Wondered if any Citation II owners have made any surface temperature readings on their amp? I just traded for one and it gets pretty hot. The surface temp toward the center of the chassis is 150 degrees. 110 on the power transformer. This is after 3 hours with the preamp turned off and the transformer case shielded from the 6550"s.
Citation II running hot?
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Nyjblbob
Hooked on Horn's and Tubes. Go big or go home
Thats pretty normal for the Cit 2's especially on todays 120+ volts. Its also why I run all my Vintage amps on a Variac at 115 V
You will find not only does the amp run much cooler, but the tubes last longer as well. Most people just use a bucking transformer.
You might want to re-bias the tubes at the lower voltage
A fan also cools it down
How long ago has it been recapped?
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Nyjblbob
Hooked on Horn's and Tubes. Go big or go home
So then it's acting like a normal Cit 2. until you get a bucking transformer, Bias it just a bit lower, if using the stock meter,
and put a fan in front of it. They are sensitive to different output tubes. I like the now unobtainium Ei-Kt90's.
forget the Electro Harm ones though. horrible
and put a fan in front of it. They are sensitive to different output tubes. I like the now unobtainium Ei-Kt90's.
forget the Electro Harm ones though. horrible
Running my Citation II here with about 122vac line voltage, the power transformer gets kinda hot but not too hot IMHO.
I love the EH KT90's I put in it and run them about 75 ma bias each.
I also, for a temporary experiment, upped the B+ with a boost transformer and got 90 rms watts per channel both channels driven out of it.
Attached is a cap/bias board I created that has most or all of the known mods incorporated including a bias transformer. The amp is one of the quietest, if not the most quiet of all the amps I have here.
I love the EH KT90's I put in it and run them about 75 ma bias each.
I also, for a temporary experiment, upped the B+ with a boost transformer and got 90 rms watts per channel both channels driven out of it.
Attached is a cap/bias board I created that has most or all of the known mods incorporated including a bias transformer. The amp is one of the quietest, if not the most quiet of all the amps I have here.
Attachments
In my experience, some output tubes can run in the 300-350ºF range (150-175ºC). So, if you are pointing your IR heat thermometer near a tube, I wouldn't be too worried. Suppose you are pointing far from any output tubes and the thermometer is still reading in the 150ºC range. In that case, it prolly means that the heat generated is not dissipated very well. I recommend a fan to move the heat away from the amp. Then, remeasure.
Nyjblbob
Hooked on Horn's and Tubes. Go big or go home
That is the neatest Underhood Citation 2 wiring I have ever seen
Congrats! did you make that board?what do you think was the single reason yours doesn't cook itself running on 122V?
I don't even see any coupling caps? what type does it have?
I can agree mine is extremely quiet
I did make that board. I dunno why it seems to run ok. The coupling caps, under each factory turret board, are original if you can imagine...
Also, I didn't note the B+ as being all that particularly high under normal operation. When I boosted the B+ for the 90 watts it was well over 500 vdc.
Also, I didn't note the B+ as being all that particularly high under normal operation. When I boosted the B+ for the 90 watts it was well over 500 vdc.
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Nyjblbob
Hooked on Horn's and Tubes. Go big or go home
Jeeze
. My last remaining Cit2 has Sprague Vit Q's Huge, good on horns, a bit lifeless on normal speakers.the one I traded away had Orange drops, it had a bit more snap.and quickness.
You guys are the best! My house is running at 124.5, think I'll start there...