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SMSL SP400 Review (headphone amp)

trl

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#22
I agree. I computed 6.25 watts at 16 ohm. More may be available though if you drove it at more than 4 volts input. You would then need a DAC that can go up that high which is rare.
I see no distortions increase, so maybe you need to feed it with more voltage on the inputs? I remember this was the case of L30 too.
However, even 6W/ch. is still more than enough output power, even HE-6 owners should be happy.
 

trl

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#23
It's difficult to understand the last "channel imbalance vs volume position" table. How can I interpret this?
Left vertical axis is for the red line that represents the output level, where 0 dB means the max. volume knob (max. output voltage).

The 24 sec. from the bottom horizontal line represents the time took for Amir to lower the output power from 0 dB to -80 dB.

Right vertical axis is for the blue line that represents the deviation in dB from the absolute 0 dB, where 0 dB means the difference between the left/right channels. Basically, the blue line should remain within the +/-0.5 dB to be on the safe side, but on SP400 this is pure 0 dB due to the relay volume adjustment, which translates to "perfection".
 

PeteL

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#28

Matias

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#30
Excellent SINAD performance overall, perfect R2R volume, has remote control and competitive price. Fantastic! Congrats, SMSL.
 

trl

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#31
Very good looking indeed, but I prefer knobs and switches over the LCD + rotary knob. It's way faster to switch between inputs & gain & outputs via knobs/switches vs. a rotary knob where you need to actually get inside a menu to do any changes.

I also dislike volume +/- buttons over the rotary knob (like D90), but that doesn't means anything but a personal objective preference. :)
 

Matias

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#33
@amirm could you please also add multitone to te review? Thanks.
 
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#34
It looks plastic and cheap. Also can't get this trend of adding a lcd display to a headamp. It just adds complexity and clutter. On a plus side is the included AC power supply, simple thing but many forgets of how inconvenient it is to have a heavy, external brick.
 
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#37
@amirm Thank you for the review, can you please add measurements for XLR out? Sinad, multitone, crosstalk and so on. With remote control, this device is interesting for those who are looking for preamp with headphone output. It's good alternative to Pre90.

I own Topping A90 for 6 months already and SP400 for one month. I'm more in to loudspeakers than headphones, so my headphone comparison is limited to AKG K701 headphones.
As headphone amp I prefer A90, it's slightly more calm and smooth tone balance at higher frequencies is more pleasant for long time sessions. With SMSL SU-9 DAC it's dream match, to me better sounding than A90+D90.
The SP400 is always slightly more transparent and does uncover everything. With SMLS SU-9 it's sometimes too much and the higher frequencies can be aggressive. Topping D90 is better match to my ears, the SP400 extracts every little detail from it, yet for long session it is not hurtful.
Anyway my current favorite headphone rig is A90 + SU-9.

For loudspeakers I need more time, but my current feeling is, that SP400 will be better, but i need to work on DAC. SU-9 is sometimes still little aggressive and D90 has it's own problems with female vocals and details rendering (I attribute this to output LM6172 buffers, I regret, that with D90 Topping omitted option to easily replace output opamps). My amps are Hypex NC500 monoblocks without input buffers and loudspeakers are Thiels CS2.4.
 
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Music1969

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#38
Great amp, but pretty pricy when you Look at the market. I dont know the manufacture costs but 399 would be more in line with the market IMHO.
Unless you really need the extra power with the balanced headphone output - there is the SMSL SH-9 that's cheaper.

I'd love to know what headphones need more power than the SH-9.
 

ninetylol

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#39
Unless you really need the extra power with the balanced headphone output - there is the SMSL SH-9 that's cheaper.

I'd love to know what headphones need more power than the SH-9.
Exactly what im saying. Even their own amps makes this one obselete at this price point.
 
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