[ozhead]

Hello, I need to connect a power amp (http://www.nhthifi.com/ServiceCenter/Power-2) to my computer (Mac) via USB DAC. 
 
I have seen several kinds of DACs
 
- with headphone out & volume regulator
- with headphone and line out & volume regulator for both
 
Can I use both kind of outputs or it should be line out to connect to power amp?
 
Thank you!

 

[PleasantSounds]

Line out is preferred as the signal it outputs is in the range expected by the amp input, while the headphone out voltage may far exceed the amp input tolerance if the volume is set too high. But in principle both should work equally well, it you're careful with the volume knob.
 
A better option would be a DAC that does not change the volume on the line out - that way you always have strong signal and control the volume on the power amp only.

 

[ProtegeManiac]

Quote:

A better option would be a DAC that does not change the volume on the line out - that way you always have strong signal and control the volume on the power amp only.

 
He can't if its a poweramp that doesn't even have a gain knob. An integrated amp will best use a fixed lineout; that NHT amp I assume is a pure poweramp without a gain knob (as I can't see any mention of it in the page), and with a traditional set-up even a passive preamp should be between that and a source.
 
A word of caution though - don't jump blindly into getting a DAC-headphone amp with a stepped attenuator, since you can't predict how differently it will behave using its own headphone amp on your cans and with the poweramp on your speakers. If you can, try one both in your listening room and with the headphones.

 

[ozhead]

The power amp does not have a gain control. 
 
Based on what you are saying the best options are:
 
- DAC with gain control on line out
- DAC and add a passive gain control
 
In theory both options should be equal, correct?

 

[ProtegeManiac]

Quote:

The power amp does not have a gain control. 
 
Based on what you are saying the best options are:
 
- DAC with gain control on line out
- DAC and add a passive gain control
 
In theory both options should be equal, correct?

 
Yes, but do take note the cheapest passive gain/volume control I know of is the NHT, unless you can DIY it (but even the Pass-Aleph DIY version might cost nearly as much as, if not more, than the NHT if you have to pay someone else to make it). Also, there are many one-box DAC with headphone amps that has line level output signal straight from the DAC or through the preamp, so this one might be simpler. Just a few examples:
 
1) AudioGD NFB 11, NFB 12 and NFB 15 (11 has a manual switch for preamp and headphone output)
2) NuForce HDP (tried it with an HD600 and some Plinius power amp on Polk RTi8's - liked it better with the latter as it had some bloat and upper bass distortion on the headphones)
3) M1 HPA (USB in only - no SPDIF, but with preamp option) ; I think the older X-Can V8 has similar features too
 
But like I said don't blindly jump for the ones with stepped attenuators - like the Burson HA160D - unless you can try them with both headphones and speakers.

 

 

[ozhead]

Thank you all for the help.
 
I will stick with my old and not so trusted (due to the age of it, not sure how good the capacitors are & the input selector is shot, makes all kinds of noise when touched) Yamaha C-4 preamp. I either fix it or replace it with a passive attenuator.