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My Sansui 1000A Restoration

One channel is pretty closely matched, the other not so much.

Right channel:
V20: 335mV & V21: 315mV

Left channel
V16: 335mV & V17: 285mV

I see the need for individual bias now.
 
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By the way is it common for the 1000A power transformer to “whine” or in other words make a bit of noise? I’m used to hearing that on my Soundcraftsmen A5002’s but haven’t ever heard it coming from my tube amps.
 
maybe flip V16 for V20. That will get you less of a mismatch.

some transformers do buzz a bit, sometimes you can tweak the mounting screws a bit to quiet it down. Have also seen people unmount the transformers and put a rubber grommet or O ring between the transformer body and the chassis so it doesn't transmit noise through the rest of the unit on things that just would not shut up.
 
Haven't had my 1000A powered up in a couple years, but don't remember any hiss except for a faint hiss in Phono, Tape Head, and Mic, most likely due to the germanium transistors. All other inputs, AM/FM come in AFTER the EQ (phono) board. You could have a noisy tube or tubes (12ax7 or 6AN8's). 6AN8's tended to be noiser for me, I finally found a pair of Matsushita's and they've been good for over 10 years. 12AX7's, I like the GE 12AX7's in it as they are quieter than RCA's and most Sylvania's. But EH12ax7's are pretty good and relatively cheap compared to old stock domestics and Tele's, Mullards, etc.

On the sources that have a RCA Jack, install a shorting plug (AUX, Tape monitor, tape head, and phono 2) and recheck. If they quiet down, start checking the carbon comp resistors (they do get noisy after years. Carbon Film or Metal Film resistors of same value and wattage are smaller physically. And they both reduce noise levels Metal more so over Carbon. You could do one channel worth then compare to other side. (Do the worst side). Also test your 12AX7's, 6AN8's.
 
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probably was actually very forward-thinking. Transistors were the new hot thing to have in the mid 1960s. Unfortunately the early ones were not so awesome. I have a Sony tape recorder from 1964 full of germanium. Swapping the resistors for modern ones lowered the noise floor considerably but there is just some amount of hiss you get from those things. Most of what was in the Sony were carbon comp and well off-value.
 
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