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Filter tweak for digital backwash?

As my system improves, it’s easier to hear anomalies. The search is now on for a tweak to filter only digital backwash in my AC. The culprit is the regulated transformer power supply (120vac/19vdc converter) to the dedicated laptop for streaming.

The balanced power conditioner has separate outlets for analog and digital. The digital outlets already have built-in filtration for backwash. They work well. But, I need even more. When the laptop is running on its internal battery, the music is very smooth. Unfortunately, the battery life is short. When the laptop is running on the power supply, there’s a slight stridency. When the power supply is plugged in anywhere else, there is huge stridency. So, I’m looking for some gizmo to clean up the digital backwash in-between the conditioner digital outlet and the power cord to the regulated power supply.

I’m not looking for an overall line purifier. The balanced power conditioner does a pretty good job already. Any suggestions?


steakster
georgehifi's avatar
georgehifi
4,966 posts
 
I thought it was pretty easy to deal with noise injection(?)
It was 10 years ago, we had relatively low levels of noise to deal with. Today now we have designers making new things, like Class-D, Delta Sigma converters and SMP(S) (sorry Bob), that introduce even more complex noise structures and with much higher output of those noises, now these have to be dealt with as well. Without effecting the core body of the fundamental that we hope should not change "the music and it’s harmonic structure".

Cheers George
cleeds
2,065 posts
 
randy-11
Why aren't the engineers designing expensive audio gear dealing with these problems?

I thought it was pretty easy to deal with noise ...
I think working to reduce noise is a very tricky business, and I agree with georgelofi that there are more sources of complex noise than ever before. The problem is also compounded by the endless combinations of equipment that can be used with any given component.
steakster OP
720 posts
 
Thx all for the excellent suggestions. I’ll update when I implement a ’fix’.

In the meantime, I’ve been swapping wire on a different linear ps (120vac/12vdc) that goes to my Empirical Audio Off-Ramp. From Ebay’s Tajacob’s - Jake’s Old Western Electric stuff, I’ve been sampling a variety of vintage WE 20 gauge wire - solid core tinned w/paper insulation, solid core un-tinned w/plastic insulation, solid core tinned with cloth insulation, etc. They each affect the sound considerably differently - sometimes, significantly. Crazy-making. Maybe taking up golf would be a good alternative.
randy-11
1,913 posts
 
When I see engineers post on various forums, they usually say it is trivial to design noise rejection into a circuit...

Dunno myself.

I'm sure there are more sources of complex noise than ever before but they are usually RF and often in the GHz range so should be even easier to filter out than other "historical" noise.

OTOH, I did see a recent white paper from Intel on USB-C showing significant noise down to DC.


steakster OP
720 posts
 
Update: @shadorne Your suggestion worked - of putting a filter in the DC leg between the laptop and its power supply. I installed an ICT PCM-12 ADL, which is used for automotive electrical. Now, both the AC & DC legs are filtered. The laptop power supply is still plugged into the AC digital outlet of my balanced power conditioner. I like this filter so much, I’m going to get another one for the 12vdc power supply to my digital re-clocker. ICT has two versions: a PCM-12 ADL for 1-100vdc. and a SPM-12ADL for 0-17vdc.

My system has been fairly resolving for a while - now it's more so. It’s interesting to observe that digital noise offers the perception of ‘body’ to the music. When the noise is stripped away, the music can sound a bit ‘lean’. Then comes the challenge of adding weight back to it again - sans noise.


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