stupid simple over drive

[samhay]

samhay

Have you seen this thread? http://www.diystompboxes.com/smfforum/index.php?topic=105324.0

I have now.

I was playing more of a devil's advocate with respect to my last question, and I would have been quite surprised if the answer was no. However, I don't think the ~10k impedance of Jimi's pickup is likely to make a big difference to the gain - can you hear the difference between a gain of 50 and 100 with a 9V supply if it is then clipped to ground?

Jimi - I'm not surprised it is unpleasantly bright when buffered first. There is no low-pass filtering other than from the low input input impedance (unless you added a cap across the feedback loop of the op-amp; I couldn't quite follow). In any case, it's a cool way to get that effect with an IC, rather than a Fuzz Face style circuit.

Oh, and good to see that you still have the 1590A bug.

[gjcamann]

Sat through the video, sounds great! I'll have to try this sometime. Even simpler than a rust driver and maybe better sounding!

[pinkjimiphoton]

that is my second 1590a build. likely to be my last.

lol

i gotta whole carton of radio shack boxes in the mail a week or two ago.

i REALLY like the interactivity of this thing. if it's the low impedance of the input 10k resistor, that's cool... it was an accident, i was just trying to pad down some nasty rfi and the 10k's were sitting there handy.. so i stuffed one in.
the noise went away. so i left it.

the output 10k was added just to try and pad it down a little, and it sounded marginally warmer with it, so i kept it.

the .47 was on my bench, the leftover from rob/deadastro's chasm debugging. the .047 same thing, it was a pull from the debug. so it was really just bits and pieces on the bench, and what can ya do with 'em?

i figure if it's simple and toneful, so be it.

i did try several bypass caps on the feedback resistor, but i thought it negatively affected the tone. this sounds like the guitar, only louder and to the point of a nice germanium fuzzface with a slightly dead battery... but without the mud (cuz it's not germanium) and without the usual shrill of silicon.

the more i play with it, the more i think i could gig with that, a wah and an echo and do 90% of what i need.

i did end up adding antipop resistors. best on the circuit itself i think, not the switch. ended up using 4 4.7m resistors from input/send and return/out to star ground. eliminated the switch pot almost completely. may seem like overkill, but it did seem to help.

it's boxed and i'm digging it. i have an idea or two in mind for this circuit still... and i wanna try gus's transistor version.

[Kipper4]

Great little project Jimi.
Thanks

[pinkjimiphoton]

 


i was wrong, it's definitely in the blue clipper kinda vein...been playing with it all nite, got a bslightly different version... the pink clipper... coming soon

[DDD]

Charming charming charming charming guitar sound!
Thank you Jimi for the great pleasure!
*** I think LM4250 programmable OpAmp can make the battery last forever in such a stompbox 

[midwayfair]

Did ... did Jimi just post a 1590A? 

[pinkjimiphoton]

here's the over complex version, based very loosely on the blue clipper.

it's gotta cool diode clipping arangement in the feedback path of the opamp, and footswitchable boost... one stomp, big ass cap added on the front and tone cap lifted on the end, next stomp it's small cap in front and tone cap engaged. or you could use individual switches. there's overkill power supply filtering, and it's running quite happily on my breadboard.

again, no knobs required i tried to make it so you just use the guitar knobs and it seems to do fairly well. you may wanna tack a 10-100k output volume pot on there... i'd suggest 50k is probably fine.

again, wanted to see how simple a circuit i could make. all real standard values, no special tolerances... the electros can be anywhere from 1u to 10u, the chicklets can be whatever sounds good to you.
above 220k on the feedback resistor it gets too dark and a bit muddy. 100k is fine there, too, a little less dirt.

the added cap and resistor adding feedback between inv/non inv tunes the distortion somewhat.. you may wanna play with it a little bit. it brings up the juice a little so the led's drive a bit harder.. the 1n34's add a little sweetness. it responds like a nice fuzz box still. a little more aggressive toned than the ssod. but damn near as easy.

will shoot video later... watching breaking bad in it's entirety.

here's the schematic. try it on the breadboard.  it's just a slightly more complex version of the ssod or blue clipper, almost the front end of the ssod, the ass end of a blue clipper and a diode clipper in the feedback path. it sounds really sweet. nice treble boosted clear sound with the guitar low, and nice filth without "fuzz" and not too muddy when cranked.

i dunno if i'll box this one or not. i probably will.

[bluebunny]

Did ... did Jimi just post a 1590A? 

Nah.  It was one of these, but Photoshopped:

   

[pinkjimiphoton]

this original one in this thread and the first LKB1 boost are both in 1590a's.... where you guys been?

noddaloddaroomindere!!!

i just revised the revision above. ditch the 220k resistor in the feedback loop. replace with 1 meg pot wired as a variable resistor (no ground connection, wiper and whichever terminal makes the knob work right for you connected)

easy breezy gain control. when ya get up to full blast it becomes a nice fuzztone with decent cleanup. about 1/4 up it's a nice overdrive that's stupid dynamic. have fun.

this is different from anything i think i've done before, and a direct result of attempting to blow shit up on the breadboard.

i think it's kinda like a blue clipper with a rat-ish feedback loop clipper and an assym arse end.

definitely gonna get boxed. this one's a keeper... tele sounds like a tele, les paul sounds like a les paul, strat sounds like a strat... to me, that's close enough for rocknroll!

[tubegeek]

which circuit did i reinvent this time??

If I squint my eyes a little, it sorta looks like the Kay Univox Effector Fuzz.

[pinkjimiphoton]

funny, cuz we were just mentioning that ont he univox thread.

[tubegeek]

no way!

[pinkjimiphoton]

this is what's on my breadboard now... will build it tomorrow to verify it, then i'm boxing this bitch cuz man, i likes it.

[pinkjimiphoton]

two mistakes on my vero, and one revision... the revision is use a 500k for the gain pot, it works better... 1 meg can motorboat.

also, r6 on my layout needs it's bottom connected one row lower, or from hole 6 on row e to hole 6 on row H, not row G.
and the gain pot should be pins 1 and 2 to e1, and pin 3 (top, if looking from the back with pins to right) connected to c1.

sorry for any inconvenience... will update my layout asap.
peace

outside of that, the layout above is verified.

[pinkjimiphoton]

[pinkjimiphoton]

when all was said and done, i added a 100k linear output master volume pot.

also added 4.7m resistors from the switch to ground on both in and outputs... made a difference in the popping and seemed to smooth the tone just a little...

and finally, i added a .0047u cap to ground from the output, right on the switch. that nukes a lot of noise and hiss and still leaves plenty of sparkle for the guitar, and warms it up some.

gonna pair this in a box with mictester's really cheap compressor i think, as well as the 1590a build for standalone applications.