Inexpensive mini-amplifiers: Discussion of power ratings and distortion

[amirm]

I would like to add the SMSL AD18 into the mix. Being an fully digital 80W amplifier, that retails for €129.

I have bought it and will review "soon."

 

[ssbarnea]

I wonder if someone could recommend me a mini-dac-amp that I can use with my 2017 iMac which no longer has optical output, mainly I need one that uses USB. The speakers are a pair of Klipsch RP-160M (100W@8o) and soon a powered subwoofer. At this moment I use an old 5.1 home theatre LG 805HT with a startexh usb dongle that does 16bit-96khz (LG chokes on 24bit). Also LG has only powered subwoofer output and I am afraid it may not have many more years to live, prefering to sell it for about £50 before it becomes scrap.

The room is quite small (12sqm) and I do listen at low volume so a mini amp should do just fine, still i want something that would be of decent quality and not ruin my buget. Any recomandations? Even what I should avoid would be useful. So far I found the SMSL q5 pro that looks of decent price and with right feature but not sure how it would compare with what I have now.... anuthing else to consider?

 

[BillG]

I wonder if someone could recommend me a mini-dac-amp that I can use with my 2017 iMac which no longer has optical output, mainly I need one that uses USB. The speakers are a pair of Klipsch RP-160M (100W@8o) and soon a powered subwoofer. At this moment I use an old 5.1 home theatre LG 805HT with a startexh usb dongle that does 16bit-96khz (LG chokes on 24bit). Also LG has only powered subwoofer output and I am afraid it may not have many more years to live, prefering to sell it for about £50 before it becomes scrap.

The room is quite small (12sqm) and I do listen at low volume so a mini amp should do just fine, still i want something that would be of decent quality and not ruin my buget. Any recomandations? Even what I should avoid would be useful. So far I found the SMSL q5 pro that looks of decent price and with right feature but not sure how it would compare with what I have now.... anuthing else to consider?

I've been using the following for the past few months now to drive some Infinity Reference 152's on a bedroom, PC based system, and quite like it. While it's not fancy, it gets the job done quite well with no audible distortion unless driven to ear bleed levels...

https://m.aliexpress.com/item/32594...tooth-4-1-CSR8670-150W-2-CM6631A-24Bit-192KHz

It's quite well liked in DIY audiophile community, as they like to make minor modifications to it, and it's inexpensive - I've not found any modifications to be necessary, though, as it sounds just fine running stock:

https://www.diyaudio.com/forums/class-d/302748-am-v200-wifi.html


https://www.diyaudio.com/forums/class-d/280228-am-v200-fx-audio-d802-optimisation-tpa3116.html

 

[vert]

I'm a "convert" to class D and FDA amps. My opinion has little weight, as I 've never owned hi end amps. But my little $70 FxAudio amp runs circle around the two amps I've had in recent years, a ~$450 class AB Teac and a Harman Kardon home cinema receiver. It makes no background noise and doesn't heat up. Most of all it sounds great. The better the source the better it sounds. Same goes for speakers apparently. It doesn't end there - see the following articles - Google Translate should give people the gist of them

http://www.audiophile-magazine.com/autour-des-1000-et-moins/fx-audio-d802/
http://audiolalies.blogspot.com/2015/05/retour-sur-le-fx-audio-d802.html?q=802&m=1

 

[teej]

I picked up a pair of desktop amps recently, the Topping PA3 and the Fosi Audio BT20A to audition for a desktop application. I was planning (based on the stated specs of each amp) to drive either a pair of 6-ohm Elac Debut B6.2's or possibly a pair of the 4-ohm Uni-fi UB5's. After reading this it seems now I'll only be able to drive the Debut's with either.

This is a bummer.

 

[madmax2069]

I have bought it and will review "soon."

I can't wait for the review of the AD18. I love looking through the forum and reading your reviews and tests.

One quirk/issue I've found with my AD18 is the volume, volume lvl 1 has no audio output just like volume lvl 0, and sound lvl 2 is where it starts producing sound. The boot screen of my AD18 says version 3.1.

Everyone that I've asked that has a version two and higher AD18 seems to have the same issue, version 1 (the version without the subwoofer output) doesn't seem to have the issue.

I did tell SMSL about it and they replied "1 is sound, please listen carefully". I have pretty sensitive ears, and even with my ear on the speaker the AD18 doesn't produce sound until lvl 2.

