Have amplifiers finished evolving?

[Joe P]

mercalia,

ah not for the heatwave conditions we will be getting in future?

The power consumption of my toob amp was a concern, so I bought a power meter to see how much juice it draws.

Turns out it's about 150 watts when it's on, so not too bad. I also voluntarily pay more for green energy, so presumably the energy my amp uses isn't contributing to my carbon footprint.

Joe

P.S. I'm not looking to get a bigger toob amp. If anything, I'd swap the Stingray for a Leben CS300.

 

[Tony L]

The power consumption of my toob amp was a concern, so I bought a power meter to see how much juice it draws.

Turns out it's about 150 watts when it's on, so not too bad. I also voluntarily pay more for green energy, so presumably the energy my amp uses isn't contributing to my carbon footprint.

IIRC my Leak Stereo 20 draws about 100 Watts, which makes sense as it has half the number of EL84s as your Stingray, but has got a big hot GZ34 rectifier. That is nothing at all compared to a big Krell or whatever. I had light bulbs that drew that before I went LED! I once shared a flat with one for a while and turning it on dimmed the lights and sent the electric meter spinning - the bill was horrible! I have no issue running the Leak as the act of using vintage audio itself is green. The very worst thing an audiophile can do IMHO is to buy unserviceable crap that will end up in landfill. The Leak is 57 years old and after a rebuild to replace tired caps and resistors it is as good as new. Proper fully maintainable hi-fi.

 

[Fulci]

You have lots of new technology in amps, Nad M32, Devialet is as high tech as you can get, Bang & Olufsen like it or not, PS Audio, Primare... even Bryston and Audio Research are using class d. You get lots of new ideas in Hegel, they have very fresh approaches on amp design, Arcam too.

Which doesn't mean that they are better than topologies made 50 years ago. I don't think that the future is in better sound quality, but in way better power management, lower consumption, smaller equipment, portability and cost reduction, bringing better sound to lower models. That's where research is being put nowadays.

 

[JensenHealey]

You have lots of new technology in amps, Nad M32, Devialet is as high tech as you can get, Bang & Olufsen like it or not, PS Audio, Primare... even Bryston and Audio Research are using class d. You get lots of new ideas in Hegel, they have very fresh approaches on amp design, Arcam too.

Which doesn't mean that they are better than topologies made 50 years ago. I don't think that the future is in better sound quality, but in way better power management, lower consumption, smaller equipment, portability and cost reduction, bringing better sound to lower models. That's where research is being put nowadays.

Yup,I agree

 

[sq225917]

Yeh some of those power mosfet are good for 100 watts each these days.

 

[Joe P]

Tony,

The very worst thing an audiophile can do IMHO is to buy unserviceable crap that will end up in landfill. The Leak is 57 years old and after a rebuild to replace tired caps and resistors it is as good as new. Proper fully maintainable hi-fi.

My 10-year-old SACD player and 20-year-old CD player might be garbage when they die, but the rest of my system is easily serviced. The fact that I can get OEM parts for my nearly 60-year-old Tannoys says a lot.

Not that I was considering the Devialet Phantoms, but that they can't be serviced at all would take them off any contender list.

Joe

 

[cubastreet]

Class D amps are more efficient. The obvious advantage is they use less power. Other benefits are that they don't need huge heatsinks (more compact, less cost) and you don't have all that heat to wear out your electrolytic caps.

 

[gints]

Not all D class are the same. For example, NAD M32 do not need D/A conversion before amplification like normal D class amplifier, if I get their description right.

 

[Yank]

Class D amps still have a way to go before they can equal analog amps in the top octaves.

