SMSL A300 Stereo Amplifier Review

[ampguy]

I've gone back to using them in mono BTL mode, with no BTL connection on the 2nd amp. I don't use the SMSL remote, controlling system gain through my main preamp's remote. But I still find overall amp gain easier to balance and tweak when both amps are separate from each other.

I've also noticed in the short time of using this type of connection that the overall sound is a little clearer and better defined. Not dramatically so, and it may well have to do with the way the amp's gain are presently set, but I find it a bit more resolving and I like it better.

I guess that way should be fine, it is the way Toku ended up using his pair in another A300 thread here. I would just caution that I personally would not leave these with volume on full 60 and just use preamp attenuation, not sure these were built to be full on all the time …

 

[saberger0357]

I guess that way should be fine, it is the way Toku ended up using his pair in another A300 thread here. I would just caution that I personally would not leave these with volume on full 60 and just use preamp attenuation, not sure these were built to be full on all the time …

Thanks. I have them both somewhere in the 40's(not using at the moment so can't remember exactly. I have found that as I increase the gain on them they do get a little hissy, so keeping them lower and using the preamp to increase overall gain works best in my system.

 

[Elvom]

My smsl M300 mk ii dac started making weird noises on the right channel, double checked and its the dac fault, so i just plugged the A300 to my pc and it sounds fine.

A300 is showing only a setting of 16 bit and 48khz on windows on generic drivers, since theres none on smsl website.

Theres a downgrade on sound quality, not huge but i can tell, i read somewhere its the bluetooth chip decoding, but its better than nothing while my old Dac gets fixed or while i get new one.

 

[mcebrian]

I had two units at home. One (the first one) was noisy no matter the volume or brightness.

This second one is much better (SINAD = 87.6dB)

Yes, I know it is 5.5W instead of 5W like Amir but it was exactly the same (I didn't click the screenshot because I was testing another thing, you will have to believe me it was exactly the same number). This was tested using two 4Ohm 1% resistors. Both channels driven into a Cosmos grade A ADC.


Strange beast this A300. I would say some of them are better than others??

 

[TonyJZX]

i have an early a300 and its only usuable between say 10-45 on the jog shuttle... above 45 its noisy

BUT i thought this was just normal for crappy cheap class d amps... at the time it didnt bother me as I had it hooked up to preamps and dacs that you can just dial up the source and leave it at 35 etc.

so that problem tells you its a vol. pot. issue, not really an amp gain problem?

this also means i'm relucatant to buy a 2nd one as how you can channel match these??? i dont need the headache

 

[saberger0357]

I haven’t had any issue channel matching my amps in bridged mono.

 

[dr_mick51]

I had two units at home. One (the first one) was noisy no matter the volume or brightness.

This second one is much better (SINAD = 87.6dB

Yes, I know it is 5.5W instead of 5W like Amir but it was exactly the same (I didn't click the screenshot because I was testing another thing, you will have to believe me it was exactly the same number). This was tested using two 4Ohm 1% resistors. Both channels driven into a Cosmos grade A ADC.


Strange beast this A300. I would say some of them are better than others??

Hi. I'm interested on how you tested the A300. I mean, what input signal did you use and what was the volume on the amp. Because everyone knows that beyond 40/60 the amp get very noisy. And the way Amir tested with the volume at 48/60 is not going to give good measurements. I think most of the people use this amp with a good and at least 2Vrms DAC which produces music at around 0.5Vrms (-12dBFs), and the volume at around 30/60 at least in my case. And it sounds good and loud. Some people even use a preamp which increases the input signal even more.
For example, when Amir tested the Loxjie A30, initially the measurements were really...really poor. But then he gave a 1.9V input signal and the measurements improved 13dB or more. In the end the A30 received a good valoration.
Why the same cannot be done with the A300? Sometimes they way the amplifiers are tested does not correlate with the way the amplifiers are used in real life.

 

[JSmith]

I owned this amplifier, but I found the soundstage to be muddy and congested. The soundstage was also very narrow and intimate, which I didn't prefer. I think it may not be a good match for my speakers, as I prefer a wider soundstage with more clarity and separation. The amplifier also didn't seem to have enough power to drive my speakers to their full potential. Overall, I was disappointed with the sound quality of this amplifier and would not recommend it to others.

So because you didn't get an amp with sufficient power, you're going to blame the amp for a "muddy and congested" soundstage?

You did see this, right?

So depending on what speaker you throw at it, the treble may be a bit bright or subdued. There are some tone controls you may be able to use to compensate.

You're only going to get a clean 50W out of this amp @4R;

What speakers are you using?


