Holy boost batman.....

[Caferacernoc]

So I'm messing with a later black Ross distortion pedal. I'm "upgrading" it and also plan to switch to germanium diodes like the tan model but set up asymetric and with a softness control so it's still loud  like the black model. Anyway, I was adding to the value of the cap to ground to cut off some more fizz and I decided to just cut out the silicone diodes so I could hear the transistor by itself. WOW! Is thing thing a loud boost with no clipping diodes in there. With the level wide open and the gain at 9 o'clock it's a loud, clean boost. And I was also amazed how much distortion is still available with no clipping diodes. Turn the gain past 9 o'clock and there is a lot of dirt. It's a Malaysion JRC4558 chip by the way, sounds pretty good. I was just suprised to realize how much transistor distortion is part of the sound of a distortion pedal. Not that I didn't think you could hear the difference, but on this pedal it's probably adding half of the distortion! I had built one transistor boost pedals before, but never with a gain control in the feedback loop to overdrive them so easily like on this pedal. Well, now I know! And I think the JRC4558 makes a good boost by the way, I'm sure I'm not the first to realize that.  :-)
What is the "brownest" sounding chip I could throw in there by the way? Thanks.

[analog kid]

 TRANSISTOR(S)  ... IN A ROSS DISTORTION!!??  Where??
  And A "brown sounding" CHIP HUH? Well not that I don't believe that there may be some IC's that are less hi fi which may 'help' to exert a little more of the brown sound you're referring to, but I don't think any IC change on it's own is going to give more of that 'sound' .  But hey I could be very wrong! I'd say just a 741 IF it was setup for a single config, so I guess that would mean a LM1458
... interested to hear about this 'transistor'

[Caferacernoc]

Sorry, I didn't mean to imply that there was a transistor in addition to the JRC4558(malaysion) op amp chip in my Ross pedal. Anyway, I just found it interesting how much distortion there is in this circuit with no clipping diodes. And I realize that an op amp won't provide the "brown sound", I'm just wondering in general which tube screamer type chip has the least fizz. The stuff I've made from scratch is all 2N3904, 2N5089 type stuff. Thanks for any info.

[analog kid]

 The FIZZ you are describing may well be what others like out op amp clipper type crkts.  A more HiFi chip may well be what you're going to me more partial to.  Maybe an NE5532 or BurrBrown OPA2227 (great sounding chip!), 2134, 2132 fet     I don't remember which MODEL you said you had, if black then you may want to leave that opamp for now (as it's a real good one) and look at the clipping diodes . If I'm not mistaken they don't have the old Germanium diodes in there but instead silicon 4148/914 type. (May be mistaken)    BUT if so that may be your 'fizziness' as some describe silicon diodes that way compared to Ge'

[Caferacernoc]

Thanks for the info. Yeah, I already took care of the clipping diodes. Ge 1N34a, 3 in one direction, 5 in the other. (Eight pack from Aron!) Then I put in metal film caps for the input and output(doubled the output size for more bass). I also upped the size of the low pass treble cut cap to ground. I'm happy now, it's about as slick as this simple circuit is gonna get. Loud, crunchy, but warm sounding. I just need to convert it to true bypass and it's done. I don't think I want to try to change the op amp, I'd hate to mess up this "vintage" pedal any more! And I've learned what I needed to learn from it. For now!

[petemoore]

  Get yer perf on...Dist+ is great unit.
  I like the way a 741 oa makes distortion+ sound, 'upgrades' had IMO 'downgrade' of distortion 'richness'.
  Have you pulled the 5 diodes series in one direction, I don't know that the circuit would meet that clipping voltage threshold.

[Caferacernoc]

Yeah, the jrc4558 definitely has the juice to clip five Ge diodes in one direction and three in the other. Should work out to 1.5 and .9 volts. I first tried it with 1.2 volt LEDs and they lit up at 1/3 on the gain knob. Plus you can easily hear the difference when you take the diodes in and out of the circuit.