SMSL A100 Review (Stereo Amplifier)

[Keened]

What do you mean here? USB-A input for DACs is common, so you use an A-A cable to connect one to your computer. Do you have reason to believe that the SMSL is unusually out of spec?

Why is USB Type-A to USB Type-A never used?

I was wondering why almost all USB cables that exist are USB-A to (Micro-USB | USB-C | USB-B | etc.) Why was USB-A to USB-A not a popular thing? Is there a technical reason this cannot work?

electronics.stackexchange.com

Also a picture of unknown veracity

It's not a supported spec for the older generation of USB which used a host-client topology for data and power delivery. Newer ones don't have that issue. You can change the pinout and use an A-A connection just like with Ethernet without a switch or router inbetween, but you want to know that the port are capable to negotiating that. Hence non-standard and in *some cases* potentially dangerous for the equipment.

USB-A on a DAC, to me at least, indicates either the DAC outputing analog audio over USB OR support for reading from a flashdrive/hard drive of some kind.

 

[carsknivesbeer]

I'm wondering why you would buy such a low powered mediocre amp, when there are so many excellent alternatives available for just a little more money. There is a sweet spot for good quality budget audio but it is not as low as $100.

e.g. Topping PA5 puts out close to 50W into 8 ohms and received a rave review from Amir. It costs US$350, so for another $250 you get reasonable power output with excellent performance.

When you consider the crazy cost of some "name" amplifiers, $350 is inexpensive for a quality amp, especially if you take a long term view and amortise it over say 10 years or longer. Sometimes paying a little more for quality just makes sense.

Topping PA5 Review (Amplifier)

This is a review and detailed measurements of the Topping PA5 stereo desktop amplifier. It was sent to me by the company and costs US $349. PA5 enclosure looks like their standard DACs and such: Hard to imagine that an amplifier can fit in the same size but here we are. There are large...

www.audiosciencereview.com

Just add a Wiim Mini (or chrome cast) streamer and a Topping E30 DAC and you have a SOTA front end that will produce an audibly transparent signal and enough power to make any decent bookshelf speaker sound good. All for little more than US$500.

Enjoy your weekend,

Ajax

I bought this amp specifically to get tested and to test my own subjective experience of it. It was only 80$ at the purchase time, easy to ship and ticked on the boxes for a class D desktop amp. Not quite ready to throw down a good chunk of money on Hypex or roll the dice on the QC of some other cheaper (but more expensive than the A100) class D amplifiers. There are plenty of situations where power is not the most important factor in an amplifier, especially in a desktop setting, and wanted to regain some desk real estate over an integrated Yamaha.

I have learned a lot from ASR, enjoy the idea of object measurements regardless of price, and wanted to contribute to the objective findings. That was my personal reasoning for purchasing this amp and trying to find where the line of audibility/cost is in my own setups.

 

[sarumbear]

This is one of the most surprising things I've ever read on this forum.

May I ask why

 

[Ajax]

I bought this amp specifically to get tested and to test my own subjective experience of it. It was only 80$ at the purchase time, easy to ship and ticked on the boxes for a class D desktop amp. Not quite ready to throw down a good chunk of money on Hypex or roll the dice on the QC of some other cheaper (but more expensive than the A100) class D amplifiers. There are plenty of situations where power is not the most important factor in an amplifier, especially in a desktop setting, and wanted to regain some desk real estate over an integrated Yamaha.

I have learned a lot from ASR, enjoy the idea of object measurements regardless of price, and wanted to contribute to the objective findings. That was my personal reasoning for purchasing this amp and trying to find where the line of audibility/cost is in my own setups.

Thanks for your feedback, obviously we all have our own individual needs and what we feel provides good "bang for your buck". A couple of questions - how's the sound, what have you got it connected too, what's the DAC like?

Thanks,

Ajax

 

[dr0ss]

USB-A on a DAC, to me at least, indicates either the DAC outputing analog audio over USB OR support for reading from a flashdrive/hard drive of some kind.

It is nevertheless quite common as input for DACs, especially in the budget Chinese audio sector. (Though I agree that if I saw one on an amp my first guess would be as support for a flashdrive.)

Thanks for the chart, I was not aware that A-A was officially considered 'nonstandard'.

May I ask why

Because I would have assumed that he'd accumulated at least as wide a variety of cables as I had over the years, and I have several A-A cables in my 'random cable' box. Especially since, as I said above, USB-A input is not especially rare for budget DACs, which he tests regularly.

 

[raif71]

If you don't have an A-A, get one

 

[Ra1zel]

This is a real advantage with class D that people rarely mention

Probably because no modern class AB suffers from this in audible way.

