1969 Marshall Super Lead 100 Black

I don't come across old Marshall amps all that often. When I do I send them off to my tech, who spent the early part of the 1970s at Wurlitzer Music in Boston, tech-ing these amps on a daily basis.

The visit to my tech resulted only in a bias adjustment as everything about the amp checked out as fully functional and ready to rock.

This Super Bass amp arrived in the US at a time when everyone wanted Super Lead amps, and it is documented out there on the web that the US distributor performed the non-invasive mod needed to make this a Super Lead. The Lead sticker on the back is the obvious sign of this.

The circuit was serviced in the 90's - many caps throughout were changed as routine maintenance. The power cable was changed to a fixed cable.

Marshalls from this period are somewhat difficult to precisely date. This example does not sport a date code letter after the serial number, which started out with the letter A in July of 1969. The front "shelf" under the control panel is sharp, not rolled, which puts it to early 1968 or earlier. The model code on the back puts it to 1968 or later. The feet are changed.

The amp absolutely rocks. There really is no comparison.

Shipping will be expensive because I plan on separating the chassis from the head cabinet. I see the cabinets take damage in shipping from the heavy chassis causing stress on them. I will attach a plywood plate to the chassis to cover the circuit, and the chassis will be double boxed. All tubes will be wrapped and packed in the back of the cabinet.

Some Marshall history info from https://solodallas.com/the-vintage-marshall-guide

...The JTM-100, now with four EL-34s too, also gained a proper 100w transformer. The name? It was called Marshall Super Lead 100w #1959 (Although they still didn’t have the “JMP” mark on the front, In my view, this amps are already into the JMP territory, because they have all of the JMP characteristics).

I think you are all familiar with this amp. Many consider it to be the ultimate rock amp. It’s indeed, a lengend on it’s own. This early “Plexi” versions (up to 1968) are really articulate and have a real nice “roar”. If you want to hear this amp, listen to any Free live performance. Paul Kossoff was the man who really knew how to use these. When I listen to the Free Live! album, and I hear the sweet tone of that Les Paul through his Super Leads, I feel I’m in “tone heaven”

The change to the solid state rectifier

By late 1966 – early 1967, Marshall stopped using the GZ34 tube rectifier in all the models and started using a solid state rectifier instead.

The JTM50 now definitely turned into the JMP incarnation of the 1987 model, although the “formal” name remained the same.

This amp is basically the 50w version of the Super Lead, so the sound is really similar to it’s “big brother”.

New Models of the “Transition Era”

While all those changes happened, new models started being developed to expand Marshall’s catalog. Here are some of them:

Marshall Bass and Super Bass

The Marshall Bass 50w #1986 and the Marshall Super Bass 100w #1992 appeared after the change to the EL-34 tubes. Related to the #1987 and the #1959 respectively, they were designed for bass players. But many guitarrists also decided to try those and they found out that they could get really interesting tones with them. They were a bit smoother and had a tad less gain than their Lead counter-parts. They can easily be converted into Lead circuits as well. So, if you find one for a good price, grab it

It used the same headbox as the Super Lead. Front panel was also identical.

The “Plexi” JMP era: 1967 – 1969

And now, we are oficially into the JMP era.

The first JMP marked amps came out around late 1967, although, as you saw, all of them already had JMP characteristics. So, it was more of a “brand” renewal.

An important note is that, by 1968, there were some changes on the circuits that made the amps more aggressive. All the models mentioned above are still being produced here.

The amplifiers that were shipped to America had an extra toggle, wich was the polarity switch. That happened until around 1976.

A notable user of these amps is a guy named Eddie. Yes: On Van Halen’s debut album, a 100% stock 1968 Marshall Super Lead #1959 was used. With a thing called variac, he was able to kind of “attenuate” the amp and obtain more gain.

Jimmy Page of Led Zeppelin is well know for his use of a 1959 Les Paul and Marshall Super Lead #1959 amps (Did you notice that both have 1959 on their name? Coincidence? :P). I’m not sure of the year his amps were made, but something tells me that they are from around this period (1968 or 1969) or maybe from the early Metal-Face years. Anyway… It’s said that his amps were modded to accept KT88 power tubes, boosting their power to 200w (and actually, he really told so on an interview in 1977), but the question is: When was it done? – My opinion is that maybe he did that around 1974, since his tone was a lot different in the 1975 tour, but, of course, I might be wrong.

Malcolm Young said his favourite amp is an old Super Bass amp, probably from this period too (it could be an early Metal-Face as well).

There is some discussion about this type of conversion amp on the Marshall Forum here

"I've seen a few of these. They appear to be Super Bass amps that were reassigned to Super Lead amps. Were these done at the Marshall factory in the early 1970s?

Here's what I think I know:

They all have the same "LEAD" sticker over the word "BASS" on the back panel, using an old typeface.
They all have "SB/A" serials.
They all have "BASS" sign off sheets on the chassis.
Turret positions on the boards would indicate the boards were originally intended for bass models.
At least one has additional date stamps near the sign off sheet that are a year or two after the original serial-matching date stamp on the sheet.
I'm pretty sure I've seen one that went the other way, also (a SL/A serial "LEAD" read panel with a "BASS" sticker over it) but I can't find any photos to prove it now, so maybe my memory is playing tricks?

Just curious about the history of these amps and their story. Did they originally leave the factory like this, perhaps because Marshall didn't have enough Lead models to meet demand at a time? Was it a service Marshall offered to owners who sent them back in for conversion after purchase? Someone must know more about these."

Color: Black
Dimensions (HxWxD): 11"x29"x8.25"
Weight: 44lbs
Watts: 100
Date: 1968
Where date is noted: Serial Number
Extension Speaker Out?: Yes, 2
FX Loop: no
Reverb Or Other Effects: No
Power Tubes: (4)xEL34
Pre-Amp Tubes: (1)x7025, (2)x12AX7
Pots: Appear all original
Tolex: Original Black
Grille: Original
Knobs: O)riginal
Handle: Original, one crack
Power Cord: Changed
Notes: Feet changed