Vintage Marshall Super Lead identification help

[LanierP]

Hey Guys,
The Story
About a year ago, I picked up a Marshall SL at the Orlando guitar and Amp show at the Central Florida fairgrounds. It was the last day of the show, and with only a couple hours left, all the sellers were starting to pack up their shit. After canvasing the show from one side to the other, I came across an old German guy from Tampa packing up some cool looking vintage Marshall cabs. He asked what I was into,,,I told him I was looking for a nice unmolested vintage SuperLead. 'I just packed it up' he said. I followed him out to his truck in the parking lot where he revealed what looked to be an early 71' SuperLead. It was a good time to bargain,,, the show was all but over,,,he said that he had it out all weekend during the show,,tire kickers only,,,he was asking 4k but would take $3,500. I told him the price was good if original,,,,but I only had 2,800$ to spend. Any issues with it I asked? He told me that it was completely stock, and that his best friend is an amp wizard and went thru it completely, put new fuse holders in it, maybe a cap job (I can't remember) and biased it not too hot so that it could be played for years to come. He also mentioned that his amp buddy clipped the bright cap but left it in place. I told him I'd do 2800, but buying it without playing thru it was a bit of a risk, and if I get home and open this thing up and find out that the amp is all wrong and not what you're telling me, we are gonna have a problem. He contemplated my offer for a few seconds and then agreed to sell. Just then, the old German dude got a call on his cell phone, which he answered. It was his Amp Guru buddy asking him if he wanted to meet up for dinner later. The old guy agreed to meet at some Diner, then he handed me his cell phone, offering me to ask any questions I wanted about the Amp to the guy that actually worked on it. So I hopped on his phone and asked the normal questions anyone would,,,,,are the transformers original, has the circuit been messed with etc,,,,his buddy on the phone was nice, albeit firm and very opinionated. His name was Tony; Tony Bruno. The Tony Bruno of Bruno Amps, I.e. the Underground 30,,Cowtipper,,,etc,(AC30-esque type amps). I actually have an Underground 30. This was kinda weird, but made sense,,,I knew that Tony Bruno lived over on the West Coast of Florida, and this guy sounded like a 'Tony Bruno' ,,,heavy Northeast accent, and very 'headstrong' about the details of the amp.

Long story-short,,,$2,800 sold. I Zelle'd the old Geezer the cash right on the spot and the deal was done. I got contact information for both Tony Bruno and the German fellow. (Bruno offered up contacting him with any questions and or having him do any needed tuneups/biasing,,,,and had an odd protocol for getting in touch, (he doesn't do emails, phone text only, then he circles back if he wants) or something to that affect. Ok.
(Sorry for the dissertation guys, but I wanted to set the scene a bit in hopes that it may provide clues when looking at the pictures of the Amp)

I did pull the chassis on the super lead once I got home, and for the most part, everything looked OK. I'm no expert, but I did notice a few little things here and there that I have questions about and maybe you guys might know the answers.
The Amp sounds fantastic, and now I'm finally having a chance to go through it with a fine tooth comb to see what exactly I have here.
Per the tag on the top of the chassis, the amp was made around January 11 of 1971.(see pics).
The transformers all look nice and crusty and original to the Amp, but there are no identification numbers on either of the transformers or the choke, The two 72' 50 Watt (1987) lead Marshalls I have have identification numbers on the transformers and the choke. Basically I was wanting an experienced set of eyes to tell me if everything looks OK here.

Thanks in advance,
Len

 

[LanierP]

A few more photos, including picks of a
"3rd speaker jack?" I'm pretty sure this was added afterwards at some point. Anyone know what this is?

 

[harddriver]

I think you got a helluva deal for $2800. Yes that is an early 71. They used the dark paxolin turret board which is cool. Usually the 69's used the reddish boards that had like a crosshatched fiber in it. That amp looks mostly original, including the power and output transformers.

