Btw...I found the owners manual here:
http://ampwares.com/schematics/Twin_Amp.pdf
and the schematic here:
http://ampwares.com/schematics/Twin_Pro_Tube_Amp_SchE45.pdf
The Phase Inverter tube is V4 and it is a 12AX7 type, which is good, these are actually easier to find at the generic music store. Any brand will do, I would probably get the lowest cost one here, such as a JJ or whatever the local store has. If you are buying online from Tube Depot or whatever, you have a broader selection but have to pay shipping...this tube will not effect your tone too much (if at all), so it really doesn't make sense to drop big money on this particular tube location.
For the power tubes, in the owner's manual there is instructions on biasing the power tubes should you decide to replace those. While it may seem complicated, if you follow these instructions step-by-step, you will see it really is no big deal. Nothing against guitar techs that are trying to make a living, but why spend the money for their "bench/bias" charge when you can easily do this yourself?
Output Tube Bias Adjustment Instructions —
1. Turn on the amplifier and let it warm up for at least two minutes
with the STANDBY SWITCH (item C) in the ON position and the
OUTPUT SWITCH (item D) in the OUTPUT HIGH position.
2. With a digital voltmeter set to its most sensitive DC voltage scale,
measure the voltage between the two BIAS TEST POINTS (item K)
labeled “BIAS” and adjust the OUTPUT BIAS ADJUST control (item J)
for a reading of .08 VDC (80 mVDC).
3. Connect the digital voltmeter to the two BIAS TEST POINTS (item
K) labeled “BALANCE” and adjust the OUTPUT BALANCE ADJUST
control (item L) for 0 VDC.
Notes:
1. Make bias and balance adjustments only when necessary. If you
are unsure about setting bias and balance, it is best to LEAVE THIS
FEATURE ALONE, as it is pre-set at the factory.
2. For optimum sonic performance, set bias to .08 VDC, then set balance.
3. For optimum sonic performance with increased tube life, set bias
to .06 VDC, then set balance.
4. For optimum tube life, set bias to .04 VDC, then set balance. If a
bias measurement of .04 VDC cannot be obtained, replace the
6L6GC output tubes.
5. If the output tubes can’t be balanced, check the bias setting
and/or replace the 6L6GC output tubes.
http://ampwares.com/schematics/Twin_Amp.pdf
and the schematic here:
http://ampwares.com/schematics/Twin_Pro_Tube_Amp_SchE45.pdf
The Phase Inverter tube is V4 and it is a 12AX7 type, which is good, these are actually easier to find at the generic music store. Any brand will do, I would probably get the lowest cost one here, such as a JJ or whatever the local store has. If you are buying online from Tube Depot or whatever, you have a broader selection but have to pay shipping...this tube will not effect your tone too much (if at all), so it really doesn't make sense to drop big money on this particular tube location.
For the power tubes, in the owner's manual there is instructions on biasing the power tubes should you decide to replace those. While it may seem complicated, if you follow these instructions step-by-step, you will see it really is no big deal. Nothing against guitar techs that are trying to make a living, but why spend the money for their "bench/bias" charge when you can easily do this yourself?
Output Tube Bias Adjustment Instructions —
1. Turn on the amplifier and let it warm up for at least two minutes
with the STANDBY SWITCH (item C) in the ON position and the
OUTPUT SWITCH (item D) in the OUTPUT HIGH position.
2. With a digital voltmeter set to its most sensitive DC voltage scale,
measure the voltage between the two BIAS TEST POINTS (item K)
labeled “BIAS” and adjust the OUTPUT BIAS ADJUST control (item J)
for a reading of .08 VDC (80 mVDC).
3. Connect the digital voltmeter to the two BIAS TEST POINTS (item
K) labeled “BALANCE” and adjust the OUTPUT BALANCE ADJUST
control (item L) for 0 VDC.
Notes:
1. Make bias and balance adjustments only when necessary. If you
are unsure about setting bias and balance, it is best to LEAVE THIS
FEATURE ALONE, as it is pre-set at the factory.
2. For optimum sonic performance, set bias to .08 VDC, then set balance.
3. For optimum sonic performance with increased tube life, set bias
to .06 VDC, then set balance.
4. For optimum tube life, set bias to .04 VDC, then set balance. If a
bias measurement of .04 VDC cannot be obtained, replace the
6L6GC output tubes.
5. If the output tubes can’t be balanced, check the bias setting
and/or replace the 6L6GC output tubes.
Even though I won't attempt to do these things someone here could really benefit from it. The tutorial here would certainly make a good sticky or at least a good reference. Thanks again!
