• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

See you want a lot from others.1)Reading the Data sheets of 3 chips that are usually not of much use couse the implimitation counts. We dont know that specific implementation.
2) Knowing at what Watt you listen?

but ok lets forget this. The hard part comes.
Imagine that a person can heare for sure a thd difference of 0.1 to smaller than 0.1. Thats very hard for me to imagine this. Did you ever test this?

Dont think the tpa3251 is a bad chip. But the reasoning? Mhhh??

Btw. have a nice christmas!
All I can do is guess, but at the risk of repeating myself, the difference between the (indeed) TA2020 and the couple of TPA3118's I tried wasn't (isn't) subtle, and at least corresponds in some ways with the data. Small sample size obviously (and as you say, implementation is important), but if I'd bought handfuls of amplifiers (I did actually end up going through quite a few) it would have ended up being anything but a 'budget' exercise.
 
Didn't know that about the preamp stage, but I think you are probably right. I think 32v with 5-6 amps is a good power point for these amps. 32v ok as well.

I think a medical grade supply type PSU is safer to leave on, if you have some sort of casing for it and/or good protection for the wire leads... What is your reason for leaving the amp on all the time? Folks here go back and forth on that issue... I understand the off/on lifespan point of view. As for me, I power a system on in the morning generally and turn off when I am done for the day with it, but I don't leave running all the time. I've had only one brick problem with the D amps, a 24v 5a supply for one of my SMSL SA-50's from years ago - it developed a squealing sound, but didn't overheat, but I retired it nevertheless. The latest power bricks that came from Fosi and Aiyima have presented no problems thus far.

The whole SPL/watts race on these amps is just kind of silly marketing in my view...each of the makers trying to emphasize what they think will push the most units. Same with the op-amp swappability. These are very good little amps for the 50wpc - 75 wpc normal type of listening, for people really wanting to play at 110db they should be spending up and buying a Hyex or Purifi amp, or a modern Class AB amp. They are still good products for most listeners, hype on the specs aside.

I agree with those on the board who continue to point out that the power ratings for them are overstated, but I differ in that I think that does not make them toys or junk. Will they last as long as an old 1970s class AB amp? Probably not, but we don't know. We're likely to get more use out of each amp than the lifespan of our cell phones, at least.
The power ratings for switching amps are deceptive even if they're honest because of the way they go into hard clipping so abruptly at even 10% beyond their rated 'clean' RMS (perhaps some more advanced, expensive designs/implementations allow for that and use some kind of 'soft clipping'). Linear amps are far less abrupt and hence have "music power" (as they used to call it) that might be double their RMS figure (as ascertained using the standards imposed by law in the US to put an end to the 'ad speak' around amps). As I recall my Rotel was rated at 25+25W which is very similar to the TPA3118 on 19.5V, but no way would the latter play as loud and stay listenable.
 
Interesting to note that on Farnell ALL external PSU's currently available of more than about 65W use 4-pin DIN connectors (2 pins each for +/-), I guess there's been some legislation about it recently (there are numbers of high wattage PSU's with barrel connectors that are "no longer stocked"). It's also impossible to find female DIN to male barrel adapters, plenty of barrel-to-DIN.
 
All I can do is guess, but at the risk of repeating myself, the difference between the (indeed) TA2020 and the couple of TPA3118's I tried wasn't (isn't) subtle, and at least corresponds in some ways with the data. Small sample size obviously (and as you say, implementation is important), but if I'd bought handfuls of amplifiers (I did actually end up going through quite a few) it would have ended up being anything but a 'budget' exercise.

Good. Its just about not being so fast with the conclutions. You like it more in that special implementation thats the facts. Nothing else. And to like it more, hehe is very subjektive.

Still have a nice christmas !
 
There's a point where you can expect too much at once for very little money. Power, quality, longevity, customer support, all at once? Maybe it's worth a consideration going a step up, save some money, get a basic Hypex poweramp or AB Yamaha integrated for 500 moneys for example, and be done with it for years.

I perfectly understand a low money situation, but there's a point where an investment is very much worth it in terms of cost over time, with continued satisfaction. I'd say 500 moneys (€$£) is exactly that point.

+1 I realized I could drive myself crazy comparing all these chip amps or I could spend 2x once and get a Hypex NC252MP that will anchor my desktop for as long as I can imagine, with accessible support/service (Buckeye Amps). I enjoy reading about all the new options but am comfortable with what I have.
 
Found Mean Well 24V 5A/120W supplies on ePay cheep! (about half what RS-online and others are asking for the same unit, practically AliExpress no-name price), going with one of those. If 24V doesn't work, well I'm not out much cash.

My calculations are that on 24V into 6Ω speakers the TPA3251 will deliver 50+50W @ 0.1% THD and 61+61W @ 10% THD (rapid onset of clipping in D-amps evident in these numbers as usual - a linear integrated with a rating of no more than 25+25W RMS 8Ω would easily match its SPL's/loudness in real world listening).

So right on the limit for a 24V PSU, but in reality (i.e for my purposes) the amp will rarely ask for even 30W continuous with millisecond peaks that still won't get close to 120W (which the PSU itself probably won't actually 'see' anyway)

ETA >> there are also some 'Nobsound' PSU's going, 24V/6A, 32V/5A and 48V/5A for similar sort of money but I'm slightly more confident of the quality and safety of the Mean Well branded one.
 
Last edited:
Tilear (Aiyima A04) TPA3251 installed yesterday, with the 24V/5A Mean Well PSU, along with an 'iFi iDefender' (powered) which fortunately pre-empts the GPU/USB noise problem I'd otherwise have with an earthed PSU.

It's very nice so far, appears to match the old TA2020's space, detail and dynamics at similarly low volume, and as I suspected it will go far louder even on 24V than I'll ever want/need.

That said, I've added a big dollop of <80-100Hz gain with EqAPO or Foobar's equaliser (I'm using bookshelf speakers that start rolling off there, although room reinforcement with my layout already makes it far less apparent) and actually rather enjoying the extra presence of kick-drums, bass guitars with bottom B-strings etc' which I didn't even try with the TA2020 on the assumption it wouldn't have the 'welly'. ETA >> I was using a Denon PMA-60 (a class-D 'digital' integrated amp) for a while last year, which for some reason it didn't occur to me to try it with (now in the wardrobe waiting to go to a new home).

AS an aside, I discovered that I'd forgotten to check Foobar's device config (must have been at least since I got the Sanskrit III many months ago, I recall reinstalling it) and both DAC's were being fed 16-bits (the SMSL SU-1 and Sanskrit will both accept 32-bit) so I was unwittingly losing detail/resolution using Foobar's attenuation/volume and DSP's (often use 10-12dB of attenuation and EQ was knocking off another c. 4dB, already down to barely 13-bit right there). Oops.
 
Last edited:
How do the D amps sound powering AMT's?
I use a K-88 tube amp for AMT's now, liking it well, but always looking to improve.

I was thinking of pairing a FOSI with Dayton Audio AMTPRO-4 Air Motion Transformer.
 
How do the D amps sound powering AMT's?
I use a K-88 tube amp for AMT's now, liking it well, but always looking to improve.

I was thinking of pairing a FOSI with Dayton Audio AMTPRO-4 Air Motion Transformer.
Me? I've never owned any and I have a horrible suspicion that my ageing ears wouldn't be up to hearing any advantages AMT's might have over conventional tweeters. Although I've heard they can 'image' quite spectacularly and D-amps can also sometimes do that well, so you never know ....
 
Cued up Blondie, Plastic Letters, next thing I knew it's gone dead quiet cos it's ended. Damn, I enjoyed that.
 
Back
Top Bottom