How original is my 74 Marshall Super Lead?

[rambo123]

I just bought a 1974 Marshall Super Lead MKII. I'm wondering how original it is. The head box looked suspicious so I opened her up and uploaded some pics, I'm no tech wiz so I need this forums insight.

Here are the Pics:
ImageShack Album - 11 images

 

[wkcchampion]

Hi. First, i'm NOT a tech.

The transformers and choke look originall to me. Good!
I see no mods in the circuit. Good too,.

The filter caps (the blue cans) are original, however it's dangerous to play an amp with such old capacitors. I'd suggest replacing them (at a tech).

Ther power valves are absent, I see. I can't know how old are the pres of course.

 

[rambo123]

thanks for the input man, any other thoughts?

 

[Clammy]

A few things:

There's a master volume mod (the knob on the back)
One or both switches are changed (the one marked "Made in Mexico" is for sure)
A few resistors have been changed (not sure if they were simply replaced or used to alter the circuit)

All the important stuff looks to be original - transformers, mustards, etc...

How does it sound?

Cheers!

 

[rambo123]

Yeah I knew about the Master volume when I picked her up, didn't bother me. As for the tone its really warm, vintage sounding with some balls and more bottom end then i thought (probably the 6550s) I think I want to experiment with some other tubes see where that takes me.

 

[charveldan]

Your gonna need a filter cap job if you intend to play it, be sure to replace the bias filters as well.

Looks like all of your screen grid resistors are not the same, 3 are one type, 1 is another, it's hard to see.

One of the power/standby swiches has been replaced, and you know about the master volume.

All in all pretty good shape.

 

[TiPiMods]

I wouldn't change anything, if the amp runs without hum. I have a BF Deluxe Reverb from 63, dead stock with original Caps and it works flawless and sounds great. If an amp ist played constantly, this caps can last quite long. What makes them bad, is when the amps stays unused for a longer period.
The PPI-Mastervolume can easily changed to stock, but it sounds cool, and if you set it on full, its like a non master.
What I would change: EL 34 instead of the 6550. Sounds definitly more like a Marshall should. Or if you want it cleaner an more "Plexi": KT66.

 

[pman]

I could be wrong but it looks as though the OT has been taken off and put back on. The mounting brackets look newer. Is the iron on the OT 1.5". That was standard for the Dagnal C1998. Maybe it was replaced with a correct era Dadnall. The Speaker outputs have been replaced. I see an area under the PT mounting washers that looks like another washer was there before. Again, it looks as though it has been taken off. A filter cap job will be necessary sooner than later. I bet that thing is a tone monster. Those 1st and 2nd year PCB had lower plate voltage (some were around 410 B+). They are absolute tone monsters that will rip your head off with a good PPIMV mod. The red tolex looks a little shiny. Normally, the vintage tolex loses its luster over the years. Is the back of the tolex white fabric or red? 74' is a very great year for early break-up Super Leads.

 

[Clammy]

I could be wrong but it looks as though the OT has been taken off and put back on. The mounting brackets look newer. Is the iron on the OT 1.5". That was standard for the Dagnal C1998. Maybe it was replaced with a correct era Dadnall. The Speaker outputs have been replaced. I see an area under the PT mounting washers that looks like another washer was there before. Again, it looks as though it has been taken off. A filter cap job will be necessary sooner than later. I bet that thing is a tone monster. Those 1st and 2nd year PCB had lower plate voltage (some were around 410 B+). They are absolute tone monsters that will rip your head off with a good PPIMV mod. The red tolex looks a little shiny. Normally, the vintage tolex loses its luster over the years. Is the back of the tolex white fabric or red? 74' is a very great year for early break-up Super Leads.

I disagree about the plate voltage on early PCB amps. I have 3 Super Basses (2 '73s and a '74), and they all put nearly 500vdc on the plates. My '77 50 watter (model 1986) puts about 400vdc on the plates. I've actually never heard of a Marshall 100 watter putting less than 450vdc on the plates. I DO agree that they're tone monsters!!!

The OT looks original to me. The red dye is still intact on the through bolts. The bracket looks ok too. Check the rust and red dye on the clamp screws. It does look like the wires at the impedance selector might have been re-soldered at some point, but that could be due to re-tensioning of the sockets, or when the output jacks were changed.

Cheers!

 

[demonufo]

Only the 50 watters from the mid 70's up to early 80's had different PT's with lower plate voltages of around the 400 mark.

 

[pman]

My bad. Forgot about them drakes from the early 70's 1987/86's. 475 plate voltage is normal for that 74 1959. The tranny's look correct. In the pics, it appears that they were, or may have been taken off of the chassis. The bell housing doesn't need to come off in order to remove them. Only the lower mounting brackets. The OT bracket looked significantly less oxidized than the main's. On the other hand, the mounting screws seem to be un-marred. They are soft brass and you can usually tell if a screwdriver was taken to them.

I bought a 71 1959 on ebay that was sold as "all original". I compared it to 74, 69 and 70 that I had too. I checked the leads and saw resoldering. When either of the trannys are removed and not put back in place exaclty, one can normally see a cleaner, less oxidized area on the top of the chassis where originally they were put during the manufacturing process. On your pics, I thought I saw some clean "circular" areas where washers may have been shifted.

Don't get me wrong, I hope that the main components on your amp are original. There are some shady sellers that mix nail polish colors and match the red solder insulator. I think you can even buy that red insulator today. After years of aging, the organic pigments can turn dark from age and heat. An early metal face PTP superlead that I bought had 3 different shades of red on the joints and also had marred areas where the red color was perfectly intact.

No bad vibes meant to be given. Just my thoughts.