Sound master # 34 tube amp

[Khaled011]

Hi everyone,

I bought a new tube amp: "Soundmaster No.34" (Convergence Corporation No. 34 Sound master Tube Amps)

Does anyone have a schematic diagram?

I am new to tube amps and would like some help since I noticed that high frequencies disappear at high volume, but sounds good at low volume. Is this normal with tube amps?

Thanks in advance.

 

[IceFyre13th]

Velleman, Inc. - International - Overview

Looks real similar if not a direct copy of.................

 

[DF96]

I am new to tube amps and would like some help since I noticed that high frequencies disappear at high volume, but sounds good at low volume. Is this normal with tube amps?

No. It could indicate that the volume control is too high a value so creating a low pass filter with the Miller capacitance of the next stage. This effect would be at its worst at -6dB volume - so nearly maximum assuming a log law pot.

 

[Khaled011]

IceFyre13th: Thanks for your reply. The chassis looks nearly the same but not the same amp. Mine is only 2 ECC82 and 2 EL34 per channel.

 

[Khaled011]

Dear DF96, Mostly you are right.
But I can not confirm without having the schematic diagram. If I find one otherwise I would have to draw myself. Thanks a lot.

 

[kevinkr]

Pretty easy to confirm even without a schematic if the volume control pot resistance is anything greater than say 100K. A quick measurement or visual inspection should confirm. Even worse if there is an input LPF in the first stage right after the volume control.