SMSL A300 Stereo Amplifier Review

[dudewithcans]

That could be acceptable if absolutely hassle free customer service network

to be fair, i bought my units via amazon and return/refund was hassle free and no problem at all.

I have recently won a bag of chips in work raffle, I feel my luck is used up for at least 5 years...

it might work again...

 

[ampguy]

If you have hiss or other issues off the bat, then yeah, return them. I’d expect that with Amir’s measurements, one might notice the high end roll off with 4 ohm speakers vs a reference amp, and if golden ears maybe some distortion?? I guess I am lucky, both a300s work, bought months apart with no hiss, then again, my original pa5 also works great.

 

[ampguy]

I am going to give an opinion that pertains to the A300 as well as other "power amps" that have volume controls, that may be controversial, but is just my opinion having had dozens of power, integrated, and receiver amps over the decades of all major classes. If it's a power amp with a volume control, I would not max the volume out and just leave it there. The volume control is likely there for more than convenience, and the amp was probably not rated to be at max 100% of the time. If there is no volume control on the power amp, It is likely designed and rated with proper thermal and shutdown capabilities and can be driven with a preamp and last years if not decades or longer.

Don't use your DAC as a volume control, use fixed volume. Use your Amp with volume control (or a dedicated preamp) for your volume, and your amp should last a long time. If you notice different sound with low DAC or preamp, or source levels, and need amp with volume cranked, take a look at your impedance matching between the components. Perhaps it is not optimal. Again, just my opinion. It's your gear, set it up how you want to.

 

[Elvom]

i find that more than incredible on an 87dB KEF R3...
it must mean (if your hearing is in good condition) that both of the A300 units i had (different retailers btw), had serious quality issues and should have never seen the market in the first place. good and useful quality control seems to be an alien concept for SMSL then, what else should i make of this...
and i say this again: i would REALLY LIKED to use this amp... besides the noise issue on my units, i though it did sound good and i like it functionwise aswell.

Yeah my hearing is fine(just got checked) and im also a professional classical musician very sensitive to high pitched sounds, a loud hiss is unbereable for me.

Also tried the amp with a 83db Usher speaker and it sounded just fine, of course i dont use the volume too high, i set on my volume knob 20-30/60 and its pretty loud with a near field use, more than enough for my use, maybe i got a lucky perfect unit or it works just fine with a moderate volume.

 

[ampguy]

Yeah my hearing is fine(just got checked) and im also a professional classical musician very sensitive to high pitched sounds, a loud hiss is unbereable for me.

Also tried the amp with a 83db Usher speaker and it sounded just fine, of course i dont use the volume too high, i set on my volume knob 20-30/60 and its pretty loud with a near field use, more than enough for my use, maybe i got a lucky perfect unit or it works just fine with a moderate volume.

With my LS 50s at 86 or so db efficiency, I rarely go past 25. You are also breaking the audiophile rule of the amp must cost xx % of speakers or you have some zen imbalance

 

[mykeldg]

I know these demo videos are frowned upon in this forum. but if anyone is interested, I did a quick compare to the well-revered schiit aegir and another decent Class AB Amplifier I had (Onkyo 9150). The A300 is a surprise and quite decent. Sounds quite focused and composed and not harsh (as the class D reputation I expected it to be).

link for anyone interested :

 

[grogi.giant]

Don't use your DAC as a volume control, use fixed volume. Use your Amp with volume control (or a dedicated preamp) for your volume, and your amp should last a long time. If you notice different sound with low DAC or preamp, or source levels, and need amp with volume cranked, take a look at your impedance matching between the components. Perhaps it is not optimal. Again, just my opinion. It's your gear, set it up how you want to.

I never thought we are getting into black cats, spilling salt and other types of superstition?!

What are you talking about? Power stage has fixed gain and it doesn't care where the signal is attenuated or pre-amplified. It might be volume control in the integrated amplifier at volume control, at the dedicated preamplifier or at the Dac. One doesn't want to have your integrated to the max only not to amplify any noises that are introduced before the volume control stage. It has no bearing on longevity of the amp.

Another question - what is impedance matching?! You realize that ideally one wants to have infinite input impedance and zero output impedance in your sound chain. That's why there are buffers in your devices... Where is the impedance matching here? Where impedance matching is important is with cables that carry high-frequency signals (exp. coax S/pdif), so that they don't turn into RF emitting antennas.

 

[doremo]

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.

 

[Sokel]

I never thought we are getting into black cats, spilling salt and other types of superstition?!

