My preamp uses one cathode-follower tube in the line stage but has 8 tubes (and 4 MOSFETs) in the power supply. My phono stage has 3 tubes for RIAA and 4 tubes in the power supply. The point is that tube preamps tend to use the most tubes regulating the power rather than amplifying the signal. And where there is a dearth of tubes, there is a reliance on solid stage regulation instead.
Tube Preamp: How many tubes does it take to .................
My McIntosh Tube Tuner/Preamp has 17 tubes (some for tuner of course).
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This EAR 802 Tube Preamp has 14 tubes (and either MM or MC phono)
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Some have as few as 2 and no mention of Hybrid
Some call themselves Hybrid
What _____________________________?