SMSL SP200: Do We Get Golden Samples For Review?

[SmackDaddies]

This is quite different than the review sample. First, the level would not change for quite a while and once it started to change, it fell apart a lot sooner than the review unit. You can only get 30 dB of attenuation before channel balance becomes extreme relative to 70 dB before.

It seems to me until you check other units, they clearly first did send you a unit not representative of production models. Yes, SMSL is more transparent, yes, I own and recommend SMSL units, but clearly the production model is seriously different than the pre-pro.

 

[Jimster480]

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!

Well it seems that this pot doesn't have the same performance as amir tested and it is quite different. Maybe you guys should try to use A type Pot on all the models.

 

[Toku]

Well it seems that this pot doesn't have the same performance as amir tested and it is quite different. Maybe you guys should try to use A type Pot on all the models.

In the first place, it is a mistake to use B-type pod for SMSL volume control.
This means that SMSL doesn't understand anything technically, or SMSL ignores audio fans.

I'm sorry that audiophiles don't see this as a problem. .

 

[elira]

In the first place, it is a mistake to use B-type pod for SMSL volume control.
This means that SMSL doesn't understand anything technically, or SMSL ignores audio fans.

I'm sorry that audiophiles don't see this as a problem. .

I've seen companies use B-type pots to increase the perceived power of the unit. A lot of people see that it gets super loud within the first 1/4 of a turn and assume the amplifier has a lot of power. For practical purposes it becomes hard to get reasonable volume levels with efficient headphones without having noticeable channel imbalance.

 

[Jimster480]

In the first place, it is a mistake to use B-type pod for SMSL volume control.
This means that SMSL doesn't understand anything technically, or SMSL ignores audio fans.

I'm sorry that audiophiles don't see this as a problem. .

I just looked up the difference between A type an B type; I didn't realize that they actually varied in design. I just thought it was a different Pot.
So B-Type is Linear and A-Type is Logarithmic... and a Log style pot is what you need for audio since our perception of volume is logarithmic.

So then you are right that it makes literally no sense to use a linear style pot which is used for things like oscilloscopes.

 

[FourT6and2]

I just looked up the difference between A type an B type; I didn't realize that they actually varied in design. I just thought it was a different Pot.
So B-Type is Linear and A-Type is Logarithmic... and a Log style pot is what you need for audio since our perception of volume is logarithmic.

So then you are right that it makes literally no sense to use a linear style pot which is used for things like oscilloscopes.

On its own, taper shouldn't matter. A linear pot set to 450K and a log pot set to 450K are both... drum roll please... 450K. But as someone else said, a lot of people like to EQ or adjust things like volume controls with their eyes instead of their ears. And so they pay attention to where, physically, the knob is pointing, rather than what they hear and this plays into psychoacoustics and placebo. Now... I don't know how else an A-type vs B-type affects channel balance in this context. But just talking about taper... meh. Doesn't matter to me personally. I turn the knob until it's at the volume I want. Pots come in all sorts of tapers: linear, log, reverse log, custom, etc. As long as the taper isn't all bunched up into a small window of adjustment, they all work in my experience.

But again, if this affects channel balance in some way, that's different.

 

[Jimster480]

On its own, taper shouldn't matter. A linear pot set to 450K and a log pot set to 450K are both... drum roll please... 450K. But as someone else said, a lot of people like to EQ or adjust things like volume controls with their eyes instead of their ears. And so they pay attention to where, physically, the knob is pointing, rather than what they hear and this plays into psychoacoustics and placebo. Now... I don't know how else an A-type vs B-type affects channel balance in this context. But just talking about taper... meh. Doesn't matter to me personally. I turn the knob until it's at the volume I want. Pots come in all sorts of tapers: linear, log, reverse log, custom, etc. As long as the taper isn't all bunched up into a small window of adjustment, they all work in my experience.

But again, if this affects channel balance in some way, that's different.

From what I read; channel imbalance is worse with a linear pot. Depending on the cost/quality it can be really bad channel imbalance especially at lower volumes.

 

[Giulio]

Do you think the pot can be easily replaced?

 

[AnalogDE]

Do you think the pot can be easily replaced?

How good are your de-soldering/soldering skills?

 

[Toku]

Do you think the pot can be easily replaced?

Pot replacement is possible.
However, it requires skilled soldering techniques.

