View Full Version : Nakamichi SR-4A


M Jarve
03-23-2006, 09:50 PM
I posted some time ago about maybe buying a Nakamichi SR-4A in the new Dollars and Sense forum, but my mind was already mostly made up.

I bought it today, for a little more than I intended to (the seller had no change). It was just as well, as it did need just a thorough cleaning and new power fuses. I took the liberty of replacing some of the dreadful "pig-tale" soldered-on fuses with smaller 20mm fuses with holders (the holes and solder points were already on the PCB's). I also noted a dark area on the inside of the power cabinet where corresponding to the location of a power regulator.

I switched it on, the fuses did not blow, and protection did not kick in. All good signs in my view. Checked DC offset (-0.01mV in one channel, 0.03mv in the other).

I then cleaned, cleaned, and cleaned the inside (it reeked of smoke), and did the same to the outside. I removed every knob and cleaned them. It is now tolerable, though I would prefer it to be cleaner inside.

I then got around to hooking it up. To start with, I connected up the Altec 890C. I put the tone controls to their center position, adjusted the variable loudness to its minimum setting, and placed the CD.

My first observation was that it was very quiet. Not in background noise or anything (which it is), but it seemed that the volume needed to be turned up higher than I would have thought to obtain a given power level. Granted, it was being used for the first time in about a decade, but I was a little surprised none the less. I then turned up the loudness, and it seemed to bring up the volume to where I would expect, but it created a “smiley-face EQ” sound that I had to counter with the tone controls.

After I had the tone controls, volume, and loudness thing figured out, I started to listen. The Altecs, despite being “west coast” speakers, are very flat in their frequency response, and with the SR-4A, they need a little boost in the treble to get a little sparkle. I adjusted the receiver to that and everything fell into place.

Bass is very strong, quick, and clean, but it seemed to be missing the very lowest octaves. Mids are a little laid back, but highs are clear and “sparkle”. Basically, this is what I would have expected it to sound like with the Altecs. It has been said before that the 890C is a revealing truth teller. Indeed, it seems to allow you to listen to the equipment without adding any bias or prejudice of its own.

After listening to the Nakamichi, I connected the Equasounds so as to hear its potential. I installed the active EQ in the processor out-in loop (preamp out/main in) so that, like with the SAE/Kenwood setup, the active EQ can do its job on the signal after it has already been processed.

The Equasounds sounded a little disappointing on the SR-4A. The normally strong, yet balanced mid range was gone, and the overall sound again had a “smiley-face EQ” sound. It tended to be a little boomy and one-note sounding in the bass, and highs were a little edgy. The most noticeable thing was the mid-range deficit. The woofers seemed a bit much for the amp to handle too, judging from the slightly sloppy sound.

With the Equasounds needing more from the SR-4A than it could provide, I went in the opposite direction, to a set of bookshelf speakers, the Wharfedale Diamond 7.2 ALE. Now it found its pace. The Diamonds matched up to the SR-4A like peas and carrots. Bass was full and punchy from the little CD-sized woofer, and it had midrange, bless it! The highs were squeaky clean, with the slightly dry character British mini-monitors are known for.

Now that I had found a set of speakers that complemented it, I tried out some of the other functions. The tuner works pretty well, pulling in local stations cleanly, but it cannot pull in some of the more distant stations that do no trouble either my Mitsubishi DA-F30 or Sansui TU-7900. Compared to my Denon HT receiver, it does as well or better, but it is still no match for a good separate tuner.

The SR-4A was definitely worth the money and time I put into it, but it cannot stack up against something like a comparable h/k 680i, when it comes to larger speakers. The slump in the mid-range and slightly sloppy bass when confronted with a low Fs woofer put it at a disadvantage, at least with large speakers. When used with smart bookshelf speakers, it is more at home, with plenty of power and gusto to fill a medium sized room with clean, smooth music. I was expecting a little more given the Nakamichi pedigree, but when taken as a 1980’s 60WPC receiver, it certainly holds its own.

