SMSL SP400 Review (headphone amp)

[mkawa]

i'm one of those that are perfectly satisfied with the gain settings. even with quiet classical recordings on my single ended dt880 600o HPs (5.3db gain), i'm pushing my ears at 75 high gain. keep in mind that unlike most amps, this amp is absolutely distortion free between 0 and 99 at any gain, so i have plenty of room to blow my ears out. for anything mixed a bit hotter, I have to lower to 50 or less. for my 300o, and 80o balanced HPs (11db), and 150o (5db) I'm between 20 and 35-40 high gain. I think I might have gotten to 50 with the hd600

I'm running my m400 balanced out at 80, so the input is slightly hot, but a number of people who were unsatisfied with loudness were also pairing with. m400s

re: whether it's worth the price. the sp400 has higher power and lower distortion at all gain levels than the sh-9 at a bit less than twice the price (with the preorder apos deal i got). however, it's debatable whether the difference is audible; the sh-9 is also excellent and as amir has said, both are "instrumentation grade". in fact, if you look at the pcbs of the two, it's obvious that they copy pasted the sh-9 time to make two sh-9s in parallel. if you are looking to maximize price to performance, get the sh-9. if you want a freakishly high power and low distortion fully balanced HP amp, then the sp400 is worth your time.

 

[raif71]

i'm one of those that are perfectly satisfied with the gain settings. even with quiet classical recordings on my single ended dt880 600o HPs (5.3db gain), i'm pushing my ears at 75 high gain. keep in mind that unlike most amps, this amp is absolutely distortion free between 0 and 99 at any gain, so i have plenty of room to blow my ears out. for anything mixed a bit hotter, I have to lower to 50 or less. for my 300o, and 80o balanced HPs (11db), and 150o (5db) I'm between 20 and 35-40 high gain. I think I might have gotten to 50 with the hd600

I'm running my m400 balanced out at 80, so the input is slightly hot, but a number of people who were unsatisfied with loudness were also pairing with. m400s

re: whether it's worth the price. the sp400 has higher power and lower distortion at all gain levels than the sh-9 at a bit less than twice the price (with the preorder apos deal i got). however, it's debatable whether the difference is audible; the sh-9 is also excellent and as amir has said, both are "instrumentation grade". in fact, if you look at the pcbs of the two, it's obvious that they copy pasted the sh-9 time to make two sh-9s in parallel. if you are looking to maximize price to performance, get the sh-9. if you want a freakishly high power and low distortion fully balanced HP amp, then the sp400 is worth your time.

I'm so so happy for you

 

[mkawa]

we can't all be downers here

 

[JB5150]

if you want a freakishly high power and low distortion fully balanced HP amp, then the sp400 is worth your time.

LOL
You have an interesting perception of "freakishly high power"

 

[Artaois]

I wonder if the power supply in this is being highly underrated? Despite what power an amp claims if the power supply can't keep it fed current the sound will sound lethargic no?
SP400 has a pretty big power supply. Double of the SP200 I believe and quite a bit more than the A90 if I'm not mistaken. Thats one reason it can power the Susvarna better than others. There is a difference between loud and powered correctly. Correct me if I have anything wrong. =)

 

[raif71]

I wonder if the power supply in this is being highly underrated? Despite what power an amp claims if the power supply can't keep it fed current the sound will sound lethargic no?
SP400 has a pretty big power supply. Double of the SP200 I believe and quite a bit more than the A90 if I'm not mistaken. Thats one reason it can power the Susvarna better than others. There is a difference between loud and powered correctly. Correct me if I have anything wrong. =)

I went ahead and got this amp. Pairing it with m400 via xlr. I must say that I'm pretty satisfied with its power. Using hd600 and using medium gain, with pop songs I'm at around 4+ on the volume scale and with soft classical, I'm at 7+. The hd600 is using balanced xlr jack. With hd800 using 6.35mm jack (SE), I'm at 6+ for pop songs and 8+ with soft classical, this too is at medium gain.

