Who is using their DAC as a preamp?

It all over the place, they say 50k input but don’t say which one, which means a 50k pot. Could be the cheap 24mm they have, as you can’t see the value on it.
But the pic if you zoom on the Alps (Blue Velvet) says 100kohm A taper (log) pot and it would be a 100kohm input impedance.

Whatever it is (50k or 100k), 10kohm is the best value to have, as all decent sources can handle 10kohm load (save for a couple of silly tube output ones)

A 10kohm pot has "at worse" 2.5kohm output impedance which is fine for any poweramp with >33kohm or higher input impedance.

Would be nice if you open it and find an Alps 10kohm A-taper (log) Blue Velvet for $40 with box and decent rca’s and free shipping.

Cheers George

George, picture is just a picture. Did you know that Alps never referred to the control as a Blue Velvet. Nowhere on their web site have I found it. If you could find it, please post it. I believe some audiophile engineer, in using it, gave it that name. I am sorry Georgi, but this device is an EXCELLENT passive unit, for cheap, according to my ears, and the dozen or more power amplifiers I have tried with it. The control has a sexy, very high end feel, and the little box is non resonant, and built really well. Enjoy ! MrD.

There is the even better, the Alps "Back Beauty", but they cost a lot more.

https://i.ebayimg.com/images/g/O1kAAOSwQolbFS19/s-l300.jpg

https://www.picclickimg.com/00/s/MTA3MVgxNjAw/z/W~QAAOSwYGFUv3Ah/$/1pcs-ALPS-RK40-50KA-Black-Beauty-...

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSrMqGsGmwCWfSPDB1Y9O6LrTsKEfybIOqvEkwLGaCSU4Li...

I am sorry Georgi, but this device is an EXCELLENT passive unit

As for the sound, I don’t doubt you like it,. and what you get is a bargain, I’m just pointing out the confusion of their ad in what actual value Blue Velvet is used and you get, all values will work as I pointed out, some better than others, because of proper >1:10 impedance matching input and output.

We just have to wait for someone to have a look at what’s inside them.

Cheers George

George, I am sure you meant Black. Do those pictures say Black Beauty anywhere ? I cannot find it. I know about the Black bodied attenuators that Alps made, but they are no longer made, as the " Blue " does the trick. A buddy of mine purchased 4 of them, based on my recommendation of trying one, and he is using 2 per system, 1 for Left and one for right ( single channel only of the passive ), and tells me he hears an improvement in sq vs. using one. I have not been over to hear it, as he is out of state of my location, but, George, what do you think ?

Yes typo "Black Beauty" if you came through Audio 70's/80's you know all about the Alps Black Beauty and Blue Velvet.
https://www.google.com/search?q=Alps+%22Black+Beauty%22&rlz=1C1CHZL_enAU820AU820&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjZ5Lv4n-_hAhVYWysKHWNkD_UQ_AUIDigB&biw=1408&bih=869

https://www.google.com/search?rlz=1C1CHZL_enAU820AU820&biw=1408&bih=869&tbm=isch&sa=1&ei=fcHDXNK9ONmR9QPNn73ICw&q=Alps+%22Blue+Velvet%22&oq=Alps+%22Blue+Velvet%22&gs_l=img.12..0i30j0i24l6.25691.35942..38034...0.0..0.207.1739.0j11j1......0....1..gws-wiz-img.......0i7i30j0i8i7i30.28dFrooeV2A

As for using a separate pot, same value, for each channel, there is no EE reason that it should be better or worse.
  
But I get the same thing with owners of two Lightspeed Attenuators, the  Stereo version and the Dual Mono version, they swear the Dual Mono sounds better.
I think it's because they can dial in an exact central stereo image with the left and right level controls, regardless of room/equipment/ music source influences, and this has an slight influence on the sound to them.


Cheers George