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I have mated a AB165 preamp with a AA864 power amp. I am having some real weird problems that I cannot account for.
With a speaker connected, but no NFB I get about 250 VDC on the pots of the Normal Channel. When I connect the NFB, those numbers go down to about 10 VDC.
With a speaker and the NFB connected I get some real weird numbers on the preamp grids.
V2 Pin7 -23.0 VDC
V3 Pin2 -4.3 VDC
V4 Pin 7 -2.9 VDC
If I disconnect the NFB, the numbers on those grids are normal. I have only been working on amps for a year or two, but I have never seen anything like this. I printed a layout and checked everything against the layout, and all my connections/components seem to be right. But that can't be, I must have done something wrong somewhere, but I cannot see what it is.
Do any of these problems sound familiar to you guys??? I really do not know what to do at this point. The power amp seems to function as normal. I will post some pics below, just in case you see something obvious.....
Thank You
With a speaker connected, but no NFB I get about 250 VDC on the pots of the Normal Channel. When I connect the NFB, those numbers go down to about 10 VDC.
With a speaker and the NFB connected I get some real weird numbers on the preamp grids.
V2 Pin7 -23.0 VDC
V3 Pin2 -4.3 VDC
V4 Pin 7 -2.9 VDC
If I disconnect the NFB, the numbers on those grids are normal. I have only been working on amps for a year or two, but I have never seen anything like this. I printed a layout and checked everything against the layout, and all my connections/components seem to be right. But that can't be, I must have done something wrong somewhere, but I cannot see what it is.
Do any of these problems sound familiar to you guys??? I really do not know what to do at this point. The power amp seems to function as normal. I will post some pics below, just in case you see something obvious.....
Thank You