What is a 'plexi' amp?

[dc_danman]

Hey everyone. I think the title is rather informative as to what this thread is about. Looking at some of the older marshall amps in plexi palace, some of them are called plexi's. what does this mean exactly? is it just a name given to some amps, or something a bit more informative than that? Thanks.

[bnwitt]

If you want a little history of the progression of marshall amps go here:

http://www.drtube.com/marshall.htm

The plexi panels ended in 1968 and metal panels came in in 1969. Alot of folks refer to the model 1987 Marshall as the plexi amp as well.
Barry

[zenstate]

I thin plexiglass was another name for what is actually perspex....??

[ampkits]

Hi,

Plexiglass is trademarked by GE(?).

I have seen several plexis with broken panels. The way these panels break, i am not real sure that they were actual plexiglass.

They're more like the common acrylic/perspex.

Any comments?

thanks!

Nik

[dc_danman]

Oh, so its just the panel on the front then? oh. how mundane.

[ampkits]

Oh, so its just the panel on the front then? oh. how mundane.

Dan,

It's not mundane.

Plexi equipped amps sound wayyy better, that's why the pros pay gazillions for em.

If you can afford one, try looking for one that gives a good "Thunk" when you knock the panel.

This would be the holy grail.

)

Nik

[bnwitt]

As is shown in the Drtube link above, Plexi is a reference to certain Marshall amps built in a specific time era and not just the panel material. The Marshall model 1987 is the amp that is most referred to as a "Plexi". This amp rocks big time. The Plexi and the jtm45 are the two holy grail Marshall amplifiers in many opinions. I'm not sure how we got into the discussion of panel material when you asked about what a plexi amp really was.
Barry

[dc_danman]

First of all I wasn't saying that plexi amps were mundane, I was just... I'll stop digging..
And now I know what you actualy meant, plexi amps are an era of amps, and the fact that they have a plexi panel is just an identifier of that. Not so mundane (not at all) anyway
Its not my fault I lose intelligence every time I sneeze, apparently.

[ampkits]

Hi Barry,

Yes, true. But i guess meaning of plexi should also be given as to what it really is.

Hmm...I am not sure it's a good idea to call later 1987 amps as plexis as well.

Can you imagine:

"Hey I got a plexi amp for sale. USD 2000.00"
" Dude, here's the money man!"
Amp arrives...
" &#*#$&#*(! This is from 1972....metal panel.."

Plexiglass paneled amps were rumored to be the ones sounding better. Although circuit doesnt change much, i am not sure that as time goes by, the newer metal panel amps would have different components. They did go PCB sometime in 70s I think.

I would guess the amps that were built right after termination of the plexi panels would be same circuit/components?

But what you is true as well - we dont call the 18W as plexi amps altho the panel is same material.

Thanks!

Nik

[jaysg]

Although circuit doesnt change much, i am not sure that as time goes by, the newer metal panel amps would have different components.

I would guess the amps that were built right after termination of the plexi panels would be same circuit/components?

I think it's fair to suggest that while the circuit doesn't change much, there's a date at which the OT does and that's the devil in the details. I can testify that putting an OEI Plexi OT in a JCM800 changes the tonal spectrum towards bass and midrange, away from treble and presence. There's some irony to the notion that Jim Marshall was simply responding to the customer. Today, those not-bright-enough amps are the bees knees. Imo, the quality of PA and monitoring systems is responsible. No one really needs all that whompf coming off the stage.

As to the second question, I believe that early (1969 ?) metal panel amps are identical to '68 plexi's and are very desireable.

[chuck]

1973 is when they went to pcb.....some 73's are PtP some are pcb....