What are you talking about? Power stage has fixed gain and it doesn't care where the signal is attenuated or pre-amplified. It might be volume control in the integrated amplifier at volume control, at the dedicated preamplifier or at the Dac. One doesn't want to have your integrated to the max only not to amplify any noises that are introduced before the volume control stage. It has no bearing on longevity of the amp.

Another question - what is impedance matching?! You realize that ideally one wants to have infinite input impedance and zero output impedance in your sound chain. That's why there are buffers in your devices... Where is the impedance matching here? Where impedance matching is important is with cables that carry high-frequency signals (exp. coax S/pdif), so that they don't turn into RF emitting antennas.

Performance aside,maybe using a DAC as VC with an amp at 100% is not a very good idea as we saw in some threads,you never know when they'll "forget" their last setting and blow speakers and ears sky-high.

Nevertheless if that's the case,better try to determine the highest safe output you want of your amp with the DAC at 100% and leave it there as a safety measure.
It may not be ideal but peace of mind is more important.

 

[grogi.giant]

Performance aside,maybe using a DAC as VC with an amp at 100% is not a very good idea as we saw in some threads,you never know when they'll "forget" their last setting and blow speakers and ears sky-high.

Nevertheless if that's the case,better try to determine the highest safe output you want of your amp with the DAC at 100% and leave it there as a safety measure.
It may not be ideal but peace of mind is more important.

Absolutely. There are both performance and non-performance reasons to use volume control at the amp. Reduction of produced heat, which extends longevity, is not one of them.

 

[nsfgp]

Now Cheapaudioman on YT added another layer of confusion for the A300 volume control/balance issue when he connected a pair in Master-Slave bridged mode.
Watch the video here (timestamp adjusted to that section) and compare to your own bridged A300 setup and tell us if consistent with what he said?!

Basically what he said is you should have the volume balanced on the pair and then masked off the IR receiver totally on the right-channel amp so the volume setting on it does not change with the remote; and you just control the volume from the master/left-channel amp. If you do not do that (and raise volume on both amps in tandem the right-channel/slave amp will gets louder and louder compared to the left-channel and shift volume balance to the right side.
That sounds totally different from what @ampguy did/experience and probably others who uses master-slave connection.
So confusing but FYI.

 

[saberger0357]

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.

What speakers?

 

[saberger0357]

My bridged A300's continue to work beautifully with my Allison One speakers. Obviously plenty of power, and the sound is very, very good. I really like this amp a lot.

My only wish was that this amp was safe down to 2 ohms. I'd love to be able to bridge these amps with 4 ohm speakers(The Allison's are 8 ohms), and while I did so for a brief period while trying it out with my AR3's, I really don't want to do it without knowing for sure that the amps can handle that.

 

[ampguy]

Now Cheapaudioman on YT added another layer of confusion for the A300 volume control/balance issue when he connected a pair in Master-Slave bridged mode.
Watch the video here (timestamp adjusted to that section) and compare to your own bridged A300 setup and tell us if consistent with what he said?!

Basically what he said is you should have the volume balanced on the pair and then masked off the IR receiver totally on the right-channel amp so the volume setting on it does not change with the remote; and you just control the volume from the master/left-channel amp. If you do not do that (and raise volume on both amps in tandem the right-channel/slave amp will gets louder and louder compared to the left-channel and shift volume balance to the right side.
That sounds totally different from what @ampguy did/experience and probably others who uses master-slave connection.
So confusing but FYI.

Just watched this, so yes, the remote controls both amps, and to me, that was a feature, as the range of listening levels never changed the balance, because the remote was controlling both amps, and I had initially setup the balances (low and high) for my ranges. Now my amps were stacked vertically (with 1" spacers for better cooling), while this guy is using them L/R, so if you cannot arrange them so the volume always controls both simultaneously, from your remote angle, you may have to set the 2nd amp at a fixed high volume and base the balance on the BTL level, but I would not max the 2ndary amp to 60, 40 or 50 maybe, but I don't believe these cheap amps were meant to be used like old school power only amps, and just left cranked. I'm surprised he blew out Elacs, I don't have any Elacs, but with LS-50s, the dynamics of dual mono can be heard at medium loud (~80 db) room filling sound. My amps never got hot on the outside, but sometimes that is a good thing, if the case is being used as a heat sink (I don't know how this A300 is designed). Also, the guy is using SDB (my daughter uses an A300 now with this setting with Infinity R162s) which is kind of a dynamic loudness setting, actually sounds pretty good), but he's not using it flat as a reference amp, didn't note what speakers he is using either.

