SMSL SP400 Review (headphone amp)

[JB5150]

Thanks sounds possible but would not seem huge difference?
JB5150, on paper it seems pretty weird if on medium gain A90 is louder, that should not happen; unity gain VS high gain...

ON PAPER, I agree.
Not much different.
IN REALITY, SP400’s lower gain, COMBINED with the “improved volume range”, makes for a MUCH lower output than other amps.

 

[HITMAN]

This is not my experience. I’ve had both at the same time . A90 is MUCH louder.
Even A90 on medium gain is louder. Facts.View attachment 106998

Hi I have the SP200 and the M400 could you please tell me if there is much difference sound wise from SP200 to SP400 is it worth the upgrade thank you.

 

[JB5150]

Hi I have the SP200 and the M400 could you please tell me if there is much difference sound wise from SP200 to SP400 is it worth the upgrade thank you.

Just my opinion. It’s not worth $600.
SP400 DOES sound a bit cleaner and more detailed.
this detail and cleanliness come at the cost of output level. SP400 is not even close to as loud as SP200.
I would encourage you to find a retailer who’s allows for in home demo, so you can see if it fits into your setup. Many people seem to be ok with the lower output, and really enjoy this amp.

 

[HITMAN]

Thanks, think i will hang on as SMSL will probably do a version 2 as most are complaining about the output.

 

[JB5150]

Thanks, think i will hang on as SMSL will probably do a version 2 as most are complaining about the output.

Yeah.
If I’ve learned anything about SMSL, it’s not to buy their stuff. Especially newly released items. They addressed the RCA output issues on the M400 with an “upgraded” revision, but will not replace my unit that was purchased at release. They expect me to open the unit, and solder parts myself. Which by the way, invalidates my Extended Warranty with Apos.
I figured I’d buy this amp, because it matches my DAC, but lesson learned. And amp returned.
I’ll never buy an SMSL product again.
I certainly wouldn’t purchase a launch item from them ever again.

 

[mkawa]

if you're listening on a pair of headphones at 99 and wishing it were louder can you raise your hand and list the pair of HPs, the dac and whether you're bal or unbal input and bal or unbal output? (SE out gain is lower in one case)

 

[Sak]

SP400 DOES sound a bit cleaner and more detailed.

There should be absolutely no audible difference. Most likely the volume levels are different.

 

[nobody]

Hi I have the SP200 and the M400 could you please tell me if there is much difference sound wise from SP200 to SP400 is it worth the upgrade thank you.

Hi I have also SP200 and SP400, but different DACs (SMLS SU-9, Topping D90 and Topping D50s). Overall the SP400 is definitely cleaner and more calm, SP200 is always slightly more nervous in direct comparison. No problem with power output with my AKG 701 headphones on both. With balanced input, I have no need to change from low gain and volume on SP400 is between 40 and 80.
SP200 is little more warm sounding, but I still prefer SP400 without question. Vocals and high octaves are much cleaner.
My favorite DAC is currently SU-9, unfortunately I'm not familiar with M400.
If you don't need remote control, you can also consider Topping A90. In direct comparison it's warmer sounding than both SP200 and SP400 with more robust bass. The warmer balance makes it sound not as super transparent as SP400, but details are definitely here, only slightly tamed down.
Both SP400 and A90 are worth the upgrade, I can live with both of them. I'm going to sell SP200.
According Sandu's review you can consider also SMSL SH-9, if you don't need pre-out. https://soundnews.net/amplifiers/headphone-amps/smsl-sh-9-thx-888-headphone-amp-review/

 

[Lero]

