Mic preamp as hifi preamp.

kenrhodes

E-bay keeps sending me ads for microphone preamplifiers. Some look to have really good specs and use American tube's like the 12ax7 with 0db gain and balanced output. Any reason these shouldn't be used as Hifi preamps? If these are so afordable why are Hifi preamps astronomical?

Wolf

0dB gain means it is unity gain and no preamp function. More of a buffer, if I understand your query.

kenrhodes

0 to 26db variable gain seems to be average. Some also offer a volume control outside of the gain.

4thtry

Many high quality tube microphone preamps use expensive input coupling transformers between the microphone and the first 12AX7 gain stage. I take it that these do not use input transformers. Are you thinking of using one of these as a line stage preamp only? If so, I see no reason that it would not work.