolated from the drain and source? in other words, doesn't it just use capacitance to pinch off the current? do you really NEED an input cap, or is it just good practice?

hmmmmm..not sure on that man...

ive not seen many circuits without some input cap and resistor setup..

if you look at the big daddy it just has a 4m7 resistor to ground from input (G)...it does have a 15k from the 9v (D)though!..

also it has a 2.2k and a 2.2uf going to ground from the source.

[deadastronaut]

deadastronaut,

Very good hand-grinder-jigsaw-drill-metalworshop sounding (and playing, indeed !) +

I was waiting for the decay : it cames in your second sample, and is unfortunately bad, blunt, abrupt... I am not surprised : I had the same rotten decay with my LM386 trials, but without the good sounding you achieved ! So I didn't go further. Electron Tornado seems to draw the same conclusion concerning the decay's quality.

I think that the LM386 is probably unable to de-saturate gently, even if you put truckloads of gain at its input. So maybe something can be done at the output, then... As the LM386 is a power amp, do you tested it with a louspeaker directly connected, to see if the decay changes ?

A+!

so you think it may be an output problem then?..i havent tried it with just a speaker but i have just got an old radio that im ripping apart
i will give it a go and see if there is any difference..hmmmm interesting.


what i may do is actually use another breadboard and do the big daddy and see if that has the same fizz splutter on the dying notes too...
as long as i can still achieve hi tight gain still.........

anyone had success with big daddy and no fizz.....hmmmm..

[culturejam]

anyone had success with big daddy and no fizz.....hmmmm..

I built a Big Daddy a long time ago, and no fizz. I've also mucked around with the 386 quite a bit and never got the fizz decay. But I have gotten it with a LM301 in a simple dirt circuit. I was too lazy to really figure out the issue, so I just tacked on a single clipping diode to ground, and that got rid of it.

Also, I've noticed that some LM386s are just bunk and sound bad when used as a distortion generator. If you haven't already, I'd suggest trying a few different 386 ICs to see if any of them sound better than what you have in there now.

[deadastronaut]

anyone had success with big daddy and no fizz.....hmmmm..

I built a Big Daddy a long time ago, and no fizz. I've also mucked around with the 386 quite a bit and never got the fizz decay. But I have gotten it with a LM301 in a simple dirt circuit. I was too lazy to really figure out the issue, so I just tacked on a single clipping diode to ground, and that got rid of it.

Also, I've noticed that some LM386s are just bunk and sound bad when used as a distortion generator. If you haven't already, I'd suggest trying a few different 386 ICs to see if any of them sound better than what you have in there now.

cheers . when you say you just tacked on a single clipping diode was that from the out put to ground?....

as for the 386's...i'm using lm386n-1/3/4.......i remember ubaid saying that about certain models of the same ic....

will have to do a search around for others i think....i'll definately try the big daddy then and see if i can bosst the hell out of it..ha ha..

can you recommened a 386 model?...mine are JR96AC models..

[deadastronaut]

Sounds Great! I think I'll give it a try.

yeah go for it paulyy..i remember you saying you were going to mess around with a j201/386 type circuit..

if we can nail this fizz problem it'll be a really cool pedal...

any ideas..improvements..welcome......

[culturejam]

cheers . when you say you just tacked on a single clipping diode was that from the out put to ground?....

Yes.

as for the 386's...i'm using lm386n-1/3/4.......i remember ubaid saying that about certain models of the same ic....

I mean that if you have 10 of the same type of chip (LM386-n1, for example), maybe 2 or 3 of them just won't sound good in a distortion circuit. I usually audition a few of them in each circuit to see if one sounds better.

[deadastronaut]

cheers . right gotcha..

ive just breaded the big daddy...heres the soundclip...same problem..if not worse.....

its exactly as the schematic, except i put a 25k trim in place of the 15k resistor from 9v to drain...

must be the ic then???

http://dl.dropbox.com/u/7464107/bdaddy1.mp3


what a pain in the ass....hmmm i'll try swapping different ic's then..

[tubelectron]

Hi again,

what i may do is actually use another breadboard and do the big daddy and see if that has the same fizz splutter on the dying notes too...
as long as i can still achieve hi tight gain still.........   

anyone had success with big daddy and no fizz.....hmmmm..

Among others, I tested the big daddy on its 2 variants (input FET buffer / input FET booster), none of them worked right : bad decay, bad sounding, at a point I was thinking that my LM386 were defective... A substitution proved not. But may be I had an unconsistent lot of LM386, as stated by culturejam.

A+!

[deadastronaut]

cheers tubelectron..

ive tried 3 ic's, ..on the big daddy on bread...same noise!...hmmmm...

its a real shame because this ic makes an excellent distortion....

rob.


edit... back to plan a then!......

[Wild E]

its a real shame because this ic makes an excellent distortion....

I agree, very early Van Halen-esque sounding. I was waiting for you to break out in an "Eruption"
My thought is to somehow increase the sustain of the signal going into the 386 so the decay is delayed. I have a JOEGAGAN/ZZAGAR  Bigger Muff on my breadboard that has great sustain, but I don't know enough to tell which part of the ckt. does it. Maybe someone else might.

