I recently purchased a PS Audio DMP transport and DirectStream DAC combo which I’m very happy with. I’m not a fan of the unresponsive and tacky looking touchscreens if I’m honest but that’s a small price to pay for the wonderful sound. I’ve noticed however that when I turn the touchscreens on (I have them dimmed by default) it is accompanied by a very low volume and very brief popping or pulsing sound, as if the little surge of energy to switch the displays on is somehow getting into the audio signal. Any ideas how it might be solved?
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Welcome @zenmonkey !
Do each of the components exhibit this behavior or only one of the two?
For example, if you leave the DMP’s screen on (or turn the unit off) does waking up the DSD’s screen result in the popping?
I’m not familiar with this happening with either the DSD or the DMP. Do you get the same quiet pop if you take the DSD in and out of mute?
The DAC certainly exhibits the issue as it happens when playing music from my TV or computer via USB with the DMP switched off. Whether the DMP also exhibits the issue, I cannot say, as the ‘pop’ occurs only when audio is playing and that requires the DAC. Is it possible to dim the units independently? When I press the remote control Dim and On buttons, the DMP and DAC simultaneously obey the command.
The popping does not occur when muting/unmuting, nor when undimming the units when no audio is playing. Furthermore the loudness of the popping mirrors the loudness of the audio. For example - let’s say the DAC volume is fixed at 50, undimming the units during loud passages of audio results in louder popping than if undimming (with the volume still at 50) during quiet passages of audio.
It’s all very strange. I’m wondering if maybe my passive magnetic pre amplifier (an MFA Baby Reference V2) is picking up something that actives miss? I suspect not, but later on I’ll connect the DAC directly to the power amp to see if the issue persists.
This is strange.
I do not recall anyone previously reporting this to be an issue.
I agree, it seems unlikely your passive preamp would be the cause, but it is worth checking.
I don’t know why this would change anything but do you have Windom on the DAC, the latest firmware?
The DAC is running the Windom firmware.
Plugging the DAC directly into the power amp didn’t resolve the issue, only flattened and hardened the sound, but I expected as much because, illogical though it seems, a very high quality pre amp sounds better than no pre amp.
Returning to the issue, I will simply leave the touchscreens switched on. It’s not a really a satisfactory cure but it does at least avoid the problem 
I’m curious if anything will change when the new firmware comes out. I don’t want to guarantee it, but it’s certainly possible.
Are your speakers extraordinarily efficient?
Not particularly, no. They’re ProAc Future Ones, sensitivity 87dB/W.
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I think we can rule out the speakers.
I get a tiny click/pulse through the speakers from my DS Sr when switching screen on via remote control, and also during DAC volume adjustments. I’ve just put it down to electrical activity related to the screen update that isn’t fully shielded internally. I always have the screen off during playback so it doesn’t really bother me.
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It’s not just my Directstream DAC then. As you allude to - it’s not a major problem, but it does rub a little sheen away and isn’t what one expects of a premium product. In my own system, the DMP & DS DAC replaced an Ayon CD-10 II Signature SACD player which in terms of style, design, operation and tactile joy is much superior and oozes sophistication. Of course the PS Audio combo is sonically superior and that matters most. We can’t have it all I suppose.