Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on December 10, 2017, 01:21:37 pm
-
I was given a Columbia 360 phono that was quite beat up. Turned out it had one of those "tube amps" without a power transformer in it. It had 35L6GT tubes which put out about 1.5w to 3w (I think?)
http://tdsl.duncanamps.com/show.php?des=35L6GT
I think the amp is a push/pull circuit? There is a schematic to the amp here:
https://www.audioasylum.com/forums/tubediy/messages/17/175068.html
I kept the OT from the amp thinking it might be useable for the pentode section on ECL84 tubes which have a similar output (I think?):
http://tdsl.duncanamps.com/show.php?des=ECL84
Do you guys think the OT could be used for ECL84's which I used on the SoLowWatt amp I built years ago?
With respect, Tubenit
-
You sudda kept the whole chassis and speakers, got an isolation transformer. Those upper-class phonos were sometimes magical.
The 3W is at 200V. The Columbia ran less than the 110V which gives the 1.5W result. So push-pull barely 3 Watts.
The ECL84 is nowhere near a 35L6. It needs twice the B+ just to make half the current. It is not a good match for that OT. The most available tubes suitable for that OT will BE the 25/35/50L6 or 6Y6. And at ~~100V supply; much more and the bass will just fart.
But what are you building? A stadium blaster? I guess not. A couple ECL84 @ 100V will make nearly a Watt push-pull in this low-Z load. A lame Champ, but push-pull.
-
PRR, thanks for the response! I appreciate it. I didn't know that it could have been a reasonable or good idea to have used it. :dontknow:
Anyhow, I still have the OT and tubes available to me.
With respect, Tubenit