 

[somebodyelse]

From what I read; channel imbalance is worse with a linear pot. Depending on the cost/quality it can be really bad channel imbalance especially at lower volumes.

Some datasheet specs to put this in context:
Alps RK27 series - £8.78 each at 500+ quantities, Gang error <3dB 0 to -60dB, <5db -60dB to -80dB
Bourns PTD90 series - £0.92 each at 500+ quantities, Gang error <3dB 0 to -40dB, unspecified at greater attenuation
Even the 'poor' performance of this unit is within the spec of a standard high quality pot range. Manufacturers would need to test the pots if they wanted a tighter match - not unprecedented, but probably uncommon at this price point.

Also note the lack of standard for taper letter designations - for Bourns the A[1-6] series are log tapers, while the B series are symmetrical about the centre point. Vishay do something else entirely.

 

[Giulio]

Some datasheet specs to put this in context:
Alps RK27 series - £8.78 each at 500+ quantities, Gang error <3dB 0 to -60dB, <5db -60dB to -80dB
Bourns PTD90 series - £0.92 each at 500+ quantities, Gang error <3dB 0 to -40dB, unspecified at greater attenuation
Even the 'poor' performance of this unit is within the spec of a standard high quality pot range. Manufacturers would need to test the pots if they wanted a tighter match - not unprecedented, but probably uncommon at this price point.

Also note the lack of standard for taper letter designations - for Bourns the A[1-6] series are log tapers, while the B series are symmetrical about the centre point. Vishay do something else entirely.

Do you think the Alps will fit into the chassis?

 

[FourT6and2]

Are these dual pots? What causes a higher imbalance with linear pots vs another taper? Just manufacturing ability to properly match the carbon material on the pots' track between both halves? So when you turn the knob, one side might be at 450K and the other at... 420K? I know in the guitar amp world, builders will sit there and measure/match pots by hand with a meter. You can also order custom tapers and tolerances from companies like Bourns, Alpha, PEC, Alesandro, etc. I hear the reject rate is quite high...

 

[mkawa]

Do you think the Alps will fit into the chassis?

absolutely not. the rk27 is freaking huge. they're using the much more common alps rk09

 

[dmac6419]

How should I hook up the sp200 to the dx7 pro xlr or rca ?

 

[mkawa]

@SMSL_Liu says it's designed for single ended. the dx7 pro outresolves it on both rca and xlr, so i would hook it up via rca.

It seems to me until you check other units, they clearly first did send you a unit not representative of production models. Yes, SMSL is more transparent, yes, I own and recommend SMSL units, but clearly the production model is seriously different than the pre-pro.

again, they said it was a preproduction unit and addressed the production difference concern. the pot type of the next production batch could probably change, but if the difference is between linear and logarithmic, it's a matter of preference. the channel imbalance is something that is pretty difficult to catch via QC, but could happen with a faulty pot that's either log of linear.

i personally prefer log, but i'm not a stickler. after experimenting with any pot, you just end up turning it until it reaches the volume you want so the only issue to me is that they might have a bad batch of volume pots.

 

[dmac6419]

@SMSL_Liu says it's designed for single ended. the dx7 pro outresolves it on both rca and xlr, so i would hook it up via rca.



again, they said it was a preproduction unit and addressed the production difference concern. the pot type of the next production batch could probably change, but if the difference is between linear and logarithmic, it's a matter of preference. the channel imbalance is something that is pretty difficult to catch via QC, but could happen with a faulty pot that's either log of linear.

i personally prefer log, but i'm not a stickler. after experimenting with any pot, you just end up turning it until it reaches the volume you want so the only issue to me is that they might have a bad batch of volume pots.

Thank you

 

[Labjr]

Do you think the pot can be easily replaced?

Modern PCB's are hard to rework. It takes good skills and the right equipment. Depending on the board and the component, I would probably use a hot air station or de-soldering iron. Trying to do with with a cheapo iron and solder wick would increase the likelihood of ruining the board.

I wish manufacturers would use stepped attentuators instead of pots or at least make it an option.

 

[Giulio]

I wish manufacturers would use stepped attentuators instead of pots or at least make it an option.

I wish SMSL would have left the pot the review unit had.

 

[Labjr]

My 25 year old tube preamp has a Penny & Giles pot that cost about $400 at the time. As good as it is, I'm pretty sure it doesn't track as well or sound as good as a stepped attenuator would.