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DIY Stompboxes => Building your own stompbox => Topic started by: kvb on July 18, 2011, 12:42:22 AM

Title: foxx tone machine transformer tone tweak +
Post by: kvb on July 18, 2011, 12:42:22 AM
I had read some posts about using the extra stompswitch lugs to control the highs a bit when switching into octave mode.
So, I wasn't surprised when I fired it up and switched on the octave. The highs are extreme and the bass seems to disappear a bit.
The octave up is really great, but that's all there is left. Plus I don't really want there to be a boost in volume when I flip the "up" on.

I decided to switch in something right after the tone section rather than at the sustain/fuzz pot. First I tried some resistance with a trim pot. 25k seemed to tame the overdone highs OK. But there was still some thinness to the sound. Plus, I had a TM018 transformer sitting there waiting to be used.

- The signal is going through one side of the transformer as an inductor -

I am surprised at what the transformer does to the sound. (As it is on the bench the Xformer is still paralleled with the 50K pot.) The high frequency splatter is gone, the mids are strong and the bass seems to be a bit more apparent. All in all it is a more coherent tone that is more in balance with the straight fuzz mode.

.........................

Also, I have a diode switch to select Ge, none, Si diodes. I used sockets to to test a variety of diodes. This allowed me to A/B the 1n34a Ge with the (Percolator) 1n695 Ge.  There is a very slight difference between the two. It was a blind test, because I did not know where each set of diodes were, on the switch. One set was just a tiny bit quieter (more volume cut) from tighter clipping, and there seemed to be a bit more noticeable harmonic activity in the swell/decay of notes.

I was certain which set of diodes was responsible, and anyone who has played around with these diodes would know the answer. I'm not saying anyone should be removing 1n34s from finished builds but if germanium diodes are being used for clipping I'll be using these rediscovered germ gems.

Peace,
Kevin