Maybe you could also confirm this when you do review the AD18 (that is if you got version 2 and above).

 

[teej]

The Topping PA3 *seems* to have no trouble driving the 4-ohm Elac Uni-fi UB5's. I don't believe they sounded quite as good as they do connected to my more powerful AVR (better placement there, too), but they played reasonably well even at respectable volume. I didn't really push them too hard - it was more of a proof-of-concept for me. Neat little amp! Currently have it driving a pair of Elac Debut 6.2's, and I am pretty satisfied.

 

[amirm]

Maybe you could also confirm this when you do review the AD18 (that is if you got version 2 and above).

Will do.

 

[Tunnelrat81]

The Topping PA3 *seems* to have no trouble driving the 4-ohm Elac Uni-fi UB5's. I don't believe they sounded quite as good as they do connected to my more powerful AVR (better placement there, too), but they played reasonably well even at respectable volume. I didn't really push them too hard - it was more of a proof-of-concept for me. Neat little amp! Currently have it driving a pair of Elac Debut 6.2's, and I am pretty satisfied.

It's interesting to hear your thoughts on the PA3. Since first posting on this thread, I've replaced my Elac B6's with the newer Elac B6.2 (thanks to the black friday weekend sale). I've now had a chance to test the Topping PA3 with the Pioneer BS22, Elac B6, and finally the B6.2's. First off, I feel like the B6.2's sound better in pretty much every way than the B6's. I like the less subdued, more detailed highs as compared to the original B6's. Somewhat oddly, with the original B6's I would flip flop between running the sub woofer and keeping it off, and since moving to the B6.2's, I much prefer listening without the sub. The bass is plenty deep and much cleaner to my ear than running them with the old klipsch 10" sub.

My main system is a Pioneer VSX45 that I purchased new a couple of years ago. Both the B6's and B6.2's sound great in stereo running off of it.

When I first received the PA3, I hooked it up in the garage to my BS22s and tried to do a side by side with the SMSL SA-98e amp that I've used out there for the last couple of years. The Topping sounded a bit less dynamic and alive than the SA-98e. I went back and forth trying to match the gain and listen carefully. The difference was somewhat subtle on the BS22's, but it was there. The SA-98e simply sounded a bit clearer and more pleasant.

Recently I swapped in the PA3 to compare the sound with that of the Pioneer AVR, and the difference was stark and disappointing. Not only does the bass seem over emphasized through the PA3, but the lovely highs that I've been really enjoying out of the B6.2's simply don't make it through in the same way. I wouldn't say that the sound is bad, and perhaps some people might like the overall warmer sound, but for me it's not a good paring. To my ear, good sound is when the bass is just deep enough without being boomy, the mids are very present with voices sounding clear and close, and the highs shine through with a little bit of sparkle, without being shrill. Through the PA3, the vocals sounded less clear and further off, and the highs were at least as subdued as they had been on the original B6's, possibly even more so, while listening to the B6.2's.

The one small mark against the B6.2's that I've noticed is that during some music, certain low frequencies (I assume the ones targeted by the port tuning) do jump out a bit more than those above and below in a slightly unnatural way. For most listening this doesn't ever show up at all, and the extended bass provided by the ported box is more benefit than hindrance. With the Topping PA3, however, those slightly over emphasized lows are emphasized even further, and it moves into the realm of being too boomy.

I will be keeping the amp, only partly because I'm past my return window with amazon. Had I been able to listen and compare ahead of time, I'd have gone with a different amp. I love the interface, and appreciate the nice power button and input switching on the PA3 as compared to my SA-98e, but as for its sound, it falls short of the SMSL, and falls miles short of the Pioneer receiver.

-Jeremy

 

[AnalogSteph]

Somewhat oddly, with the original B6's I would flip flop between running the sub woofer and keeping it off, and since moving to the B6.2's, I much prefer listening without the sub. The bass is plenty deep and much cleaner to my ear than running them with the old klipsch 10" sub.

This makes sense. Given the same abilities in frequency response, having two bass drivers over one tends to even out some room mode related unevenness.

Recently I swapped in the PA3 to compare the sound with that of the Pioneer AVR, and the difference was stark and disappointing. Not only does the bass seem over emphasized through the PA3, but the lovely highs that I've been really enjoying out of the B6.2's simply don't make it through in the same way.

Sounds like low damping factor.

The one small mark against the B6.2's that I've noticed is that during some music, certain low frequencies (I assume the ones targeted by the port tuning) do jump out a bit more than those above and below in a slightly unnatural way.

