Can I use my passive preamp with tube amps?

It could work better, depending on the amp. Pick one that has a fairly sensitive input requirement if possible. In a recent test of the Creek passive it was found to work very well with tubes. Keep interconnect between source and preamp and preamp and amp as short as practical. I have two passives and often use them with very good results. Interconnects will make a difference but are system dependent so experiment with the ones you have or can borrow.

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?

If you're asking why he'd want to go to tube monoblocks: If you really need an explanation, you wouldn't understand.

In terms of impedance matching, a passive will in most cases work better with tube amps, they are simply easier loads to drive. What is the input sensitivty of you amps? What is the output volatage of the DAC? In all likelyhood, it will be a very good match.

Rodman99999999999999

That was not what I was asking. I was asking why he would want to use a passive preamp.

The fewer things in the reproduction chain, the better it sounds. Nothing sounds as good as nothing is a reasonably accurate description. I use both but for the greatest detail passive is very hard to beat. Some will still prefer active but passive should be tried by anyone with doubts. Stan Wallen, Alternative Audio

Perhaps he wants his music to sound real, rather than to sound like audio. He did say that he prefers the sound with a passive. Stan's comment is right on the money. The goal used to be called, "straight wire, with gain."

That's tell en um rodman. Hope you found your gold.

The Sonic Euphoria PLC was designed in a shop that ran Antique Sound Labs Hurricane mono amps on practically a daily basis.
So long as the output from your source components will drive the input of the amps to full volume, you'll do just fine.
With the PLC's autoformer based design, it also does not care so much about the length of interconnects that you're running. Of course, keep them to reasonable lengths, no more than is really needed and you'll do just fine.