stupid pedal tricks : stiff hippy II overdriver

[pinkjimiphoton]

thanks, gonna check your phaser out...peace!

[pinkjimiphoton]

wow, dave, that would be a hell of a vero undertaking!!!

looks sweet tho...do you have any clips of it?

[Electron Tornado]

PinkJimi, what "flavor" of 386 did you use? I built a pedal with a 386 and found that the 386N1 had a fizzy decay. I changed it for a 386N3 and that fixed the decay problem.

Modding the 1k pot to 500 ohm might improve the gain control.

[digi2t]

PinkJimi, what "flavor" of 386 did you use? I built a pedal with a 386 and found that the 386N1 had a fizzy decay. I changed it for a 386N3 and that fixed the decay problem.

Good question. I ran into that with my Parallel Universe II build, but the opposite way. Only the N1 would give me the oscilliation required for the P.U. II mojo. The others just would not go into oscillation. I tried all four of them, but only the N1 would work. Maybe that explains the fizzy decay as well. N3 would probably be better here.

[pinkjimiphoton]

no fizzy decay with this...some have, some haven't....just kind of the nature of the box i had thought.

this wasn't as fizzy as some of the other ones i built to begin with, but it's very smooth now with the weird tone control placement.

it could have been any number of different 386's ...i built the pedal a long time ago, just did the modification to it recently.

probably came from radio shack, maybe mouser...hard to tell.. not very knowledgeable about mojo.

500r pot may indeed work better, thanks for the tip. i kinda like how ya hit a point where it turns to fuzz tho. next time i'm at rat shack i'll get a 500r and try it maybe.

peace

[edvard]

I've noticed that almost all the vintage amps everybody drools over have the tone controls right up front, right after the first buffer/gain stage.
I've wondered aloud about it before:
http://www.diystompboxes.com/smfforum/index.php?topic=86035.0
Maybe you ARE working some mojo there, after all.
Awesome sound you got there, Jim, keep it rollin'...

[pinkjimiphoton]

thanks edvard!

it just seems counterintuitive to put it last...no amps do it that way, you're right. an amp often will have a PRESENCE control, but tone controls are usually right after the first stage (buffer).

tacking it across the output will and does work, but you lose gain. putting it first, who cares? ya probably have enough gain where it doesn't matter.

too much of a newb...i just experiment with things until i have smoke, or sound.

if i got it right, you can be SURE it was an accident!! 

[Electron Tornado]

If you bought the 386 at Radio Shack, it's a 386N1. Why it doesn't have a fizzy decay for you is a real mystery. I wonder if that fizziness right at the ends of notes is frequency dependent and your tone control is somehow filtering out the right freqs to prevent the fizz.

Re: tone controls - to really do some tone shaping around a distortion circuit, put an equalizer right before and right after it. An equalizer is essentially a tone control.

After any passive tone control you need some kind of gain recovery to bring the signal level back up. I wonder if the reason for amp makers putting tone controls early in the circuit was because they then had other gain stages between it and the output.

[Earthscum]

I was playing around and built another CDOD on the breadboard using N-1's from Tayda... they fizz. The CDOD I designed had an RS chip (N-1), but it's nice and smooth, zappy. Tried this circuit last night with the new ones, and yeah... it's fizzy. I am gonna play around with it some more tonight (only got about an hour to screw around last night). As well, I'ma gonna try swapping out chips in my finished CDOD and make sure it isn't just another breadboard bug. I think it's all in the chips, though. This is almost like the PT chips, eh? or some of the 555's. 

[tubelectron]

Hi,

An interesting device +++ to be tested, at the listening of your video. Surprisingly, the few trials of LM386 overdrive I have made were all deceptive : bad decay, fizz oscillation, sounding like a bad broken amp... (i.e. Grace / BigDaddy LM386 ovd)
So let's see with your circuit - much more convincing, it seems !

A+!

[pinkjimiphoton]

it could be a 386 from jameco, rat shack, allelectronics....beats me. i'll try to look at it, but it's probably NOT  mojo.

i mean, as built, it was trebley and crackly. i hacked a gain and a tone control into it. it's the SAME CHIP that sounded  like crap before!



that said,,,,

yeah, you can put eq pre/post/both but they all will sound different, and contribute to noise and signal loss.

i imagine lossy tone control matters less before a high gain preamp than after it in terms of function.

put a wah before distortion, it's much smoother than a wah after. both are useful, but both are different.
this is probably more like the former i guess.

[rutabaga bob]

Finished building mine, used a LM386-N, rigged it up on my test board (which is a piece of wood with 2 metal sides...one has input/output, the other has holes for whatever pots you're using...everything connected with jumpers), and it sounded awful - all crackly, with signal droput, etc..  Unhooked it and put in a JRC386-D scavenged from another build, and, AW, YEAH!  That's the ticket!

[Earthscum]

Yeah, I confirmed last night that the RS chip I have is nice and smooth, but the ones I got from Tayda are going to be better suited for high-gainers. They do make an ALMOST decent CDOD, but the signal is actually less than unity. Gonna have to order a different round for those, and one of these I guess.

I have a modem that has a 386 surface mount... and SMD resistors and caps and such. I might have to see just how small I could make one of these, for giggles. 

[pinkjimiphoton]

you could probably mount it all on your input jack.

glad iy works fot ya!

[prabuchresno]

Hi pinkjimi, thx for your veroboard schematic. It will easier for me to built.
Previously I made small ruby amp with LM386, but when I hear the sound of this overdrive, I've plan to convert to it.
My question is, can I put the output directly to speaker? or I have to connect it to amplifier?
Thx

[pinkjimiphoton]

hey bro,
you could probably go either way. if you want it to be feeding a speaker, you'll need a big cap...say 220u or so from the output to the speaker.
if you want it to be an overdrive, you'll need a much smaller output cap as done here.

it may sound really good if ya keep the jfet input stage, add the tone control after that before the 386 chip. you could use a switch to choose between a small and large value output cap, then you could use it as an overdriver OR an amp!

[prabuchresno]

Hi, thx for the quick response. I will try your schematic first with change 2.2uF to 220uF, I will think to add jfet later.
And thx for the idea of installing both output cap and add switch to change between them.

[pinkjimiphoton]

hey, no worries, let us all know how it works out!

[prabuchresno]

Hi bro, just build it last night. Not satisfy with the result
I've change output cap to 220uF (as your suggestion), use all 3 diode 1N4148 (substitute of 1N914, my only available stock) and feed output directly to speaker (8Ohm-0.5 watt)
Result: gain/vol control only work only last 5% rotation (quiet up to 95% rotation) and the tone control is not really has a big effect.
My question is, If I change D1 with diode 1N34A will this solve problem? Or I have to change the gain pot value?  ;)Thx

[pinkjimiphoton]

can you draw me up a simple schematic of what you built exactly?
hard to advise without being able to look at it.
did you drop the jfet input stage of the ruby?
i'd try adjusting the bias on the jfe some to make it louder than unity, and put the diodes right there on the output of it after the coupling cap between the volume control and the input of the 386.
putting the diodes on the output may or may not be helping; try 'em and see.
you can use 914's, 4148's, whatever... sounds better to my ear with silicon diodes usually anyways.
germanium is awesome in some things, snake oil in others.
i don't think going to a bigger pot will help much..
i'd check the resistor to ground from the input of the jfet and maybe make the bias adjustable.
the ruby itself is a great little amp,
the stiff hippy should be @#$%in' RUDE!!