Record Engineering Development Department Type 47 inspired dual tube preamp used on well known 1960’s British recording sessions to replace the Siemens V series amps.  Featuring a pentode front end and second stage military parallel triode configuration.  (EF86/EF806/6267 and 6DJ8/6922/E88cc respectively). Stable, quiet, compact and efficient 290-300 VDC power on preamp PCB; linkable for stereo units. Very clean signal path with 2 high quality coupling capacitors and extra bypass cap options.  Film bypass caps on cathodes.  Practical NFB 12 position gain switch using an ubiquitous Grayhill PCB mount switch with 2 polystyrene caps for HF compensation.  Film bypass caps on high voltage decoupling caps.  4 Auxiliary PCB’S make P48, dual PAD, DI, and GAIN wiring a breeze. 2 relays take care of automatic MIC/DI switching and Output polarity switching duties.  Some engineers have really been enjoying the subtle ‘SQUISH’ compression option.  Filament options for AC or DC and stage 2 tube variations like a 12V 12bh7.  Tweeker’s Delight!

Power PCB sets P48 and relay power, balances Filament AC, and provides and easy route to ON/OFF indicator lamp. Optional circuit to elevate Filament ground reference. P48 doubler or trippler. Unregulated Relay/Auxiliary 12 or 24 volts.
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