Hi I have also SP200 and SP400, but different DACs (SMLS SU-9, Topping D90 and Topping D50s). Overall the SP400 is definitely cleaner and more calm, SP200 is always slightly more nervous in direct comparison. No problem with power output with my AKG 701 headphones on both. With balanced input, I have no need to change from low gain and volume on SP400 is between 40 and 80.
SP200 is little more warm sounding, but I still prefer SP400 without question. Vocals and high octaves are much cleaner.
My favorite DAC is currently SU-9, unfortunately I'm not familiar with M400.
If you don't need remote control, you can also consider Topping A90. In direct comparison it's warmer sounding than both SP200 and SP400 with more robust bass. The warmer balance makes it sound not as super transparent as SP400, but details are definitely here, only slightly tamed down.
Both SP400 and A90 are worth the upgrade, I can live with both of them. I'm going to sell SP200.
According Sandu's review you can consider also SMSL SH-9, if you don't need pre-out. https://soundnews.net/amplifiers/headphone-amps/smsl-sh-9-thx-888-headphone-amp-review/

sp200 i way louder in single ended and sp400 measures slightly better in general( i can't say if its audible) but i don't really know how "calm" is a parameter.

 

[nobody]

sp200 i way louder in single ended and sp400 measures slightly better in general( i can't say if its audible) but i don't really know how "calm" is a parameter.

It's my subjective evaluation of those headphone amps... Well, maybe it's all my imagination, but I can hear those differences consistently with different DACs and even when used as preamps in my loudspeakers rig. Maybe it has something to do with better power supply in SP400... Or better crosstalk, which unfortunately amir refuses to measure on DACs and headphone amps...

 

[BDWoody]

Well, maybe it's all my imagination, but I can hear those differences consistently with different DACs and even when used as preamps in my loudspeakers rig.

Did you use any controls when doing your comparisons?

It's hard to figure out where the differences you describe would come from.

 

[raif71]

Thanks, think i will hang on as SMSL will probably do a version 2 as most are complaining about the output.

All this talk about the output being weak has put on hold my plans on getting this unit. When the sp200 came out some people complained about it being too powerful, now for the sp400, some say it's weak. I guess smsl have to find that sweet spot, at least on par with the a90 output. So... SMSL SP400 v2 ?

 

[Veri]

All this talk about the output being weak has put on hold my plans on getting this unit. When the sp200 came out some people complained about it being too powerful, now for the sp400, some say it's weak.

Indeed it's all very ironic..

 

[raif71]

This is not my experience. I’ve had both at the same time . A90 is MUCH louder.
Even A90 on medium gain is louder. Facts.View attachment 106998

Hi. How do you connect your sp400/a90 to the dac? Is it via xlr or rca? Thanks.

 

[nobody]

It's my subjective evaluation of those headphone amps... Well, maybe it's all my imagination, but I can hear those differences consistently with different DACs and even when used as preamps in my loudspeakers rig.
Take it or leave it...

Did you use any controls when doing your comparisons?

It's hard to figure out where the differences you describe would come from.

No, straight from foobar or Tidal thru WASAPI (to avoid Windows resampling/volume control) to USB DAC.


My amateur theory is, that measurements are made on separate components and not as entire system. From DAC to headphones/loudspeakers. And the components interacts to each other. Most measurements are made with pure resistivity load. But loudspeakers, headphones even all components have also capacitance and inductance load which is/can be frequency dependent and can cause different phase shifts at different frequencies. Then it depends on output stage of previous component how it can handle those loads. With power amps it's proven that amplifiers with higher damping factor are better with wild impedance loudspeakers.


Another thing is power supply filtering, when I've compared D50s with 5V phone charger and with battery power (4x AAA batteries), the sound with battery power supply is definitely more transparent. Same with Monoprice THX 887, 2x12V battery, more transparent sound compared to crappy switching supply delivered with the amp.


Another thing is "noise" transferred via "ground wire" to previous component. I'm not the "cable guy", but when I tried to use XLR cables from preamp/DAC to my Hypex nCore 500 monoblocks without attached ground pin, the sound again became more transparent...looks like some noise traveled back to preamp/DAC.


But as I said, I'm only amateur with very limited electrician education from high school...

 

[Veri]

Another thing is power supply filtering, when I've compared D50s with 5V phone charger and with battery power (4x AAA batteries), the sound with battery power supply is definitely more transparent. Same with Monoprice THX 887, 2x12V battery, more transparent sound compared to crappy switching supply delivered with the amp.


