68 Marshall 50W plexi on the bench

[TubeGeek]

Hey guys, I have a cool amp on my bench! It's a 68 plexi.


I have attached a before and after pic of what I have done so far.  The owner wanted new caps installed and a rats nest above the power supply to be cleaned up. I am fairly pleased with the clean up job.


Couple questions I have though....


There are a couple of 0.22uF caps on the anodes of the rectifier diodes. What is their purpose and are they necessary?  I get the feeling they are there for transient noise suppression or something to that effect.


I have the standby wired up a little different than stock...is this ok?  The rectifier diodes cathodes connect to the 50/50 cap which then connects to the standby switch.  The other side of the standby switch connects to the B+ fuse and then onto the Ct/screens/choke.   RESOLVED.


Is there anything else you recommend for this amp?  I want to make sure I do good on it, since it's a bit of a gem or holy grail amp.

[TIMBO]

Hey mate, I think your right about the .022s
Is the amp's standby NOT wired as per the schematic?

[DummyLoad]

Is there anything else you recommend for this amp?

as little as possible. if there are any mods done, revert to stock. 

--pete

[TubeGeek]

Hey mate, I think your right about the .022s
Is the amp's standby NOT wired as per the schematic?

The  standby switch was not wired as the schematic when it came to me. I suppose in my mind I was just following what was already wired in place. And now that you have clued me in I will wire it as per the schematic. I don't know why that didn't cross my mind before posting this!


Update: wired as per schematic now

[TubeGeek]

Is there anything else you recommend for this amp?

as little as possible. if there are any mods done, revert to stock. 

--pete

 Yes I agree. I even hesitated at working on the amp because I wasn't sure if I should. When I opened it up and saw the rats nest above the power supply I figured I'd at least give it a go and try to clean it up somewhat. It's not all stock, the output transformer has been previously replaced.  There were poor solder connections throughout and general poor attention to details.

[purpletele]

Nice work, it looks a little sharper.

That's a cool amp!