Can you recommend a simple Tube pre amp?

So as for the rest of my system, it seems I can either get a pro 8 channel power amp and a mixing board to take stereo into the 8 channels OR use a powerful stereo power amp and a speaker multiplier which uses resisters to increase impedance as needed (and thus is not as efficient) and a stereo pre amp. A reasonable mixing board is $250. Since I posted this thread, I have been warmed that a two channel power amp needs to be a PRO amp or else it will probably fail within a few years as home stereo amps were not designed to drive across a few hundred feed of wire. And I have not even mentioned the speaker placement/design as that is fairly complex as well if you want uniform sound and minimal zones with sound interference. Not such a simple project if you have not done one before, but interesting. Again, thank you for all of your suggestions.

I would suggest the Antique Sound Lab Line Two DT, which uses one 12AU7 tube and costs $450.

A few years ago I used its predecessor model, the Line One, in my system while my main preamp was down. It performed very respectably, and of course its sonics can be significantly modified and tailored at modest cost by substituting different makes and vintages of the one tube.

The one caveat I would cite is that its output impedance is spec'd at 1,000 ohms, and most likely rises to significantly higher values than that in the deep bass region. Therefore, and taking into account your mention of the bottom octave as not being a concern, I would not recommend using it with a power amp or mixing board having an input impedance of less than around 25K, and preferably somewhat more.

Regarding driving the 8 speakers, assuming that you don't need to be able to control their volumes independently you might want to consider the possibility of connecting each of the two channels of a stereo amp to two paralleled pairs of two speakers in series. If each speaker is 8 ohms the amp would then see a load on each of the two channels of 8 ohms, although the maximum amount of power the amp could deliver to each speaker would be 1/4 of its rated maximum into 8 ohms. Also, for good sonics all of the speakers (especially the ones that are wired in series) should be identical models.

Good luck. Regards,
-- Al

P.S. to my previous post: By connecting the speakers in the manner I described (two speakers in series paralleled with another two speakers in series, for each channel), you would most likely not be using long runs of + and - conductors that are in close proximity within the same cable. That would greatly minimize the contribution of the wiring to the load capacitance seen by the amp between its + and - output terminals, which I would expect to eliminate the concern you expressed about driving long runs with amps that are not intended for pro applications.

Regards,
-- Al