Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dscottguitars on July 28, 2012, 10:40:29 am

Title: Power tubes too close to power transformer
Post by: dscottguitars on July 28, 2012, 10:40:29 am

Hi, has anyone had a problem with 6L6's or any other power tubes being too close to the power transformer?  I have a chassis that puts two of them, one side of the push pull, in front of the power transformer about half an inch away.

Thanks...

Daniel

Title: Re: Power tubes too close to power transformer
Post by: triode on July 28, 2012, 01:07:11 pm

Dynaco sold a ton of MK III's, no one ever complained or had problems with the tubes being that close to
the transformer : http://www.head-fi.org/t/513514/fs-2-dynaco-mark-iii-amps (http://www.head-fi.org/t/513514/fs-2-dynaco-mark-iii-amps)

Personally, I have never had a problem, other than sometimes I think it can make the transformer get
hotter than I would like. Personally, I see heat as the main problem with putting them really close. Is
it well ventilated?

Title: Re: Power tubes too close to power transformer
Post by: dscottguitars on July 28, 2012, 01:36:06 pm

Hi, thanks for the reply.  Yes it is well ventilated, completely open in front and back.  I'm wasn't worried about the transformer getting hot, only the effect on the tubes if any.  Glad to know it's been done before.

Title: Re: Power tubes too close to power transformer
Post by: thelonious on July 28, 2012, 02:26:28 pm

This little 2x6V6 PA amp I'm converting has about 3/8" clearance between one of the power tubes and the PT, and it has been functioning happily since the 40's, if I'm reading the date codes correctly. Other than the PT getting hot like Triode mentioned, it seems to work quite well.

Title: Re: Power tubes too close to power transformer
Post by: Tyrannocaster on July 29, 2012, 06:33:26 am

Let me add to the chorus: my latest build (a tweed Pro-ish thing) has an OT that is bigger than I realized - in fact, the damn amp won't fit in the cab because the OT won't quite clear the speaker frame. I just measured the distance between the OT and the 6L6s and it's just under half an inch. The amp sounds fine - no hum at all. Anything else about its sound that I might not be crazy about I ascribe to the fact that I just prefer Marshall style sounds to tweed, LOL.