Audio Research Sp-4a Preamplifier

A Tune-up for the Audio Research SP-4/4A Preamp

http://conradhoffman.com/SP4A_caps.htm

A Tune-up for the Audio Research SP-4/4A Preamp. Introduction. The ARC SP-4 preamp was ARCs first solid state preamp. It was controversial at the time and some say it almost destroyed the company. Opinions about the sound quality …

Audio Research SP-4 Stereo Pre Amplifier Manual | HiFi Engine

https://www.hifiengine.com/manual_library/audio-research/sp-4.shtml

The SP-4 preamplifier was designed around the Analog Module which acts as a 'super tube' because it takes the best qualities we see in the vacuum tube much closer to the theoretical ideal. The SP-4 surpasses our vacuum tube preamplifier in the most important areas. It has increased musical depth and definition with a smoothness that will satisfy any vacuum tube enthusiast.

Audio Research SP4 Preamplifiers user reviews : 5 out of 5 ...

http://www.audioreview.com/product/amplification/preamplifiers/audio-research/sp4.html

I currently also own an Audio Research SP6E tube preamp, and Carver C-4000t preamp I got this for a steal. First off, the build quality is to be marvelled at. Yes, the SP6E is also built like a tank, but when I removed the cover from the SP4 I was staggered at …

Audio Research SP 4 | Solid state | Audiogon

https://www.audiogon.com/listings/lis9e745-audio-research-sp-4-solid-state

This is a classic solid state Audio Research SP4 A pre-amplifier with the rare MCP-1 active head amp for MC cartridges and rare ARC original wooden case. This is a very clean and complete unit. I purchased this from an engineer at Audio Research who upgraded many of the coupling caps with unbranded TRT (Wonder) Stealth Caps which are used in ARC reference series equipment.

Audio Research – High-end audio equipment

https://audioresearch.com/

The best sounding Audio Research Line Stage preamp

https://forum.audiogon.com/discussions/the-best-sounding-audio-research-line-stage-preamp

i think you are better off looking for an earlier audio research such as the sp 10. yes i know it is a full function preamp. also consider one of the earlier sp3 models. i think the newer models do not have the signature of tubes. perhaps, you can get lucky by finding some nos tubes with the ls5.

Audio Research SP-9 Preamplifier – Old School | TONEAudio ...

https://www.tonepublications.com/old-school/audio-research-sp-9-preamplifier/

Clearly, the Electronic Industries preamp I had on the bench was quite a bit different from the Audio Research SP-9, which was created later in 1987. This preamplifier was a standard tube design. The latter, as Johnson explains it, is the culmination of numerous experiments with transistors and eventually FETs to come up with a hybrid design ...