Magnavox 8802 Sound Degrades

[MagnoliaSea]

Hi All,

Brand new to the hobby and looking for some help. I have a Magnavox 8802 or 8804 (how can I tell the difference?) that a friend gifted me after he did some restoration work on it. I recently replaced all of the tubes (1x 6CA4, 2x 6EU7, 4x 6V6). When I use the amp it sounds great for about an hour, but then the volume and bass decline and there is an echo to the sound. I looked underneath the amp and it looks pretty well refreshed by my friend (i.e. some newer wiring). I know nothing about how to repair these, but I would love to learn enough to do any additional restoration/mods the amp needs myself. It sounds awesome when it works! Any ideas on why the sound changes after a relatively short amount of use? Could it be overheating and I just need to use it for short sessions? Thanks for your patience with a new guy.

 

[tonyg88]

If on both channels could be power supply related or preamp tube acting up.

 

[century tek]

Has it had new can capacitor replacement(s)? Coupling capacitors? Maybe a tired rectifier tube? Just some things to check!

When working properly, you can use it for days at a time if you wanted to. Just because it is tube doesn't mean you have to limit your listening. People used to leave their consoles on 24/7. At least my neighbor did while growing up.

 

[tonyg88]

Has it had new can capacitor replacement(s)? Coupling capacitors? Maybe a tired rectifier tube? Just some things to check!

When working properly, you can use it for days at a time if you wanted to. Just because it is tube doesn't mean you have to limit your listening. People used to leave their consoles on 24/7. At least my neighbor did while growing up.

My magnavox was ran 24/7 when I had it until I did a failed recap

 

[danrclem]

Welcome and if you post a closeup picture or two of the bottom somebody here should be able to tell you if it's had the capacitors replaced.

If it hasn't been painted it should have 8802 or 8804 stenciled on it.