Review and Measurements of the PS Audio Stellar Gain Cell DAC

[RayDunzl]

Audio Buddy came over last night for Beer Saturday...

He bought a Stellar DAC a few months ago, and had read this thread. I don't think he's joined, but has looked in from time to time.

He asked about the audibility of the distortion levels.

I turned up what we were already listening to a bit, to the just above long-evening comfortable level at the preamp.

Then, at the miniDSP, turned down the signal by 60dB (distortion level above), and waited for his comment.

There was just a hint of sound, not enough to recognize what was playing.

"Thanks."

At -70dB:

"I can't hear a damn thing."

He thought it was a good demonstration.

 

[amirm]

Then, at the miniDSP, turned down the signal by 60dB (distortion level above), and waited for his comment.

Did you stop eating potato chips right next to his ear? I bet you did not!

 

[RayDunzl]

Did you stop eating potato chips right next to his ear? I bet you did not!

Rant:

Your AP, in linear terms, can detect a tiny little sand castle you built on the beach at sea level only 0.035 inches high while standing on the top of Mt Everest at 29,029 feet. How it can do that is beyond my feeble imaginations, but there it is.

That may not even be your AP limits, since I chose -140dB as a nice round figure and surely not beyond its range.

Math:
29,029 ft / 10,000,000 *12 = 0.0348348
29,029 ft height of Everest / 10,000,000 140dB ratio *12 to make the result inches = 0.0348348

You're spoiled, and while it is fun to see just how far things can be taken, well, that's how I see it...

Other factors:

120dB 1,000,000 or 0.35 inches
100dB 100,000 or 3.48 inches
80dB 10,000 or 34.83 inches (now we're getting somewhere!)
60dB 1,000 or 348.34 inches, or 29.029 feet

Next to Mt Everest...

Put it into a log display, which squashes all the life out of linear things, it looks different.

 

[amirm]

Your AP, in linear terms, can detect a a tiny little sand castle you built on the beach at sea level only 0.035 inches high while standing on the top of Mt Everest at 29,029 feet. How it can do that is beyond my feeble imaginations, but there it is.

The ear has an electro-mechancial gain stage that can shift he dynamic range up and down to enable hearing an incredible 115 dB of dynamic range. You can increase the sensitivity of your hearing so much that you can hear blood rushing through your veins, as people in anechoic chamber tend to do:

As amazing our hearing is, it doesn't hold a candle to dogs. Our female guard dog can hear my wife driving to our house some 30 seconds before I do! It is uncanny how she detects that, I think it is a false alarm, only to see her eventually show up. She can focus he hears forward and zoom in to hear much better than we can with ours.

Across our bay, I can hear people fishing and talking half a mile away on a calm day. I can't understand what they are saying but can hear them talk.

 

[RayDunzl]

The ear has an electro-mechancial gain stage that can shift he dynamic range up and down to enable hearing an incredible 115 dB of dynamic range.

Yes, but you can't hear that range of loud and soft at the same time.

The AP can.

Across our bay, I can hear people fishing and talking half a mile away on a calm day. I can't understand what they are saying but can hear them talk.

Yes.

Shoutometer says, oh, let's call it -60dB, ignoring the possible temperature gradient above the water, and other possiblities, and since you say they are talking and not shouting.

Can't hear them while weedwhacking or while a jet ski is going past your preserve a few feet offshore.

 

[amirm]

Yes, but you can't hear that range of loud and soft at the same time.

You don't. Just let a loud note decay and you will have both parts of the dynamic range.

 

[RayDunzl]

As amazing our hearing is, it doesn't hold a candle to dogs. Our female guard dog can hear my wife driving to our house some 30 seconds before I do! It is uncanny how she detects that, I think it is a false alarm, only to see her eventually show up. She can focus he hears forward and zoom in to hear much better than we can with ours.

Their sense of smell can be even more extraordinary.

I read about a kidnapping and murder case, where the dog began sniffing at the house, and down the street, and on to the nearby interstate, where they had him sniff around at each exit till he found one he liked, and they took that road to a dirt road to the scene of the crime.

