Heathkit GR64 shortwave radio

[dieseljeep]

Originally Posted by Electronic M

I've got two Heathkit A-7E monoblocks (the ones with the ultra linear screen taped output transformers and phono pre amp stage) which use two 12A6 tubes each as PP outputs. I'm listening to them now and it sounds awesome!

Always was curious why they used that type as an output, and not a 6V6 or some more common type for that, but I can't really complain that they did.

I was talking to a man that used to buy and sell war surplus electronics. When I inquired about the 12A6, he replied that they were sold for something like ten cents each, in quantity.
The 211's were sold for less than $1.00 each.

[Electronic M]

Originally Posted by dieseljeep

I was talking to a man that used to buy and sell war surplus electronics. When I inquired about the 12A6, he replied that they were sold for something like ten cents each, in quantity.
The 211's were sold for less than $1.00 each.

Is it really bad to operate my amps with the 12A6 tubes? I've put a lot of hours on those mono blocks and aside from some caps and a resistor they have been quite reliable....Not like I have or can afford getting two new pairs of output tubes for the next couple of months anyway....

What are 211's BTW?

[dieseljeep]

Originally Posted by Electronic M

Is it really bad to operate my amps with the 12A6 tubes? I've put a lot of hours on those mono blocks and aside from some caps and a resistor they have been quite reliable....Not like I have or can afford getting two new pairs of output tubes for the next couple of months anyway....

What are 211's BTW?

I wouldn't worry about them failing. I guess if they were OK, 55 years ago, they should OK today. It was just an observation on my part about them.
They weren't used much in production equipment.
RE: the 211's they're using them in those pricey, Chinese built SE mono-block amplifiers, that are sold today. They were common in WWII, surplus transmitters.

[wkand]

HI:

Excuse my neophyte question, but I've seen posts before in the forum where folks have suggested rewinding power transformers.

I've seen the inside of many over the years, and all look impossible to rewind due to the lamination of the core being enameled/glued. That enamel looks pretty sturdy. How does one get the iron plates apart without destroying them?

I assume that step would require some sort of solvent, but what would you use that would not damage plastic or phenolic coil form parts?

Would the rewind have to destroy all the wire in all windings to get the enamel off. Does heat work?

Thanks!