[tubelectron]

Yes, deadastronaut...

Listening to your samples proves it : the distortion is (very) good (I never had that, or even something vaguely close !), but there is this problem of abrupt decay - I must confess that I can't stand that (mainly because I am a rhythm & blues player).

Just for info, I found a satisfactory issue with a Vintage RAT RI (3-knobs, big box) that I rebuilt to original specs, and also with my DIY Doctor FUZZ distorsion pedal (2-knobs), using a 1458 in a boosted version of the distortion section of the Muff Fuzz Crying Tone Pedal I had for years (and sold stupidly). But yes, even if these are heavy distortions with long and regular sustain and smooth vanishing decay, it is not as devastating as your sampled trials, indeed and unfortunately... (In addition, I am not very qualified for metal playing... with my ES-335TD and Silverface Fenders... And somewhat "roots" playing style).

Here's a quick shot of my 2-knobs Doctor FUZZ (made in 1996) :



But there is some guys here who strangely seems to have good results with the LM386 that we haven't. The chip selection musn't be the sole mystery !

A+!

[phector2004]

its a real shame because this ic makes an excellent distortion....

I agree, very early Van Halen-esque sounding. I was waiting for you to break out in an "Eruption"
My thought is to somehow increase the sustain of the signal going into the 386 so the decay is delayed. I have a JOEGAGAN/ZZAGAR  Bigger Muff on my breadboard that has great sustain, but I don't know enough to tell which part of the ckt. does it. Maybe someone else might.

Maybe a simple compressor after the FETs?

[Quackzed]

maybee tack 2 opposed leds on the end, see if its the op amp clipping harshly? or try a resistor to ground at the 386 input and dial back the volume on the input of the opamp, maybee you could remove alot of the fizz without losing a noticable amount of dirt?
it does sound good expt for the fizz/decay...
and the playing is goood.
or try a series resistance at the output? 10k?

[blooze_man]

The Smash Drive has a 500k resistor coming out of the 386 to the output and as far as I know does not fizz...

[deadastronaut]

nice suggestions  guys.

@phil hector , a simple compressor?..how would i go about that?....


@tubelectron...yeah i dont see how krank got away with selling the distortus maximus if it has this problem?

they and others must have had this grief when designing and got round it somehow.. personally  i have tried 4 different diy versions and all have the same decay fizz/flutter  problem.....


@quackzed, led clipping then..or 10k out . i'll give it a go...

@bloozeman. yep i'll try it!..


i'll try these  today and see what happens....

more clips to follow  ...we'll get there im sure!.....


aron!..did you have any grief like this with your smash drive too!.. as it is a 386!!!!

[deadastronaut]

waheyyy.what an improvement... listen to this one..i tried all the suggestions apart from the compressor..
to no avail still fizzed...

then i had a brainstorm and remembered a friend telling me about power filtering!.(which i have seen a million times on other circuits ).
so i stuck a 50v 100uf across the 9v to ground..(i'll try some other values later on)..

much much better..loses a bit of top end..but that can be pulled back with an eventual tone /stack/control i think!..(maybe buffered etc.)

but for now i just want to get it cleaned up and usable first..

heres the clip..it starts with the 100uf cap on...then without it....then the last bit is putting the cap in and out while decaying...

i'm a great believer in hearing what it sounds like..rather than diagrams/pics ok..this is still the 'big daddy' i am going to revert back to my original 2 j201 design

later ok. then i will re-post that again, with the cap included...

http://dl.dropbox.com/u/7464107/100uf1.mp3

a lot cleaner!

what do you think!.. or 

[Electron Tornado]

Deadastronaut, see my posts on the Smash Drive thread.

[deadastronaut]

Deadastronaut, see my posts on the Smash Drive thread.

yep have...


anyway upon this journey of breading both the smashdrive and the big daddy i ended up (i think) improving them both and
combinig a bastardized version of them both.and it works ok...no problems...

introducing the 'big daddies bastard sister'




right , anyway now ive been toally side tracked ,im going to apply the same principal to the original 2xj201 design and see what happens there..keep em peeled.......

[culturejam]

Much better!

Since you still have it on the board, you should try adding a 100nf cap in parallel with the 100uf. Give it a bit more "fast response" on the ripple rejection than just having the 100uf.

You may not be able to hear any difference, but I think it's worth a shot.

[deadastronaut]

Much better!

Since you still have it on the board, you should try adding a 100nf cap in parallel with the 100uf. Give it a bit more "fast response" on the ripple rejection than just having the 100uf.

You may not be able to hear any difference, but I think it's worth a shot.

cheers man..will do!..the above schematic works fine..but yeah i'll try that too while its on there...and before my cat knocks it about


edit: just tried it...gave off a rumble at the decaying note though...


heres the soundclip of the 'big daddies bastard sister above....gain allthe way dow...then full on...it seems to work ok...

http://dl.dropbox.com/u/7464107/bastardsister1.mp3

what dya think guys..?