The claim is dog was smelling skin flakes that blew out of the window as the perp drove away.

I'll see if I can dig that up again, since it seems totally ridiculous.

 

[LTig]

You don't. Just let a loud note decay and you will have both parts of the dynamic range.

But the HD of the loud note decays as well, and usually faster.

 

[RayDunzl]

You don't. Just let a loud note decay and you will have both parts of the dynamic range.

Once that loud (and distorted at -xx decibels) note decays, there's no more distortion to hear.

Noise, maybe, I'll give you that, if it is above the just detectable level along some of its spectrum.

 

[amirm]

Once that loud (and distorted at -xx decibels) note decays, there's no more distortion to hear.

I didn't realize that was the context of your comment. Look at the hearing threshold for low frequencies. It is quite high. So what doesn't seem that loud on low frequencies, can create harmonic distortion that lands in mid frequencies where our hearity acuity is much higher.

As an extreme case, imagine you have a 21 kHz tone that is not audible to you. If that has jitter that lands in audible band in mid-frequencies, then it will be audible even though the primary tone is not.

 

[RayDunzl]

Oh well...

 

[RayDunzl]

Their sense of smell can be even more extraordinary.

I read about a kidnapping and murder case, where the dog began sniffing at the house, and down the street, and on to the nearby interstate, where they had him sniff around at each exit till he found one he liked, and they took that road to a dirt road to the scene of the crime.

The claim is dog was smelling skin flakes that blew out of the window as the perp drove away.

I'll see if I can dig that up again, since it seems totally ridiculous.

Newpaper version: https://www.denverpost.com/2011/09/...-it-was-neighbor-long-suspected-and-now-dead/

An embellished version: https://unsolved.com/gallery/alie-berrelez/

Map...

Considering how many dead skin cells Yogi had to sniff among, it's just insane to me.

 

[Thomas savage]

Newpaper version: https://www.denverpost.com/2011/09/...-it-was-neighbor-long-suspected-and-now-dead/

An embellished version: https://unsolved.com/gallery/alie-berrelez/

Map...

Considering how many dead skin cells Yogi had to sniff among, it's just insane to me.

Better cover your tracks next time.

 

[scott wurcer]

Better cover your tracks next time.

A few years ago we bought a loft in a rehabbed chocolate factory with ~50 units. My dog was getting very old so we left him at home during the entire move. When I brought him to the building the first time he walked right up to our unit and waited for me to open the door.

 

[digicidal]

Makes you wonder if we were all still largely hunter-gatherers how much better our senses might be. Not that I mind... I'm quite happy that I can't smell the odors of all the other people within a few miles of me when I go outside.

 

[Geoff]

I love my stellar gain cell dac but i don't use the dac, i use it as a preamp, it's very versatile and it serves me well

 

[dcollins]

What I don't understand is that you have to deliberately work to make something this bad with the average quality of the cheapest IC's and passives available today.

I believe this it what they mean when the unit is "voiced." Performance would be 100dB better otherwise,

 

[amirm]

I believe this it what they mean when the unit is "voiced." Performance would be 100dB better otherwise,

I think you are giving their hearing way too much credit.

 

[dcollins]

I think you are giving their hearing way too much credit.

Ha, these things are easy. Why let the D/A chip do it's datasheet performance? The desingers at PS audio

I think you are giving their hearing way too much credit.

I should have used my sarcasm font! What happens, as far as I can, tell goes like this:

Start with a cheap D/A chip (-106 spec)
Attach a lousy power supply
If the data sheet says “never use just a resistor for I/V” you use a resistor, etc.
Eschew any modern IC opamps, in favor of “Custom Class A circuitry"

Then comes the ‘voicing’ part, where you monkey around with the implementation, apparently going for whatever makes the most harmonics and noise.

Viola! You get nothing but great reviews in the audiophile press, until someone with no axe to grind and a an APx555 has a look then it’s spit-takes all round.

DC

 

[graz_lag]

...Viola! ...

DC

Voilà ... not Viola !!!