• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Review and Measurements of SMSL SP200 THX HP Amp

maxxevv

Major Contributor
Joined
Apr 12, 2018
Messages
1,872
Likes
1,964
Alrighty. Edited.

BTW, I did some reading one or two years ago on those designs. It's just the extremely low impedance and high current draw it needs. There were a few similar products back then. The conversion box he used is just designed for power amplifiers, which is deliberately lowering the sensitivity. The other companies who make these have converters suitable for headphone amps.

There aren't many ribbon driver headphones on the market at all. I know the Raal's sound pretty good to my ears, no idea how the others sound outside of their interweb sharing / reviews.

Outside of test prototypes / proof of concept presentations, I only know of 2 (manufacturers) who have made their products available on a consumer basis. One being Raal and the other being located in China and offers 2 models. I am tempted to try those out. Shall see if there are any good offers for them come 11.11 sale.
 

SMSL_Liu

Member
Audio Company
Joined
Oct 15, 2019
Messages
27
Likes
112
It is a very different output level. And as noted, we don't know what filtering was used (that would be to the left of the screenshot shown).
Dear Amir, finally I got time to review this post, very much appreciated your work, maybe I can provide you with some of our information. The sp200's amplifier section has only 2 channels, but it is designed in a "balanced" way. According to the THX guidelines, all XLR socket traces are returned to the amplifier. And because it is an unbalanced amplifying part, the RCA does not need to pass an XLR->RCA amplifier like the XLR input. Therefore, the performance of the RCA input is the best. We test the input using 5Vrms (because this is the best point of our ap's signal generator), the A-WTD is not used, the attachment is the result of the RCA and XLR inputs we tested, all with a 33OHM load, where the XLR input is 0.00009%, because this is the result of the 1st prototype test. For 2nd generation prototype, we modified the resistance of XLR-> RCA, THD+N down to 0.000085%, and the results of the five prototypes were consistent. BTW, we are using APX555B, I also attached THD+N of the APX555B 5Vrms.
 

Attachments

  • RCA IN.jpg
    RCA IN.jpg
    337.6 KB · Views: 663
  • XLR IN.jpg
    XLR IN.jpg
    337.7 KB · Views: 666
  • APX555B.jpg
    APX555B.jpg
    332.5 KB · Views: 613
Last edited:

maxxevv

Major Contributor
Joined
Apr 12, 2018
Messages
1,872
Likes
1,964
@amirm mentioned:

"As a side note, when I designed this test, I did not think to turn on the low-distortion mode of my audio analyzer thinking it was not needed. It actually is here! When I turned that on (not shown) distortion at the bottom right was even lower. For consistency, I am leaving it the same but you should note that with this setting, the distortion of my analyzer is the limit, not these headphone amplifiers! "

Would be interesting to show the results of the mode turned on. ASR is in the business of showing what SOTA is capable of, so I guess it would be insightful/useful to show that separately too ?
 

MediumRare

Major Contributor
Forum Donor
Joined
Sep 17, 2019
Messages
1,949
Likes
2,275
Location
Chicago
So we are spoiled for choice, for sure. apos.com said the SP200 will be available soon. Any suggestions how to choose between it and the Monolith THX887?

I have cans with about 50 ohms impedance and can use the balanced output, so I am leaning toward the Monolith due to the extra power. But maybe that's academic if I'll never go about 1 watt.

My DAC will be the D50s, so RCA output only, no need for balanced interconnect.

The other factor I'm considering is the rear-panel pass-through available on the Monolith, so I can leave it connected in series between my DAC and main amp.

What do you experts say?
 

Veri

Master Contributor
Joined
Feb 6, 2018
Messages
9,596
Likes
12,036
So we are spoiled for choice, for sure. apos.com said the SP200 will be available soon. Any suggestions how to choose between it and the Monolith THX887?

I have cans with about 50 ohms impedance and can use the balanced output, so I am leaning toward the Monolith due to the extra power. But maybe that's academic if I'll never go about 1 watt.

My DAC will be the D50s, so RCA output only, no need for balanced interconnect.

The other factor I'm considering is the rear-panel pass-through available on the Monolith, so I can leave it connected in series between my DAC and main amp.

What do you experts say?
If you want the pass-through and balanced the monolith seems the way to go. The extended warranty is also nice.
On the other hand the D50s is a great match with the single-ended SP200 and is cheaper.

Up to you :D
 

olinko

Member
Joined
Oct 16, 2019
Messages
72
Likes
41
First post! I'm hoping to buy the SP200 and the SU-8 combo on 11/11 but I'm annoyed that the SU-8 is gone from the official SMSL store on AliExpress.
I'll take the SP200 over the Monolith just so I don't have to import stuff from the US into the EU, I've had nothing but horrible experiences.
Plus, if you're getting an SMSL DAC, might as well pair it :)
 

MediumRare

Major Contributor
Forum Donor
Joined
Sep 17, 2019
Messages
1,949
Likes
2,275
Location
Chicago
Last edited:

Veri

Master Contributor
Joined
Feb 6, 2018
Messages
9,596
Likes
12,036

or965

Member
Joined
May 22, 2018
Messages
35
Likes
24
@SMSL_Liu Is the amp will work with low impedance balanced driver earphones, like for example a earphones with a impedance that vary with a minimum of 8 ohms ? I ask it as the DROP THX 789 product manual warn to use with low impedance earphones .
 
Top Bottom