This tube preamp was based on the early silverface Fender Dual Showman Preamp stage that provides a clean sound. David has used this in conjunction with his early Leslie 144, but soon replaced it as his go-to preamp for his Yamaha RA-200R to bypass the solid-state preamp built in. This preamp is discussed in detail [here](http://www.gilmourish.com/?page_id=71) on a well-known site about David's gear. "As I mentioned, he likes his initial signal to be very clean. To achieve this he uses a mid-Seventies Alembic F2-B bass preamp and the power stage of six 100-watt Hiwatt heads. The Alembic F2-B is a very straightforward unit -- it has a bright switch, volume, bass, middle and treble controls. We, however, have altered it just a little bit. We put an extra tube in the preamp secton to give it a little more drive, lowered the impedance in the output and changed the capacitor in the bottom end to eliminate some of the lows, because it was very boomy through closed-back cabinets." - [Phil Taylor, David Gilmour's guitar tech](http://www.pink-floyd.org/artint/dagear.htm)more
Alembic F-2B bass pre-amp. It has tubes in it. I bought this originally to run two sides of the Chapman Stick through it. Hadn't used it for about a decade when I pulled it out to sell three years ago. I actually did sell it, but the guy who bought it had reservations about really wanting it and I had reservations about wishing I had it back. So we did an unsell and I got it back. Now it sits as one of my main ways to bring guitar or bass into Logic Audio. I'm replacing it's tubes this week.more
Using this Preamp in conjunction with the Yamaha RA-200R was a match made in heaven. With a warm, tube analog sound, the Alembic F2-B works perfectly to replace the preamp/tone stage of the Yamaha and open it to a new sonic level! In this case, the Alembic had to be modified with an additional tube to help signal loss from extending the location of the preamp to the Yamaha. Tone capacitors had to be replaced in order to cut lower frequencies from passing through to the large cabinets of the Yamaha RA-200R. Overall key element in the quest for the Gilmour Sound!
The preamp from a blackface fender showman with the opto trem circuit removed from channel 2. Sounds great. Tried replacing my showman with this and some stereo effects into an H&H but I missed the output section.