NOS DACs

I've tried it with its USB as well as with a Mutec MC-1.2 (not tried with the MC-3+USB). I haven't tried plugging in a wall wart, but I might try one. I believe the batteries will actually mitigate any real benefits that would be seen there, but I'm asking about that.

So far, the RCA coaxial input is pretty bad [UPDATE: Nope, it had to do with my work machine. It cannot be trusted. Info a few posts down.]. It drops out frequently, which is very weird because I've had a DIR9001 in multiple DACs and it has always been very reliable. Not getting the same issues with USB, so I'm not sure what is up.

 

Okay so I unplugged the USB and popped in an iFi 15V wall wart and it's not doing the dropout thing. Maybe it doesn't like having both inputs plugged in at once.

 

Yeah, not sure what's up with this. It sounds quite good, but sometimes it just starts shitting on itself a little bit and crackles, clicks, or drops out momentarily. It does seem to happen more often if the battery indicator is red than if it's yellow. But I have it plugged in right now and not playing anything and it's been red for a while. Maybe the batteries aren't charging properly?

 

My wife won't let me do a 3-way comparison.

 

Okay, I experimented with the DAC 3 a bit more. By that, I mean I uninstalled a crapload of old drivers from my work machine, then I noticed that some USB drivers were recently installed automatically. They had some BS "Turbo" function enabled. That, apparently, made all of my USB squirrely. I nuked that crap completely and I stopped getting the random crackles, dropouts, and snafus from the DAC 3.

 

A while back, I won the ebay auction for his nos battery dac (DAC 2 I guess), it sounded flat to me. I think the direct output from the dac isn't strong enough so there is some sound quality losses that I experienced. The Bifrost Uber that I had at the time sounded better so I returned the NOS battery dac

 

The output on the DAC 3 is definitely quiet compared to most DACs I've used. It leans heavily on the amp to make up for it.

 

Hi, I am currently learning all I can about NOS DACs as I am considering purchasing one. Am I reading this thread correctly that 44.1 sample rate music could sound a little thin on a NOS DAC? That is probably a huge generlisation but all my music is 16bit / 44.1 and I am interested in a NOS DAC for the realistic tone and weight to voices but do not really want to have to use a software upsampler to feed the DAC.

Cheers.

 

Not thin, but the top end gets slightly rolled off. If you get a tube DAC, you can punch that back up a little.

 

Thank you for the input. @Luckbad and @Hands . That is very kind of you.

My budget is not limitless so I am researching into the new Audio-gd NOS 19, or may go a different route entirely and get the Bitfrost multibit instead of a NOS.

Cheers.

 

Bit of a thread resurrection. A conversation I had yesterday with @Kattefjaes and @Muse Wanderer reminded me about something I tried with my Metrum Hex a few weeks back.

In order to see what the high frequency issues are with a NOS dac, I figured I'd send some hf tones to the Hex to see what it did. I first tried a 15KHz tone,which reproduces just fine via my sabre dac. With the Hex, however, I could hear a faint 15KHz tone, but a much louder 2 - 3KHz tone (approximately, measured with my smartphone). Similar results with other hf tones, just that the "ghost" tone changed in pitch.

When I tried feeding the Hex the same tones, but upsampling to 176 using HQPlayer (which is how I usually feed the Hex), all the hf tones sounded correct, with no ghost distortion tones.

Is this normal for a NOS dac, this level of hf distortion?

 

I recall it being mentioned to me a couple of times that all NOS DACs have a treble roll-off, and that it's normal.

Now there are two points to consider: How many fundamentals are out there anywhere near 15 kHz? Highest fundamental I'm aware of is at ~8 kHz tones. So at 15 kHz are we dealing with full-blast fundamentals, or barely audible nth order harmonics...
The other point is which sample speed you use to begin with. If it's 44.1 kHz, then yeah I can see problems arising at 15 kHz related to aliasing distortion. But if we're feeding 96 kHz sampling speeds, then 15 kHz tone should exhibit no issues (in theory, and depending on implementation details like brickwall filter, etc.)

 

Thanks. If I understand you correctly then, the 2 - 3 kHz "ghost" tone (as I'm calling it)...this is a result of aliasing distortion...and this isn't present with, for example, with 96kHz feed because these distortions are pushed up into the inaudible range? If this is the case, I didn't realise the aliasing distortion could manifest so far down into the frequency range. I presumed it would only affect the highest audible frequencies (say, 10+ kHz).

 

I wonder about filter ringing issues. If you give it a bitstream at a much higher sample rate, the filter will be at a much higher frequency (I think), which would hopefully take it out of the audible band- you could have a total brick wall filter with no issues. Having thought about it on the way home, this sounds a lot more like what's happening..