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Big expensive quality amplifier market dead?

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One of things I've noted is that many of the new Class D offerings list unrealistic and uselessly optimistic specs. Ie: claiming that a $70 amp with the 3255 chip produces 600 watts is wishful thinking. The same amp might realistically offer 100ish usable watts per channel into an easy to drive load if you use the right $70 48V 10amp power supply, which doubles the price of the amp...still cheap, but how many people will run any power supply other than the one supplied? Driving real world impedances of an actual speaker is different than driving a resistor on a test bench.

These amps might replace average mid-fi receivers, but so far my experimentation tells me that my 40 year old 100 wpc BK ST-140 hits harder with more control when used as a woofer amp than something like a Fosi or Aiyima chip amp, and the BK has always been considered a budget amp that's not known for it's bass impact. I wouldn't hesitate to get one of these chip amps for my youngest daughter to get started with in a situation with relatively modest demand...the small size is great. I'm not giving up on them yet, and a beefier power supply is on the way, but the "but" still exists for me.
 
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“Figures lie, and liars figure” Holds true in so many contexts.

It has been a while so pardon me (and correct me) if my memory is not exact, but here’s how I remember some of these specs:

100WPC in a spec, did require pre-conditioning of the amplifier, but it is not music power, … it is a pure sine wave of 2kHz (not sure on the frequency but that is my memory). It is a whole lot more difficult to produce this power into music and throughout the entire music spectrum, than in a 2kHz burst.

X% THD can be again a 2kHz sine wave, and it can be a percent of the maximum output, and much larger percent of lower power output thus .01% of 100W being 1/1000th of the 100W or 10mW which is pretty insignificant at 100W, but at the normal “first watt” power levels it can be huge. Also it is not required to be music nor full-spectrum.

This is just part of the specs. In these and other cases, it is easy to hide what’s really happening. My mother taught me when I was very young to listen to what isn’t said, I always look at what is left out in specifications. Compare for example what you see in some of the mid-priced consumer gear’s specifications to professional sound equipment (ex: JBL Pro) and note the big difference in how things are specified. In real pro-gear settings, the customer measures and knows the installed performance and also specs these things very carefully, you don’t get away with partial specs and BS. In consumer gear it’s more wild west as most people can’t measure and value bright colors and circles of tweeters over real performance.

Anyway, I believe in specifications, but am not interested in buying for example a speaker that is spec’ed 20Hz-25kHz response (or something like that without the context of +/-dB and whether it is anechoic, etc. Give me graphs and complete specs, a “white paper” and I have something that is real, not marketing BS.

Most of high-end audio marketing proves P. T. Barnum to be correct.
 
knotscott said:
... Driving real world impedances of an actual speaker is different than driving a resistor on a test bench. ...
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Maybe you'd consider challenging Amir's measurements?

Granted, most people don't have 2 ohm load but to suggests they can only deliver with easy loads and test bench resistors certainly isn't the case.

Fosi v3 mono.

Screenshot_20251018-112113_Edge.jpg
 
whoaru99 said:
Maybe you'd consider challenging Amir's measurements?

Granted, most people don't have 2 ohm load but to suggests they can only deliver with easy loads and test bench resistors certainly isn't the case.

Fosi v3 mono.

View attachment 3616505
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Last week I hooked a Fosi chip amp into my system with the supplied 24V power supply as a woofer amp operating below 65hz into an 8 ohm Focal woofer. It replaced an old BK ST-140. At first glance, it sounded pretty good and I was encouraged. However, when I gave it even a little bit of volume (that my wife didn't even react to), the amp lost control and flapped the woofers. I'd be surprised if that amp was making 10 usable watts into that woofer with the supplied PSU...it truly wasn't very loud. It's possible it was defective, but it's also possible that as received it simply doesn't produce anywhere the advertised output into a speaker.

The Fosi got returned, and replaced with an Aiyima that came with a 32V supply. The Aiyima fared better than the Fosi in the same situation, but still does not do what the old BK ST-140 does. A 48V power supply is being shipped, so I'll give the Aiyima another try with more supply juice.
 
DavidTT said:
Class D stuff. It... poses no burden to... repair
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This seems unlikely to me (unless you simply mean that nobody even tries to have them repaired, thus no burden).

But I speak mostly from ignorance. Have you had a class D amp repaired, to your satisfaction?

Honest curiosity, trying to be attitude-free though I know my prejudices are showing.
 
knotscott said:
Last week I hooked a Fosi chip amp into my system with the supplied 24V power supply as a woofer amp operating below 65hz into an 8 ohm Focal woofer. It replaced an old BK ST-140. At first glance, it sounded pretty good and I was encouraged. However, when I gave it even a little bit of volume (that my wife didn't even react to), the amp lost control and flapped the woofers. I'd be surprised if that amp was making 10 usable watts into that woofer with the supplied PSU...it truly wasn't very loud. It's possible it was defective, but it's also possible that as received it simply doesn't produce anywhere the advertised output into a speaker.

The Fosi got returned, and replaced with an Aiyima that came with a 32V supply. The Aiyima fared better than the Fosi in the same situation, but still does not do what the old BK ST-140 does. A 48V power supply is being shipped, so I'll give the Aiyima another try with more supply juice.
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You need to look at the specs to see about where you're at, and of course we'd need the amp models to really discuss what might be going on because they have various models and they're not all the same.

Whether the inexpensive amps use real TI TPA3255 chips or knockoffs I don't know. But, if you want to see qualified specs of what an original TI TPA3255 can do at various voltages, various loads, in BTL or PBTL, etc., etc., look at TI's datasheet for TPA3255.

