[doggiehowser]

Not quite the same thing but my Ayon CD5S has an analog tube preamp using 6H30s

I thought it was pretty close to my original Audio Research Ref 5 but it was outclassed by the 5SE and 6 that I upgraded to.

It did have the option of adjustable high or low gain which is great - that low gain should come in handy with high gain power amps like Pass.

It does have a fairly high output impedance so just check what the input impedance of the Pass is.