I've got a Rivera-era Fender Concert on the bench.
I've rebuilt the rectifier circuit and swapped out all the old Mallory electrolytics. All the important resistors check out OK and the main board caps are all orange drops which I don't believe need replacing. All the tubes have been tested, V1, phase inverter are new, and the output 6L6 set has been replaced and biased.
I think the amp sounds great, the 2nd channel is plenty loud. But, as it was when it arrived, I was surprised to see the first channel volume needing to be pushed up to 7 to be as loud as a 60s/70s era Fender set to 3. Is this normal?
The voltages on V1 and V2B are approx 200V on the plates and my test signal voltages corresponds to the mVac specs listed on the schematic at those tubes.
Thanks in advance!
I've rebuilt the rectifier circuit and swapped out all the old Mallory electrolytics. All the important resistors check out OK and the main board caps are all orange drops which I don't believe need replacing. All the tubes have been tested, V1, phase inverter are new, and the output 6L6 set has been replaced and biased.
I think the amp sounds great, the 2nd channel is plenty loud. But, as it was when it arrived, I was surprised to see the first channel volume needing to be pushed up to 7 to be as loud as a 60s/70s era Fender set to 3. Is this normal?
The voltages on V1 and V2B are approx 200V on the plates and my test signal voltages corresponds to the mVac specs listed on the schematic at those tubes.
Thanks in advance!
I would follow the stated signal path on the manual and watch the the levels. That will tell you straight away if there is an issue.
I followed the service manual notes - all controls on max, boost off, with 1kHz @ 4mV rms. My measurements match the listed values.
I don't have as much experience with 80's+ circuits, I'm not sure if it's normal for the first channel to be so quiet v.s. a deluxe reverb (RI or not) at the same settings. If any other 80s Concert owners are reading this, please chime in!
I don't have as much experience with 80's+ circuits, I'm not sure if it's normal for the first channel to be so quiet v.s. a deluxe reverb (RI or not) at the same settings. If any other 80s Concert owners are reading this, please chime in!
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If the measurements are correct, then that is that. Must be a reason for it as that is how it was designed.
I don't know how much of a holdover the characteristics of those Rivera amps were compared to the red knob series but I had a red knob Super 112 and I had the same number differences as you had. Really nice cleans, as good as it gets but had to have it on 7 to be loud enough to cut through the mix.
There is quite a bit more output when overdriven to distortion so that could be a large part of it.
There is quite a bit more output when overdriven to distortion so that could be a large part of it.
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