Review: Pioneer C-90 Preamplifier

Category: Preamps

If you can find this preamp, you should buy it. It came out around 1987. Julian Hirsch did a review of it in “Stereo Review” when it came out and he said it was one the best measured preamps he had ever tested. If you remember the old “Stereo Review” reviews, they did an excellent job discussing the measurements, but said very little about the sound quality. I came upon one in great condition at a local pawnshop for $160. I hate to pass on a good deal, so I bought it thinking I could use it in my office or bedroom. I’ve owned several preamps such as the Audible Illusion M3A, B&K Ref 30 and the Bel Canto SEP1. The Pioneer is very well built. It has a large chassis and weighs about 25 pounds. It has a dual mono power supply. This contributes to its excellent measurements providing a separate power supply for each channel. It has video switching (which I don’t use) and tone controls that are defeatable. According to Julian Hirsch, it has the quietest measured phono stage he has ever tested (the review was in 1987), so the phono stage should sound great. I do not have a turntable, so I’m unable to test the phono stage. Nevertheless, the line stage is absolutely amazing. I was stunned by how good this preamp sounded. I tested using PSB Image 7PT speakers. This is not the best pair of speakers I own, but it is the only full-range set of speakers. The PSB’s are actually nice sounding speakers, but are a fussy match. I think the PSB’s are dry sounding speakers. I’ve used them with different solid-state integrated amps such as the Linn Majik and Rega Mira and they sounded awful. I think they sound great with tubes and the Audible Illusions made a good match with the PSB’s; tubes give the PSB’s a little sparkle. The amp I’ve used for a long time is a Crown D-150 Series II. The Series I model was the professional standard through the 1980’s. The Series II version came out in the late 1990’s with new cosmetics. The Crown is a very revealing amp. It can sound a little bright if used with a bright preamp. However, the Crown has awesome detail and dynamics and sounds wonderful with a tube preamp.

The Pioneer has a surprisingly warm sound. Voices come through very detailed, but with a rich and transparent quality that matched the Audible Illusions. I was amazed at how closely these two preamps sounded alike. In terms of transparency, I’ve have not heard anything better than the Pioneer C-90. The vocals sit in front of the instruments, but possess a rich liquid shimmering quality that sounds very lifelike. It sounded like Norah Jones was sitting in front of me. I have not heard such presence in any preamp. Even Robert Cray’s “Heavy Picks” which sounds very bright and too much like a recorded compact disc, sounded lifelike. I felt I was no longer listening to Cray on a CD, but a few rows back at a one of his concerts. As much as the Audible Illusions comes close, it does not match the Pioneer’s level of transparency. This preamp sold for $800 in 1987. If you factor inflation, it would probably sell for $1200. This is amazingly cheap for such a well-built and awesome sounding preamp. I think the Pioneer would be right at home in a much more expensive set-up. I just wish Pioneer would continue to make quality value laden separates that could compete with the high-end manufactures.

Associated gear
Crown D-150 Series II Amplifier
PSB Image 7PT Speakers
Toshiba SD-9000 DVD Player

Similar products
Audible Ilusions M3A
B&K Reference 30
Bel Canto SEP1
Kirk's take on this preamp is dead on. A superb and under-rated preamp with a killer phono section. I have a Ortofon MC10-Super and this preamp just opens it up. Killer good looks too. I got mine fora "steal" price on Ebay of $112. All it needed was some Deoxit for noisy controls. Best $112 I have ever spent. Grab one of these if you can!
The weak link in this preamp appears to be the function switches that activate little relays to select different modes such as Tuner / CD / Phono etc. Now this preamp is getting some age on it I am starting to see some audio dropouts after long terms in storage. At first you think this is from dirty pots and switches when it actually is the little relays acting up. I have two of these preamps and both acted up for several days after powering up.
The good news (in my case) is that after a few days they come around and start working properly. I never unplug one either when finished I place it in standby, this seems to help as well. Point is once you buy one of these guys give it time when you power it up, dont be too hasty determining it is not working correctly.
Over the years I have owned 5 mint C-90s all were superb Preamps, the two I have now are wonderful.