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Switching/D-class amps and their supposed improvements over the years;

You sound like you are talking about the past...
I wish it wasn't so eerily applicable to today. But let's not get too political, shall we.

I'm still lusting for the fucking sixhundred peak kilowatt tube radar amplifier of the MiG-25, running off a generator that effortlessly makes two or three megawatt, while that's just a few percent of the whole machine's power o_O
 
There's a 'Tilear' TPA3251 on Aliexpress which someone referred to as identical to the Aiyima A04, it's cheap (c. £43 including shipping, no PSU) and I'm procrastinating about ordering one.

ETA >> Meh - actually over £50 all-in, same price as Aiyima A07, but again, I have a couple of good 19.5V bricks (ex Sony Bravia 4.2 and 6.0A) ready to go that will power them but not the A07.
 
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Is there a reason you've ruled out the Fosi V3 or the Aiyima A07 MAX? Those are models with a big user base and people mostly pleased with them...good reviews from Amir...good volume control for softer listening...wide range of power bricks that can be used with them...for your use case, you could probably just go 32v 5a...?
 
Is there a reason you've ruled out the Fosi V3 or the Aiyima A07 MAX? Those are models with a big user base and people mostly pleased with them...good reviews from Amir...good volume control for softer listening...wide range of power bricks that can be used with them...for your use case, you could probably just go 32v 5a...?
I just have a suspicion that the cheap D-amp chips from TI and the like don't scale particularly well, or at least they have a range of output levels where they work best that's proportionate to their rated output or supply voltage.

Admittedly my experience is limited, but when I tried out some TPA3118's back in the late 2010's which everyone said were a major upgrade from the TA2020 ... they weren't - they could go louder but none of them were anything like as good as the Indeed TA2020 I've gone back to at 'calm' or 'late night' volume levels. And I've got a box of PSU's, the largest being 19.5V which will give me all the SPL's I need but won't power a TPA3255.

I don't want or need an amp any louder the TA2020, it would just be nice to have a bit more headroom for non-brickwalled recordings.
 
I understand...the one bit of advice I can offer, some of the newer amps have the better volume taper pot rather than log...for me, that's really key for listening at lower levels. I understand you ideally don't want to buy another power brick, but most of the newer amps want a bit more voltage, and that would provide the headroom you say you are seeking...

Don't however get an Aiyima A07, it's still a good amp, but you have a lot less low level volume control than with the Fosi V3 or the Aiyima A07.

My little A04 works so fine in my bedroom system, it's a keeper - you may be able to still find one in the wild if you are persistent.

I got the A07 for a very low price from them because I got the A04 and found it a little underpowered for what I'd intended to use it for...they sold me the A07 for the price of a power brick, basically. So I got both amps and the power brick for around a hundred, I believe. I have found both Fosi and Aiyima folks generally helpful and responsive to email queries.

If you have multiple inputs needed, keep an eye out for Fosi's little P4 preamp - I think it will come out in January. No price yet. Here are photos of it in my workroom. I'll be posting a review on it next week. It pairs very nicely with the V3 amplifier.

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Manufacturer's data for TPA3116, TPA3251 and Tripath TA2020-020, THD+noise, 1KHz c. half-power;

TPA3116 - 0.1%
TA2020-020 - 0.03%
TPA3251 - 0.005%

If these figures are remotely relevant to how good they sound then it shouldn't be a surprise that the TPA3116 doesn't sound any better than the TA2020 (ETA >> implementation , surrounding components and circuitry probably having far more bearing). I have to assume that people being impressed by 'louder' was the reason for the hype around the TPA31xx back in the day.

The TPA3251 (3250 and 3255 are similar) is theoretically, literally almost an order of magnitude better than the TA2020 and so much better than the TPA3116 it isn't funny.

So what the hell, ordering a 'Tilear' TPA3251
 
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I understand...the one bit of advice I can offer, some of the newer amps have the better volume taper pot rather than log...for me, that's really key for listening at lower levels. I understand you ideally don't want to buy another power brick, but most of the newer amps want a bit more voltage, and that would provide the headroom you say you are seeking...

