70's and 80's AMPS

[GRollins]

For what it's worth, I owned a Phase Linear 200, a 400, and a 700. None of which ever gave me a bit of trouble. Nor did any of the Phase Linears belonging to people I knew. I'm sure that scads of them blew up, but like people who have gone ballistic saying that the old Haflers were prone to failure, I think that you should look at these things in context. Not how many amps failed, but what percentage of them failed. I'd say, conservatively speaking, that Phase Linear sold about twenty gazillion amps. So someone claims to have seen 'dozens' or perhaps even 'hundreds' of dead Phase Linears. So what? Express that as a percentage of units sold and you'll find that they were actually fairly reliable. As reliable as McIntosh, for instance? Perhaps not. But they also sold for far less. As for sound quality, you could do better, but this is rapidly going to go from a discussion of "what's good?" to "at what price?" There are few classic (in the sound quality sense) solid state amps from that era (tube amps are a different matter, entirely), so you'll not likely have to take out a second mortgage to buy a used solid state piece.
I don't recall seeing anyone putting in a plug for an old Hafler 200 or 500. Consider them. Great, cheap low frequency amps. Very modify-able. Tell any old hand that you've got an old Hafler that you want to mod and they'll be on your doorstep with a soldering iron in thirty minutes.
I've still got two Threshold S-500s that I bought back in the '80s. They make good low frequency amps, too, but they're more expensive.

Grey

[Mark A. Gulbrandsen]

Gray,

Actually Threshold 400A's go for typically 400 to 700.00 in the used market. Thats a very decent price for what is really quite a good amp today, ditto for KSA-50's if you can find one... KSA-100's are more plentyful but start at a grand go up to about 1600.00. An 80's amp that is quite good and can be had fairly reasonably is the Threshold S-300... prices range about the same as the 400A but there are a number of versions to watch for on these. Tha later optical bias version IMHO was the better one, owned one of these for a couple of years. The larger Nakamichi Stasis amps were also good but today I'm not sure about service or semiconductor availability on them. So that could be a risk.

. I don't quite agree on the ealry Haflers though... we replaced alot of those with BGW's that were installed doing Cinema duty in the early Dolby Stereo days back in Chicago. They sounded fine but didn't hold up well, were not truely stable under those conditions.... early mosfets I presume. BTW: Both 35 and 70mm analog film sound can tax an amplifier to death, literally.

I think you'd find that most of the Phase Linears and Crowns that gave much trouble were the early on versions for about two years after introduction. I first owned a 400 when I was a senior in High School in early 1973, it too blew up. After graduating I then went to work at a factory service center of a local HiFi store chain where we were warranty service for just about everything under the sun.

Later B model Phase Linear amps were quite stable but the build quality actually got way worse than the originals were. Only Bob Carver could build them worse but make them more reliable! Crowns build quality actually got better in later years..... with the DC-300A and so on. We all know that McIntosh sacrificed sound quality for reliability... those too are class B. I was actually told this once by a McIntosh factory rep back in those days.

Mark

[planet10]

Originally posted by anatech
Carver would be good choices for that, especially the Carver.

Yuk... i wrote Carver off when i had an NAD 3020 smoke a Carver Cube (late 70s). Not a big fan of the Phase Linears either althou Allen Wright says careful application of CCS can transform them.

I know where there is a Dynaco 400 -- and priced at the point where it would be worthwhile looking at it for just Chassis & iron. If they still have it the Bryston 4B would be a better buy.

Hitachi & Toshiba (Aurex) made some decent power amps, and since they get little respect they sell cheap. I also have a Sears amp (OEMed in Japan) that is a fully dual mono MOSFET amp and quite decent (certainly better than a DC300A) and it was cheap, cheap, cheap.

Haflers of that era are fairly decent, and have mod bits available to make them 1st class. The Onkyos SY mentioned are 1st rate & Kenwood made a couple models in the same class.

I also have an old monster Pioneer receiver that makes a reasonable sub amp.

dave

[planet10]

I should mention that i worked hifi from 1976 to 1981... the best amps we sold consistently were NAIMs, with Brystons, Halflers, and PS Audio selling in greater numbers (the NAIMs were most expensive, and rated at 50 & 70s watts so a hard sell -- the NAIMs being the only ones that did a decent job driving Dayton Wrights). We had a lot of other amps thru the shop, but these were the right combination of price, performance, availability, & reliability (althou the PS Audio were prone to breaking)

dave

[anatech]

Hi All,
Planet10, some Carvers sounded okay. The cube was nasty (I've repaired a fair number of these). M-500's sounded much better. Lots of M 1.0t's out there - yes better sounding units exist. Like the original Lightstars. But then, Marantz kicked most brands out of the park for sound quality and reliability. How about the Marantz 500? I think '74 was the last year for these but they sounded really good when set up. I repaired Dayton-Wrights old 500. The Nakamichi rep loved it. Kills a Naim any day (fixed those too). Bryston (2,3,4)B's sounded really bad and had bias circuit design faults, a weak power switch and a face that would rip off when roaded - plus they were ugly. Fixed some of those too. Why did people attempt to drive Brystons with tube amps? Didn't work out.

-Chris

[SY]

Originally posted by GRollins
For what it's worth, I owned a Phase Linear 200, a 400, and a 700. None of which ever gave me a bit of trouble. Nor did any of the Phase Linears belonging to people I knew. I'm sure that scads of them blew up, but like people who have gone ballistic saying that the old Haflers were prone to failure, I think that you should look at these things in context. Not how many amps failed, but what percentage of them failed.

Grey

I did repair a whole bunch of them, all with almost identical problems. Sure, P-L sold a lot of them, but we saw more of them coming through the shop than we saw of more popular brands. As soon as someone walked in the door carrying a P-L, I'd immediately start fishing through our output transistor stock before even asking what the problem was.

[serosmaness]

They are normally very reliable and you will not hear the commutation in your subs.

What does the commutation sound like?
Thanks Steve

[K-amps]

Don't know what the commutation sounds like in the older carvers, but in the Sunfire, you will cover your ears at 2-3kHz and 6-7kHz tones... just too harsh and glaring...

[EchoWars]

Originally posted by Mark A. Gulbrandsen


Nothing fomr the 70's was really any good, so my favs from the 80's were in order......

<snip>

Beyond these there isn't anything solid state from that time period thats worth the time of day.

Mark

Well, Markie says so, so it must be true. I guess I'll set fire to all my vintage amps.



(sweeping generalizations are rarely accurate, and the technically literate should strive to avoid them)

[anatech]

Hi EchoWars,
Well I'm really going to have to agree with you. What colour do classic amps make when they burn? What ever have you been listening to Mark? There are classic, great sounding amps from every decade.

serosmaness,
You can hear a definite "edge" to the music. With a 'scope you can see tiny "pips" riding on the waveform as the commutating transistors switch the supply voltage up and down. Later designs from Carver used a variable commutator that sounded much better. The best solution was a high frequency "down converter" that was used in the Lightstar. Basically PWM of the 125V rails and filtered. At idle the outputs had around 13 VDC on them. They sounded the best of all the Carvers.

-Chris