DS Mute Function


#1

I confirmed yesterday that the DS mute function does not mute the analog outputs. It cuts off the digital signal to the output stage, but the analog outputs remain active.

If you have the DS connected directly to your amp as I do, I recommend that you put the DS into standby before you power down your amp.

Note: If this information has already been covered, please delete the topic.


#2

Are you sure about this?

Mine seem to work…


#3

Dan is definitely correct. Listen for the click of the mute relays to know that the outputs are shorted when you go into standby or power off.

The software mute (the result of the mute button) should be quite good, but there’s still low level ultrasonic noise. Most people won’t notice a difference but it’s there.


#4

Ok, my bad - I misinterpreted this to be the mute button on the Remote.


#5

My audio chain is DSD > preamp > power amp.

I always thought that the correct power down sequence was:

(1) power amp

(2) preamp

(3) DSD (ON to standby)

Is this not correct?


#6

With a preamp in the chain, you’re fine with that sequence.

The DS mute function is a problem when it’s connected directly to a power amp.


#7
dan said

The DS mute function is a problem when it’s connected directly to a power amp.


What problem might I expect to have?

#8

My DS is connected to a ARC REF 75, if I power it down with the DS in its mute mode the reproduced noise is a concern, which is why I called customer support.

I really don’t understand why there’s no mention of this issue in the DS owners manual.


#9

I know someone who blew the tweeters on his Magico speakers because of ultrasonic noise.

He didn’t have a DSD, though.


#10

That’s not even remotely close to what this tiny noise is. There’s no chance of it hurting anything.


#11

Is not this low level ultrasonic noise present at all times the DS is operating in any event?

As a separate observation, any source component which can accurately reproduce 192/24, for example, must produce ultrasonic frequencies by definition. These high frequencies are going to be there on the output if a recording being played is true high-resolution.

In any event most amps, including the very nice Audio Research Reference 75, roll of their bandwidth within an octave of the highest possible frequencies output by high-resolution PCM.


#12

The noise is only a problem when I power down my amp without putting the DS into standby. If I just mute the DS and power down my amp, weird noises come out of my speakers.

I never heard noise like this with any other DAC with a volume control/mute function directly connected to my amp.


#13

Dan, is this problem why you are selling the DS? It might be something that can be resolved with some investigation by PS Audio. Have they not been able to help?


#14

If someone has an amp that modulates a signal like than when it’s powered off (which could be simply a side effect of an input overload protection device on the amp) then they should hit the OFF button on the DS remote instead of the MUTE button before powering the amp off. If we changed the behavior then there’d be pops and relay clicks every time someone muted or unmuted. (I presume the noise he is talking about doesn’t happen when his amps are powered on.)


#15
tony22 said Dan, is this problem why you are selling the DS? It might be something that can be resolved with some investigation by PS Audio. Have they not been able to help?
I already talked to customer support and their recommendation to put the DS into standby solves the power down noise issue. I was also told there are currently no plans to change the way the DS mute function works.

I’m selling the DS because I have another DAC that sounds better in my system.


#16

Well, this will raise some interest by more than just me, I imagine. Which DAC did you settle on?


#17
dan said If I just mute the DS and power down my amp, weird noises come out of my speakers.
Very quirky. It would be interesting to know if any other amp does this.

#18

Just speculation: You can imagine an amp that clamps it’s input between, say, a negative rail and a positive rail with protection diodes to keep downstream things from overloading with bogus inputs. When the power’s off those clamps would be much closer together and would be clamping the tips of much smaller signals to approximately GND. That clamping action is nonlinear and just like a crystal radio the diode can modulate higher frequencies that exceed the lower clamping threshold into the audio band. Not that it’s directly related but my neighbor has a stereo, that even when it’s off, the speakers buzz when someone walks by with a cell phone.


#19

Your scenario certainly makes sense as a possibility.

Diodes are one of my favorite components; they allow voltage to go only one direction, except when they don’t. Avalanche diodes are particularly neat (and noisy in operation).


#20

The only thing I find “quirky” is that PS Audio calls this function on the DS a mute, when it does nothing to the output stage.

Does the mute function on any other piece of audio gear on the planet function this way?

Why don’t you try connecting your DS directly to your amp and power it down with the DS “muted,” and tell us what you hear.:wink: