pre-Black Flag Transitional 100W

[Ned B]

Near disaster on the shipping - leaning OT and crushed valve. Pulled off the bar clamp OT straightening trick without damaging anything. It's not completely straight, but it wasn't before shipping. Still there is a partial tear at the base on the opposite bell from the 1202-119 stamp. With that out of the way for now, I will begin planning on getting this ready to play which will involve a slow methodical process of not cleaning, removing replacing (yet) anything. I will give those RS filters a chance though not likely to survive if I determine this amp is a player and not a collector. Certainly, the damaged end bell is hopefully the worst of the situation, can be replaced and the OT fully straightened. But first, first is this going to produce the "god-like" tone one would hope from one of the first "golden era" 100 watters?

What we have here is a Black Flag with an aluminum chassis and JTM 45 front panel. Likely 02/67. It doesn't appear that it ever had a mixer or volume pot brite caps plus the standoff bolts for a PA board maybe indicate this was intended at some point to be a PA?. I will delve deeper and update.

 

[Brewster]

Love the inspection tag since it appears so generic. Also did the chassis get tweaked from the hit or drop?? Crazy how that OT moved so much.

 

[Ned B]

It doesn't take much. Even less than a 2ft drop on the heavy end will do it. It's the physics of inertia. That is why Marshall eventually rotated the OT 90 degrees.

 

[Brewster]

So does the cabinet reflect the hit? Weird since heads fell off stacks at concerts back in the day so where they like done or totaled?? I can see it though since my jtm got tweaked just due to the OT being so top heavy.

 

[Ned B]

No effect on the cabinet. By nature these aluminum chassis are fragile. The rigors of touring took their toll.

 

[TAZIN]

Nice amp. It looks like there was only maybe 40 Super Leads built with this transitional configuration until they switched to the steel chassis. Good to see you were able to straighten out the OT.

 

[Ned B]

Nice amp. It looks like there was only maybe 40 Super Leads built with this transitional configuration until they switched to the steel chassis. Good to see you were able to straighten out the OT.

It needs more straightening. This was as much as I could do with the boards in place. If they need to come out I can clamp down directly to the top of the chassis with ample leverage. Otherwise, I risk damage to the chassis doing it the way I showed. I am looking for some discreet "L" brackets like what I have on my '66. Not sure if original, but perfect, attaching at the base and half-way up.

 

[neikeel]

Well caught.
Often find that injury fractures the feet of the OT.
The clamps can be installed without removing the boards fully but you do have to remove the brass screws, slightly lift the OT to wriggle the clamp past the wires and the bell, also need next sized up length of brass 2BA screws to cope with thickness of the brackets.
I had one of these in the 100xx range (pics posted on Plexipalace years ago.

Sounded at its best when xf2 Mukllards biased scarily hot.

 

[Ned B]

I doubt those brackets are an off-the-shelf item, but shouldn't be too hard to replicate.

 

[ElvisNixon]

That is a beautiful and of course very rare amp. Once you get the errant leaning tower of transformer squared away, I bet it’s going to be a great and fun project that will be very rewarding both sonically and financially if you ever decide you want to sell it down the road.

I also think the OP is correct about the stand-off studs for the PA sub-board would indicate that it was originally planned to be a PA amp. The factory probably got a large order for lead spec amps in the middle of the production run and the call was to build it as a lead spec amp.

At the time that this amp was being built, there were fewer and fewer PA models being used by professionals. Large scale PA systems were becoming more and more prevalent. Think Monterey Pop Festival or Woodstock or the Grateful Dead’s “wall of sound” PA systems.

I have a late ‘66 JTM45/100 “version 3b” with the crazy high plate and screen voltages (my plate voltage is 635V !!). Mine has a tube socket mounted in the normally plated over 4th preamp tube location and heater wiring was also installed.