Don't however get an Aiyima A07, it's still a good amp, but you have a lot less low level volume control than with the Fosi V3 or the Aiyima A07.

My little A04 works so fine in my bedroom system, it's a keeper - you may be able to still find one in the wild if you are persistent.

I got the A07 for a very low price from them because I got the A04 and found it a little underpowered for what I'd intended to use it for...they sold me the A07 for the price of a power brick, basically. So I got both amps and the power brick for around a hundred, I believe. I have found both Fosi and Aiyima folks generally helpful and responsive to email queries.

If you have multiple inputs needed, keep an eye out for Fosi's little P4 preamp - I think it will come out in January. No price yet. Here are photos of it in my workroom. I'll be posting a review on it next week. It pairs very nicely with the V3 amplifier.

...
Thanks for the info, appreciated.

That's VERY interesting. Occasionally (well more than occasionally) I use the optical-out from my TV for streamed video (amazon et al), and those defeatable tone controls (which I'd otherwise never consider) would actually be very useful.

I bought an SMSL Sanskrit III DAC/'preamp' a while back partly because it gives me at least remote volume control for the optical-in. Also, the Fosi pre-out would allow me to go back to using only my SU-1 DAC for all inputs (i.e. dispensing with the Sanskrit) ETA >> the pre-out could go to my headphone amp, to which the SU-1 is currently dedicated.

It occurs to be that I actually enquired on ASR last year about the availability of exactly this kind of preamp!
 
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Thanks for the info, appreciated.

That's VERY interesting. Occasionally (well more than occasionally) I use the optical-out from my TV for streamed video (amazon et al), and those defeatable tone controls (which I'd otherwise never consider) would actually be very useful.

I bought an SMSL Sanskrit III DAC/'preamp' a while back partly because it gives me at least remote volume control for that optical-in. Also, that pre-out would allow me to go back to using only my SU-1 DAC for all inputs (i.e. dispensing with the Sanskrit).

It occurs to be that I actually enquired on ASR last year about the availability of exactly this kind of preamp!
Yeah, I was bringing it up a lot too - now we have the new Schiit Saga 2 at $279, which I own, and now the new Fosi is coming along too. I expect we'll see some others, but these two options will really fill that gap. The Schiit does not have tone controls, but it does have a relay stepped attenuator, very very accurate all the way down to 0 volume. I hope Fosi will price their unit around $125 - I think it would do well at about that price point.

The interior on that Tilear does look identical to my older A04, so it's probably the same board, etc. Seems to also have the ability to swap op-amps, if you ever wanted to.

Your 19.5v power supply may be a bit underpowered even for that guy, but see how she plays with what you have...
 
I understand...the one bit of advice I can offer, some of the newer amps have the better volume taper pot rather than log...for me, that's really key for listening at lower levels. I understand you ideally don't want to buy another power brick, but most of the newer amps want a bit more voltage, and that would provide the headroom you say you are seeking.
I use digital attenuation/volume from my PC (via a remote), the volume knob on the Indeed is left at 12'o'clock, so fortunately low-volume channel mis-matches on the pot of whatever amp I use is moot.
 
...

Your 19.5v power supply may be a bit underpowered even for that guy, but see how she plays with what you have...
I reckon it won't be problem, the TA2020 on 13.5V has been plenty for 99% of my listening for years now, hopefully a TPA3251 on 19.5V will just give me some more headroom to accommodate 18db+ RMS-to-peak 'vintage' recordings in my library.
 
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Just to re-iterate;

has anyone else ever found that their audio rigs, while kicking-ass at 'realistic' SPL's, are just flat, un-detailed and boring when they try and listen at levels that don't make crockery rattle and antagonise their neighbours?

I can't believe I'm the only one.
 
Just to re-iterate;

has anyone else ever found that their audio rigs, while kicking-ass at 'realistic' SPL's, are just flat, un-detailed and boring when they try and listen at levels that don't make crockery rattle and antagonise their neighbours?

