Metropoulos Forum

I found a 1974 Marshall super lead mk II on guitar center used that someone ruined so badly that guitar center had to remove the vintage tag. At some point in the amplifier’s life, someone changed the front metal face to a JMP 2-input, scrubbed off the JMP masking, and removed the polarity switch. The board was swapped for what looks like a real Marshall jcm800 100W 2203 board.

I have the serial number and matching identification tag. How do I get a replacement metal faceplate non-MV that has the correct MKII marker? I reached out to my friend over at scumback speakers and he sent me here saying George used to help him on problems like this? Thank you ahead of time!

-Matt

Correct 4 hole JMP metal front panels are available on e-bay, both worn originals and new repros.
The Mk II Master script rear panel will be much more difficult to find.
I have a blank serial rear metal panel to spare but my front panel is a plastic copy (not bad, but not original)

It’s not a JMP from what I know, I thought those were 75-80? The rear panel has block lettering, will that matter? The front panel has virtually no lettering left on it at all so anything would really look better.

I looked on eBay and couldn’t find anything before posting here or asking around for help. Is there an eBay store you watch explicitly?

Thanks for the help,
-Matt

A 1974 100w Superlead will be a JMP 100, Model number 1959 with gold brushed aluminium panels.

On some US amps there was a polarity switch where the JMP went.

If you are restoring the amp I suggest you delete the polarity switch and use a JMP front panel.

The SUPERLEAD 100 will be in block as will MKII

Post some pictures of the whole amp and we can see.

Sorry for the delay, out of town on holiday travels.

Here’s some pictures:

It has been recovered in elephant tolex (covering up the gold piping channels).

Any board pics?

I have none so far, but i know it’s a 2203 jcm800 board that someone swapped out. It’s been modified for sure and has a ton of gain. It looks like someone who knew what they were doing was in it at some point, and then someone who had no business near a soldering station was in it. Tons of electrical tape and shoddy work, but all fixable.

If the headshell was retolexed then it was done in the 70’s or 80’s. The headshell is beat up really bad.

My 74 can take more pics if you need

Pics wont post

Here's some interesting info, it was posted on reverb about 2 years ago in FL. I guess the owner couldn't sell it privately, so he ripped off guitar center. I'm sure they sent it to CA to be evaluated as a vintage model where it sat for the past few years:

https://reverb.com/item/4134601-vintage ... input-6550

https://www.thegearpage.net/board/index ... e.1823845/

The board is identical in shape in these pictures as it is now. It's quite the project, but I plan to do the following:

- All new PEC pots
- New 16 AWG 12-foot power chord
- ARS 50/50/500V caps
- Mojotone replacement faceplate
- Dual output Standalone 12V and 6.3V 120V AC-DC Regulator
- Install a metro-loop (Are these good enough to install in series or should it be in parallel with a mix knob?)
- Replacement period-correct headshell from Stonage
- Replacement Logo as this one is cracked into 11 pieces - likely when it was removed for the re-tolex
- Keep the board it has now, but clean up the wiring, remove dodgy work, and improve the ground plane/signal integrity
- New bus wires
Bring back the polarity switch and use it as a switch for 50W/100W mode
Install a pentode/triode switch in the location of the direct out hole
Use the line level hole as a resonance knob

I do plan on installing another master volume in the rear of the amplifier which will be relay footswitchable, along with the effects loop. The footswitch will plug into the front of the amplifier in an un-used jack.

The amp sounds great as is and the chassis has already been drilled/devalued with the current mods. I plan to simply bring it back to life.

I may have to remote mount the metro-loop as I'd like to use the original effects loop holes to keep from drilling new ones.

I did confirm it has the original PT. The OT is questionable, I have a 50/50 hunch someone removed the bells from the original OT and replaced the core. I need detailed OT pictures from a period correct model along with what the leads look like from an original to really tell if it's also original.

I didn't lose my behind on it money wise and actually got a great deal considering it's tag and serial number check out - so don't worry there at all

I plan to keep everyone updated as to how it goes. I may need some help along the way.

The board actually looks very clean and original for a late 70s version (later than the 74 type).

Remember PEC pots don't solder so you need to raise the bus bar above the pots by threading through the pot loops.

neikeel wrote: ↑

Sat Apr 27, 2019 8:15 pm

The board actually looks very clean and original for a late 70s version (later than the 74 type).

Remember PEC pots don't solder so you need to raise the bus bar above the pots by threading through the pot loops.

Thank you for the tip, I didn't know that about PEC pots. I've actually considered removing the board completely and starting over with all new hardware, sockets, switches, etc. It makes sense to only do this once.

Where can I source replacement bat wing switches? Would it be period correct to go to Cliff metal toggle switches? Mojotone said they would be glad to help. Polarity switches were found on the left-most of the faceplate correct?

https://www.ebay.co.uk/itm/MARSHALL-Bla ... SwfZ1WZmOi

These are the correct switches, c/w the dress rings (albeit modern ones)

I do not see any point in ditching the original board unless it is faulty or you are modding extensively. The resistors are better quality than most and those red caps are quite popular for their tone.

Certainly the wiring needs tidying up and ideally a new front panel.

As there are holes on the back I would spend my money on a Metro loop rather than new pots. The original CTS pots are pretty good, I would clean them with Deoxit cleaner and then lubricate them with Deoxit gold, just my 2cents.

Adding a polarity switch adds nothing nowadays and serves no purpose.

In fact those are the correct Arrow black bat switches in the pictures!

Here’s the status so far.

I have completed a recap job, I designed a dual bias daughter board that needs testing. I’ve designed and had made a replacement Marshall faceplate. The front doesn’t match the brushed aluminum back but I’m ok with that - this is a bastard build if there ever was one so I’d expect nothing less.

I have a DC heater supply for the preamp tubes and I’m floating the power tubes on 12V CT.

I ordered a variac, isolation transformer, and power meter to be able to turn it on slowly to test the recap job and the bias board.

I’m building the relay circuit now so that the stock switches can be used to turn on the DC supply without being damaged by the inrush current of it which they are not rated for.

Stay tuned!

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