I would check out a pre-owned Conrad Johnson ET-5. It is essentially 1/2 of a CJ GAT1. It listed for $9,500 when discontinued a couple of years ago and are now available for $3,500 to $4,000.
This preamp uses a single 6922 tube, and it’s pretty easy on them, too. So, I run a Telefunken 6922. It sounds great with the Siemens 6922 tube, as well.
i am an owner of an et-5 as well, love it for its utterly beautiful, spacious sound and build quality, and the fact it runs a single tube, so tube rolling is effortless and cost effective
however, it is well known among owners of this unit that it runs the tube fairly hard (6.3 to 6.4v heater voltage, which is slightly above the spec for a standard spec 6dj8 tube) - so that tube will typically get noisy after about 1 year of regular use
there are solutions to this issue but i did not want those folks who may be considering the et-5 to believe that the single small signal tube will last as long as other tube linestages
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as a separate note, to the other post... the audible illusion mod 3a is infamous for being very hard on its tubes, and for not being at all forgiving of even slightly noisy tubes... furthermore their customer service over the years has been spotty at best... that unit sounds lovely when it is working right, but there are some issues/challenges to long term ownership