Vintage amplifiers that could challenge or approach current state of the art amplifiers

[DonH56]

If'n I take off gloves and socks, I cain't count no to more'n 20, so most anything older than that gots to be antique.

 

[restorer-john]

I cain't count no to more'n 20, so most anything older than that gots to be antique.

Well that makes us all antiques I guess. Rare, collectible and likely to go up in value if looked after.

 

[Mosfet]

Vintage Classé CA-200 Power Amplifier. Original owner, bought it brand new, it's quiet, powerful, transparent and works perfectly. And it's 65 lbs.

 

[watchnerd]

Vintage Classé CA-200 Power Amplifier. Original owner, bought it brand new, it's quiet, powerful, transparent and works perfectly. And it's 65 lbs.

How hot does it get?

 

[Mosfet]

It stays pretty cool. The heatsinks are external and located in the back. The heat depends on how high you have the volume, the type of speakers used and what the amp is required to do during musical peaks.

 

[TomJ]

Also the KAV-250a stereo version. Fully balanced, 2kVA, class A input and driver stages, 5pr BJT/ch output stage, very high build quality. Still using mine every day after 20 years, 100% reliable and dead quiet. At time of purchase, SQ in blind listening tests like FPB of same power.

To your question about what you give up compared to the Krell FPB: class A output stage with microprocessor controlled variable bias (the KAV operates in class AB biased to run the first few watts in class A), DC offset protection circuit, CAST interconnects, Link IR remote interface, standby mode and the hi end external heat sinks and case design. The three channel KAV-250a/3 has the same modular amp boards as the stereo KAV-250a but smaller heat sinks and proportionately less power supply reserve per channel.

 

[patate91]

https://archimago.blogspot.com/2020/08/retro-measure-pioneer-sx-880-receiver.html?m=1

 

[anmpr1]

https://archimago.blogspot.com/2020/08/retro-measure-pioneer-sx-880-receiver.html?m=1

I see Arch has changed his look?! His comments about TIM (and other deep diving measurements) are well taken. In the late '70s there were all kinds of 'explanations' about why the JC-2 'sounded better' than the PAT-5 even though both had great specs. Mark couldn't tell you, and David suggested it was imagination. I think Hafler was more to the point.

Of course, if you were using weird loudspeakers like the Apogee you couldn't use a Pioneer receiver. For that you might have wanted four (a bridged pair per channel) ML-2. But for any reasonable load, the Pioneer (or Kenwood, or Yamaha, or ______ fill in the blank) was OK.

That said, none of these '70s designs would match current top tier amplification (AHB2) in absolute measurements. Most modern amps don't even come close to that.

 

[tmtomh]

So the conclusion so far seems to be that virtually no vintage amps can challenge or approach state of the art - but a good number of vintage amps perform(ed) very well indeed and no doubt are close enough to today's state of the art that they will sound indistinguishable from current state of the art in most use situations.

Yes?

 

[sergeauckland]

So the conclusion so far seems to be that virtually no vintage amps can challenge or approach state of the art - but a good number of vintage amps perform(ed) very well indeed and no doubt are close enough to today's state of the art that they will sound indistinguishable from current state of the art in most use situations.

Yes?

Yes.

S.

 

[Frank Dernie]

Well, the noise injected by the power supply could easily be measured and shown. I don't see how this could be wrong. There is quite a bit of literature on the distortion caused by switching transformers of LED lights, etc. Running a dedicated power cable from the fuse box will lessen the effect, but not, if the amp or DAC power supply injects it right where the music plays. Not saying it can't be eliminated through clever filters, but I have not heard it yet.

The world is now full of items with varying quality of SMPS, from high quality ones in HiFI (Chord Electronics have used them since they started in the business many years ago) to cheap phone chargers and tens of millions of computers and TVs.

Any engineer worth employing will be filtering this hf dross out of the mains supply at the mains input in his/her designs. Only badly engineered products will sound any different as a result of mains borne rubbish.
My advice is sell anything which you imagine sounds bad due to SMPS and don't buy from that manufacturer again, they are incompetent.

 

[tmtomh]

Well, the noise injected by the power supply could easily be measured and shown. I don't see how this could be wrong. There is quite a bit of literature on the distortion caused by switching transformers of LED lights, etc. Running a dedicated power cable from the fuse box will lessen the effect, but not, if the amp or DAC power supply injects it right where the music plays.

