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Projects => IC-based Overdrive => Topic started by: genghistron on March 10, 2011, 11:39:26 AM

Title: Works great with TL071 IC
Post by: genghistron on March 10, 2011, 11:39:26 AM
Built this one last night.  Great tutorial and really nice sounding OD circuit, thanks gauss!  Still going to try a few diode combinations before boxing it.

I didn't have the LM741 but with a bit of search found that the TL071 is a drop in replacement and sounds great in mine.  Anyone looking to try some alternative IC's give it a go.  Very smooth and balanced sounding (though i don't have the 741 for comparison), I'd be confident to box it up without a tone control, it was that sweet.
Title: Re: Works so-so with TL071 IC
Post by: genghistron on March 10, 2011, 03:29:32 PM
may have spoke too soon...

the circuit is sounds good but i'm getting alot of noise.  With the gain and volume all the way up there's serious buzzing that seems to be related to the position of the pots in my guitar.  I'm playing a strat, with the volume all the way up the hum isn't so bad, as I move from 10 to 7-8 the buzz gets worse.  similarly with the tone pots, using the bridge pickup with tone @ 0 sounds okay (still noisy though), when tone gets to 10 the buzz is very loud.

Anyone else have similar experiences? (with this or other pedal builds).  I've rechecked the wiring and everything seems to be in the right place, I'll have some more time to spend with it this weekend. Shame, cause it sounds really good other than the persistent buzz.

Title: Re: Works great with TL071 IC
Post by: newfish on March 21, 2011, 03:17:12 PM
Have tried a few single Op-Amps in this circuit with the following results...

LM741 - ordinary.  grainy-sounding.  Pretty good.
TL061 - More presence. Clearer highs, but not as loud. (TL071 and TL081 also have the same pin-out).
LM308 - Very very loud. Plenty of dirt on-tap.
OP27GPZ - More volume and distortion than the TL061.  Not as distorted as the LM308.

So there we have it - all tests were carried out with Distortion and Volume controls set to 10.  

Incidentally, I subbed a 330pF cap for the 25pF cap in the feedback loop to tame some of the 'fizz' I was getting from the stock unit.

Hope this helps anyone looking for a 'sub' transistor... ;-)

Title: Re: Works great with TL071 IC
Post by: bukas on February 14, 2013, 08:39:28 AM
replace ceramic caps with poly and box it