The only items I see that are not original is that 820 ohm resistor on V2A is a regular Carbon comp instead of an Iskra 820 ohm and there should/could be a .68uf mustard bypass cap there for 71 but some amps sometimes didn't get the .68uf for what ever reason, out of caps or a lazy factory builder. Also that 3rd speaker output jack has been added by someone as the jack is newer so the chassis was drilled. This can be used to tap a line level signal out via something like the Suhr Iso Line out or Bray line out box. Most Marshall had two or four speaker jacks. You can add a .68 uf mustard


Your amp appears to have two original RS 500pf mica caps on the 470K mixer resistors and the tonestack like the 68 plexi did very nice. Also your 5000pf bright channel bright cap has been disconnected and taped. You may like it without it but it's there if you want to hook it back up. Also your NFB resisttor is 56K which is closer to the plexi spec of 47K than to the Superlead spec of 100K that started in 1969 and the red die look to be intact so it was a factory anomoly which is cool. Also it appears that your 56K NFB is connected to the Yellow 8ohm tap instead of the black 4 ohm tap which again is plexi spec. The standardized Superlead specs by 69 were the 100K NFB conencted to the black wire 4 Ohm impedance tap. So basically you have a 1971 that was factory built to 68 plexi specs except the superlead filtering which is negibile IMHO. All the pots look original to the amp and the inside of the chassis is very clean with little corrosion.

Your 10uf bias capacitors are newer which is good and some of the filter caps have been replaced and that's just general maintenance really. The 1K screen grid resistor on the power tube sockets still look to be original which could mean the amp never blew a power tube and took out one of the screen grid resistors which also could mean the output transformer was never stressed with an output tube failure in it's lifetime which would indicate a more healthy original output transformer which is awesome.

You sir..... have a killer, beautiful amp that can be returned to 100% stock very easily and easily double your purchase price because of the original transformers! Great Find, I hope it sounds as good as it looks!

 

[LanierP]

I think you got a helluva deal for $2800. Yes that is an early 71. They used the dark paxolin turret board which is cool. Usually the 69's used the reddish boards that had like a crosshatched fiber in it. That amp looks mostly original, including the power and output transformers.

The only items I see that are not original is that 820 ohm resistor on V2A is a regular Carbon comp instead of an Iskra 820 ohm and there should/could be a .68uf mustard bypass cap there for 71 but some amps sometimes didn't get the .68uf for what ever reason, out of caps or a lazy factory builder. Also that 3rd speaker output jack has been added by someone as the jack is newer so the chassis was drilled. This can be used to tap a line level signal out via something like the Suhr Iso Line out or Bray line out box. Most Marshall had two or four speaker jacks. You can add a .68 uf mustard


Your amp appears to have two original RS 500pf mica caps on the 470K mixer resistors and the tonestack like the 68 plexi did very nice. Also your 5000pf bright channel bright cap has been disconnected and taped. You may like it without it but it's there if you want to hook it back up. Also your NFB resisttor is 56K which is closer to the plexi spec of 47K than to the Superlead spec of 100K that started in 1969 and the red die look to be intact so it was a factory anomoly which is cool. Also it appears that your 56K NFB is connected to the Yellow 8ohm tap instead of the black 4 ohm tap which again is plexi spec. The standardized Superlead specs by 69 were the 100K NFB conencted to the black wire 4 Ohm impedance tap. So basically you have a 1971 that was factory built to 68 plexi specs except the superlead filtering which is negibile IMHO. All the pots look original to the amp and the inside of the chassis is very clean with little corrosion.

Your 10uf bias capacitors are newer which is good and some of the filter caps have been replaced and that's just general maintenance really. The 1K screen grid resistor on the power tube sockets still look to be original which could mean the amp never blew a power tube and took out one of the screen grid resistors which also could mean the output transformer was never stressed with an output tube failure in it's lifetime which would indicate a more healthy original output transformer which is awesome.

You sir..... have a killer, beautiful amp that can be returned to 100% stock very easily and easily double your purchase price because of the original transformers! Great Find, I hope it sounds as good as it looks!

My friend,
Thanks so much for your expertise on this. I've stared at gut shots for hours on what's supposed to on board, but really am a novice at understanding what's under the hood and or why someone would have changed it. Very grateful for the explanation.
Best,
Len

 

[Anje]

I agree, looks like a nice amp to me; mostly original early '71, including the Dagnall transformers (printed numbers on the metal housings were for Drake; Dagnall often had small stickers instead that can just fall-off and get lost, you can still see the mark of it on the OT side for instance), nice tubes, added 3rd speaker output, no big deal (can actually be a nice practical feature as harddriver said, so that you can still directly plug a full stack & a line out box).
IMHO I would try to reconnect that bright cap if you intend/can push that amp (you should ).

Congrats & enjoy!

 

[Greazygeo]

. Also it appears that your 56K NFB is connected to the Yellow 8ohm tap instead of the black 4 ohm tap which again is plexi spec. The standardized Superlead specs by 69 were the 100K NFB conencted to the black wire 4 Ohm impedance tap.

