NAD: 1970 Marshall Super Lead (plus restoration)

  • Thread starter Thread starter FourT6and2
  • Start date Start date
FourT6and2 said:
With mains at 120.4v AC:
Vp: 486v
Screen drop: 7v
Heaters: 3.26 on first tube, 3.18 on V1
V1a plate 151v
V1b plate: 204v
V2a: 272v
V2b: 293v
PI node: 345v

Bias is set at 34.4, 32.4, 35.2, 34.2 (V4-V7 respectively).
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Where was the B+ on a 1970? Were these originally 500DCV and above? Acccording to Dave Friedman the 12 series 68 that sound best were around 460DCV supposedly. I don't know what year this voltage chart is applicable to but it might help.

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Happy NAD! After your restoration I expect it to be better than new🤘🏻
 
harddriver said:
Where was the B+ on a 1970? Were these originally 500DCV and above? Acccording to Dave Friedman the 12 series 68 that sound best were around 460DCV supposedly. I don't know what year this voltage chart is applicable to but it might help.

View attachment 389286
Click to expand...
Yes, the 1970-73 100w had the T2562, 2623, 3556 that had unloaded PV around 540-560v. Monsters. My 72 is 540v, T3556. I have a 68/69 SuperTrem but I haven't measured that PV yet.
 
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