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Preamplifier in progress

KNielsen · 2025-01-14T18:16:42+00:00

Hey AK's Just a short intro into this project I wanna share. After several protobuilds where all worked, this end-build might be in sight within a few months. I have most of the parts, except chassis/relays and other minor parts, but most I have in my inventory. All drawings are made in KiCAD with my own designed footprints to give the "look" I want for this preamp. The input circuit itself is based on a 90's elektor magazine design, altered a bit due to obsolete parts where I had to find replacements. The original schematic calls for MAT02/03, which I replaced with THAT340. Outputs are upgraded from BC327/337 to TTA/TTC004 or A1381E/C3503E, both work. The PSU is a zener emitter/follower, powered by a 2x18VAC 30VA R-core transformer with a dual LT4320 active bridge rectifier and a RCRC configuration. I've been looking at LM317/337 many times, but I have all parts in stock for the emitter/follower, so that's what I went with. Normally I've been refurbishing Acurus amps, and if you Google Acurus/Aragon it's easy to see a great deal of inspiration from these units. To be continued:) Best regards