Hot Transformers
From kee–(at)–den.com Sun Mar 16 21:46:19 CST 1997
From: kee–(at)–den.com (R.G. Keen)
Newsgroups: alt.guitar.amps
Subject: Re: Tremolux Questions
Date: 16 Mar 1997 14:41:00 GMT
Xref: geraldo.cc.utexas.edu alt.guitar.amps:42108
John Templeton (jtempl–(at)–orldchat.com) wrote:
: I’ve just finished refirbishing a 64′ Tremolux. The best output tubes I
: can come up with are the stubby NOS 6l6WGB from phillips. What should
: the CAthode idle current be for biasing. I’ve got in dialed in at 36ma
: but the amp still seems to run a bit hot. Looks OK on the scope, in fact
: a bit cold if you’re used to that method. THe other thing I’ve noticed
: is that they really skimped on the power tranny. After an hour or so
: that sucker is real warm, you can touch it and leave your hand there,
: but it’s warm. Any ideas?
I’ll defer to someone with more experience on the biasing question, but
on the transformer, it’s probably not too bad if you can touch it but leave
your hand on it. That means that the transformer is down around 100-110F,
well below the limits for class A insulation (different from class A
biasing) in transformers.
If nothing else seems wrong, just too much heat in the cabinet and you
don’t just want to watch and wait, putting a 12VDC muffin fan in the cab
set to run on rectified 6.3VAC (which makes 8-9Vdc) will run very quietly
and move enough heat to chill things out inside the cab dramatically. Any
moving air at all over tubes and transformers runs the temperature rise
down a lot. You’d want to do any mounting work so it could easily be
removed, perhaps with nylon or acrylic tabs set on double sided foam tape.
From Teleologis–(at)–orry.NoEmail Sun Mar 16 21:47:09 CST 1997
From: “Teleologist”
Newsgroups: alt.guitar.amps
Subject: Re: Tremolux Questions
Date: 16 Mar 1997 15:32:48 GMT
Xref: geraldo.cc.utexas.edu alt.guitar.amps:42112
R.G. Keen
> John Templeton (jtempl–(at)–orldchat.com) wrote:
> : I’ve just finished refirbishing a 64′ Tremolux. The best output tubes I
> : can come up with are the stubby NOS 6l6WGB from phillips. What should
> : the CAthode idle current be for biasing. I’ve got in dialed in at 36ma
> : but the amp still seems to run a bit hot. Looks OK on the scope, in fact
> : a bit cold if you’re used to that method. THe other thing I’ve noticed
> : is that they really skimped on the power tranny. After an hour or so
> : that sucker is real warm, you can touch it and leave your hand there,
> : but it’s warm. Any ideas?
>
> I’ll defer to someone with more experience on the biasing question, but
> on the transformer, it’s probably not too bad if you can touch it but leave
> your hand on it. That means that the transformer is down around 100-110F,
> well below the limits for class A insulation (different from class A
> biasing) in transformers.
>
Definitely agree that this tranny is not really too hot. Being able to leave
your hand on it after an hour of playing is a good sign! The piggyback
Fenders do retain more heat due to limited circulation – you could probably
fry an egg on top my Dual Showman head after an hour or 2! 🙂
The Tremolux uses the same lower voltage power tranny as the Vibrolux. It
could probably take a little more current (38ma) if you want a fatter sound.
Watch the plate voltage though, things can start getting muddy IMHO if its
falls much below 400V in these amps. Remember – this amp lacks the extra
preamp gain stage of a reverb model & won’t distort the same. I’d leave it
cleaner & try playing it together with your DR – maybe with a volume pedal to
control the distortion on the DR! 😉