TrexT
03-24-2006, 07:36 AM
Nice job in saving that Nak M Jarve. I've owned several Nak receivers my first one was yours and then later I bought the little Receiver 3 for a bedroom setup. Still have the Receiver 3 and it sounds as good as it did when I bought it in 1991. Enjoy :thmbsp:

markmarc
03-24-2006, 09:14 AM
Mike:
I owned the 680i for many years starting in 1982. That was one beast of a machine. I ran a dance for 600+ at my university using it and a pair of Polk 10b's. It went full throttle for 4 hours. At the end of the night I put my hand on the cover, it was warm, but not uncomfortable by any measure. At the end of the year the school paper awarded the dance with the best sound prize.

TrexT, for a very similar review of the SR 4A, try the February iss of AffordableAudio.org.

atrens
03-24-2006, 08:39 PM
Hey Mike,

Quick question for you. I'm just now retiring my Nak SA-2A .. bought it in '90. It's been a great receiver, but the end is nye! The pre-amp side is pretty dead, I've replaced some components, but it's still not doing too well.

So I thought I'd dish out some bucks and replace it with a NAD C-372. A lot more beefy, and shiny-new. :)

I'm using it (the NAD) to drive an old pair of Energy Ref-22's (bought in '88, still sound great), and a pair of small KEF Coda's (bought in 96).

Anyhow, enough blah-blah, on with the question....

The Nak has/had a variable loudness dial that really perked up the KEF's, to use your expression, they 'sparkled'. Not so with the NAD - they sound
pretty flat.

Is there some component, that you'd recommend, that I could in-line (line-level) on the NAD that would allow me to acheive a similar effect as the variable loudness feature available on the Nak ?

Interestingly, the Energys sound awesome with the NAD. I don't think the Nak ever could drive them properly. :)

I suppose the other variable is cable. I have some very beefy cable (4 guage?), and relatively short (about 10ft) wiring up the Energys. The KEFs have 18 guage I think and the cable length for them is about 30-35 ft (they're in another room).

Thanks man!

Andrew.

Negotiableterms
03-24-2006, 09:17 PM
Is the SR-4A a Stasis model? If so, it ought to sound better than you're describing. I say this only because a friend of mine had one, and we were always amazed at its sound quality.

People who've read a lot of my posts know that I'm an admirer of Nelson Pass' work product, but even with that bias, the Nak Stasis stuff sounded pretty good.

It's quite old...could it be time for a trip to EW?

atrens
03-24-2006, 09:47 PM
My SA-2A is definitely a Stasis. :)

M Jarve
03-24-2006, 10:08 PM
Is the SR-4A a Stasis model? If so, it ought to sound better than you're describing. I say this only because a friend of mine had one, and we were always amazed at its sound quality.

People who've read a lot of my posts know that I'm an admirer of Nelson Pass' work product, but even with that bias, the Nak Stasis stuff sounded pretty good.

It's quite old...could it be time for a trip to EW?

The SR-4A is a STASIS unit. I noticed today that it is designed for use with speakers with a nominal impedance of 8-ohms or higher. While the Altecs and Diamond 7.2's are rated as such, the Equasounds are rated at 4 ohms, and have a pretty low DCR (around 1.8-2-ohms). Whether that may have something to do with it, I don't know. It does seem that bass tightens up with higher impedance speakers, though it still seems to be slightly lacking in the very low frequency department. Low DF, maybe?

I do know that it has some lack of midrange; that or an exaggerated bass and treble. I tried it on the Bozaks this evening (a marvelous mid-range/vocal speaker), and even they sounded lacking in the 900-2K range.

It is indeed getting old, relatively speaking, and it has not even been powered on for the past 10-12 years (since it originally blew the fuses). That may be part of it too. Or, it could just be a less than stellar implementation of the Pass design.

I’m going to continue monkeying around with it; maybe hook up an equalizer or something. Something in the back of my mind is telling me that I am missing something here. Perhaps it just needs a second breaking in after so many years of inactivity.

