Admiral power amp SEP questions.

[jeb98]

I recently pulled a power amp from a junked Admiral console. I don't know much about tube equipment from a technical standpoint, and this amp uses just three tubes: two 6bq5 tubes and one 5u4 rectifier. So there are no driver tubes, such as the 12ax7. My question; can this amp be used as a stand alone power amp with no driver tubes?? Sorry if this is a stupid question!

I will take pictures when j get the chance.

 

[wa2ise]

It will need a driver tube stage. It probably was on a tuner subcahssis. But a driver stage can be constructed on the amp you have, assuming there is enough space to mount it.

 

[Tom Bavis]

The 6BQ5 would need about 8VRMS, 23Vp-p for full output. Some preamps can do this, but no tuner, cd player etc. would come close. And without any negative feedback, there will be high distortion, poor frequency response. Wiring the 6BQ5s as triodes would help with both, but would need even MORE drive and give less output.

 

[jeb98]

The 6BQ5 would need about 8VRMS, 23Vp-p for full output. Some preamps can do this, but no tuner, cd player etc. would come close. And without any negative feedback, there will be high distortion, poor frequency response. Wiring the 6BQ5s as triodes would help with both, but would need even MORE drive and give less output.

Thanks for the replies. Maybe I can turn this amp into one of the Magnavox 8600 amps that Dave Gillespie came up with the modifications for?

Best,

Jonas

 

[primosounds]

I have made just such a mod by installing a tube socket for the driver tube. I recommend the RH84 circuit which is simpler and better sounding (imho). Here is a picture of an RH84 that was built on a recycled console amp chassis. I am using a 5v4 rectifier instead of the 5u4. The power supply is choke input instead of capacitor input for better sound. The lay out of the tubes is not optimal as i decided to use the original placement of the tube sockets.