I can't believe I'm the only one.
It's your ears. Human hearing is volume-dependent in terms of frequency response. It's the reason why loudness functions exist: they're attempts to correct for this behaviour.

And then there's the psychological aspect: music triggers an emotional response, and if you aren't listening loud enough, that response is less pronounced. Louder is better.
 
It's your ears. Human hearing is volume-dependent in terms of frequency response. It's the reason why loudness functions exist: they're attempts to correct for this behaviour.

And then there's the psychological aspect: music triggers an emotional response, and if you aren't listening loud enough, that response is less pronounced. Louder is better.
Yes and no. Of course louder is moar better. But I've repeatedly tried to make the point that my tiny TA2020 amp conjures detail and space that others don't at similar volume.

ETA >> lest I be misunderstood, it's not just a matter of 'detail' and 'space' but also dynamics and proper bass-lines. I dunno, but I'm tempted to say a kind of 'bonsai' representation of the recording.
 
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I think the RSL iA255.1 probably offers desktop users the biggest value with Bluetooth, RCA and USB input, pre out for subs, bass/treble adjustments and an optional 90Hz HPF switch on the mains. All for $110.
Also no load dependency!
 
Just to re-iterate;

has anyone else ever found that their audio rigs, while kicking-ass at 'realistic' SPL's, are just flat, un-detailed and boring when they try and listen at levels that don't make crockery rattle and antagonise their neighbours?

I can't believe I'm the only one.
Of course this is what in "the old days" we more or less solved by using the loudness circuit. Those varied in quality from manufacturer to manufacturer, but it was a nice way to make a quick adjustment when playing at a lower/background level to boost the bass and treble without fiddling with the tone controls. I still rotate/use a restored Marantz 2216 and Kenwood KA-3500 just for their all-in-one convenience, and I do enjoy having that available. The built in phono preamps sound pretty good, too.

My favorite circuit of that type was in older Onkyo equipment. An old workhorse receiver, the TX-8511, had "selective tone control" that always sounded just right to my ears. Another older Onkyo that I just gave to my older son for his girlfriend's system had an interesting bass boost/slider combination as well as regular tone controls. Same kind of thing, a way to apply quickly a varying level of bass boost.

And of course we can replicate loudness today by having an alternate Equalizer APO preset for a set of speakers when playing low - but that's not as easy as just pushing a button.

Truth is, while I love all my new equipment - you just don't get as much functionality as what got packed into 70s and 80s integrateds and receivers, and for a decent price. Tape dubbing, loudness, four inputs, tone controls, balance adjustment, etc etc. The tradeoff is greater transparency, specs and flat frequency response...
 
The best loudness circuits were variable.
They were common in the 1950s and into the tail end of the vacuum tube hifi era (early 1960s) and observed spottily in the field, so to speak, for a couple of decades afterwards. Yamaha offered variable loudness for a relatively long time on most of its receivers and integrated amplifiers, albeit omitting it on the "best" of their midline equipment, e.g., the CA-2010 (US model designation) integrated amplifier.


(from the Yamaha CR-2020 stereo receiver manual, ca. 1978)

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Variable loudness on ca. 1980 Yamaha R-1000 stereo receiver)
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CA-2010 sans loudness ;)
source: https://www.hifiengine.com/manual_library/yamaha/ca-2010.shtml

As a mostly-but-not-entirely irrelevant aside: empirically, ;) single-ended, direct heated triode power amplifiers and high-sensitivity loudspeakers retain subjectively :p rich tonal balance (and impressive dynamics) down to very low volume (more to the point, SPL) levels -- Fletcher-Munson notwithstanding. Nope, I cannot explain it, either objectively nor even with fluffy audiophile verbiage. Sorry!
 
Nice to see that curve graph. I have two unrestored Yamahas that I still use, a CR-420 and CR-240, and both have the variable loudness knob. Yeah, that was kind of unique to Yamaha in the 70s and early 80s.
 
There was a very nice article on the evolution of Class D design evolution at

 
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