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Projects => IC-based Overdrive => Topic started by: emosms on August 02, 2013, 04:11:55 PM

Title: rc booster clone - blocking distortion
Post by: emosms on August 02, 2013, 04:11:55 PM
Hi,
I've built a clone of the xotic rc booster:
http://schematic.exteen.com/images/Copy%20of%20xotic.JPG
--
The point is that now I think I have the so called blocking distortion.
Here is the sample (no RC/ RC engaged):
http://picosong.com/RzJt/
--
What part of the circuit is best to tweak, in order to remove this? Pretty nasty and raw distortion in the low end. Sounds like broken  :).
Playing no chords and on the thin strings is not bad for soloing, but in general there is smth wrong.
--
Gain is set at half. The low/mid tone control behaves pretty reasonably.
Output volume is set at level close to the bypass level, so I don't think I am overloading the preamp next.

Best Regards
Title: Re: rc booster clone - blocking distortion
Post by: alexradium on August 03, 2013, 05:00:44 AM
Quote from: emosms on August 02, 2013, 04:11:55 PM
Hi,
I've built a clone of the xotic rc booster:
http://schematic.exteen.com/images/Copy%20of%20xotic.JPG
--
The point is that now I think I have the so called blocking distortion.
Here is the sample (no RC/ RC engaged):
http://picosong.com/RzJt/
--
What part of the circuit is best to tweak, in order to remove this? Pretty nasty and raw distortion in the low end. Sounds like broken  :).
Playing no chords and on the thin strings is not bad for soloing, but in general there is smth wrong.
--
Gain is set at half. The low/mid tone control behaves pretty reasonably.
Output volume is set at level close to the bypass level, so I don't think I am overloading the preamp next.

Best Regards
keep in mind that RC has 6 diodes,it should be dead clean with the gain at 0 and the volume maxed,tone controls at noon.
post pics of your build and layout
Title: Re: rc booster clone - blocking distortion
Post by: emosms on August 03, 2013, 07:19:49 AM
Thx :)
So the 6 diodes is for RC and 3 diodes (asymetrical) for AC booster? Here (http://revolutiondeux.blogspot.com/2008/06/xotic-rcac-booster-overdrive.html) seems to be explained, I missed that.
Here is the build:
http://postimg.org/image/m3lornq4b/
http://postimg.org/image/w7rg80aub/
Totally handmade. The thing above is EP and RC booster incorporated in a box. Not much place for 6 diodes now :).

Wanted to stack ep/rc together and get overdrive-like thing. But maybe it is better to have the AC booster in the box instead, the EP gives transparent boost.

Title: Re: rc booster clone - blocking distortion
Post by: emosms on August 03, 2013, 06:06:26 PM
Havent changed the clippling diodes but I got weird readings at the transistors (2n5088):
Q1 - e 1,7v; b 1,33
Q2 - e 3,15v; b 2,7v
How came the emiter is @ higher potential than the base..?