Picked up LEAK TL/25 Plus Monoblocks & Point One Preamp!

[BassKulcha]

Sounds like the right kinda guy then, but I'm not a big believer in magic capacitors or circuit changes without careful consideration.

but yeah there isn't any real magic about cathode bias. "Automatic bias" sounds fancier, but its just current flow across a resistor. It more or less sets itself, but its not in any way intelligent about it. If the tubes are tired, its under-biased. If the tubes do not reasonably match the characteristics of whatever tubes it was designed around, its over- or under-biased.

As for original condition, I'm reasonably sure someone has been in here before. I have my doubts that C-D caps were original in an English amp, and I think those pink caps on the output tube sockets are Soviet surplus parts. The caps in the pink and blue shrink wrap are probably original though.

On looking at the Sam’s TL/25 Plus service manual, it’s clear that some of those caps are not original. I’m just hoping that no modifications were done to the circuit (doubtful, but I’m a little concerned about the caps across the tube pins...)

 

[jjmcf]

You mention "restoration" ? But why not connect them and use them ? Chances are that they
will work just fine as they are, and if anything won't be perfect you can make a note
and compare after any "restoration/repair".

Sometimes "restoration" results is destruction and nullifies any value of the amps. If yoi later decides
to sell to a collector they should be in stock or near stock condition.

Unlikely they will work properly as is, if not burn your house down. British cap design was worse than ours. You have to decide whether you want to use them as practical amps or as a passive display.

 

[BassKulcha]

This world kinda exploded since the original post a year ago, so these are still waiting patiently for some attention.

I have a variac and a dim bulb tester that I can use in series to get an idea of what’s going on with these (they have had a more “recent” partial resto so the likelihood of causing damage is pretty minimal...no leaky or bulging caps, etc).

Maybe I’ll get to them over the holidays, we’ll see...

 

[peterh]

This world kinda exploded since the original post a year ago, so these are still waiting patiently for some attention.

I have a variac and a dim bulb tester that I can use in series to get an idea of what’s going on with these (they have had a more “recent” partial resto so the likelihood of causing damage is pretty minimal...no leaky or bulging caps, etc).

Maybe I’ll get to them over the holidays, we’ll see...

Good idea. Use before surgery to know whats good and whats bad.

 

[x3workshop]

Get crackin' on those!

 

[BassKulcha]

Ha ha! Yep I know @x3workshop...I have so many things to work on it's a bit daunting (McIntosh MC225, McIntosh C20, Pilot 210, Altec A-323B and A-323S, Thordarson T-31W08, Garrard 301/1, Rek-O-Kut B-12GH, Gray Research 208 tonearm, and then the Leaks . I *might* need to sell a few things off to maintain my sanity lol...)