 

[Arkless Electronics]

I think that Class AB was held back for a while by the semiconductors available. The good old 2N3055 et al just didn't have the gain available, hence things like the Quad 303 that needed Darlington triples. However since then decent power amp tranies ahve been developed, along with PNP versions of same, so you ca now have complementary pairs, and I think the work has now been done. Whether integrated circuits can match this remains to be seen, including Class D options. I'd say yes, but I don't think that there is enough money in hifi amplification any more to make it worthwhile. So maybe there is still stuff out there, but my guess is that if there is more then nobody is prepared to pay for the work. As someone else said, we are into flavours and badges to make the diference fro those prepared to spend the money.

The issue with the likes of the 2N3055 (which version!?) and its ilk was not gain but crap gain bandwidth product (low as 800KHz for some types!) and poorer gain linearity in comparison to what we have today. At the time of the 303 a bigger issue was that PNP devices were much worse than NPN ones and even supposedly complementary devices were often far from it. Reliability of earlier silicon devices could be suspect also and NPN was more tried and tested shall we say... This is almost certainly why Walker chose the triples (two different feedback triples, not Darlington triples) of quasi complementary devices with their huge internal NFB which ensures linearity. it's still relevant today. I've made computer simulations of the Quad 303 in which I've replaced the quasi triples with fully complementary ones and it makes bugger all difference as theres so much feedback there anyway. They also have excellent bias stability.

 

[davidsrsb]

Innovation these days is on the inputs. Bluetooth aptX is coming in.
Cost reduction in the electronics is failing to keep up with the loss in production numbers, the rise in prices of components and the spiraling labour cost in China.

 

[Jonboi]

A lot of digital amp specification is downright misleading/disingenuous from what I can see, especially at the more affordable end, e.g. the rated output tends to be at an odd impedance and the distortion nowhere near what would have been acceptable even in the 1950s. The well liked Tripath chips being prime examples, e.g. the TA2020 seems to routinely be sold as a “20 Watt amp”, yet is actually spewing out 10% distortion at 12 Watts into 8 Ohms (datasheet). For comparison my wonderful sounding 1961 Leak valve amp can deliver its full rated power (10 Watts) at 0.1% THD.

I have a little Amptastic Mini-1 T-Amp and it is a very nice little amp for the money. I use it to drive the huge great Klipsch La Scalas in my TV room. I only need a couple of Watts, a 2 Watt SET can drive these speakers to literally deafening levels, so it is running clean here and sounds fine. I’d still take a nice class AB or class A amp over it, e.g. it doesn’t worry a 50 year Quad 303 that much.

I spent a couple of days recently staying in That London with a friend who has just bought a pair of active Kef LS50s, which have a digital amp on the bass-mid unit. They are rather good, I liked them a lot, so I’m not opposed to the technology, I just feel in many cases it is not being sold very honestly and I am certain *a lot* of kit is being advertised as being far more powerful or lower distortion than it actually is.

Anyway, I’d like to hear a genuinely high-end digital amp put up against a very good class A amp (tube or solid state). Are there any that could worry a big class A Krell, Conrad Johnson, Mark Levinson or whatever?

Tact, Lyngdorf and Bel Canto would come to mind - even my TADA 9000ES Class D amp which is effectively a Sony version of a Tact Millennium.

Certainly when it arrived in the mid 2000's, on US forums enthusiasts were preferring it to the likes of MacIntosh, Krell etc and swapping them out for the big Sony.

I have heard and like McIntosh - a local dealer has them coupled with Klpisch La Scalas - but i would not swap the big Sony for the McIntosh on sound quality grounds myself.

I have friends who own Audio Research, and also Krell. I've never put the Sony Amp up against them in an A/B, but again just from what I've heard, I'd see no reason to swap the Class D Sony for the US amps on sound quality.

I don't personally have anything against Class D or for that matter switch mode power supplies.

The Class D Sony has a dinner plate size transformer and Nichion Gold and Black Gate capacitors in it's power supply - supposedly awesome grade components according to audiophile folk lore, but other components in my kit have switch mode power supplies and it all sounds good, so I just enjoy the music and leave the engineering concerns and fine details to those who know best.

