Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ed_Chambley on November 26, 2012, 10:17:35 am
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I posted this a while ago. Guy wanted more from his princeton. The stokes brings the plate to 320 of the PI and the Paul C mod sounds better with 4m7 in-place of the 2m2. Tubeswell recommendation. Tried both, but the 4m7 kept it cleaner up the dial. Used a Blackface Deluxe PT and OT. Plates on the PT rose to 420. Massive change and is no longer a Princeton. Guy loved it, but brought it back. Wanted a 12 in it. I used a vintage 30. Can't really tell you what it sounds like unless a mini twin.
Reverb upgraded with 6 springer and dwell and 3 knob bias vary tremolo with dual bias. Cathode on PI measures 64vdc and screen 314vdc.
Problem. When he brought it back I noticed a noise when the volume is turned down and a noise when the volume is dimed. May be a bad pot. I will check it later. Not bad, just not used to hearing amp hiss from a princeton. If anyone has experienced this, please chime in as the pot was fine when it left my shop.
Bypassed 2.2uf/1500 at v1 a and b. Used a 22uf at the PI. All in all it is quite nice. No bass flab. Definitely will get over a drummer now. Added a 25k mid pot and a raw. Cool amp, but I have no idea what to say it sounds like. Just loud and clean fender.
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... Guy wanted more from his princeton. ... Used a Blackface Deluxe PT and OT. Plates on the PT rose to 420. Massive change and is no longer a Princeton. Guy loved it, but brought it back. Wanted a 12 in it. ...
Sounds like the guy wanted you to turn his amp into a Deluxe Reverb (or a Pro Reverb, but with 1 speaker and 6V6's). :icon_biggrin:
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... Guy wanted more from his princeton. ... Used a Blackface Deluxe PT and OT. Plates on the PT rose to 420. Massive change and is no longer a Princeton. Guy loved it, but brought it back. Wanted a 12 in it. ...
Sounds like the guy wanted you to turn his amp into a Deluxe Reverb (or a Pro Reverb, but with 1 speaker and 6V6's). :icon_biggrin:
Exactly, I mentioned in the initial thread I had offered to build him a Blackface Deluxe, but no. It would not have cost him but a few more dollars and he would have had 2 amps. He was focused on the dual bias and the ability to use NOS tubes that were not necessarily matched. I attempted to explain idle current and how they would only "match" at idle. It doesn't really sound anything like a Deluxe, but it does sound good. :w2:
I appreciate your explaining amplifying the Hz you want. Guy thought I was some sort of genius. I told him you guys were the ones who really did the configuration, I was just the hack with a soldering iron.
I ended up with an original set of transformers from 73 and what looks like a CTS 10 speaker. :icon_biggrin: And a few dollars. I think what he really wanted is a sleeper, what we used to call some hot rod builds when I was young enough to roll around in oil and grease. I did not try 5881, but I'll bet it is better with them.
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I think what he really wanted is a sleeper, what we used to call some hot rod builds when I was young enough to roll around in oil and grease.
Which might have been the point of the original Mesa Boogie. I *think* they were originally a 50w amp, 12" speaker and extra gain stage shoe-horned into a blackface Princeton combo.
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OK the fish is biting. :happy1:
I remember playing one of those things. Couldn't believe how much came from such a small place. The extra gain stage is something of interest and makes sense. What were those early Mesa's called. Mark 1, or was it earlier that that? I would like to see a schematic for one. I have a set of transformers for 50 watt 6L6's.
I did not really care for the amp at the time, but I remember it well. I was stuck using it in Daytona Beach and it was way to punchy for what my band was doing, but since then I usually play Modern Country and me thinks it would work well for that. However, my memory ain't what it used to be.