Friend with an old amp

[Ruidoso Bill]

How do I get into these things, must be I like punishment, brother in law told neighbor I like tubes, expert, since I built three amps.

Anyway I need some help!

Here is the amp:

Symptoms bad hum. Suspect 60 hz hum, bad ps caps, cannot clearly read values. Not many caps total, probably redo them all. I haven't tested the tubes yet either.

Anyone recognize this critter?

 

[Steve Morley]

Looks like something from an old console stereo. Keep the power transformer, junk the rest.

S.

 

[Ruidoso Bill]

Thanks Steve, I don't want or am I interested in a total rebuild, if it were mine, just a new set and be done, however not mine.

What would you think of

#1 Test all the tubes
#2 do my best to identify the caps in the ps and replace those.

if that doesn't work just say I'm sorry and give it back.

He took to some audiophile tube type in Abilene that said the same as you, rebuild it.

Second look I can't even Identify the tubes...

 

[Steve Morley]

I'd just give it back and say it's most likely a money pit. Even if running properly it wouldn't likely satisfy a non-tube loving "civilian".

S.

 

[KeesB]

I would start with new supply caps and then if necessary test the tubes, first the amp part and later (if necessary) the other ones.

 

[ticknpop]

It looks like it needs a major overhaul, caps, tube testing , lots of time etc. From the pictures it doesn’t look like it’s worth the effort unless it has some sentimental value.

 

[WhiteDragon]

It does not scream collector value.

But does not look like much more the 6 or 7 electrolytic caps.

If it still works but just loud hum.
Probably just a few caps and run again.

 

[Ruidoso Bill]

already half through the tubes, gonna start with ps caps, deoxit the controls and tube sockets and hope that's it. Thanks all for the input, very much appreciated!

 

[Technical]

You can just (CAREFULLY) use something like a 40MF 450 volt electrolytic cap with a couple of clip leads and bridge each power supply cap to see if the hum drops, then replace any that reduce the hum when you connect the substitute cap.
The cap will hold a charge so be sure to short the leads when you finish with it.

Peace,
Technical

 

[pcan]

I don't see the fuse on the primary side of the power transformer. Check it, or add a fuse holder if needed. Wiring and safety capacitors on the primary side of the power transformer need to be checked and made more safe, if possible. A new power cord with earth connection could be a good idea.