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Hey Everyone,
Got a Mesa Boogie Studio Caliber DC-2 on the bench. Customer notes that the clean channel overdrives or gets dirty too early. He also noted that he's had several techs look at this one and no one's been able to figure it out. Similar results with new tubes as well. All of the components seem to be ok and I've checked the four transistors in the contour circuit and they are fine as well. I've attached the schematic down below.
This is a 1Vpp input with the Gain at 2 and the Channel one volume at 6 (measured at the MV pot). Rigol Shot is of the output wave from the dummy load. I'm not sure what the little squiggle clipping is caused by, but it originates in the phase inverter. Any ideas what would cause that squiggle as the wave goes negative?
These shots are a 1 Vpp signal with the input gain at 6 and the MV knob at 3. Tek is again taken at the channel 1 MV pot and the Rigol from the dummy load. So a decent amount of clipping here and again it has that weird squiggle as the wave goes negative.
Both of these settings are with the output level knob (last step before PI) at 6, so pretty crankin!
Any help on this one would be greatly appreciated! I can also get more voltages and readings if needed. I'm getting 388Vdc on the plates of both EL84 and -11.5Vdc on the inputs of each.
Got a Mesa Boogie Studio Caliber DC-2 on the bench. Customer notes that the clean channel overdrives or gets dirty too early. He also noted that he's had several techs look at this one and no one's been able to figure it out. Similar results with new tubes as well. All of the components seem to be ok and I've checked the four transistors in the contour circuit and they are fine as well. I've attached the schematic down below.
This is a 1Vpp input with the Gain at 2 and the Channel one volume at 6 (measured at the MV pot). Rigol Shot is of the output wave from the dummy load. I'm not sure what the little squiggle clipping is caused by, but it originates in the phase inverter. Any ideas what would cause that squiggle as the wave goes negative?
These shots are a 1 Vpp signal with the input gain at 6 and the MV knob at 3. Tek is again taken at the channel 1 MV pot and the Rigol from the dummy load. So a decent amount of clipping here and again it has that weird squiggle as the wave goes negative.
Both of these settings are with the output level knob (last step before PI) at 6, so pretty crankin!
Any help on this one would be greatly appreciated! I can also get more voltages and readings if needed. I'm getting 388Vdc on the plates of both EL84 and -11.5Vdc on the inputs of each.
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