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I can definitely tell the tone of the percolator was very specific. I decided to expand on that just a tiny bit to closer match my particular tone tastes. As far as letting more bass in it’s just a bit extra to fatten up my single coils.
You got me there, I didn’t load test the OT. I went with basic knowledge and some educated guess work. My guess was that the compactron needed somewhere around a 6k load and I think this transformer is pretty close to that. (I have a whole collection of power and OT transformers)
I have about 3 hours on the new OT with no issues yet. If I did make a mistake, It would just be another project, I have your OT set aside in case.
I’ve been recommending this amp to my buddies, they usually look to me for gear advice. I have a pro player coming soon to really put it through its paces. When I get some more gear cash, I think I’m going to be another one of these, hopefully you’ll still have one!
When my buddy comes over, I intend to record him playing it and put it up on Youtube. (although I only have one crap video of my dad playing and zero subscribers!)Oh Geezus, What a dumb mistake, I wasn’t using my auto-range meter. I put a 220 ohm resistor in the 220K ohm position! Too much ground on pin11! That being said, it still played well with no damage to any circuitry.
As a side note, I tried a 100K resistor in that position and I get a bit earlier break up and it’s still louder than I need.I shoulda just kept my mouth shut. This is a GREAT little amp.
Quick update, I’m getting closer, It’s somewhere around R10, which makes sense, considering the preamps are fine, it’s in the power amp section, my readings for the power amp resistances to ground are wacky.
I gotta tell you though, this design is about bullet proof!Well, I finished the amp, and then ruined it. Man, it was nice and loud! although it had a muffled tone. Soooo, I went through 3000 changes to get some brightness. (I’m a Vox guy)
Somehow I got carried away fudging with the circuit and ended up with a near 100% clean amp until the volume was turned up to around 9 out of 10.(And still a bit muffled)
I decided I was an idiot and I replaced all the changes with all the original spec components.
Well, now I can crank it to 10 and its max is about at 60Db.
All test point voltages check right on except at R8, which should read close to 70v and I’m at about 90v. All resistors measure expected values within 1% ish.
I tried 3 different tubes, speakers, input equipment, and even upgraded the output transformer, no changes.I’ll tell you what though, I’ll keep at it, this is a really cool amp design!
