1970 Marshall Super Bass 100w??

[PaulHamwijk]

Hi, does this look like an original 1970 super bass or does the board look worked on a lot? resistors etc?

 

[TAZIN]

Hi, does this look like an original 1970 super bass or does the board look worked on a lot? resistors etc?

Looks pretty good with only a few changes.
The Bulgin plug socket was changed out for an IEC style.
The 220K resistors for the bias circuit are changed.
All the 0.1uF coupling caps have been changed out with exception of the Presence cap.

 

[Seanxk]

Very nice and I agree, not much work. Nice standup PT which is a laydown really.
Correct Snubbers and 16uf Bias cap's.
Looks like a late 70 Aug, Sept?, judging by the addition of Pihers but still retaining the odd 1/3W Iskra in places.

 

[TAZIN]

Very nice and I agree, not much work. Nice standup PT which is a laydown really.
Correct Snubbers and 16uf Bias cap's.
Looks like a late 70 Aug, Sept?, judging by the addition of Pihers but still retaining the odd 1/3W Iskra in places.

I'd guess late October 1970...

 

[79 2203]

Looks similar to my 70 Super Bass. Though mine’s not as clean.

 

[neikeel]

Very nice an exceptionally clean. The others have pointed out the output couplers and grid leaks (1/2 an hour with iron and correct parts. I think the screen Rs have been replaced too.
Only bad is the hogged out iec hole and the extra holes on back for ? Line outs or footswitch

 

[StingRay85]

It's not on Marktplaats.nl, I checked

Never seen the blue/brown heater wires before.

 

[Ramhead]

Only bad is the hogged out iec hole and the extra holes on back for ? Line outs or footswitch

Don't know what kind of socket is that..

 

[neikeel]

It's not on Marktplaats.nl, I checked

Never seen the blue/brown heater wires before.

That’s ok - I have
You’ll find speaker wires with same colours in early 70s too.
Tazin might have the range of dates jotted down somewhere

 

[StingRay85]

I also didn't claim to be an expert on this matter, because surely I'm not. I assumed only black and red was used.

 

[Matthews Guitars]

Those reservoir caps are about to lose their black discs due to label shrinkage from running warm. An indicator that they are likely at the end of their useful life span. That's OK, they're 50+ years and owe you nothing.

 

[TAZIN]

That’s ok - I have
You’ll find speaker wires with same colours in early 70s too.
Tazin might have the range of dates jotted down somewhere

The blue & brown heater wires seem to creep up around August-September 1970 (#8000's) and stay until January 1971 when the red & black wires make their return. Around mid-August 1971 (Approx.. #3300C - 3500C) the blue & brown heaters wires make a short return.

 

[Gene Ballzz]

@neikeel , @TAZIN , etc,
Here's a dumb question for the smart kids: "Is there a supposed, preferred correlation between the heater pins 2 & 7 of octal power tubes and the 4/5 & 9 pins of noval preamp tubes?" I'm betting there is, but am wondering what the theory and/or reasoning is behind it. I often (but not always) see octal pin #7 on the same wire as noval pin #9!
Thank You, Smart Kids,
Gene

 

[TAZIN]

@neikeel , @TAZIN , etc,
Here's a dumb question for the smart kids: "Is there a supposed, preferred correlation between the heater pins 2 & 7 of octal power tubes and the 4/5 & 9 pins of noval preamp tubes?" I'm betting there is, but am wondering what the theory and/or reasoning is behind it. I often (but not always) see octal pin #7 on the same wire as noval pin #9!
Thank You, Smart Kids,
Gene

Actually, that's an interesting question. Electrically I don't see any reason why Marshall always paired pin #9 on the 9-pin miniature socket with pin #7 on the Octal socket therefore, I would assume it was done this way for easy OC of assembly and troubleshooting aspects. The only other thing that comes to mind would be that it was easier to keep the wire twist neater and 'in place' verse a more random pattern.

 

[bassmastermkii]

Very nice and I agree, not much work. Nice standup PT which is a laydown really.
Correct Snubbers and 16uf Bias cap's.
Looks like a late 70 Aug, Sept?, judging by the addition of Pihers but still retaining the odd 1/3W Iskra in places.

Damn! Amp whisperer…