[sdk]

I'm considering getting one of the new filterless and non-oversampling DACs from either Scott Nixon ( www.scott-nixon.com ) or Ack Industries ( www.ack-industries.com ).

My system consists of a Bent NOH passive preamp, Art Audio Carissa SET tube amp, and Reference 3A Royal Virtuoso speakers.

The amp has an input impedance of 180k Ohms and an input sensitivity of 600 mA.

Given the specs of each DAC (listed below), which DAC do you think might be a better match for my system? Or are both of these not really optimal for use with the NOH? Any comments are greatly appreciated.

Ack DAC specs:

Output impedance: <100 ohms
Signal amplitude:  2V peak-to-peak for 1KHz 0dB signal  
The manufacturer states that "downstream component should have >10K ohm input impedance"

Scott Nixon DAC specs:

Output impedance: ~100 ohms
Output voltage: 1.75V

[John Chapman]

Hello!

Given enough gain in your system they's both be just fine. I have heard the ACK at a local friends place with a NOH and it worked out fine - but none to much gain. His system has some pass amps and dunlavy speakers and so not high efficiency really. With +6 Db he'd just make it for level with quiet disks.  Most disks would be just fine.

The Scott Nixon has a slightly higher output level (assuming the 1.75 is RMS - usual units for level) but not all that much so if one is just fine for gain likely the other would be as well.  

Both have low output impedances so the only thing we'd need to check is gain. What level is the NOH at now for loud listenning and what is the source you use now - that'll kinda tell us where you are for gain.

Thansk!

John



Many Thansk!

John

[sdk]

John,

I'm currently using a Sony SACD player with a 2 volt max output. Most of my listening is done between the 10 and 12 o'clock positions on the volume knob. There are few CDs (Rob Wasserman's Duets) that I have turn it up to 3 o'clock.

I'm a bit confused by one of the things you said. So the Nixon DAC with an output of 1.75 is greater than the ACK with a 2 volt output? I'm not sure if RMS is a different measurement than a max voltage?

So which DAC has more gain?

Thanks,

Steve

[sdk]

John,

I'm currently using a Sony SACD player with a 2 volt max output. Most of my listening is done between the 10 and 12 o'clock positions on the volume knob. There are few CDs (Rob Wasserman's Duets) that I have turn it up to 3 o'clock.

I'm a bit confused by one of the things you said. So the Nixon DAC with an output of 1.75 is greater than the ACK with a 2 volt output? I'm not sure if RMS is a different measurement than a max voltage?

So which DAC has more output?

Thanks,

Steve

[John Chapman]

Hello!

RMS voltage is kinda like an average of the waveform and peak is the top so the 1.75 RMS is higher than 2V peak. Here is the  first  page I stumbled onto:

http://ourworld.compuserve.com/homepages/g_knott/elect39.htm


 It is not a HUGE difference in terms of loudness but it is there so if your system was running out of gain it could make the difference. The 1.75 RMS is close to the 2V of the sony - maybe 1 step higher with the Nixon to get to the level of the sony . The ACK is like 0.7V RMS so you'll likely need to turn the ACK 4  steps up to get the same level you have now. This should give you a good test to see when the levels would be.

Let me know if any other questions come up and how you make out when you try one of them!

Thansk!

John