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View Full Version : Tone manipulation on a 2 stroke


IBTom
05-08-2009, 07:49 PM
A few months back I built the 2 stroke amp from Dave Hunter's book. I made a few minor changes in the build...I used MM trannys with a choke and disconnected the negative feedback. I used .022 Sozo caps for the coupling caps.

I figure I've played a few hours on it since completion, which should be good to let the caps do their thing as far as sound goes.

The existing tone is much too bright and glassy as is now.

Reading Gerald Weber's book on Amp Essentials, a method for voicing the amp can be to change the value, as well as the brand of these caps. I've ordered a couple of orange drops and a couple of Mallory 150s, both in the .047 size (which should allow more bottom) and am impatiently awaiting their arrival.

So, while I fidget around in anticipation, has anyone out there played around with voicing their 2 stroke build? Obviously, tone quality and what we're all looking for is very personal and subjective, I realize that.

Just looking for other items to explore into in this venture along with other's experiences...do's and don'ts, etc.

btw, I'm running with 1 KT66, a 12ax7 plugged into a 2x12 equipped with a Greenback and a Carvin 100. Speakers are wired for 16 ohms and my OT I put in has multiple taps, so it's 16 to 16.

Bring it on....

Tom

skipm45
05-10-2009, 10:00 AM
Hi Tom,
I've been doing some tone tweaking on mine as well.
Mine is set up as follows:
SoZo .022uF coupling caps, 40uF, 40uF, 20uF power supply caps. I also used a choke in the power supply. OT is a Weber WSE15.
Tube compliment is a JJ GZ34, Mullard EL34, and a NOS RCA12aX7

Mine was a bit too dark with .01uF coupling caps, so I went the .047 and finally .022uf route. I think you may find the orange drops to be even brighter than the SoZos.

I upped the preamp voltage so that I currently have ~240 v on the first stage and ~290v on the second stage. This improved the headroom, and now the amp begins to compress at ~10 on the volume control.

I used a 1uF cathode cap on V1a and don't have the "bright" selector switch.

I'm driving a Weber Silver Bell speaker.

An observation: Mine sounds a lot better when cranked up beyond "6" on the volume control.

Skip
www.skipzcircuits.com (http://www.skipzcircuits.com)