I don’t think this is correct. Both my ‘69’s (one is early plexi and one is later metal panel) and both have the nfb hooked to the speaker jacks. All the 69’s I have come across have been the same. They must have started that later. 70 perhaps.

 

[Racerxrated]

Yep; what they said! Great looking amp, not sure if it's worth quite 6K but at least 4 or a bit more. For 6k you can find 'mostly' original 69 Plexis IMO...I have an early 69 SuperTrem that I found for 4k last year. Both panels are in great shape; it did have a 1 wire '2203' mod but was easily returned to stock with period correct parts.

Enjoy it! Every Marshall dude should have one of these PTP Superleads in their stash.

 

[FourT6and2]

Nice find.

The glass-reinforced "self leads" of the OT secondary are a dead giveaway as to what OT it has.

I believe this amp was a non-North American export. Amps exported to the USA had a polarity switch and four speaker output jacks. This amp has a third speaker output jack added after the fact (as mentioned earlier) and the third switch added next to the power switch doesn't look to be original either. That, combined with the UK mains power socket tells me this was most likely a UK-sold amp. Somebody added that third switch (that currently doesn't look to be connected?). Most likely as a polarity switch. But I don't see a "death cap" anywhere, which is good.

Pilot light was also replaced at some point.

 

[harddriver]

I don’t think this is correct. Both my ‘69’s (one is early plexi and one is later metal panel) and both have the nfb hooked to the speaker jacks. All the 69’s I have come across have been the same. They must have started that later. 70 perhaps.

I was aware that alot of 69's and some 68 Superleads especially Super Basses had the NFB on the speaker jacks. It's also possible that someone moved the NFB to that tap in it's lifetime. It's cool to see these factory anomaly amps with slight spec variations due to part selections either from being unavailable to the factory builder just grabbeb what they wanted.....we shall never know. My 72 has a 1K on V2A instead of an 820.....820 was probably none in that builders bin that day........

The one thing for sure is that the 56K NFB resistor was factory since the red layout dye/ink is still on the joints which make it kinda cool IMHO. The fact that this amp has the RS mica caps on the mixer and tonestack along with the 56K NFB will definitely give this amp more of that 68 plexi tone and feel.

 

[harddriver]

Yep; what they said! Great looking amp, not sure if it's worth quite 6K but at least 4 or a bit more. For 6k you can find 'mostly' original 69 Plexis IMO...I have an early 69 SuperTrem that I found for 4k last year. Both panels are in great shape; it did have a 1 wire '2203' mod but was easily returned to stock with period correct parts.

Enjoy it! Every Marshall dude should have one of these PTP Superleads in their stash.

If he replaced the 820 CC with a correct 820 Iskra and reinstalled the .68uf on V2A with it being clean and original transformers I don't think 5K is out of bounds with the market being what it is right now. I've heard plenty of 69-71 amps that are as epic sounding as any 68 12 series amp.

 

[mixn4him]

And its Rosemary!! Good job, enjoy the amp..

 

[FourT6and2]

And its Rosemary!! Good job, enjoy the amp..

lol the Rosemary thing is hilarious. Rosemary wired the back panel, at least on this amp. That means she wired the impedance switch, output jacks, and fuses. For some reason, people began associating Rosemary with a better quality build throughout the amp, even though she never touched the rest of the amp.

 

[Racerxrated]

lol the Rosemary thing is hilarious. Rosemary wired the back panel, at least on this amp. That means she wired the impedance switch, output jacks, and fuses. For some reason, people began associating Rosemary with a better quality build throughout the amp, even though she never touched the rest of the amp.

I think it's more of a "It's gonna be a good one!" thing with Rosemary vs the wiring. Lol. At least that's what I read long ago. Good Mojo follows her builds!

 

[Greazygeo]

I was aware that alot of 69's and some 68 Superleads especially Super Basses had the NFB on the speaker jacks. It's also possible that someone moved the NFB to that tap in it's lifetime. It's cool to see these factory anomaly amps with slight spec variations due to part selections either from being unavailable to the factory builder just grabbeb what they wanted.....we shall never know. My 72 has a 1K on V2A instead of an 820.....820 was probably none in that builders bin that day........

The one thing for sure is that the 56K NFB resistor was factory since the red layout dye/ink is still on the joints which make it kinda cool IMHO. The fact that this amp has the RS mica caps on the mixer and tonestack along with the 56K NFB will definitely give this amp more of that 68 plexi tone and feel.