 

[ampguy]

My bridged A300's continue to work beautifully with my Allison One speakers. Obviously plenty of power, and the sound is very, very good. I really like this amp a lot.

My only wish was that this amp was safe down to 2 ohms. I'd love to be able to bridge these amps with 4 ohm speakers(The Allison's are 8 ohms), and while I did so for a brief period while trying it out with my AR3's, I really don't want to do it without knowing for sure that the amps can handle that.

I understand, I wouldn't want to risk AR3a speakers, you will probably get good sound with a single unit. Do folks do series resistors with these old AR3as or do they affect the sound negatively?

 

[saberger0357]

I understand, I wouldn't want to risk AR3a speakers, you will probably get good sound with a single unit. Do folks do series resistors with these old AR3as or do they affect the sound negatively?

My AR's are 3, not 3a's, BTW. But the speakers I'd like to use the bridged amps for are Polk RTA-12's. While you're right that the one amp, or even just using them as mono blocks will be fine, having that extra headroom for these somewhat difficult to drive speakers would be nice. I don't have to use the amps, as right now I'm using the Fosi V3 which delivers 190 watts at 4 ohms, which is plenty. But just would like to have the option.

Yes I'm sure

 

[nsfgp]

Just watched this, so yes, the remote controls both amps, and to me, that was a feature, as the range of listening levels never changed the balance, because the remote was controlling both amps, and I had initially setup the balances (low and high) for my ranges. Now my amps were stacked vertically (with 1" spacers for better cooling), while this guy is using them L/R, so if you cannot arrange them so the volume always controls both simultaneously, from your remote angle, you may have to set the 2nd amp at a fixed high volume and base the balance on the BTL level, but I would not max the 2ndary amp to 60, 40 or 50 maybe, but I don't believe these cheap amps were meant to be used like old school power only amps, and just left cranked. I'm surprised he blew out Elacs, I don't have any Elacs, but with LS-50s, the dynamics of dual mono can be heard at medium loud (~80 db) room filling sound. My amps never got hot on the outside, but sometimes that is a good thing, if the case is being used as a heat sink (I don't know how this A300 is designed). Also, the guy is using SDB (my daughter uses an A300 now with this setting with Infinity R162s) which is kind of a dynamic loudness setting, actually sounds pretty good), but he's not using it flat as a reference amp, didn't note what speakers he is using either.

@ampguy Just to ask the same questions again to confirm as you may not totally get what he meant to say.
1. His remote is covering both amp ... so well that he is using duck tape to blind the right channel amp.
2. Can you confirm this if possible for your master-slave setup:
- Assuming you have your pair volume-balanced now at volume setting Ln1/Rn2(n1/n2 are vol# for each side and likely different).
- You raise volume for both amp to Ln1+X/Rn2+X (in tandem, increased X for both) using your remote.
- Now is your pair still volume-balanced?? *****
***** -> What CheapAudioMan said is now your pair will be off-balanced and the right-channel will be louder.

 

[ampguy]

@ampguy Just to ask the same questions again to confirm as you may not totally get what he meant to say.
1. His remote is covering both amp ... so well that he is using duck tape to blind the right channel amp.
2. Can you confirm this if possible for your master-slave setup:
- Assuming you have your pair volume-balanced now at volume setting Ln1/Rn2(n1/n2 are vol# for each side and likely different).
- You raise volume for both amp to Ln1+X/Rn2+X (in tandem, increased X for both) using your remote.
- Now is your pair still volume-balanced?? *****
***** -> What CheapAudioMan said is now your pair will be off-balanced and the right-channel will be louder.

No, mine works fine when the remote ups both and maintains balance, though the L is the main when using remote for overall volume. I can skew the balance by manually changing the dial on the 2ndary amp. Could be he didn't have his secondary at a good level (too low or high?) even though he shows a nice 46 in the video, or possibly he didn't have the 2nd one in BTL mode and is bridging his main, and using the 2ndary amp with just one channel. Or maybe he has newer firmware?? Just do what works for you.

 

[saberger0357]

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.

 

[doremo]

What speakers?

I had previously tried using micro digital amps with my speakers, but I was never satisfied with the soundstage. The micro digital amps sounded too congested and closed-in, and I couldn't get the imaging to be right. I'm glad that I finally found an amplifier that can deliver the soundstage I've been looking for.
Now I am very happy with the soundstage of my Dali Oberon 3 speakers when paired with the Cambridge Audio CXN v2 streamer and CXA81 amplifier. The soundstage is wide and spacious, with excellent imaging and sound separation.