HELP Digital bad, vinyl good???

First thought...have you disconnected the vinyl rig to listen for any change?

Second, this could be a bad tube or tubes. Doesn't the VAC use separate tubes for the phono stage? If you have spares for the linestage, I'd suggest changing them to listen for any improvement.

I have not changed tubes because I always thought that the phono stage provided RIAA reverse eq; and gain to be bring the signal to line level, and then the line stage provided additional gain to the signal to provide sufficient voltage for the amp. If I am wrong (which it seems I must be), then I stand corrected. I will have to disconnect the phone and then check the line stage tubes.

Happy Christmahanukwanzadan everyone.

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.