All mine were on the speaker jacks when I got them decades ago. It was easy to tell they were originally that way. Like I said, nevrr seen a ‘69 that wasn’t that way. Not that I have seen them all by any means, but quite alot. I think that is a later thing. After reading about the feedback wire being on one of the taps I tried it of course. Moved it back to the speaker jacks. Prefer it that way.

Never had a 68 for some reason. Always thought my Super Trem was a 68 but turns out its a 67.

 

[Racerxrated]

All mine were on the speaker jacks when I got them decades ago. It was easy to tell they were originally that way. Like I said, nevrr seen a ‘69 that wasn’t that way. Not that I have seen them all by any means, but quite alot. I think that is a later thing. After reading about the feedback wire being on one of the taps I tried it of course. Moved it back to the speaker jacks. Prefer it that way.

Never had a 68 for some reason. Always thought my Super Trem was a 68 but turns out its a 67.

My early 69 SuperTrem has the NFB on the speaker jacks as well. Red dye still intact. Interesting fact about 69s....you can usually tell a 69 SL by all the filter caps on top of the chassis, vs the 68s that had 2 cans on top, the rest underneath. But, the Super PA and Trems kept the 68 looks...2 caps up top, 4 underneath. They lagged behind until the metal panels started in mid 69. I thought I had a late 68, the OT is also oriented the old way too...supposed to cause hum so they moved the OT to the present orientation in 69. But it is a Jan/Feb 69 build.

 

[harddriver]

All mine were on the speaker jacks when I got them decades ago. It was easy to tell they were originally that way. Like I said, nevrr seen a ‘69 that wasn’t that way. Not that I have seen them all by any means, but quite alot. I think that is a later thing. After reading about the feedback wire being on one of the taps I tried it of course. Moved it back to the speaker jacks. Prefer it that way.

Never had a 68 for some reason. Always thought my Super Trem was a 68 but turns out its a 67.

I put my 68 NOS build NFB on the speaker jacks.............,it's been there since I built it....

 

[FourT6and2]

My '70 Super Lead and my '71 Super Trem both had their NFB attached to a speaker jack from the factory, as apposed to one of the output taps. I promptly moved both over to the output tap of my choosing, which I prefer. I'd rather not have my NFB change depending on the speakers I use.

It's also important to note that the NFB setup might have also changed slightly depending on whether the amp was originally equipped with 6550 or EL34. A lot of people in the USA overlook this when using vintage Marshalls and chasing that sound. They're using amps that might have originally come with 6550s, that were properly converted to run EL34 again in terms of their bias components. But the NFB circuits are rarely addressed.

 

[Greazygeo]

My early 69 SuperTrem has the NFB on the speaker jacks as well. Red dye still intact. Interesting fact about 69s....you can usually tell a 69 SL by all the filter caps on top of the chassis, vs the 68s that had 2 cans on top, the rest underneath. But, the Super PA and Trems kept the 68 looks...2 caps up top, 4 underneath. They lagged behind until the metal panels started in mid 69. I thought I had a late 68, the OT is also oriented the old way too...supposed to cause hum so they moved the OT to the present orientation in 69. But it is a Jan/Feb 69 build.

My 67 has the PI and preamp can caps. The rest are underneath on the board. Laydown PT. Always thought it was a 68…but it is a 10,000 serial number. 2 speaker jacks and polarity switch. My ‘69 plexi is March and the Metal is August. Look identical inside other than the plexi only has 2 speaker jacks and polarity switch while the Metal has 4 speaker jacks and polarity switch. And the standby switch is wired differently. Going to change polarity switches and wire it like my plexi at some point.

 

[Greazygeo]

My '70 Super Lead and my '71 Super Trem both had their NFB attached to a speaker jack from the factory, as apposed to one of the output taps. I promptly moved both over to the output tap of my choosing, which I prefer. I'd rather not have my NFB change depending on the speakers I use.

It's also important to note that the NFB setup might have also changed slightly depending on whether the amp was originally equipped with 6550 or EL34. A lot of people in the USA overlook this when using vintage Marshalls and chasing that sound. They're using amps that might have originally come with 6550s, that were properly converted to run EL34 again in terms of their bias components. But the NFB circuits are rarely addressed.

Interesting. Ive never had a 68, 70 or 71. Plenty of the others. My first was a 72 50 watt and my cab was a sound city 412 and then got a 68 slant cab. Neither were marked in any way and not knowing anything about ohms etc, had no idea about what the impedance selector did. I just tried each position to see how they sounded. To me the 8 ohm sounded best, so that is where it stayed for years. Later I found out it was a mismatch.

 

[mentoneman]

reckon you fellas would’ve enjoyed where i was last night