2004 Full-Drive 2 cap question???

[AC30Dirty]

Hey guys, I'm not that skilled at reading schematics yet, although I'm getting better. Anyway, I have a fulldrive II pedal I've been studying to understand for building a vairiant of it. I however can't figure out what this one capacitor is for. It has the numbers 203 on it . So i figured it would be the C1 value on the TS808 General Guitar Gadgets layout but that value cap has the numbers 223 on it, making it a .022 cap. The other caps on the pedal look about exactly the same as A TS808,9, as it rightfully should, but this cap is stumping me. Please help. Thanks

[Bernardduur]

203 is, I guess, a 0.020 uF cap

[jimbob]

I trade between those 2 values all the time without any noticeable difference

[AC30Dirty]

Thanks guys. Thats what i was thinking but i just wanted to make sure. Here's waht i've done so far. I replaced the two  1uf electrolytics with 1uf metal film caps from digikey and it seemed to tighten the pedal up and help on noise. I also replaced the IC with a RC4558P, which to my ears REALLY sounds better than the 4558D. Lastly, I experimented a bit with the cap value I asked u guys about and I ended up with a .1uf film cap in there and it seems to have given the pedala smoother gain structure. I still need to listen closely and examine a bit more though. Thanks guys. Any suggestions, feel fee to post..

[Torchy]

Its basically a TS anyway, and youve just done most of the Keeley TS9 mods. Only ones left are ...

After that I change two resistor in the drive circuit (51K--> 20K metal film and the 4.7K--> 2.4K metal film).  I change the values so that you have more distortion (about twice as much) as you turn the drive control clockwise and less distortion at the counterclockwise position of the drive control.  This has the effect of pleasing both crowds of people.  It has less overdrive in the low position and more distortion in the high position.  Throughout the middle of the drive control it is possible to get every stock TS9 drive sound.

Back to main page. www.robertkeeley.com

[AC30Dirty]

thats what i figured. I have had alot of TS9's and modded many of them with different mods. Its cool that I dint have to mod that much on this pedal though.

[AC30Dirty]

Ok guys, so I've been jamming on the pedal for about an hour or so; and I still can't quite put my finger on what this one cap does. It seem to have made the pedal a little more aggressive to my ears. Smooted it out if I may say. But, I'm not sure. Can you guys help me out as to what this certian cap value (.022uf) on a regular TS9 or TS808 does. Thanks

[AC30Dirty]

I'm gonna feel really dumb it this question i'm about to ask it true. Is the particular cap I'm asking you guys about (.022uf), the input cap? If so, could you explain what it does to the circuit if I increased it like i have to .1uf? Thanks

P.S. Be Gentle.

[Torchy]

From the schematic, yes, thats the input cap. You should read the GEO article "Technology of the Tubescreamer", its here.

[AC30Dirty]

Thanks guys for all the help. Thanks Torchy for the link. It cleared up alot of questions.