Provided it's engineered properly, and apart from audiophile angst and resistance to change, as I say, I don't have an issue with Class D, and I should imagine properly engineered and implemented they'd match anything one might hear from Class AB, or Class A.

Even hallowed Naim used Class D at one stage in it's NVI - albeit bought in, allegedly from either Texas Instruments or Bel Canto.

B&O's ICE power Class D technology, and also Hypex is used extensively in many different Hifi brands when one digs below the surface, so not all is at it seems in the audiophile world....

Cheers

 

[stevec67]

Thanks arkless, that's interesting. You confirm what I already knew about early PNP devices. I didn't quite follow what you mean re the difference between Darlington triple and what you describe, I'll have to look at the diagram again and see if I can understand it. My electronic knowledge is limited and rather dated.

 

[davidsrsb]

Buying in B&O ICE modules is a short cut to CE EMC approval. Class D amplifiers are inherently RF dirty and take expert layout to pass the tests.

 

[John Phillips]

Been thinking about the technological innovation of amplifiers - it's clear that digital has been evolving at a rapid rate, but what about amps? For those of you keeping up are the latest and greatest a lot better than the older models?

I wonder if class A and A/B amplifiers have improved topologically at all since Douglas Self's "blameless amplifier" topology of about the late 1970s(?).

There's modifications for class G (AKA Krell's "sustained plateau biasing" if I understand it correctly (no guarantee)) which steps the power supply voltage to match the output voltage and class H which varies the power supply voltage continuously. But this is for efficiency purposes, not performance.

Certainly in class A and A/B (G, H), bipolar output devices (and power MOSFETS) are so much better than when I started in the electronics business. Better bandwidth, greater power handling, gain better sustained at high current. So there's better amplifier bandwidth and better linearity open-loop before applying any feedback. Getting good amplifier performance at 20 kHz was once a challenge. Now flat to 200 kHz is not uncommon.

I do think class D (not really "digital" - the letter D just came after C) has been rapidly developing. I think that many (but not all) early class D amplifiers had shockingly degraded performance at high audio frequencies. Just like class A and A/B did with early power semiconductors. That has improved no end over the last decade.

 

[Tony L]

Tact, Lyngdorf and Bel Canto would come to mind - even my TADA 9000ES Class D amp which is effectively a Sony version of a Tact Millennium.

I heard one of the earlier Bel Canto amps (the integrated that’s about Naim shoebox sized) up against a little Leben tube amp and a big Luxman integrated. It was very decent, but I preferred the other two amps, they were just more believable somehow. In fairness I think it was the cheapest of the three. An admittedly early Tact Lyngdorf system with digital room correction ranks as one of the worst I’ve ever heard in my life; it sounded dead and gutless in the listening seat, and just hopelessly coloured anywhere else in the room as the response notching/filtering was so obvious. I’d be curious to listen to this technology again one day, but I remain hugely skeptical and view it only as a last-ditch fix for a truly desperate situation. I’d like to hear a Lyngdorf or Hypex power amp though, on paper some of these better class D amps do look good with a lot of power and often the ability to double power as impedance halves the way serious high-end stuff like Krell and Levinson can. I just want to know if they can do that liquid spacious walk-around soundstage thing and natural smooth clean top a really good valve or class-A amp can (e.g. my humble 57 year old Leak!).

 

[Cereal Killer]

IMHO digital amps sound and feel good for a while, but if/when you switch back to A, A/B, you experience something which digital amplification just cannot deliver, even from the likes of BelCanto's ACI-600 and Devialet's Expert 250 Pro.

 

[S-Man]

Maybe class AB amps would sound similar to switching amps if they had a ferrite cored inductor in the output?

 

[Cereal Killer]

Why turn the clock back? the only benefit of the Switching amps is they are much less power hungry, for example my current amp is rated at MAX 1400w

 

[S-Man]

Is there a parallel between the evolution of amps and that of people?
Amps seem to be getting bigger, heavier and more ornate.