Anti-aliasing or anti-imaging (reconstruction) filter? I suspect you mean the latter.
/pedant
/pedant
My measurements show "high" because of the length of cable and connectors used in my setup. Classic way is to measure it right at the terminal with no wires which is what the above is. I can do that but it is not realistic relative to what people do (i.e. wear headphones with wires).I noticed one interesting thing, Amir measurement show the amp have 1.9 ohm impedance while the Russisn site shows 0.1 ohm and then rise to 0.5 ohm at 20 KHz but this is probably becose of the 19 KHz low pass filter.
I think it is becose Amir powered it only through USB and didnt use powerbrick. Maybe with powersupply connected it will have 0.1 ohm output impedance?
It is weak. I like to see 100 milliwatts at 300 ohm and S2 only outputs 10% of that.Weak? It will drive HD800 to 108db, thats not weak in my opinion.
Anti-aliasing or anti-imaging (reconstruction) filter? I suspect you mean the latter.
/pedant
My measurements show "high" because of the length of cable and connectors used in my setup. Classic way is to measure it right at the terminal with no wires which is what the above is. I can do that but it is not realistic relative to what people do (i.e. wear headphones with wires).
It is not just the cables but the connectors. They can fit loose or tight and as a result easily add or subtract few tenth of ohms. 1/4 inch versus 3.5mm makes a difference too.But you measured other amps that show sub ohm impedance. If this S2 is really 0.1 ohm and your cable adds 1.8 ohm, then you must used different shorter/lower resistance cable to get those 0.4 ohm results that Burson Play got.
Surprised this is not listed with the other DAC in the SINAD comparison chart
Someone has offered one for second review....
Hello,
To be recommended in "Stereophile" is really good?
I think not always ...
I'm thinking about grabbing the S2 an feeding it from my CCA (needed for wi-fi Roon receiver). Would that combination work or do I need something else as a "front-end" wifi receiver to feed the S2?
Fig.19 Pro-Ject Pre Box S2 Digital, Optimal Transient filter, HF intermodulation spectrum, DC–30kHz, 19+20kHz at –3dBFS into 100k ohms, 44.1kHz data (left channel blue, right red; linear frequency scale).
...I was pleasantly surprised by the Pro-Ject Pre Box S2 Digital. This tiny, inexpensive box offers almost state-of-the-art measured digital performance. I note that KM didn't say definitively which of the eight reconstruction filters he preferred, mainly using the Optimal Transient filter. However, I suspect from the measurements that the Hybrid filter offers the best balance between time-domain and frequency-domain performance.—John Atkinson