SE amp problem

overdrajv · 31st October 2010, 06:05 PM

I just finished my first project. An all tube SE kt88 guitar amp with reverb. When I turned it on everything sounds fine, but when I turn the master volume above one quarter it starts to produce some audiable high frequency oscillation through the speaker,and a moment after that something starts to hiss in the amp head (I think it is the OT). I also noticed that if I turn the reverb full on, and the master volume just below the oscillation, then if I turn the reverb lower it starts to oscillate again.

Any ideas?

Miha

kevinkr · 31st October 2010, 08:54 PM

How about pictures of build and schematics to start, and then we might have some ideas of what to tell you..

Symptoms you describe sound like oscillation, but without the above information we can't tell you anything useful.

31st October 2010, 06:05 PM	#1
overdrajv diyAudio Member Join Date: Dec 2007	SE amp problem I just finished my first project. An all tube SE kt88 guitar amp with reverb. When I turned it on everything sounds fine, but when I turn the master volume above one quarter it starts to produce some audiable high frequency oscillation through the speaker,and a moment after that something starts to hiss in the amp head (I think it is the OT). I also noticed that if I turn the reverb full on, and the master volume just below the oscillation, then if I turn the reverb lower it starts to oscillate again. Any ideas? Miha

31st October 2010, 08:54 PM	#2
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	How about pictures of build and schematics to start, and then we might have some ideas of what to tell you.. Symptoms you describe sound like oscillation, but without the above information we can't tell you anything useful. __________________ www.kta-hifi.net

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