Can I use my passive preamp with tube amps?

Find out the passive's output impedance over the standard frequency range, and check that it's well below the amps' input impedance. If OK, proceed as above.

I am using a Reference Line Preeminance 1A passive preamp with Atma-sphere M60 II.3's with stellar results. Very transparent with great detail.

I have run the same preamp with Sonic Frontiers SFS 40 with good results using both EL34 & KT 90 tubes in the SF amp.

So, yes it is possible to do it with excellent results.

I am using a Sonic Euphoria passive preamp that employs autoformers with a McIntosh MC275 V with outstanding results. Rock solid extended bass, huge soundstage with what sounds like limitless high's and a naturally delineated midrange. Of course, IC's are very critical when one employs a passive preamp and experimentation here definately pays off. I found AQ Cheetah's running the DBS at 72vDC between the preamp and amp to be a stunning match in my system.

Passive attenuators can be very transparent/faithful to your signal, regardless of amp topography. In addition to the above: Listening satisfaction will depend on the output voltage of the source/sensitivity of your amp. If the source(CDP, DAC, phono pre, etc) isn't putting out enough to drive your amp to adequate SPLs; you won't be happy. Having owned the(most excellent) Placette Passive Linestage, I found that some pressings, recorded/engineered at lower levels, were less than satisfying. Then again- I like my music loud, and most of my collection produced excellent results.

You could but why would you want to?