HELP Digital bad, vinyl good???

You might be right about the way the circuit in the VAC works, but since neither of are sure, it seems like a good troubleshooting technique to change the linestage tubes to listen for a change.

I suppose the first thing I'd do is disconnect the vinyl.

Happy Christmahanukwanzadan to you, too.

Swampwalker: your description is right in how most preamps work, but as Tvad mentions, we aren't sure that's how this specific preamp works. His suggestion to disconnect the phono rig from the preamp ( interconnects, ground wire, power cord, etc... ) is where i would start. After that, it is a matter of tracking down the offending tube in the preamp, if there is one ( or two if dual mono ).

As a side note, the phono stage may not drive the line section as hard as your CD players do. As such, you might not hear as much distortion from the phono rig as you do the CD player. This would be due to the increased heardroom / lack of drive from the phono stage. This is just a guess though, so don't put too much faith in it. Sean
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Swampwalker, do you notice if the distortion is in one channel or both? if it's in both channels, it would indicate to me something other than the linestage tubes since it's unlikely two tubes...left channel and right channel...would go bad simultaneously.

It is in both channels, and it is significant. You would have to be deaf not to hear it. Seems to be mostly in the mid-range (I'm running Merlins and they are 2 ways). But my new Teres still sounds fantastic. Perhaps the line stage of the VAC uses each half of a dual triode somewhere for each channel, before the phono stage feeds in? Nope, just checked web site
Tube complement: Line stage, 2 x 8416, 2 x 12AX7; Phono stage, 3 x 12AX7.
Still wrapping gifts, will check by removing phono and then tubes, when this is done. Many thanks to all, and to all.... nahh, too corny even for me.

Line stage almost never provides voltage gain; under most circumstances, attenuates signal. The voltage coming out of a linestage source component, if plugged dirtectly inot your amp, would be terribly loud, and therefore needs to be attenuated. I think the preamp may provide current gain (my term, probably not a correct electrical term), which is to say that if the amp requires more current than the source is capable of providing, the preamp will be able to provide it.