Probably room modes. They may have become more noticeable with speakers that go deeper. Measurements could confirm this.

Oh. I didn't think these Elacs would be 6.5" bookshelves. Apparently some of the differences between the two models are a larger, now front-ported cabinet (with the larger size, it might be tuned lower and avoid a "hi-fi" bass bump), a new woofer and a tweeter with a decent waveguide that's crossed over low (nice). Looks like woofer-tweeter spacing is about as low as it can be, too. It doesn't look like edge diffraction has been addressed, but otherwise this design would seem to be doing quite a few things right. I wouldn't be surprised to see rather good dispersion characteristics.

 

[GGroch]

.........When I first received the PA3, I hooked it up in the garage to my BS22s and tried to do a side by side with the SMSL SA-98e amp that I've used out there for the last couple of years. The Topping sounded a bit less dynamic and alive than the SA-98e. I went back and forth trying to match the gain and listen carefully. The difference was somewhat subtle on the BS22's, but it was there. The SA-98e simply sounded a bit clearer and more pleasant....Jeremy

It would be interesting to see how measurement and sound quality of these little Class D amps is impacted by implementation as compared to the Chip used. A few months ago I bought a little eBay only "2018 Indeed Class D Amp TDA7498E MKII" using the same TDA7498E as the SMSL-98e. For a $30-40 premium it has 16,400 µF of capacitance vs 4700 µF, & air core vs ferrite core inductors. I do not know enough about circuitry to notice any other differences...but the Indeed listing has a nice story about starting as a HiFi club and I am convinced good stories improve sound quality.

The power supply included is another variable. Most of the Class D chips have a range of acceptable voltages...and the output wattage varies widely depending on which is used. This is something to notice when choosing an amp unless you are going to replace it. The TDA7498E has a 36V max voltage rating. Depending on the vendor (or perhaps the revision) the 98e ships with PS voltages between 32-36 & 3-4 amps. The Indeed a slightly larger 36V 5A that they point out is well shielded...another nice story.

The 160 WPC spec on these TDA7498E amps is wildly optimistic (4 ohms & 10% distortion) but that does not mean they cannot sound great at 8 ohms and 40 WPC. But that spec won't sell many. Similarly large caps may improve the sound and usable volume but would not improve the spec.

I understand there are boutique class D amp manufacturers who offer Class D chip amps with all the right stuff...at 3 times the price or more. Do those sound and measure better?

I am very pleased with the amp...it does the expected stuff well - sounds good, is stable, no turn on/off pops. But I am not sure how much of my satisfaction is based on reality. Included are a couple of photos from the listing.

 

[PierreV]

I'm a "convert" to class D and FDA amps. My opinion has little weight, as I 've never owned hi end amps. But my little $70 FxAudio amp runs circle around the two amps I've had in recent years, a ~$450 class AB Teac and a Harman Kardon home cinema

I have one has well. And I do also have hi end amps and speakers (too many ).
While I am a big fan of objective measurements, I still believe opinions matter, at least at a personal level. After all, you are the one listening to your music.

Measurements are essential
- to clear up the FUD and hype surrounding many current "high-end" products, especially everything that involves the digital aspects, cables, etc...
- to identify poor or simply dangerous designs.
- to educate the public.

Listening is essential
- for your enjoyment.

One does not exclude the other, one does not need to fall into the opposing extremes.

I can switch at will between 3 high ends amplifiers and 3 high end set of speakers. Guess what... they sound different. Speakers very much so. Amps much less.

How does the FX 802D fit into that picture? Well, I also have my "cheapest of cheapest" system which consists of a couple to Tannoy passive monitors (I think Tannoy 3 Monitors), a CCA and the FX 802D which I happen to be listening to right now. It is a very nice sounding system for less than EUR 300 in total.

I enjoy it. That is what matters.

I also tried the FX 802D on my Giya G3, Blade II, Kef LS 50, Klipsch reference and yes Bose 901 Type VI it behaved quite decently.

OTOH, I expect it breaks down utterly in terms of distortion at high power. Measurements will tell us that. Will that spoil my enjoyment? I don't think so. SNR at 75dB, 90dB, 100dB? The same.

 

[vert]

I have one has well. And I do also have hi end amps and speakers (too many ).
While I am a big fan of objective measurements, I still believe opinions matter, at least at a personal level. After all, you are the one listening to your music.

