Is it a 1971 or ‘73 JMP 50W? Or something else?

[WillietheWimp]

Thank you, I’ll post it when I get time to also put it on YouTube.

 

[WillietheWimp]

You have to upload the video to a hosting site or YouTube and link it. If you click on the second set of dots at the top of the reply window, you’ll see an icon that looks like movie film. Click on that, and there will be a place to paste the link to the video.

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The first video is me playing it on Monday.
The second video is from 6 years ago, a former owner of the amp compared it to two other JMPs. He has it listed as a ‘71 in the video.

 

[Deftone]

Sounds killer to me!

 

[FleshOnGear]

Yeah sounds great! Despite the overwhelming room reverb in the second clip. In the second vid the 1972 sounded the softest to me, but I’m not sure they had the levels totally equal.

 

[TAZIN]

View attachment 131434
@WillietheWimp just trying to help....

The amp appears to have been originally a Bass circuit which was converted to mostly Lead specs. I recommend changing the bias feed wire to the hot side of the Standby switch.

 

[Mott]

Def a '71, that's the C in the serial number. S/A means 50 watt.

 

[Central Scrutinizer]

Welcome to the forum.

Nice score @WillietheWimp !

Enjoy that bad boy!

Are you proud you bought it? Cause, this is the month to have pride in your purchases!! Woo Hoo !!

I bought a ‘77 Marshall 2204 on 5/26/23, which is close enough to 6/1/23. I have enough Pride in that amp to last me the entire month of June, hell, maybe through July.

( not trying to steal your pride, seriously congrats)!

 

[tonelicious101]

It's a 1971 amp. Looks pretty decent based on the photos.

Yes it looks identical to my 71. Still my favorite 50w for the Marshall thing. It just has that harmonic magic and touch feel to it. It's happiest running around 110 volts on my BrownBox as well.

 

[Scumback Speakers]

Gut shots of my 71 JMP 50w, in case you need them. Mine has had a lay down PT added to it, and a MV volume mod removed.

 

[WillietheWimp]

Welcome to the forum.

Nice score @WillietheWimp !

Enjoy that bad boy!

Are you proud you bought it? Cause, this is the month to have pride in your purchases!! Woo Hoo !!

I bought a ‘77 Marshall 2204 on 5/26/23, which is close enough to 6/1/23. I have enough Pride in that amp to last me the entire month of June, hell, maybe through July.

( not trying to steal your pride, seriously congrats)!

Thank you very much! And yes very proud, I’ve only had clones, newer origin, class 5…those have been sold…nothing like the genuine article.

 

[WillietheWimp]

Gut shots of my 71 JMP 50w, in case you need them. Mine has had a lay down PT added to it, and a MV volume mod removed.

Thank you. By the way I’ve been looking at a set of your metal handles for my ‘73 1960B if I can’t source some older ones with patina. Much respect and appreciation for your work.

 

[Scumback Speakers]

Thank you. By the way I’ve been looking at a set of your metal handles for my ‘73 1960B if I can’t source some older ones with patina. Much respect and appreciation for your work.

The original Marshall handles from the 60s will not fit your cab without drilling new screw holes. The ones I make are sized to replace your plastic handles directly. Good luck with your new head!

 

[Purgasound]

Def a '71, that's the C in the serial number. S/A means 50 watt.

There are thousands of 100W amps with S/A in the serial number. That doesn't really mean much.

 

[Ray Ramadon III]

Sounds killer! Was that head plugged directly into the deluxe cab with no effects pedals?

 

[WillietheWimp]

Sounds killer! Was that head plugged directly into the deluxe cab with no effects pedals?

Yes, just a Weber Mass 100W attenuator.

 

[stickyfinger]

Its defiantly pointing to a 71 as the script on the mustard caps and use of a ceramic disc in the mixer.
By October 73 Marshall was using .68uf on the presence control. Cream colored boards were now brown (Probably PCB by now I forget)

 

[WillietheWimp]

Its defiantly pointing to a 71 as the script on the mustard caps and use of a ceramic disc in the mixer.
By October 73 Marshall was using .68uf on the presence control. Cream colored boards were now brown (Probably PCB by now I forget)

What are you referring to with the ceramic disc in the mixer?

 

[79 2203]

Congrats, you are gonna love it. My Dec 71 1987 is the best amp I’ve played.

 

[TAZIN]

What are you referring to with the ceramic disc in the mixer?

He referring to the 470pF ceramic disc seen at the channel mixing resistors (470K). There are other indicators which point towards 1971 too. If the amp were a '73 you'd expect to see more Piher resistors. The chassis cutouts for the filter cap cans would be larger for '73. The serial number would be stamped in the chassis for '73. The serial number would be higher (around 6000 or so) for a October '73 build.

 

[neikeel]

There are thousands of 100W amps with S/A in the serial number. That doesn't really mean much.

Well, do we want to discuss this😉
The first gold panel 50w were Sxxxxx
The first 100w were SLxxxxx or SB.
When the metal panels came out S/AxxxxA was 50w 1969 to 1970 then C in 71 etc
The 100w had some plexi SL/A or SL/B without suffix, then the metal panel with SL/A xxxxxA or SL/BxxxxxA and on was the norm.
So strictly speaking no, there are not lots of 100w with S/A serials.