SMSL SP200: Do We Get Golden Samples For Review?

[Veri]

golden is called cherry pick

someone linked the internal

either their qc is very bad, or..

What do you mean? From Amir:

Conclusions
I see little evidence of SMSL having picked a special unit to send me. Performance is as superb as the review unit. Volume control has some issues but as mentioned, I think there are other explanations for this than a golden sample.

There's many other products which you can purchase and have a worse/slightly worse volume balance. The luck of the draw...
This product isn't in the $400-$500 price range either, so volume pot variation is not unexpected.

 

[SMSL_Liu]

either their qc is very bad, or..

It's the same performance from the prototype, we decided to use B-type pot instead with the A-type which was in the prototype.

 

[somebodyelse]

Dear Jimster480, Yes you are right! we use B type Pot on the mass product, the one we sent to amir was a A type, but they are the same series pot. the performance is the same! just the volume position is changed!

What's the channel matching spec for that series, and is it the same for both tapers?

 

[Giulio]

It's the same performance from the prototype, we decided to use B-type pot instead with the A-type which was in the prototype.

So we have to expect type-B performance (30dB attenuation without channel imbalance) in the products now available?

 

[Toku]

It's the same performance from the prototype, we decided to use B-type pot instead with the A-type which was in the prototype.

Do not use Btype for the volume pot. It is impossible.

 

[mi-fu]

I think one thing for sure is that though the review sample may not be cherry-picked, there are hardware differences in the review sample and the mass production unit.

And from the measurements of the two units, the volume pots perform differently.

 

[mkawa]

1. it was made clear to amir and hence to us that the unit he was given was a near-final, but not shipping unit.

2. @SMSL_Liu has been extremely transparent that they made a production change to a different volume pot part number based on measurements that showed no difference between them

3. smsl had no issue with amir measuring a production unit and showing that there does seem to be a volume pot difference. however, the production sample performs within measurement variance in every other way.

in summary: calm down. if you do rely on the analog volume pot, maybe wait until the next production run or audition a unit and see if the shipped pot works for you. as amir said, there is zero evidence that he was given a golden sample; in fact, it was made clear he wasn't even given a production sample! it was also made clear that smsl only made one small change that should not have affected the functionality or quality of the production run in shipped product. if you ignore the volume pot change, the unit performs almost exactly as well as the preproduction sample. that is the opposite of bad qc; it's excellent QC.

sigh. SMSL/sabaj is one of the few manufacturers on here that is completely transparent with their design decision, customer support, and future plans. i personally think we should be applauding their actions here, and as per the OP, they are perfectly happy taking back the unit that the buyer felt did not perform up to par because of the potentiometer change. i can't see what else smsl could do better in this situation.

finally, potentiometer QC and uniformity is a huge PITA. it's hard to fault them for a bad pot.

ps, remember, this unit is > 100$ less than all the other thx amps, and performs just as well if not better in some ways. it is also widely available, where the other units are almost impossible to buy.

 

[Veri]

finally, potentiometer QC and uniformity is a huge PITA. it's hard to fault them for a bad pot.

ps, remember, this unit is > 100$ less than all the other thx amps, and performs just as well if not better in some ways. it is also widely available, where the other units are almost impossible to buy.

I really do agree. It's noteworthily cheaper than the Massdrop/Monoprice THX amps, and has a neat gain design as well as internal PSU as opposed to external switching ones the competition offers.. It has everything I want and at a very attractive price. Also, if you order with a reputable seller you can definitely return and get a new unit if you have a faulty volume pot.

What's not to like

 

[Jaysz]

Sure companies send items for review and change specs
Happens with pc components.
They haven't been clear about m500 specs.
When should led be magneta
Slow filters dropping volume when mqa should not use filters .
Why doesnt dac show firmware update is it just a driver update .

 

[FourT6and2]

As an advocate for controling volume with a variable output DAC, analog potentiometers are no issue for me. I reccomend everyone get a DAC with volume control so that you can leave your amp at max and have perfect channel balance.

Interesting. Is there a downside to running amp at 100% and using DAC as volume control, compared to running DAC at fixed output and using amp's volume control?

 

[AnalogDE]

question about the channel imbalance plot:

1) Shouldn't the difference curve turn upward as the difference gets larger? (past T=11s)

2) Why is the x-axis in time units? How is this test performed?

 

[elira]

Interesting. Is there a downside to running amp at 100% and using DAC as volume control, compared to running DAC at fixed output and using amp's volume control?

It depends on the specific amp. A lot of amps have the volume pot as a first stage, in that case the only downside is that you are sending a low level signal through the interconnects. There are other amps that have a preamp stage at the input, others use the volume pot to adjust the gain instead of attenuating the signal, in those cases it depends on the specific amp design.

 

[flowjm]

Slightly off topic, but why do so few manufacturers use opto-couplers instead of potentiometers as analogue volume controls?

 

[SIY]

Slightly off topic, but why do so few manufacturers use opto-couplers instead of potentiometers as analogue volume controls?

Far lower performance. Which is why they're the darlings of tweak audiophiles.

 

[amirm]

2) Why is the x-axis in time units? How is this test performed?

I set the volume to max and initialize the test so that the output then is 0 dB. I then start the continuous recorder, measuring the output level and difference between channels. I then turn the volume control by hand from max to zero and the software plots the values. When I get to minimum, I stop the test. The X-axis then is how long it is taking me to go from max volume to min. By itself it has no significance.

 

[flowjm]

Far lower performance. Which is why they're the darlings of tweak audiophiles.

Interesting. I looked into buying one a few years ago, having read all the glowing reports of transparency. Good thing I changed my mind.

 

[SIY]

glowing reports

I see what you did there.

 

[flowjm]

I see what you did there.

Pun not intended.

 

[somebodyelse]

Interesting. I looked into buying one a few years ago, having read all the glowing reports of transparency. Good thing I changed my mind.

measurements and an explanation of the distortion mechanism common to currently available LDRs

 

[flowjm]

measurements and an explanation of the distortion mechanism common to currently available LDRs

Thanks.

Edit: I believe that the appropriate exclamation is "oof".