SS Pre-Amp / Tube Amp

There is something backwards about using a solid state preamp with a tube power amp. Why? If there are any disadvantages to vacuum tubes, they are related to the difficulty of driving speaker loads and low impedances as well as the need (in most cases) for output transformers. Those problems do not exist in the preamp where the tubes get to drive a delightfully high input impedance in a power amp. So it would seem that there is no downside to tubes in the preamp whatsoever.

Another thing to consider is that preamps are more about finese, fine detail, and microdynamics while power amps are more about brute force and macrodynamics. This argues for tubes in the preamp and solid state in the power amp rather than the reverse.

From a practical standpoint tubes in the preamp are also much more maintenence free and therefore easier to live with than power tubes, which also cost much more, last less long, make more heat and draw more power from your electrical service.

This is, of course, a generalization and there are surely examples where what I call backwards will work quite nicely, but still the generalization makes more sense.

In my opinion, the speakers enter into the picture.

In many if not most systems, the most important component pairing is speaker and amplifier. If the speaker works best with a tube amp, then that's the place to have tubes in your system. From there, the preamp can either be tube or solid state. On the other hand if the speaker works best with a solid state amp, go with solid state amplification and then choose whichever kind of preamp you like best.

Duke
dealer/manufacturer

I use a solid-state preamp with my vacuum tube amps in the reference system for my audio company. I chose this particular solid-state preamp because, other than a slight leanness, it is extremely neutral, as a reference should be (I was able to eliminate that leanness later, to my delight). Solid-state amps usually have high damping factors, and tend to offer overdamped bass--dry and unnatural-sounding, IMO. An extreme example of this was a friend who had Klipsch Cornwalls and drove them with a Crown DC-300A ss amp (known in the 70s for its high damping factor). We thought the speakers had no bass, but the problem was that the Crown amp was telling the 15" woofer to stop before it could overcome inertia and get all that mass to move! He bought a used ARC tube amp, and, voila! Low frequencies!

It's an unfortunate dilemma of life and physics that a low output impedance is necessary to eliminate frequency response variations, but that it strangles the bass via overdamping. You have to accept the compromise that works best for you in this regard. As for me, I'll take slightly underdamped over slightly overdamped anytime (until perfect bass becomes an option). Obviously, some tube amps are waaayy underdamped, and I find this as unacceptable as solid-state bass. As a learning example all you need to do is go to a live concert, pay careful attention to the bass, go home, listen to a live recording of similar music on your soid-state-amp stereo, and cry. BTW, once you become aware of the overdamped-bass problem, you realize it's not just a problem in the bass, but in all frequency ranges.

This is a perfect example of why you need a good dealer or trusted, experienced adviser for building a system; the answer to these types of questions is the "it depends".