[Arny Krueger]

"west" wrote in message
news:uFLbi.6710$xg4.2401@trnddc08

Can we take an off the shelf CD Player and install ,
let's say a 10K stepped attenuator or Alps type pot
inside the CD player on the output line? Would this make
a cleaner audio input to the tube amp?

Cleaner than what? If your baseline is a tubed preamp such as those made by
Conrad Johnson, then a well-designed passive attenuator would provide a
measurably cleaner connection than that provided say, a typical C-J preamp.

The 2 alternatives
are an outboard passive "preamp" with let's say 100k
attenuator or installing it inside the amp.

To review, a 100k attenuator connected to the grid of a tube with typical
and nominal amounts of wire and circuitry is also just fine as far as it
goes.

If the tube is always part of the signal path like the input stage of a
power amp, then it is part of the baseline system and causes no additional
harm. I might add that this kind of system would probably be more
effective if the tubed amp had a bit more gain than is usual.

If the tube was added to the signal path, at least partially to solve the
issues raised by the choice of such a high resistance potentiometer, then
there is some harm that is at least measurable.

Well-designed tubed circuitry generally has more distortion than equivalent
SS, but either can reasonably be expected to be sonically transparent.

I tried the
passive preamp route with mixed results but got
straightened out from info in a previous thread by using
a much shorter interlink cable.

IOW you made some mistakes with the design and/or implementation of the
passive attenuator, and it came around and bit you, at least in your
perceptions.