Excellent affordable preamps keep springing UP

TAD150 Signature

No longer made, but they are still supported & available.

If a transformer volume control (TVC) passive preamp meets with your system needs, the Promitheus Audio units are an outstanding value. Most of the Promitheus TVCs sell new for between $300 and $700, and the sound quality is truly excellent. TVC passives are easier to successfully work into a system in comparison with resistor-based passives like the Placette because TVCs are not as finicky from the standpoint of impedance matching and the ability to drive long interconnects.

One that shows up; but not often would be Klyne Audio preamps series 6 or 7.

I love my Tube Technology Seer, may be hard to find because they are no longer in business but can be found second hand.