It’s 100% original from the factory as that it seems as it was initially built to be a PA spec amp. the amp left the factory (sometimes the first factory amp builders worked in their garden sheds after hours to meet demand) as a lead spec amp. Everything was so fluid during those days as we know, that lots of transitions were happening weekly as well as the need to fill orders made for some unique amp-to-amp quirky rarities.

I’m sure that this Black Flag 100W with lots of rare stuff is going to sound incredible as a player no matter if you take it down the collector route or player route (or both!) I wish you the best of luck and look forward to watching your progress!

Here’s an excellent, comprehensive history of the various versions of the “golden age” 100W series starting from the first JTM45/100 prototypes all the way through the JMP era.

Apologies if everyone has seen this document before or know all I said above. There are a lot more knowledgeable folks here than I am and I hope they correct anything I got wrong above. I included the document in case anyone hasn’t read it because it’s excellent and comprehensive IMHO.

History Of The 100W Models

 

[roef]

yes this is variant 5A, the last of the jtm45s, yet the first superlead/bass and first dual rectifiers.

Its like a black flag, except for the aluminum chassis and the jtm45 faceplate

 

[Ned B]

yes this is variant 5A, the last of the jtm45s, yet the first superlead/bass and first dual rectifiers.

Its like a black flag, except for the aluminum chassis and the jtm45 faceplate

You are the author of the "History of the 100W Models" then? I couldn't get the archive links to work. I am particularly interested in the 4A&B. Would love to see some examples. I was not aware of the 1202-119 being paired with the 1204-43 for the first EL34 model still in the Super Amp period. I used to correspond with Dave Guesson at Drake some 20+ years ago. He gave me various transformer model introduction month / year dates. He had the 1202-119 and 1203-80 coming out together 02/67. I a have friend here in the Chicago area with Super PA #8509 which should a good example being likely one of last.

 

[roef]

You are the author of the "History of the 100W Models" then? I couldn't get the archive links to work. I am particularly interested in the 4A&B. Would love to see some examples. I was not aware of the 1202-119 being paired with the 1204-43 for the first EL34 model still in the Super Amp period. I used to correspond with Dave Guesson at Drake some 20+ years ago. He gave me various transformer model introduction month / year dates. He had the 1202-119 and 1203-80 coming out together 02/67. I a have friend here in the Chicago area with Super PA #8509 which should a good example being likely one of last.

yes, I am. the old URLs don't work anymore unfortunately.

I recently corresponded with an owner of an amp with the rare combination of 1202-119 and 1204-43 transformer. As expected, this amp had serious issues since the voltages were way high (around 560v), given the 1k75 Z and the el34s screens. Tubes redplated unless voltages were reduced greatly (which is exactly what marshall did with the 1203-80 obviously). With a low Z, lower voltages are needed.

 

[Ned B]

That combination was probably very short lived

 

[roef]

That combination was probably very short lived

yes, but it does work if you double the speaker load (giving a 3k5 Z) and reduce the screen voltage and current (kt66s don't draw as much screen current as el34s do so they perform better here)

Myself I am running a Marstran 1204-43 on the low voltage taps for a 495v plate voltage into a -119 (with 1k75 Z). It sounds very powerful and runs without any problems

 

[neikeel]

Good to see you here Roe. I migrated a few years ago after PP died and Metro went quiet.

 

[ElvisNixon]

You are the author of the "History of the 100W Models" then? *snip*

Hello Roef, I knew that you were an expert on vintage models, but hadn’t seen you here on MF. I really enjoyed your posts on the Metro forums when it was active.

I’ve learned a lot from your work and I hope you don’t mind me posting your 100W history here. I would have asked and credited you if I knew how to get in touch. It’s a fantastic resource and I’m glad it’s still out there in the ether.

 

[TAZIN]

From what I've seen, once you get into the 85XX range I've seen three different combinations, the 1204-43 & 1202-84 combo, the unknown Drake PT & 1202-84, or the 1203-80 & 1202-119.

 

[Ned B]

Are there any good examples of 4A & B amps on Amp Archives?