JSmith

 

[Bleib]

You're only going to get a clean 50W out of this amp @4R;

That's 8ohm...this is 4

 

[JSmith]

That's 8ohm...this is 4

I mistyped and meant @8R, apologies, assuming if running out of power the poster may have 8 Ohm nominal speakers.


JSmith

 

[dr_mick51]

That's 8ohm...this is 4
View attachment 311906

Yes, and the question is what input signal and what volume on the amp you need to get the maximum power clean power.
Again I would not use this amp at volume higher than 40/60. And then use a preamp to increase the input signal. Even a cheap SMSL SH-6 can reach a very high 6 or 7 Vrms (0dBFs) output signal which translates to 1.5 to 1.75Vrms music signal (-12dBFs).
This is better than maxing out the volume from the amplifier control.

 

[saberger0357]

Yes, and the question is what input signal and what volume on the amp you need to get the maximum power clean power.
Again I would not use this amp at volume higher than 40/60. And then use a preamp to increase the input signal. Even a cheap SMSL SH-6 can reach a very high 6 or 7 Vrms (0dBFs) output signal which translates to 1.5 to 1.75Vrms music signal (-12dBFs).
This is better than maxing out the volume from the amplifier control.

Agreed. I use both amps at 34/50 presently with a preamp.

 

[ampguy]

That's 8ohm...this is 4
View attachment 311906

Or, get 2 and get 400 wpc @ 1% THD, any other amps that powerful under $1k a pair??

 

[Bleib]

Or, get 2 and get 400 wpc @ 1% THD, any other amps that powerful under $1k a pair??

Well, I'd demand a better FR still

 

[mcebrian]

Hi. I'm interested on how you tested the A300. I mean, what input signal did you use and what was the volume on the amp. Because everyone knows that beyond 40/60 the amp get very noisy. And the way Amir tested with the volume at 48/60 is not going to give good measurements. I think most of the people use this amp with a good and at least 2Vrms DAC which produces music at around 0.5Vrms (-12dBFs), and the volume at around 30/60 at least in my case. And it sounds good and loud. Some people even use a preamp which increases the input signal even more.
For example, when Amir tested the Loxjie A30, initially the measurements were really...really poor. But then he gave a 1.9V input signal and the measurements improved 13dB or more. In the end the A30 received a good valoration.
Why the same cannot be done with the A300? Sometimes they way the amplifiers are tested does not correlate with the way the amplifiers are used in real life.

Hi!

I did many tests. You are right about finding the “sweet spot” if you can control the input voltage.

To summarize. I got the highest SINAD at 1khz and the best overall performance in THD+N sweeps, tested at 5W,10W,25W,35W at 4ohm when the input signal was 1.2VRms. (1Khz sine)

If the input signal was higher, performance degraded much, specially around 2-3Khz.

It doesn’t make total logical sense to me… But, on the contrary of what I thought, I got better THD+N with 1.2Vrms and keeping the amp at vols 28-42 than with a higher input signal that causes the Snr to improve but the THD increases quickly.

Hope it helps!

 

[Adis]

Well, I'd demand a better FR still

Use Equalizer APO, it's free.

 

[Bleib]

Use Equalizer APO, it's free.

Not all sources can run it, and in any case I sold the A300 I used to own

 

[doremo]

So because you didn't get an amp with sufficient power, you're going to blame the amp for a "muddy and congested" soundstage?

You did see this, right?

You're only going to get a clean 50W out of this amp @4R;

What speakers are you using?


JSmith

I'm using Cambridge Audio now, and the soundstage is close to what I wanted. I don't know what you mean by "not enough power." The A300 uses a standard C13/C14 power cord, not a power adapter.

However, when I increase the treble, the high frequencies overwhelm the low frequencies. And when I increase the bass, the low frequencies overwhelm the midrange. No matter what I do, I can't seem to get a balanced sound. If I switch to flat, the sound seems underpowered.

I've owned Dali, BW, PS Audio, Monitor Audio, KEF and other speakers. Only Monitor Audio and KEF were slightly better . No matter how I pair the Cambridge Audio speakers with any of those speakers, the sound presentation is at least not bad. It's just a different kind of soundstage.

I can't hear the "SMSL" signature soundstage. I guess it's because the op-amp is from the open market. I've tried multiple micro digital amps, and it's really difficult to hear the difference in the signature soundstage. The only difference is in the tone coloring. Some brands can increase more decibels.

 

[ClassicGuy]

This review might explain why despite my many attempts to use my SMSL A300 as the primary amplifier, it always ended up back in the storage. There is nothing particularly wrong with it, but I never found it that great either.

 

[CauliflowerEars]

Once I get the other power supply, I’ll do another round of listening and see what, if anything, changes.

Did you have a chance to compare the V3+48v vs A300 on the DBR62?