I didn't give up on this amp. It was put aside for awhile but I did find time to work on it again several times in the last month. I reorganized (with better components) the OD mod section of this amp. I also moved the OD insertion point to where the existing Master Volume was located in the schematic. (It is after the trem and Reverb, so Reverb can get pushed to too much easily if it isn't to subtle when the OD is switched on.)
Another thing I did to this amp was to Decrease the amount of Negative Feedback. I added a 250k pot in series to dial something in that opened up the tone and gave some nice drive/grind to the clean channel if I want it. I'll measure the sweet spot and replace it with the appropriate resister soon (probably around 50-100k). If I had tried this first, I may have never have even bothered with installing an OD... but then I would have missed out on all this fun!
So, I used this amp today for band practice and I must say that it is very versatile and great sounding now. I don't think I've ever had an amp that could pull off so many different tones with such effective controls. I had no problems with it , and I didn't experience any hint of squeals, oscillations, feedback, or unstableness anywhere near the sounds I was dialing in. (I should have tried even harder to find some, but didn't feel the need today. Things are pretty good since I have had this layout cleaned up. I have some pictures now too.
So, everything left of the blue electrolytic capacitor is part of the HRM overdrive circuit:
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http://i55.tinypic.com/skukno.jpg[/img]
And so all the controls that used to be for the normal channel are now for the HRM overdrive. Very tweakable with a huge of range in styles of tone. The Master Volume for the overdrive channel is on the very left beneath the toggle that activates the overdrive:
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http://i55.tinypic.com/2qi7693.jpg[/img]
So, I'm thinking the next step is to venture into the world of relays in order to put this overdrive switch into foot pedal form. Also, because I now have the overdrive circuit occurring after the reverb and trem in the Traynor circuit (right where the Clean Master Volume is), any significant amount reverb gets sort of too much when the overdrive is clicked in. So, I may think of doing something about this. Not sure if I would just always have the reverb footswitch ready, make another relay for it, or think about moving the overdrive again...
I'm not worried about it right now; because I go light on the reverb anyways.
Any thoughts on the whole relay idea? I've been reading the threads on it and am torn about trying to find a separate Transformer to power the relay or what... It looks like this PT has no centre tap. I also found the more appropriate schematic for this amp. I was using an older one before. Obviously, the normal channel is yanked out and the OD circuit straddles the Master volume pot with a DPDT.
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