Restoring a '69 Super Lead

[Carbia]

Hi guys!

A friend of mine sent me a '69 Marshall Super Lead he bought in eBay to service.

The amp board is pretty pristine and untouched (have the red paint in all solder joints) but sounds terrible

First thing I did was forming the filter caps using Larry's method and it has great leaks (I don't go under 20v after 24h).

After that I tried the amp anyway and when you go above 3 on the volume, the amp has an horrible compression. Sounds small and ungly, so fisrt step will be changing the filter caps.

The power tubes needs to be changed too. It's a shame because is a quad of XF2's... but they measure very poor on my tube tester.

But the thing that really annoys me is the power cord socket.
The original bulgin plug is lost, I have a cable soldered straight into the amp, but I need something to put on the bulgin hole.
I tried before the drop-in replacements for bulgins that TAD sells but they don't fit on the hole, it needs to be enlarged anyway.
Do you know some alternative?

A pic:


thank you in advance guys

[Tazin]

There is an IEC socket that should fit the pre-existing hole. It mounts vertically rather than the typical horizontal type. I forgot the damn part number though.
It's a shame that the filter caps wouldn't reform since the rest of the amp componets looks original.
Also, the amp looks more like a '70 rather than a '69....Is there a date on the tag sheet?

[Carbia]

Tazin, I think you talk about this IEC: http://www.tubeampdoctor.com/de/shop_Ka ... uchsen_318

I bought one of them to my '71 and I had to enlarge the hole
Don't know if there's another part better to do the job.

About the date... honestly I can't remember if there's a tag... I only paid attention to the serial number finished in A.

Thanks for answering

[neikeel]

A metal plate with hole drilled and strain relief for cable is neat (particularly if you use one of the plates used by Marshall to cover the unused socket on V1).

Presume you don't want a Bulgin?

[Tazin]

Yeah, those are the IEC sockets I'm talking about. I thought people were sanding a millimeter off each end in order to get them to fit?.....I believe there was enough plastic thickness there to do this.
Or you could always do what Neil mentioned with the metal and strain relief setup.

[Carbia]

Neil, you're right, I don't want a Bulgin. To me is a piece of shit

Tazin, I sanded the IEC but anyway I had to enlarge the hole a little bit.

Any place to buy one of these plates?
I guess Valve storm, but paying overseas shipping for a plate...

[Tazin]

The easiest way is just to make your own metal plate.

[neikeel]

The easiest way is just to make your own metal plate.

I can send you one, but you will have to drill a hole in the middle!

[Carbia]

Thanks Neil.

I'm going to think about and if I decide to go for the plate I'll let you know

[Carbia]

Hi Guys!

Amp is running fine now

Sounds pretty fine

Things that I did:
- New F&T electrolytic caps
- New pilot light (the other one was death)
- New tube set, a quad of JJ EL34II (great tubes by the way)
- New AC socket. IEC instead of bulgin.
- Replaced PI caps (Mustards were leaky)

After that, the amp sounded fine... but a little bit fuzzy.

After looking around for a while... I discovered the mistake.

Marshall installed a wrong V2 cathode resistor!!
It was 10k isntead of 1k.
The guy on the factory mixed up orange with red...

I'll post photos, but it was factory installed, still with the red paint on the solders.