1968 100 WATT Plexi Super Lead

[Podubbney]

Hello.Simple question here regarding the speaker jacks on the back of a 1968 100W Plexi Super Lead. Does anyone know which of the two speaker jacks on the back is which, re; OHMs, meaning if you're looking at it from the back which jack is which vis-a vis the left and the right jack?

Thank you

 

[Pete Farrington]

Their electrical function should be identical, ie it makes no difference which one the speaker lead is plugged in to.

 

[Purgasound]

The jacks are always wired in parallel. Impedance is selected by rotating the impedance selector to the desired output.

 

[21fret]

How’s it going there @Podubbney. Cool that you’re here with such a stellar amp.
We’re happy you’re here asking these questions because we’d all really like to hear this amp do the business end of it.

BTW What serial number is on that?

Nice to see someone else in the 100 watt camp.

 

[BlueX]

I hope I'm not confusing anyone, but I think some (old?) Fender amps have one Main speaker jack and one Extra, where you need to always use Main as the primary.

However, the Marshall amps I know of works as mentioned above.

 

[Joethebh]

Post some pics of the amp we want to see it

 

[Chris-in-LA]

Welcome to the forum. Don’t turn the amp on without a load connected. An old amp like that might need some special care before you turn it on. We definitely needs pictures. Any pics must be under 1 meg in size or you’ll have to use a site that hosts pictures and post a link.

Most old Marshalls have a way to set the amp to work with different speaker loads and wall voltages. Not having the right settings can damage the amp. Be careful. We can help.

 

[dro]

It's a single channel amp.
There is no right or left.
Just two outs. for plugging in two 412 cabs.

 

[Beryllium-9]

Hello.Simple question here regarding the speaker jacks on the back of a 1968 100W Plexi Super Lead. Does anyone know which of the two speaker jacks on the back is which, re; OHMs, meaning if you're looking at it from the back which jack is which vis-a vis the left and the right jack?

Thank you

Hopefully you know that is it crucial to make sure the amp is connected to a speaker cabinet, or load, before attempting to operate it. Another consideration is to operate the amp with a variac. The voltage coming out of a wall these days is risky for any vintage amp. Especially one made in 1968. It takes skill to operate and maintain amp of this nature. This website is a great resource for such discoveries that displays input from those who have passion and respect for a 1968 Marshall Super Lead. You might learn a bit more about your amp if you posted pics for us enthusiasts to see. Something like these would show mechanics of it.

 

[Joethebh]

Hopefully you know that is it crucial to make sure the amp is connected to a speaker cabinet, or load, before attempting to operate it. Another consideration is to operate the amp with a variac. The voltage coming out of a wall these days is risky for any vintage amp. Especially one made in 1968. It takes skill to operate and maintain amp of this nature. This website is a great resource for such discoveries that displays input from those who have passion and respect for a 1968 Marshall Super Lead. You might learn a bit more about your amp if you posted pics for us enthusiasts to see. Something like these would show mechanics of it.

View attachment 155695View attachment 155696View attachment 155697

Nice 10k series. I had one a few serial numbers after yours

 

[Ned B]

You can use a bar clamp to straighten the OT.

 

[Beryllium-9]

You can use a bar clamp to straighten the OT.

Great advice. Thanks!!

 

[echoplexi1974]

You can use a bar clamp to straighten the OT.

But aren't most of them crooked? The three plexi's I've owned had crooked standing OTs. Part of the uniqueness I think.

 

[Ned B]

I believe the leanining was the reason the OT' s were eventually rotated.

 

[JTM 100 Mk V]

Those pictures are just screaming originality, tone and personality.

Well Done OP !

My '67 is also a ' leaner ', and a screamer too ;-)

I've seen maybe 20+ 'leaners' over time also. Must be an explenation for it.