JMP50 Layout Diagram Needed

[guitarmancan]

I'm wanting to build a JMP50 clone from scratch not a kit. This is my first time so I need some help here please. I need a complete parts list with all the part numbers and stuff. And a very easy layout to follow of all the connections in building this amp. I have a little understanding of how one works. I have been playing the guitar for well over 30 years. But would like to explore this hobby some. I'm not big on reading schematics and most of what I have found is very hard to understand not drawn out easy enough. And the transformers I can't seem to locate a standard part number that I can cross locate from other people who make them. Any help would be fantastic.

I'm sure I should start from a smaller amp to make my first build but this is the amp I want.

I found the one I 'm posting here but I can't read all the parts in it.

[martin manning]

IMO what you are asking for is a kit. Triode Electronics sells one (actually a JTM 50), and there is also one at Ceriatone. Magnetic Components part numbers are listed with the kit on Triode's site, or you can find a JMP 50 set at Marstran or Mercury. That's a very nice and fully-legible layout drawing you posted; thanks! Here's another one: http://home.comcast.net/~mamp17/1987%20Layouts.html

[guitarmancan]

IMO what you are asking for is a kit. Triode Electronics sells one (actually a JTM 50), and there is also one at Ceriatone. Magnetic Components part numbers are listed with the kit on Triode's site, or you can find a JMP 50 set at Marstran or Mercury. That's a very nice and fully-legible layout drawing you posted; thanks! Here's another one: http://home.comcast.net/~mamp17/1987%20Layouts.html

Thanks that might be what I'm looking for. I wanted to buy all the parts a little at a time instead of going broke with a kit but this might be better.

[martin manning]

My bad, there is a JMP 50 (Model 1987) kit at Triode, and you can download a layout there too.

[Reeltarded]

The transitional model that is the first after changing OT for EL34s is the goodest one, you are building a JTM45 with silicon rectifier and 34s.

Easy to buy a kit. Best to plan it out and buy the Metro chassis. Will make the better amp of anything available I think.

[M Fowler]

What is the history of JTM45/JTM50

I see kits like Mojotone with basically a JTM45, tube rectifier but using EL34's with 3k4 OT.

Triode has the JTM50 Blackflag tube recto and EL34's.

Tubedepot has the modded version JTM45 plus with tube recto and EL34's

[martin manning]

According to Michael Doyle's book "The History of Marshall," the switch to EL34's was made in early 1966, and it was due to the high cost and poor availability of KT66's. Also for cost reasons, the GZ34 was dropped at the same time, "although the tremolo amplifiers seem to have retained the GZ34 for a while longer." Different transformers and increased treble response for the lead amps are also mentioned.

That was the spec (labeling changes were apparently cosmetic) until late 1967 when the chassis changed from aluminum to steel, and the initials on the panel were changed from JTM to JMP. These are all "Plexi's," as it was not until mid '69 that the Plexi panels were changed to "Alli."

Apparently there were some circuit tweaks, and the last Plexis' (from '69), and the early Alli's (pre-'72) are Doyle's favorite 50W's. No technical details are given, but the '72 50W is said to have a very early onset of distortion on the volume knob.

[Reeltarded]

Yes the late 71 early 72 50 is the best JMP. Bypassed everything and a 5000p bright cap. You are gonna dime it anyhow!

A 72 domestic British model was my favorite amp ever ever ever with a 71 export pretty easy second. Damn!

[menger66]

A scratch 50 watt marshall for a first build is pretty ambitious but doable it would be much easier with a kit, but sourcing all the parts is alot of fun also and really gets you tuned in to the amp circuit parts wise, and reading schematics is no big deal as there are layouts and tons of info on just about any amp you can think of out there already, transformers are gonna be your biggest cost id check out classic tone, and amp building is by far the most rewarding hobby ive ever had take your time do your research and you'll have a great time mark

[steve_p]

Head over to the metro forum and download their 50W build guide.
Basically everything you need:

Parts list, instructions with lots of pictures, schematics and layout.

http://forum.metroamp.com/viewtopic.php?f=24&t=14850


Have fun
Steve