Is there a schematic available for this series of Soundstream amps? This amp came in with a few problems which I've repaired; but Left Rear channel is not passing audio only extremely quietly. Seems mute is engaged just for that one channel.
This amp is using J108. 14 of them. There are 10 near the preamp and one for each channel. All but the LR channel has audio on that JFet.
LR Audio is passing through several opamps and the controls seem to be working OK on the preamp.
This amp is using J108. 14 of them. There are 10 near the preamp and one for each channel. All but the LR channel has audio on that JFet.
LR Audio is passing through several opamps and the controls seem to be working OK on the preamp.
Have you tried pulling the jfet for the quiet channel to see if that made a difference?
When is the voltage applied/lost on the gates of the 10 jfets? Can you make the gate voltage switch by changing the positions of any of the mechanical switches on the amp?
When is the voltage applied/lost on the gates of the 10 jfets? Can you make the gate voltage switch by changing the positions of any of the mechanical switches on the amp?
I did pull Q355 jFet last night but that didn't help. There is no audio on the pads of that jFet. This morning I found a second jFet in CH3, thats Q354. No audio on any pads of that jFet either.
The switches dont seem to make much difference. They're all passing continuity checks and dont seem to be needing service.
The switches dont seem to make much difference. They're all passing continuity checks and dont seem to be needing service.
I called Tech support and they're looking for a schematic.
10 jFets under the preamp board... There are 8 all in 2x4 rows. All 8 have equal voltages across all 3 legs. -0.1v on legs 1&2, and -0.9vDC on gates. There is No audio on ANY of these jFets from ANY input channel.
2 jFets are off to the side of these 8. Both have Rear signal on Leg 3 for both L and R channels. I believe these 2 are actually for the RCA outputs of this amp, which is passing audio correctly. So this is telling me CH3 signal is at least getting to the output RCAs from at least part of the preamp.
There are 2 jFets per channel. All but channel 3 have audio on Leg-1. Then Leg-3 has 14.7vDC for all 8 of these.
There are about ~12 resistors to the left and right of each channel. Many of these have audio on them, except for CH3 where there is no audio passing through these parts.
With the preamp board installed its proven difficult to trace audio on the board for me. Hoping I can get lucky or obtain a schematic at this point. Thank you thus far.
10 jFets under the preamp board... There are 8 all in 2x4 rows. All 8 have equal voltages across all 3 legs. -0.1v on legs 1&2, and -0.9vDC on gates. There is No audio on ANY of these jFets from ANY input channel.
2 jFets are off to the side of these 8. Both have Rear signal on Leg 3 for both L and R channels. I believe these 2 are actually for the RCA outputs of this amp, which is passing audio correctly. So this is telling me CH3 signal is at least getting to the output RCAs from at least part of the preamp.
There are 2 jFets per channel. All but channel 3 have audio on Leg-1. Then Leg-3 has 14.7vDC for all 8 of these.
There are about ~12 resistors to the left and right of each channel. Many of these have audio on them, except for CH3 where there is no audio passing through these parts.
With the preamp board installed its proven difficult to trace audio on the board for me. Hoping I can get lucky or obtain a schematic at this point. Thank you thus far.
This looks a lot like some of the PPI amps. In some cases, PPI used the jfets to switch resistors in/out of the circuit to adjust the crossover frequencies.