Another thing is "noise" transferred via "ground wire" to previous component. I'm not the "cable guy", but when I tried to use XLR cables from preamp/DAC to my Hypex nCore 500 monoblocks without attached ground pin, the sound again became more transparent...looks like some noise traveled back to preamp/DAC.


But as I said, I'm only amateur with very limited electrician education from high school...

Both of those anecdotes relate highly to online "bro" science, neither has ever been proven. Especially the PSU part:
https://www.audiosciencereview.com/...o-you-need-linear-power-supply-for-dacs.7021/
https://www.audiosciencereview.com/...-measurements-of-the-hdplex-200w-supply.7713/

The engineer behind the THX 789/887 amps btw, Andrew, choose a particular regulated switching supply and advices against replacing it without any understanding of the circuit behind it. It's hardly any random "crappy" PSU. It's not. Why do you reckon you'd know better than the engineer behind it, would be my question.

 

[nobody]

Both of those anecdotes relate highly to online "bro" science, neither has ever been proven. Especially the PSU part:
https://www.audiosciencereview.com/...o-you-need-linear-power-supply-for-dacs.7021/
https://www.audiosciencereview.com/...-measurements-of-the-hdplex-200w-supply.7713/

The engineer behind the THX 789/887 amps btw, Andrew, choose a particular regulated switching supply and advices against replacing it without any understanding of the circuit behind it. It's hardly any random "crappy" PSU. It's not. Why do you reckon you'd know better than the engineer behind it, would be my question.

Well as I said, it can be all my imagination... But it's weird, because I rate both A90 and SP400 higher as preamps than my Mark Levinson 380 preamp. Yet the aesthetics, weight and price of ML380 is on another level...so it should sound better, right?

I don't know if the particular regulated supply from THX 887 amp is different in Europe to the one delivered in other regions, but this one was genuine Chinese 24V DC switching power supply. 2x 12V battery in series is 24V DC. The batteries will definitely deliver much cleaner output...

 

[BDWoody]

No, straight from foobar or Tidal thru WASAPI (to avoid Windows resampling/volume control) to USB DAC.


My amateur theory is, that measurements are made on separate components and not as entire system.

This is true for the most part, but the way those different components will interact can be well predicted with the measurements available. When dealing with the interaction between an amp and speaker/headphone, or even some components and Preamps, there are definitely issues that need to be considered in terms of proper impedance choices, but none of that is mysterious.

If you've never tried some of these comparisons with listening controls (levels matched very closely, and not peeking/knowing what is playing), that may explain a lot more about what you're actually hearing, without it being influenced by any bias that exists (because...human).

 

[Kuma]

All this talk about the output being weak has put on hold my plans on getting this unit.

I was very close to pulling the trigger on the SP400 from Apos when it was discounted upon release. I already have an SP200, which has been fantastic, and I was looking to move that from my main listening station to my home work station, and have the SP400 be my main music listening amp. I'm glad I hesitated on the purchase.

I hope SMSL will address the gain/volume complaints in future revisions. But it would really suck for the first adopters if they did that, but left the first adopters hung out to dry. I'd be pissed.

 

[raif71]

I was very close to pulling the trigger on the SP400 from Apos when it was discounted upon release. I already have an SP200, which has been fantastic, and I was looking to move that from my main listening station to my home work station, and have the SP400 be my main music listening amp. I'm glad I hesitated on the purchase.

I hope SMSL will address the gain/volume complaints in future revisions. But it would really suck for the first adopters if they did that, but left the first adopters hung out to dry. I'd be pissed.

Yes, that would be unfortunate for the early adopters but if most of them are satisfied with current volume gain then I suppose that'll be okay. Anyway the measurement side of this amp is really good so those people that purchased it have nothing to be feeling bad about. On my side, due to current lockdown at my location, I couldn't go to the local shop for a demo and this is keeping me from buying the amp but lockdown or no if measurements and reports of the amp was satisfactory I would likely to buy it without demoing the amp. Now I have to wait until lockdown is over for me to demo and if I do find it satisfactory, perhaps I will purchase it.