I’ll keep everyone posted.

Negotiableterms
03-24-2006, 11:41 PM
Mike, you mentioned that you had to turn up the loudness comp in order to get volume. That shouldn't be the case; and would account for exaggerated highs and lows, maybe?

crooner
03-25-2006, 12:38 AM
I've heard Nelson Pass was not happy with the way Nakamichi implemented his original Stasis design. Threshold threatened to sue. Nakamichi dropped the circuit in the early 1990s. Perhaps he [Pass] felt the changes defeated the whole purpose of the Stasis approach...

atrens
03-25-2006, 08:32 AM
Mike, you mentioned that you had to turn up the loudness comp in order to get volume. That shouldn't be the case; and would account for exaggerated highs and lows, maybe?

No. Mike's right. That's how the Nak's 'loudness' feature works.
The higher the loudness, the lower the overall volume.

With the loudness dial at '9', volume should be very low.

Andrew.

thedelihaus
03-25-2006, 09:23 AM
An excellent read, Mr. Jarve. No wonder you're writing for Affordable Audio now. Your piece in that about your Sansui tuner was entertaining and informative as well.

Keep up the good work.

M Jarve
03-25-2006, 12:29 PM
I feel like such an idiot. I found out why the sound I was getting from the SR-4A seemed so off. My only excuse is that the solution (and the underlying issue) was so simple that I just completely overlooked it.

As is the case with much of the problems experienced with electronics, it was stupid user error. I was operating the variable loudness system backwards. :nono:

After I turned up (or down, rather) the loudness control to the "normal" setting, it sounded excellent. Suddenly there was as much smooth midrange as I could want, and the very low bass popped in.

I re-connected the Equasounds (and active EQ) to give the receiver a proper listen again.

With the variable loudness now where it should be (normal) and the tone controls bypassed, it is every bit a match for the h/k 680i, except, perhaps, in peak power output (the h/k 680i has two banks of 4x 4,200uFd caps each). The SR-4A has enough to drive the Equasounds to deafening levels, none the less.

Sound wise, it is a little less warm in the treble than the h/k, but it is a little more clear in the mids too. Bass is tighter than on the h/k, but it still has less presence in the infra-sonic range; it still performs in that area well, though. It does kick-drums exceptionally well: almost as good as the Kenwoods. It has the most balnaced and pleasing sound I have ever heard when running a receiver at "true flat". In short, this is a credit to the Nakamich pedigree, and to Nelson Pass for his excellent STASIS circuit.

One silly setting, and the unit goes from “ho-hum” to “get me another… NOW!”. Damn that tricky loudness control! or the idiot operator

matt39
03-25-2006, 05:22 PM
atrens as to your problem with your Kef Codas. 30-35 feet is a very long run for 18 gauge wire or even 16 gauge. Before you buy additional equipment I think it would be worth your while to get some inexpensive 12 gauge wire and see if that solves your problem. It should work better over such a lengthy run. I mean the NAD should drive those Codas no problem.
Gary

atrens
03-25-2006, 06:28 PM
atrens as to your problem with your Kef Codas. 30-35 feet is a very long run for 18 gauge wire or even 16 gauge. Before you buy additional equipment I think it would be worth your while to get some inexpensive 12 gauge wire and see if that solves your problem. It should work better over such a lengthy run. I mean the NAD should drive those Codas no problem.
Gary

Thanks. Will do. Was thinking the same. I inherited the wire fished by the previous home owner. The run might even be longer actually. I haven't crawled around to measure. ;)

Thing is they sounded beautiful with the Nak, and it's about 1/3 the power of the NAD - (50 vs 150 watts / channel ).

Maybe the NAD (being higher current) runs at a lower voltage and therefore is more lossy when used with crappy cable...

Not sure. Will find out, hehehe! :)

As an experiment I'm gonna temporarily move the KEFs into the room with the amp and run a nice 6 gauge to them to see if that is indeed the issue. :)

Andrew.