I find it kinda weird that this noise performance gets an "OK" grade but the same noise performance of for example NAD T788 got "clearly an issue".

 

[Universal Cereal Bus]

It is nevertheless quite common as input for DACs, especially in the budget Chinese audio sector. (Though I agree that if I saw one on an amp my first guess would be as support for a flashdrive.)

Thanks for the chart, I was not aware that A-A was officially considered 'nonstandard'.


Because I would have assumed that he'd accumulated at least as wide a variety of cables as I had over the years, and I have several A-A cables in my 'random cable' box. Especially since, as I said above, USB-A input is not especially rare for budget DACs, which he tests regularly.

Of course A-A is no bueno. Don't you know that USB cables are DIRECTIONAL???

 

[dr0ss]

I wouldn't buy the 'Coffee' cable. Too much jitter.

 

[laudio]

Would nice to see a teardown on that little guy. Has a built in AC supply, I've read here many times before when you are worried about the quality of the grounding. Let's see it!

 

[dr0ss]

Would nice to see a teardown on that little guy. Has a built in AC supply, I've read here many times before when you are worried about the quality of the grounding. Let's see it!

Look here:

SMSL A100 (ma 12070)

I listened to the amp and think its an excellent amp for the money. Pros - - Small form factor - Gets uncomfortably loud (Sony Core 5 speakers) - No hissing, popping - Excellent detail in music - Runs cool even when being pushed hard Cons - - Internal DAC is so so (didn't test the Bluetooth...

www.audiosciencereview.com

 

[TNT]

Isn't this is a contradiction to what Benchmark describe on their website:

"Most class-D (switching amplifiers) also use push-pull output devices. The push-pull devices in these switching amplifiers make abrupt transitions between full-on and full-off states. These switching transients occur at a high repetition rate and generally contribute to an overall increase in distortion and noise."
(https://benchmarkmedia.com/blogs/application_notes/131424519-amplifier-crossover-distortion)

Just wondering

The difference is that a class AB amp switch transistors as the music wave form passes zero - i.e. for everything you hear basically.

A class-D amp switches transistor at a couple of 100khz i.e its its switching frequency - but there is no switch of transistors for the signal you hear.

I hop you can appreciate what the difference implies.

//

 

[Deleted member 46664]

He shouldn't since it's not within the USB spec and can theoretically damage something. All A-A connections that I know of are strictly proprietary.

I don't know for certain, but it may have been done that way so you can play thumb drives as well as PC input through that connector.

 

[audioholic63]

Nice case and probably the elevated high frequency distortion isn't very audible if Amir recommends it but the Aiyima 07 remains the <$100 champ.

SMSL A100 + a pair of Pioneer SP-C22 standing upwards = perfect gift to relatives and friends so you don't have to be tortured with crappy sound when you go to their house?

My rationale many years ago for buying my sister a decent set of speakers (Paradigm). I made her buy the stands.

 

[Spocko]

I wouldn't buy the 'Coffee' cable. Too much jitter.

ROFL deserves QoTD

 

[Rottmannash]

They might ... but one would hope that before producing a chip, that cannot be modified, they might have thought of that.

Crossover distortion happens in class B amps and broken class AB amps when the output transistors, crossing 0 volts output are both off at the same time. This would actually be above the power rail and below ground ... so not the same thing at all.

Question: I assume all the power transistors are within the chip? And if so will be very close to identical, as opposed to soldering individual transistors onto a board?

 

[solderdude]

Oddly the USB input is type A

It also has a 5.0 BT input.

An A-A cable should be included with the amp. I assume the owner did not include it.

 

[carsknivesbeer]

I thought there was a USB cable in the box but I guess not. There’s no remote or any control app so I don’t know how it could play any files outside a computer. It was running through analog inputs via a D30 but I can try the USB/Bluetooth when it comes back.

 

[pma]

This is a class D amp so there is no notion of crossover distortion.

What?? The dead time distortion of class D amplifiers is a direct equivalent of class B and AB crossover distortion. Why do you think you measured all of that high order distortion mess in the spectrum? And that horrible HF linearity?

https://www.researchgate.net/publication/3380961_Effect_of_dead_time_on_harmonic_distortion_in_class-D_audio_power_amplifiers

 

[Deleted member 46664]

Question: I assume all the power transistors are within the chip? And if so will be very close to identical, as opposed to soldering individual transistors onto a board?

Yes. That is one advantage of the "chip amps" (even the class AB ones) is that with everything on a common die it is far easier to match and manage transistors, especially the problems with unequal temperatures are reduced.