80W amp with a pair of EL34

[dzseki]

Hi!

Newbie here...
I got a tube amp for free (without tubes), it was manufactured by a Hungarian factory called BEAG and the actual type is EA080. This is a PA amplifier with 100V output, it puts out 80W with two EL34s from 840Vpuffered secondary voltage (don't know the actual anode voltage). I want to build a preamp for the amp, and then I want to use it as a guitar amp. what is your opinion this set up, will the amp eat the EL34s with that high voltage?

 

[knoberik]

The 100V output is quite unconvinient to use for guitar amp as this voltage will not match with regular low impedance speakers.
I'd suggest you better to find an amplifier Beag AEX250 or AEX251 or AEX650. In Hungary I think you can find them easily. Those are real instrument amps with 16/8 Ohm output. Push-pull made on EL34. No separate preamp needed.
All amps mentioned are made on same model of output (Beag TK150) and power (Beag TH150) transformers, very good ones. Even if you can get those transformers only (from amp wreck etc), you can make easily a good EL34 PP amp of your own.

 

[dzseki]

Thanks for the advice! Yes, I know the 100V output is inconvinient, but I already have a spare line transformer which can be used to back transforming the 100V..
Although here in Hungary the beag tube amps are quite rare, and often overpriced..

 

[knoberik]

Yes, I know the 100V output is inconvinient, but I already have a spare line transformer which can be used to back transforming the 100V..
Although here in Hungary the beag tube amps are quite rare, and often overpriced..

There will be some additional distortions by meaning of signal band, when you use the line transformer. It must be quite big and over dimensioned also.
Originally the EA080 amp was designed for spreading propaganda thru hundreds of small listening point speakers, located in communist party comrades offices. Therefore was eliminated them listening the "wrong" radio stations...

In times the Beag produced I suppose if not millions then hundred of thousands of those smaller AEX25x series amps to fullfill Eastern Europe demands. I built an EL34 PP amp on Beag transformers, those play quite good.

The EA080 amp seems to work mostly in class B with such a high B+. Maybe for guitar it will be somehow suitable, but not for usual music listening, it really is not Hi-End.

 

[AndrewT]

The KEL80 is a parallel push pull 80W amplifier using two pairs of EL34 in each mono channel. B+~400V and runs in ClassAB, not ClassA.