Adcom GFP-750 preamplifier , balance design

by cutehf Thu May 26, 2022 7:20 pm

Description: Solid-state, remote-control preamplifier switchable to passive attenuator/switcher

The GFP-750 is a Nelson Pass design—essentially a variation on the Pass Labs Aleph P and Pass's DIY project, The Son of the Bride of Zen (footnote 2). The circuit couldn't be simpler. Says Pass, "It's a differential pair—the end. A single gain stage, balanced input, balanced output, no feedback....We took a pair of MOSFETs, and the inputs go to the gates of the MOSFETs. The MOSFET sources are tied together and biased with a current source, with the signal taken off the drains. [The circuit] can run unbalanced on either side, although the performance is best when it's run balanced."

Condition 7.5/10
RM 4K
+6597493656 Pos to you location.