Impressions (not quite reviews) of some 70's gear

Posted by Lee of Omaha (D) on July 8, 2012 at 06:42:40

In recent months we've had through our shop 2 Pioneer SX-1980s, an SX-1250, a SPEC-1 and SPEC-2, a Sansui 9090, and a Yamaha C-800.

I've never cared much for the most common Pioneer SX-n50 and -n80 receivers such as the SX-780. I think there is much better-sounding vintage gear.

When we got in the first SX-1980 and fixed it, I wasn't expecting much. To my great surprise the power amp section is very good. Dynamically correct, unexpectedly detailed for a high-power vintage amp. Pioneer tuners are usually good, so the excellence of the tuner section wasn't a surprise. The second SX-1980 sounded identical after repair and with the caveat that several months passed between the two units, so the fidelity of my aural memory may be an issue.

The next piece we got in was an SX-1250. After repair I hooked it up and was amazed. This is a VERY good sounding amp, better than the SX-1980. It produced bass out of my little B&W DM-303s that I didn't think they were capable of, and that no other amp has produced. And it wasn't just a bunch of overblown muddy bass; it was good tight (upper) bass. This amp sounded better in bass than any other amp in this comparison; only the little Yamaha in class A beat it overall. I think the SX-1250 may be the sweet spot in 1970's Pioneer gear. I'd like to get another.

We then got in a SPEC-1 and SPEC-2. After repair (extensive repair for the SPEC-2) both units worked up to spec and sounded decent. The SPEC-2 just didn't do anything for me. It sounds ok, and it was obviously operating correctly and at least as well as when it left the factory (we upgraded a couple of underdesigned power supply regulators) but I just didn't much care for it.

The Yamaha C-800 has a front panel switch that changes operation from 50 watts per channel in class AB ("Normal") to 15 watts per channel in class A. The switch should not be in the front, and should be integrated with the power switch. Operating the switch changes the rail voltages, which can easily blow the amp if done with the amp on if switched from Normal to Class A. That is exactly what happened to our unit prior to our getting it, and it required extensive repair. In class AB it sounds decent and typical for a Japanese amp of that power rating and vintage. I also hooked it up through an electronic crossover so it only had to handle frequencies above 80 Hz and used a power sub for the rest. WOW! I could play to any loudness I desired and it sounded very, very good. I like class A. It's amazing how loud 15 watts per channel can be if it doesn't have to handle bass. As an aside, that's one big reason I'm in favor of electronic crossovers and separate amps for bass and the mids/highs. It's also amazing how much heat 30 watts is--this guy gets pretty darn warm in class A.

The Sansui 9090 confirmed, a bit to my surprise, my memory of 35 years ago. My first roommate in the Air Force had a brand new Sansui 9090DB (onboard Dolby, the 9090 doesn't have onboard Dolby). I remember thinking that the phono preamp could be used as a noise generator. It was noisier than the stock phono preamp on my Fisher 500B, and the noisiest solid state preamp I've ever heard. Conversations with Sansui enthusiasts led me to question whether my roommates' unit was a nonrepresentative sample. We cleaned the 9090 and replaced some lamps and hooked it up. The result was exactly what I remembered from so long ago. OK sound overall with a terribly noisy phono preamp. Either I've had two bad samples separated by 35 years or they used a lousy phono preamp. Other than the phono preamp the amp sounds typical of a 1970s Japanese receiver--ok, grainy, slightly fatiguing. This is a nice looking amp with nothing to commend it aurally.

Overall, the winner in this small sample is the SX-1250, with the Yamaha C-800 an interesting amp that could be a nice part of a budget audiophile system (in Class A used for mids and highs). The loser is the Sansui. your mileage may vary.

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Topic - Impressions (not quite reviews) of some 70's gear - Lee of Omaha 06:42:40 07/08/12 (17)

So you found out about Sansui ! - airtime 09:04:15 07/11/12 (0)

RE: Impressions (not quite reviews) of some 70's gear - dadbar 06:43:53 07/11/12 (0)

RE: Impressions (not quite reviews) of some 70's gear - Bold Eagle 09:38:51 07/09/12 (2)

RE: Impressions (not quite reviews) of some 70's gear - Lee of Omaha 14:22:14 07/13/12 (0)

RE: Yes, I believe the SX-939 was a gem! - BigguyinATL 08:36:09 07/10/12 (0)

RE: Impressions (not quite reviews) of some 70's gear - Crazy Dave 08:12:19 07/09/12 (2)

RE: Impressions (not quite reviews) of some 70's gear - Lee of Omaha 14:21:15 07/13/12 (1)

RE: Impressions (not quite reviews) of some 70's gear - Crazy Dave 09:36:37 07/16/12 (0)

RE: Impressions (not quite reviews) of some 70's gear - Skylab 05:27:56 07/09/12 (0)

RE: Impressions (not quite reviews) of some 70's gear - DIY John 02:28:06 07/09/12 (2)

RE: Impressions (not quite reviews) of some 70's gear - Lee of Omaha 14:19:09 07/13/12 (1)

Thanks! nt - DIY John 07:50:24 07/16/12 (0)

Mostly agree, esp. about the 9090...(yucko!) - Otis 12:42:49 07/08/12 (0)

I suspect you mean Yamaha CA-800 - mhardy6647 11:46:00 07/08/12 (0)

interesting - tbcblues 11:08:19 07/08/12 (2)

RE: interesting - Bold Eagle 09:29:30 07/09/12 (1)

RE: interesting - FRG7SWL 08:55:02 07/10/12 (0)

Impressions (not quite reviews) of some 70's gear

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