While not in current rotation, I use my TI TPA3255 EVM eval boards with Mean Well RSP-500-48 power supplies.
 
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chazix said:
This seems unlikely to me (unless you simply mean that nobody even tries to have them repaired, thus no burden).

But I speak mostly from ignorance. Have you had a class D amp repaired, to your satisfaction?

Honest curiosity, trying to be attitude-free though I know my prejudices are showing.
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No, the point was (perhaps poorly made) that these little gems are so inexpensive that they would likely never be repaired. I will say though, that if you've seen the insides of something like the Fosi V3 stereo or mono models opened up, they are incredibly simple and I assume any tech could repair one in VERY short order. Would it be worth the time and money to do so? Probably not, considering they can be bought for peanuts.

This will be my last post here but here goes: these threads about Class D almost always become round-and-round affairs with some chiming in that they don't have enough power, or that they won't last, or that they don't sound good. To each their own. I have spoken with very few who have tried TPA3255/PFFB models with at least 48V/5A power supplies and didn't love them. I'm driving large JBL Studio 590 floor standers with the Fosi V3 Monos and they (1) sound fantastic, as good as any amp I've had in the system, (2) will make painfully high SPLs if I ever desired in this room, and are game changers for me.
 
My only caveat about my Fosi rig is those power supplies are dirty; very dirty and will add lots of emi to the lines. My solution was to piggy back a 15amp pc to the main 20amp pc for their own double filtered line. Emi still runs over 200 even will all that filtering.

Has anyone tried using a better power supply than the factory supplied bricks? I know that would be the proper solution.
 
Esoteric gear is great. I have heard it. But it will always be for a very small subset of people who can afford them. There is nothing wrong with that. They make a certain level of audio achievement possible. What's nice is the depreciation. Depreciation makes a $40,000 preamp into a $20,000 preamp, and a few years later a $10,000 preamp. And it still sounds the same. A couple of years ago, I bought an Audio Research amp off of Craigslist for $800. The VT-60. That purchase introduced me to a level of quality that I did not fully appreciate, till I got to live with it for a while. I still own it, and it serves one of my systems beautifully.
 
motorstereo said:
My only caveat about my Fosi rig is those power supplies are dirty; very dirty and will add lots of emi to the lines. My solution was to piggy back a 15amp pc to the main 20amp pc for their own double filtered line. Emi still runs over 200 even will all that filtering.

Has anyone tried using a better power supply than the factory supplied bricks? I know that would be the proper solution.
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ASR's review I looked at for a Fosi preamp looked pretty clean. If it was throwing a bunch of junk on the line wouldn't it seem it would screw up the sensitive testing gear?
 
whoaru99 said:
ASR's review I looked at for a Fosi preamp looked pretty clean. If it was throwing a bunch of junk on the line wouldn't it seem it would screw up the sensitive testing gear?
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I would think the dirty ps would show up on his testing. The v3's power amps have the bricks and the zp3 pre plugs into a 120 outlet. Since they both test very well I guess he doesn't feel it's worth mentioning.
 
Though my all time favorite amp is a Mcintosh MC 3500 mk I tube amp, they are not as cheap as they once were. The sold for $1099 new and there for a while I might find one pair pre-owned for about $1500.00. Today they go for around $15,000 each. There were only 135 or so built as I remember. The new MK II's are $17,500 now and like the old ones keeping them as new by replacing tubes more often than you would like will add to the costs. I used three MK I's when providing sound for touring groups. They were heavy back breakers for sure.

I have been a SS guy ever since. It wasn't so much the sound quality of my 240's and 275's that bothered me. It was having to have the amps tested twice a year and always finding a miniature tube or two or a pair of outputs that needed to be replaced that drove me to SS. And then I wasn't really that happy either till the MC 7200's and 7100's came along. My speakers didn't like autoformers as they made the lower mids and bass soft and fuzzy. 7200 fixed that promptly with out being dry and hard like other SS amps I tried.
 
>dead
It’s never been a huge market, save for the 1970s into 80s and that’s a long time ago. Not like 30 years ago everyone was sporting large Macs, Brystons and the like; not everyone needs it, wants it, or likes it like that.

Audio systems are barely on the radar of 99% of the population these days; anyone who walks into my home immediately comments on the living room system. That’s because absolutely nobody else has a system that isn’t a surround-ish black receiver from Best Buy.

Doesn’t mean we aren’t out there, just we are few now more than ever.
 
Gigantic said:
Agreed. Paying less for similar, if not better quality = more enjoyment.
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I always try to hit the sweet spot in bang for the buck. In stereo, that means sound bang for buck. I had a friend who had all the extreme high dollar stuff like the McIntosh monoblocks. I would go over to his house and go ooh aah at the sight of his pride and joy. His high dollar stuff was definitely dazzling to look at. Then I would go home and be smugly happy knowing my much cheaper system sounded better to my ears. But who knows? Was it only because my stuff was a better deal?
 
Dave1027 said:
I always try to hit the sweet spot in bang for the buck. In stereo, that means sound bang for buck. I had a friend who had all the extreme high dollar stuff like the McIntosh monoblocks. I would go over to his house and go ooh aah at the sight of his pride and joy. His high dollar stuff was definitely dazzling to look at. Then I would go home and be smugly happy knowing my much cheaper system sounded better to my ears. But who knows? Was it only because my stuff was a better deal?
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IMO&E there's better sounding gear out there than Mac SS and for much less dough. It's OK but doesn't impress me, never did.
 
RVT1K said:
Jaguar tried very hard to alienate their traditional customer demographic.
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mission accomplished, sadly.
Plus them abandoning conventionally-fueled vehicles was the crowning blunder.
Thus, I must preserve the old one I have. :(
 
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