• The Gear Page Apparel & Merch Shop is Open!

    Based on member demand, The Gear Page is pleased to announce that our Apparel Merch Shop is now open. The shop’s link is in the blue Navigation bar (on the right side), “Shop,” with t-shirts, hats, neck buffs, and stickers to start. Here’s the direct link: www.thegearpageshop.com

    You’ll find exclusive high-quality apparel and merchandise; all items are ethical, sustainably produced, and we will be continuously sourcing and adding new choices. 

    We can ship internationally. All shipping is at cost.


Alembic f-2b

mmrxcsr01

Member
Messages
140
Thinking of building one for a friend, and it seems to get the components into a single space rack mount, Alembic used a very small power transformer and a voltage doubler arrangement. If I DON'T have a size limitation, does anyone see any reason not to use just an off the shelf P/T (with the appropriate secondary voltages) with a full wave bridge recto setup? Thanks...

http://moosapotamus.net/ideas/alembic-f-2b-preamp/
 

jay42

Member
Messages
7,047
No. I built a half of an F-2B in a 1U rack, but a 2U would allow for more fun. Depending on what power amp tou need to drive, you may have to add a cathode follower. You can also bypass the tone controls with a .049uF cap for active basses.
 

mark norwine

Member
Messages
17,159
building in a 1U is simple.......use small flatstack transformers. Mouser has them.

Also, the circuit (a simple AB763 preamp) was designed by Fender to feed the inverter of his guitar amp circuits. Stand alone, the AB763 preamp has a gain structure that produces an output that is well above "line level" and is too hot for a typical power amp. You may want to re-design the circuit a bit for lower gain. Split-loading on the plates will help a lot.
 

jay42

Member
Messages
7,047
Thanks Jay, appreciate your input. Did you find the circuit to be a useful one, long term?
Yes. Mine was stolen, however, it got lots of positive comments from bassists while I had it. I didn't mark it as an F-2B, so it was just some DIY thing to them.

I dug into the "active" bass thing and found that some of the circuits were FET based versions of the basic blackface Fender preamp, which means that many of those players don't know they went Fender. Put another way, if it was good enough for Stanley Clarke, should be good enough for a lot of players.
 




Trending Topics

Top