 

[pimy]

I wonder if the power supply in this is being highly underrated? Despite what power an amp claims if the power supply can't keep it fed current the sound will sound lethargic no?
SP400 has a pretty big power supply. Double of the SP200 I believe and quite a bit more than the A90 if I'm not mistaken. Thats one reason it can power the Susvarna better than others. There is a difference between loud and powered correctly. Correct me if I have anything wrong. =)

"With all that said, there is one thing that I wish SMSL did differently, there is still hope as I’m having the Hardware and Software version 1.0 and maybe there is a chance, I can update it later on. The biggest issue that I’m writing about is its gain position. There is very little difference volume wise between low, to mid and then to high gain and while this doesn’t seem like a huge con, it is a huge con with hard to drive headphones like Hifiman Susvara. When you put it side by side with its smaller brother SH-9 that offers exactly half the power, it doesn’t sound more powerful at all and here are some examples.

While feeding a stronger signal of 84 dB into a 300 Hz sine wave into both amplifiers I am getting these results on high gain:

• Audeze LCD-4 will sit at 57 volume on SH-9 and that would equal a volume of 55 on SP400
• Hifiman Susvara will sit at 78 volume on SH-9 that would equal a volume of 76 on SP400

Considering that SP400 offers 12 Watts and SH-9 only 6 Watts, I expected a much bigger difference volume wise and the culprit seems to be the low gain amplifier design of both devices. From their user manuals, SP400 is having a max gain of 11.6 dB if its balanced inputs and outputs are being used and SH-9 has a max gain of 10 dB. If you are upgrading from SH-9 to SP400 and you don’t feel the increase of power, that is normal behavior, but you still should hear the improvements in terms of layering, easiness and dynamics, which are quite obvious from the start. Right now, it makes a lot of sense why that is happening, but I would still raise the high gain of SP400 to 20 dB so it would work much better with hardest loads as Hifiman Susvara, HE-6SE and Abyss 1266 TC."

https://soundnews.net/amplifiers/headphone-amps/smsl-sp400-review-a-flawed-masterpiece/

 

[Artaois]

I went ahead and got this amp. Pairing it with m400 via xlr. I must say that I'm pretty satisfied with its power. Using hd600 and using medium gain, with pop songs I'm at around 4+ on the volume scale and with soft classical, I'm at 7+. The hd600 is using balanced xlr jack. With hd800 using 6.35mm jack (SE), I'm at 6+ for pop songs and 8+ with soft classical, this too is medium gain.

You're using the DAC to control volume? I believe it's best to max the M400 and control volume using the amp. The last link in the chain.

 

[Artaois]

"With all that said, there is one thing that I wish SMSL did differently, there is still hope as I’m having the Hardware and Software version 1.0 and maybe there is a chance, I can update it later on. The biggest issue that I’m writing about is its gain position. There is very little difference volume wise between low, to mid and then to high gain and while this doesn’t seem like a huge con, it is a huge con with hard to drive headphones like Hifiman Susvara. When you put it side by side with its smaller brother SH-9 that offers exactly half the power, it doesn’t sound more powerful at all and here are some examples.

While feeding a stronger signal of 84 dB into a 300 Hz sine wave into both amplifiers I am getting these results on high gain:

• Audeze LCD-4 will sit at 57 volume on SH-9 and that would equal a volume of 55 on SP400
• Hifiman Susvara will sit at 78 volume on SH-9 that would equal a volume of 76 on SP400

Considering that SP400 offers 12 Watts and SH-9 only 6 Watts, I expected a much bigger difference volume wise and the culprit seems to be the low gain amplifier design of both devices. From their user manuals, SP400 is having a max gain of 11.6 dB if its balanced inputs and outputs are being used and SH-9 has a max gain of 10 dB. If you are upgrading from SH-9 to SP400 and you don’t feel the increase of power, that is normal behavior, but you still should hear the improvements in terms of layering, easiness and dynamics, which are quite obvious from the start. Right now, it makes a lot of sense why that is happening, but I would still raise the high gain of SP400 to 20 dB so it would work much better with hardest loads as Hifiman Susvara, HE-6SE and Abyss 1266 TC."

https://soundnews.net/amplifiers/headphone-amps/smsl-sp400-review-a-flawed-masterpiece/

He gets corrected in the comments and that double the power only equates to +3db and that's exactly what he was seeing.

 

[BDWoody]

You're using the DAC to control volume? I believe it's best to max the M400 and control volume using the amp. The last link in the chain.

