Is it possible to leave headphones plugged into DAC V1 and not mute speakers?

Posted by: Ian Brown on 04 March 2017

In my office system I am using my new Core with a Moon Audio 230 HAD which is fed into an old Sugden Optima integrated (I was using my old Nait 5 but have packed it away for now). I switch between headphones and speakers frequently.

i picked up a used DAC V1 yesterday to see how it compares to the Moon. Both are similar devices; half width, pre-amp, DAC, headphone amps.

One thing I really like about the Moon is the convenience of leaving my headphones plugged in while I listen through the speakers. I never have to unplug my phones - i simply adjust volume on either the Moon or the Sugden.

So far i haven't been able to figure out how to do that with the DAC V1. I have searched the forum withtout success.

Any help would be appreciated!

Posted on: 04 March 2017 by Brilliant

I believe when the headphones are plugged in the output amp is internally switched to drive the headphone circuit. There is some write up on this on the V1 web page.

Posted on: 06 March 2017 by Lejog

From Naim's description the headphone amp and the preamp are the same circuit operating at different output levels, so it is impossible to have both outputs active at one time..

"The single-ended Class-A headphone amplifier of the DAC-V1 cleverly uses the pre-amp output amplifier for headphone drive. The moment headphones are plugged in, the output current drive is automatically turned up five times to give dynamic drive for all headphone impedances."

The requirements for line outputs and headphone outputs are very different, line outputs require a very low current into a very high impedance while a headphone amplifier requires much higher currents into low to medium impedances. However it is possible to design a circuit which does both and they have been common in studio equipment for a long time, if less common in home hifi.