Measurements are essential
- to clear up the FUD and hype surrounding many current "high-end" products, especially everything that involves the digital aspects, cables, etc...
- to identify poor or simply dangerous designs.
- to educate the public.

Listening is essential
- for your enjoyment.

One does not exclude the other, one does not need to fall into the opposing extremes.

I can switch at will between 3 high ends amplifiers and 3 high end set of speakers. Guess what... they sound different. Speakers very much so. Amps much less.

How does the FX 802D fit into that picture? Well, I also have my "cheapest of cheapest" system which consists of a couple to Tannoy passive monitors (I think Tannoy 3 Monitors), a CCA and the FX 802D which I happen to be listening to right now. It is a very nice sounding system for less than EUR 300 in total.

I enjoy it. That is what matters.

I also tried the FX 802D on my Giya G3, Blade II, Kef LS 50, Klipsch reference and yes Bose 901 Type VI it behaved quite decently.

OTOH, I expect it breaks down utterly in terms of distortion at high power. Measurements will tell us that. Will that spoil my enjoyment? I don't think so. SNR at 75dB, 90dB, 100dB? The same.

I've revised my judgment in a later post though. I started perceiving some problems with it and no longer think the Fx-audio "runs circles around" the Teac. But I'm convinced a truly excellent cheap class D amp will come out sooner or later. 100% agree with your points.

 

[bigx5murf]

https://www.allo.com/sparky/volt-plus-d-amp.html

This one is the sweetheart of these types of devices right now. Would love to see measurements on it.

 

[Tunnelrat81]

The fact that the Topping PA3 had the same TDA7498E chip as the SMSL SA-98e was a big part of my reason for selecting it. I'd been happy with the SMSL, and hoped that perhaps the design would be similar, just using the board more conservatively for a potentially better result. A naive assumption I'm sure, as implementation of this board can probably vary greatly in both positive and negative ways. I do feel like the exterior build quality and feel of the Topping is a better, I just don't quite like the sound as much as the SMSL.

-Jeremy

 

[sir_frigorifero]

Topping PA3 owner here.
I wan to join the discussion because i found something that has been bugging me for quite a lot: floor noise.
My topping has a fairly high white noise that happen when no source is playing, clearly udible from 1 meter. the problem is definitely on the amplifer since i tried everything possible.
anyone has encountered the same problem? i already contacted Audiophonics.fr for RMA but i hope it's just a faulty unit since the amp is quite good and i'm struggling to find a proper replacement

 

[amirm]

https://www.allo.com/sparky/volt-plus-d-amp.html

This one is the sweetheart of these types of devices right now. Would love to see measurements on it.

Allo is sending one of their amps to me for review.

 

[bigx5murf]

Topping PA3 owner here.
I wan to join the discussion because i found something that has been bugging me for quite a lot: floor noise.
My topping has a fairly high white noise that happen when no source is playing, clearly udible from 1 meter. the problem is definitely on the amplifer since i tried everything possible.
anyone has encountered the same problem? i already contacted Audiophonics.fr for RMA but i hope it's just a faulty unit since the amp is quite good and i'm struggling to find a proper replacement

Not that particular amp, but I've encountered this problem with a couple of cheap tpa3116 amps. The problem is they come from the factory set at 32-36db gain. If you change it to 20db gain, the issues goes away completely. There's a video on youtube where someone shows distortion measures better as well.

 

[sir_frigorifero]

the gain on the PA3 is 29,3db gain but it does not say a thing about changing it so i suppose you have to modify the board, but since i opened a support ticket i'd rather avoid open my amp to prevent every sort of controversy with the shop.
Last thing i want to try is to search for some ground issues but i don't have a multimeter so i have to test it aproximately. if this is the problem i will ask for RMA and hope to receive a coupon so i can try something different like the allo volt+d

 

[bigx5murf]

the gain on the PA3 is 29,3db gain but it does not say a thing about changing it so i suppose you have to modify the board, but since i opened a support ticket i'd rather avoid open my amp to prevent every sort of controversy with the shop.
Last thing i want to try is to search for some ground issues but i don't have a multimeter so i have to test it aproximately. if this is the problem i will ask for RMA and hope to receive a coupon so i can try something different like the allo volt+d

Yes it requires modifying the board, specifically removing and soldering surface mount resistors, which are really tiny. I've done it myself a couple of times. But yes, it's not fun to mess with stuff that small.