Jmp. Pa 20

[taylorgateside]

Hi. Any thoughts welcome
Going to talk to Marshall about checking out my PA 20. 1972

Not been played for 20 years or so in garage storage
EL 84s are these original?
Additional handles (fitted before I got it)

How much will Marshall charge as a "have a look" fee ?

Pics enclosed

 

[strat59]

WHY would they fit 2 x carry handles on a 20w head. I have no trouble lifting my JTM-45 , JMP-50 Plexi's with the orig handle marshall fitted. Chicken head knobs.

I'd be sending it to a good tech rather than Marshall (if you're in the UK). John Chambers http://www.chambonino.com/work/marshall/marsh1.html
is top notch with Vintage amps.

 

[jon1917]

EL84's would be stock for the amp. Can only imagine something else was stood on top of the amp as they look more like brackets than handles.
Very cool amps. Delightful clean tones with volume upto about 4. Above 8 or so with tone up full, stand back, it will suprise you and put a big smile on your face.

 

[jon1917]

Also, before you plug it in, check the wiring on the transformer which will show you what impedence it is hard wired to.

 

[jph]

Are there PA20 experts online?

I have a '69 and I have always been wondering if the coupling caps are originals or not? Thin green things with the text "Hunts M312". Did Marshall use Hunts capacitors late 60s?

However the amp sounds great but I am still thinking to replace those Hunts with NOS mullards.

Speaking about amp techs. I have three vintage Marshall JMPs from 60/70s and I just noticed a funny thing. All of them have been serviced several times in 70s and 80s by Noble Music in Cardiff. What is the likelihood of that if I live about 3000km away from Cardiff?

 

[jon1917]

As they are all the same brand and the varnish on the turrets seems to match the rest of the amp, I would say they are original to the amp. Marshall may have run out of Mullards on build day.
If the amp sounds good, I would leave alone. Schematics of the amp are plentiful online so you can check the values of the Hunts match.

 

[george76]

Are there PA20 experts online?

I have a '69 and I have always been wondering if the coupling caps are originals or not? Thin green things with the text "Hunts M312". Did Marshall use Hunts capacitors late 60s?

well clearly they did. those look very much original to me.

dont mess around with vintage gear when its in original condition. ;o)

 

[jon1917]

That cab looks class. 8 x 10?

 

[jeremybusby]

One of my JMP50T has the same caps - definitely original!
I have a 69/70 metalface PA20 as well. Beautiful sound with all original Mullard Valves!

Buzz

 

[jph]

That cab looks class. 8 x 10?

Yep, it is 2034 (8x10) from early 70s. Nice bright sounding cab and suits with the pa20 very well to me. Unfortunately(?) original speakers are replaced with later ones.

One of my JMP50T has the same caps - definitely original!
I have a 69/70 metalface PA20 as well. Beautiful sound with all original Mullard Valves!

Buzz

Thanks Buzz! That I was looking for. Is your JMP50T '69?

 

[jeremybusby]

Difficult to tell - When it was made,Marshall must have been short of Mustards! There are only those Hunts Green caps and Dubiliers as well as one or two RS. I would guess it is more like 67/68 or so. Serial is T/A 10374.

Unfortunately the tremelo amps serials seem to have a mind of their own.

Lovely sounding amp 'tho - quite agressive for that period.
PT has been replaced at some point with completely the wrong one - runs 490v on the plates!
Buzz

 

[janarn]

With connection wires on top of the turret board and a T/A prefix is more likely a '69.

 

[jeremybusby]

Thanks Janarn
Do you have any idea of when changeover to the split turrets with wires underneath occurred?
Buzz

Sorry to hijack your thread taylorgateside!

 

[janarn]

Older Plexi amps had the wires underneath the turret board.
Look at the '68 and '69 amps here:
Amp Archives/Marshall/50 Watt Series 1966-1981/1987T Lead Tremolo 50W

 

[graydane]

Love those 20's I have a '69 JMP Bass 20, and a '72 JMP Lead and bass 20. Amazing heads. congrats

 

[Birk]

Nice amp!
I've got a '73 Lead&Bass 20 watt head.
As far as I know, Lead&Bass and PA are almost identical, how does a 20 watt PA head preform? My Lead&Bass doesn't have a lot of headroom.

 

[Birk]

BTW, what does these 20 watt heads go for these days?

 

[damienbeale]

In very good condition they seem to be changing hands for around £800 around here.

 

[explorickenbacker]

What!?! A 20 watt JMP?!?! What model is it? where do i get one?!

 

[Birk]

For £800 I rather keep it...