1972 superlead 100w

[Guitfire]

Hey guys,
I posted some pictures of this a few years ago from the original owner but the pictures were poor quality, so wanted to get some better pics to see if you guys can tell me what's original or not in this beast. Going to be putting it up for sale so want to be as accurate in the description as possible. Pics are in the link

Marshall

Marshall album hosted in ImgBB

ibb.co

Thanks in advance!

 

[Matthews Guitars]

It's mostly original. It's had some work done but not a lot. I've never personally seen one with the Dubilier filter capacitors in it before, but they have 1971 date codes so I'm guessing they could be original. They need to be checked to see if they're still good. Being 50 years old they are well past their life expectancy.

Some diodes in the power supply are not original. The power cord is not original. The power switch is not original, and maybe the standby switch is not original as well.

There is an added resistor in the bias circuit, bypassing the 27K with a value I can't be sure of from the photos. The two capacitors in the bias circuit are replacements as well.

The output transformer end bells look too clean and new so that transformer is probably a replacement. Same goes for its clamp brackets at the bottom of it.

The wiring of the output transformer also lacks the rubber sleeves or lacing that you can see on the power transformer wire dress. Another indicator of a probable output transformer replacement.

It does not have 5.6k grid stopper resistors installed. For safety and to prevent power tube problems, all four should be installed.

Tube sockets look original and preamp tube sockets are riveted and apparently ceramic. Original green vitreous Welwyn screen resistors are still present on all four power tube sockets.

Overall that's a pretty nice example with minimal alteration to its original specifiations. It is unmodded with no added chassis damage. (Extra holes.)
The only thing that may alter the value significantly is that output transformer. It will be more valuable if it is verified to be original.

 

[Hendrix13]

where are you putting it up for sale?

 

[Seanxk]

OT looks original to me.

 

[tWreCK]

I agree - both trannies look like the original Dagnall iron as far as I can tell. They both have glue residue left from the stickers.

 

[Matthews Guitars]

The very clean, shiny, almost new condition of the OT end bells was what made me mention it as a possible issue. They're very clean for being 50 years old. Compare that to the overall condition of the chassis surfaces, which are in good condition but not all THAT clean. It's that contrast of condition that attracted my attention. If you believe that the transformer is original then that's certainly good news. But I'll mention what attracts my attention, and let that be taken into account for further inspection.

 

[neikeel]

I agree, looks pretty good.
I too have never seen those caps in a Marshall before (early 70s Oranges - lots!) yep couple of diodes replaced. I think iron is original. Bias feed resistor parallel is not my preferred way of getting tubes into range but I guess it worked.
Will certainly need a service/check go over would like to know if those caps do turn out to be original.

 

[Guitfire]

Thanks for all the replies and insight. The previous owners tech said that the transformers were original so I'm pretty confident there. Thanks for all the info you guys provided!

 

[Fernieite]

Man, I love this place!
Nice amp btw.

 

[LoudStroud]

Man, that's a cool Super Lead.

Transformers are original. Do they have stamped codes on the end bells? I see from the pics the original stickers have come off. Dagnalls maybe, vs the typical Drake of the period? That would make it even more unusual if it had Dagnall's, which Marshall reportedly dropped away from using in the late 60's. The most noticeable aspect is that the power transformer is a "laydown" type, which is uncharacteristic for early 70's.

This amp resembles Canadian Market Marshall's of the period. The embossed tube labels on the chassis, as well as the laydown PT are the tip off. I have a '72 Bass 50 wth similar characteristics.

The "Chiclet" caps are rare but not unusual. It was possibly during a short period when Marshall was running short on mustard style caps. Both were Philips/Mullard manufacture. I have a '72 Park 75 (P.A. circuit) with the same lighter colored tagboard loaded with chiclet caps. Awesome sounding amp. Seems a little edgier than my '72 Bass 50 with mustards.

The entire tagboard looks untouched other than the added resistor in the bias circuit mentioned. The power switch was replaced. Even has the original power supply cap cans.

IMO, let the next owner deal with adding the 5.6k control grid resistors. Some owners are sticklers for originality.

 

[tWreCK]

Man, that's a cool Super Lead.

Transformers are original. Do they have stamped codes on the end bells? I see from the pics the original stickers have come off. Dagnalls maybe, vs the typical Drake of the period? That would make it even more unusual if it had Dagnall's, which Marshall reportedly dropped away from using in the late 60's. The most noticeable aspect is that the power transformer is a "laydown" type, which is uncharacteristic for early 70's

Dagnall never had stamped codes on the endbells - they had small stickers. Dagnall trannies were used all through the late 60's, 70's, 80's and are still used today on the 100W models. Drakes were used on the 50W. A laydown PT in the early 70's isn't particularly unusual.

 

[neikeel]

What would be unusual in 71 is the use of Drakes. I had a Superbass that had them.
As above 100w Dagnalls 68-80s. 50w mainly Drakes although the current RI JTM45s and 1987x are Dagnalls

 

[LoudStroud]

Dagnall never had stamped codes on the endbells - they had small stickers. Dagnall trannies were used all through the late 60's, 70's, 80's and are still used today on the 100W models. Drakes were used on the 50W. A laydown PT in the early 70's isn't particularly unusual.

Good to know on the Dagnalls related to 100 watters. But that is the first 70's 100 watt head with a laydown PT I've personally come across. Not a challenge, now seeing they're out there. I've owned a handful and seen dozens more and seemed like from '69 thru 70's the PT's were mounted upright. Which makes me wonder if laydowns were a characteristic of amps shipped to Canada vs U.S? I wonder if the secondary DC plate voltage is different or around the typical 475 of the time?

 

[Guitfire]

I am from Canada and I've been told that the laydowns are in fact characteristic for the Marshall's shipped to Canada.

 

[Matthews Guitars]

They probably made it that way for the simple reason of "We have Canadian laydown chassis, we have Dagnall transformers to fit it, we're currently waiting for Drake to deliver... so let's build this amp in a Canadian spec chassis and ship it!".

That's how Marshall operated. They used what they had to work with.

I believe that the very reason they made both stand-up and laydown transformer versions of the same amp concurrently was because neither transformer vendor alone could meet Marshall's production demand. So use both vendors, fill all the orders, and it just requires some additional versions of the chassis to be punched.

 

[TAZIN]

Good to know on the Dagnalls related to 100 watters. But that is the first 70's 100 watt head with a laydown PT I've personally come across. Not a challenge, now seeing they're out there. I've owned a handful and seen dozens more and seemed like from '69 thru 70's the PT's were mounted upright. Which makes me wonder if laydowns were a characteristic of amps shipped to Canada vs U.S? I wonder if the secondary DC plate voltage is different or around the typical 475 of the time?

It was a CSA requirement at that time in Canada.