Marshall 1968-JTM-45-Data Service Data

Voodoo Amps Marshall 1968 JTM-45 Serial #: 12354

VOLTAGE READINGS:

Pin#1 Pin#2 Pin#3 Pin#4 Pin#5 Pin#6 Pin#7 Pin#8 Pin#9 ECC83/12AX7 V1 194 ----- 1.4 H H 193 ----- 1.4 ----ECC83/12AX7 V2 300 ----- 1.08 H H 300 168 169 ----ECC83/12AX7 V3 231 ----- 42 H H 227 ----- 42 ----EL34/6CA7 V4 ----- H 490 486 -43 NP H ----- ----EL34/6CA7 V5 ----- H 490 486 -43 NP H ----- ----EL34/6CA7 V6 ----- H 490 486 -43 NP H ----- ----EL34/6CA7 V7 ----- H 490 486 -43 NP H ----- -----

TECH NOTES:

- All Pico-farad caps are ceramic (no micas at all)

- All Coupling-caps were the typical Mustard caps

- Coupling-caps for V1 & V2 were rated at 400V while all others were rated at 600V

- Both of V1’s cathodes were shared (not split)

- Mix resistor on treble channel was bypassed with a 560pF cap (labeled 560pF – not 470pF)

- V2A’s cathode was not bypassed

- No bright cap on Treble channel’s volume pot (may have been removed – hard to tell)

- Slope resistor was 56K & Treble cap was 220pF

- Feedback resistor is 47K & connected to the 8-ohm tap.