It can be measured and shown - @amirm 's reviews show both THD and noise, and you can see what frequencies the noise peaks are, and based on that plus his comments draw a reasonable conclusion about where the noise is coming from, whether or not it should be considered a design/engineering flaw, and if it is a flaw, whether or not it's likely to be audible at all.

Not saying it can't be eliminated through clever filters, but I have not heard it yet.

If you've ever heard an audio device with a switch-mode power supply and not noticed any objectionable electrical noise coming through the speakers or headphones, then of course you've heard the effect of filters - they are, as noted above, a very basic feature of most audio equipment.

You're making a very common mistake that's prevalent in audio discussion (not to mention a lot of broader science-related discussion): confusing what you as an individual know with what professionals and experts know. Don't get me wrong: I'm a layperson too. Just because you and I don't necessarily know something doesn't mean it isn't actually known as part of the current state of human scientific and engineering knowledge.

 

[patate91]

So the conclusion so far seems to be that virtually no vintage amps can challenge or approach state of the art - but a good number of vintage amps perform(ed) very well indeed and no doubt are close enough to today's state of the art that they will sound indistinguishable from current state of the art in most use situations.

Yes?

As per Infinity speaker review I think the same thing could apply to speakers. There's certainly a couple of old speakers that perform as well as new speakers. Acoustic treatments tackle a lot of the reflections issue anyway.

 

[MakeMineVinyl]

The basic topology of amplifiers has changed over the last couple decades. The current trend is fully differential amps, essentially two complete amps per channel working in anti-phase. This has led to lower voltage requirements on the power rails. Previously, amps tended to be single ended, and to get the same power, considerably higher voltage rails were required. I'm not saying this has much to do with measured performance or sound quality, but it is a definite change which has happened and differentiates contemporary amps from the past.

 

[DonH56]

The basic topology of amplifiers has changed over the last couple decades. The current trend is fully differential amps, essentially two complete amps per channel working in anti-phase. This has led to lower voltage requirements on the power rails. Previously, amps tended to be single ended, and to get the same power, considerably higher voltage rails were required. I'm not saying this has much to do with measured performance or sound quality, but it is a definite change which has happened and differentiates contemporary amps from the past.

Curious, do not know, picking your brain... Are most amps now fully differential designs, or internally "bridged" or quasi-differential with essentially two distinct amplifier paths (maybe only in the driver and/or final stages) in-phase and out-of-phase?

 

[SIY]

The basic topology of amplifiers has changed over the last couple decades. The current trend is fully differential amps, essentially two complete amps per channel working in anti-phase. This has led to lower voltage requirements on the power rails. Previously, amps tended to be single ended, and to get the same power, considerably higher voltage rails were required. I'm not saying this has much to do with measured performance or sound quality, but it is a definite change which has happened and differentiates contemporary amps from the past.

Are you old enough to remember Southwest Technical Products?

 

[MakeMineVinyl]

Curious, do not know, picking your brain... Are most amps now fully differential designs, or internally "bridged" or quasi-differential with essentially two distinct amplifier paths (maybe only in the driver and/or final stages) in-phase and out-of-phase?

A distinguishing feature of these differential designs is that the feedback is cross coupled. In a 'bridged' amp this is not the case.

 

[MakeMineVinyl]

Are you old enough to remember Southwest Technical Products?

I have heard the name, but don't know anything about them beyond that.

 

[sergeauckland]

A distinguishing feature of these differential designs is that the feedback is cross coupled. In a 'bridged' amp this is not the case.

Apart from having a marketing story to tell, what advantage does a fully differential design give? Having lower rails is only important on portable equipment or something powered off a wall-wart, so of no practical benefit for a power amp. So, if that's the case that many modern power amps are fully differential, why?

S.

 

[MakeMineVinyl]

Apart from having a marketing story to tell, what advantage does a fully differential design give? Having lower rails is only important on portable equipment or something powered off a wall-wart, so of no practical benefit for a power amp. So, if that's the case that many modern power amps are fully differential, why?

S.

That's a good question, and I don't know the answer. Slew rate is better in the differential designs, and there are some benefits of lower rails like needing less voltage capability on filter caps etc, I think there might be a heat advantage, but beyond that I can't say one way or the other.

As I've mentioned before, for my personal system, its all vacuum tubed with the only silicon being in the subwoofer amplifier. I'm considering replacing that amp with a class "D" one at some point. There's a lot of reasons I use tubes, extremely high efficiency horn speakers being one of them. I don't have anything against solid state per se, just that It isn't needed in my instance.