Why?

 

[raif71]

You're using the DAC to control volume? I believe it's best to max the M400 and control volume using the amp. The last link in the chain.

My m400 DAC is at fixed volume, I'm using the amp's volume.

 

[Artaois]

Why?

Someone here could explain it better tbh but Your Amp performs differently based on the voltage you're getting out of your DAC into it. The m400 can put out something like 5.4v but only if you max the volume. Pure DAC mode in the options will lock your volume control on it.

 

[BDWoody]

Someone here could explain it better tbh but Your Amp performs differently based on the voltage you're getting out of your DAC into it. The m400 can put out something like 5.4v but only if you max the volume. Pure DAC mode in the options will lock your volume control on it.

I agree with that, but I would think it depends on the amp it's feeding. A particularly sensitive amp might be better off with the volume attenuated in the DAC. I don't think getting the overall gain is as simple as leaving everything at max, but it looks like in this case it's perfectly fine.

 

[raif71]

I agree with that, but I would think it depends on the amp it's feeding. A particularly sensitive amp might be better off with the volume attenuated in the DAC. I don't think getting the overall gain is as simple as leaving everything at max, but it looks like in this case it's perfectly fine.

Do you mean "perfectly fine" setting the DAC using dac mode ? Also, if I'm setting DAC mode as I do with most DACs that I have, the alternative is in non-dac mode with volume at max, the DAC should essentially output more or less the same voltage, right?

 

[BDWoody]

Do you mean "perfectly fine" setting the DAC using dac mode ? Also, if I'm setting DAC mode as I do with most DACs that I have, the alternative is in non-dac mode with volume at max, the DAC should essentially output more or less the same voltage, right?

The output will be the same.

Generally speaking, DAC mode is just preamp mode at full volume.

I believe there are some that require DAC mode to process DSD, but that's not what we're talking about.

I adjust gain in a way that makes my final 'knob' have the sensitivity where I like it.

If you overdrive your amp with too much voltage, you will have very little in the way of volume adjustability.

 

[mkawa]

my understanding is that the ak4499 implementation has no lossless volume control (unlike the ess9038), and darnit i paid for a resistor ladder on the sp400 i'm going to use it

really though, adjusting the resistor ladder and leaving the m400 at 80 (higher voltage out increases sinad as well) should be optimal for distortion and noise performance

 

[m8o]

You know, I thought this would be on my short list of "want to buy". But after giving it some thought, I decided it is really short sighted of the manufacturer to engineer it such that one can only take fullest advantage of it with a DAC that is capable of non-standard maximum output, w/the 5.4 volts (or whatever it may be) balanced necessary to reach maximum output; i.e. their own DAC.

Sure, I can output from my extremely clean 4v balanced DAC, the X16, to a balanced preamp. But there is literally nothing that is affordable and will get me the extra volt and a half without injecting a fair amount of noise and distortion too; nor would I be willing to pay thousands of dollars for that extra volt and a half. So, I'll hold on to the $ I would have spent on this. My wallet, and wife, are happy at least.

I write this to perhaps serve as another in the long chorus of voices asking the manufacturer to rethink their position on this; i.e.its gain. I imagine this is not a "firmware fixable" situation. Assuming not, hope this changes with a rev 2 of this otherwise near perfect headamp.

P.s. yes, I know I am nit picking about only "the last 3dB". Consider it more the principal of the matter; and wanting to be able to get everything I pay for and am entitled to. Plus, the HE-1000 _will_ absorb the last 3dB of the transient music peaks of non brick wall compressed music.

 

[beq1990]

So, from what I understand, for sp400 it would be preferable to be connected to a DAC which can output more than the usual 4V via XLR, is this correct? If it is, I assume it would pair well with a su-9 DAC (which I think has 5.3V XLR output at max volume), right? Thank you guys

 

[mkawa]

It should pair well, particularly if you are worried about gain

 

[spacelion2077]

Hi all, I'm a current A90 owner. Is it worth it to upgrade it to SP400? I've read some reviews on head fi and soundnews that SP400 improves headphones soundstage and better slam. Would love to hear some inputs from some of its owners personal input and comparison. Thanks.