advice needed

[BaRTY]

Got a 1959 with added pot on back panel. I want to make sure it is a PPIMV.

 

[Rick Lee]

Is it a 1959 or a JCM800? They're totally different amps. Whatever that mod is, it's very sloppily done. What's that micro switch on the front panel? I have a PPIMV 1959SLP and it looks nothing like this. Your amp needs to go to a pro for a full checkup and cleanup.

 

[BaRTY]

Rick, FYI there were stock JCM800 with 1959 circuit (4 inputs). Marshall made them in small quantities during 80s.

 

[Rick Lee]

Oh, I've seen the four holer JCM800s. Just didn't know they were the same circuit as a 1959. Since all 1959s were four holers, AFAIK, why would they call any of them an 800?

 

[BaRTY]

JCM800 refers to marshall amps from 81 thru 89. Every one was a JCM800.
1959 model were produced in 80s.

 

[Racerxrated]

JCM 800 was the name change when Marshall finally got out of the RoseMorris deal. So, Like JMP model 2203/4, 1959/87, JCM 800 had those same models plus 2205/10, 4210/11, 4010/4104. I have a JCM 800 1959 out for a mod as we speak.
JCM 800 was Jim Marshall's license plate.

 

[Racerxrated]

JCM800 refers to marshall amps from 81 thru 89. Every one was a JCM800.
1959 model were produced in 80s.

I think I've seen 800s from 1991. My black tolex Jubilee 2555 is from 1990.

 

[Racerxrated]

.

 

[rstites]

Oh, I've seen the four holer JCM800s. Just didn't know they were the same circuit as a 1959. Since all 1959s were four holers, AFAIK, why would they call any of them an 800?

As already noted JCM800 was the series. There were 3 different 100 W amp models in the series: 1959 non-master super lead, 2203 master lead, 2210 channel switcher. It's funny buy I've heard people refer to both the 2203 and 2210 as "JCM800" as if it's the model. They're very different beasts. There were 50W versions of all of these too.

Also, after the Silver Jubilee year was complete, you could purchase the 2555/2550 amps as JCM800s.

 

[PatF]

Barty, That is a PPIMV but it looks pretty nasty. If those are wire strands hanging out, they could short something. It's a dual 500K pot like the original Rich mod. The later LarMar used 250K with 2.2M resistors. That dangling jack which looks like a line out must go before it shorts something out. The presence pot has a cap with too long of leads. That has to go. The ground buss is also broken off the back of a couple of pots. That switch and the yellow wires and ceramic caps that go to it looks really bad. One joint on that added terminal strip looks like it is unsoldered. Sometimes the messy ones sound killer. Not the end of the world. It just needs a moderate amount of clean up work done.

 

[BaRTY]

Barty, That is a PPIMV but it looks pretty nasty. If those are wire strands hanging out, they could short something. It's a dual 500K pot like the original Rich mod. The later LarMar used 250K with 2.2M resistors. That dangling jack which looks like a line out must go before it shorts something out. The presence pot has a cap with too long of leads. That has to go. The ground buss is also broken off the back of a couple of pots. That switch and the yellow wires and ceramic caps that go to it looks really bad. One joint on that added terminal strip looks like it is unsoldered. Sometimes the messy ones sound killer. Not the end of the world. It just needs a moderate amount of clean up work done.

ParF, thanks a lot. This is the answer I wanted. I will take care of it tonight. But it sounds fine.
Anyway I will take it to a tech.

 

[PatF]

Cool man.

 

[jcmtone1]

Barty. How does the PPIMV sound and how well does it control the volume? I have a JCM 800 1959 and have been debating adding a PPIMV or going the Fryette Power Station or THD hot plate route.

 

[BaRTY]

Barty. How does the PPIMV sound and how well does it control the volume? I have a JCM 800 1959 and have been debating adding a PPIMV or going the Fryette Power Station or THD hot plate route.

Well, it does the job just fine. I prefer using ppimv master control over attenuator.
I have got Torpedo Reload. I use it on all my amps except for this Marshall.

 

[thenine]

Barty. How does the PPIMV sound and how well does it control the volume? I have a JCM 800 1959 and have been debating adding a PPIMV or going the Fryette Power Station or THD hot plate route.

I have one too. Ive used it as my pedal platform amp, all my pedals sound the best through it. Insanely LOUD! I have been debating having some type of Master Vol installed b/c this amp mostly just sits these days. No loop is a real pain as well. Not sure what to do.

 

[jcmtone1]

They are insanely loud. The fryette power station will allow you to attenuate the volume and the. Add your effects before the power amp section. The only downside is that it is another piece of gear to buy and haul around to gigs.

 

[sahlomonic]

As PatF said, yes it is a PPIMV, but an absolute horrible and extremely unsafe job. I wonder how long those ceramic disc capacitors would last as they aren't the correct type you'd typically see in those positions.

Glad you asked about it instead of assuming it was safe to run!

Now I don't claim to be top tier/pro at wiring/soldering, but here's the PPIMV I put on my buddy's Super Bass clone last month:

 

[sahlomonic]

And might want to get that bias wheel replaced too. Not sure why it's burned up and melted like that...