Digital Harshness

Hello, my first time posting here.

I’m using a Perfect Wave Transport (manufacturer refurbished) into a Nuwave DSD DAC. The PWT replaced a CDP as transport to this DAC. I’m using a Cardas cable thru the I2S connection. With this upgrade, I was expecting to hear smoother sonics that are closer to analogue. Instead, there is a harshness in the highs.

There is a dedicated line for digital. I don’t believe it is a ground-loop because I tried cheater-plugs on all devices and got the same result. Using a Blue Circle power conditioner, but results are the same with/without the conditioner.

I’m wondering if noise from the digital power supply is generated back to the mains and affecting sonics.
I’m using Purist Audio PowerChords, which are not shielded. Is it possible that I need shielded PCs on my digital devices?

Any advice is greatly appreciated.

Hello davinci75,

Thanks for reaching out to us about this.

Bright, harsh highs can be the result of many things.

We recommend first that you ensure that you PWT’s firmware is up to date.

As well we recommend for testing purposes to audition at least two other HDMI cables if possible.

If you still have issues please reach out to us at and we’ll be happy to take your PWT and NuWave in for inspection / repair.


  • Jeremy

Harshness is not typical of PSA products, of which I own several (although not a PWT).

Your unit is refurbished, and so may have sat unused for a long time. I would first follow Jeremy’s suggestion about firmware, then put a CD on Repeat for 25-50 hours (turn off the amp if you don’t want to listen). See if the sound has changed. If not, try different cables. I am confident you can get rid of the treble harshness.

Thanks for the comments. Let me provide some background; I received the PWT and auditioned 2 coax and 2 HDMI cables. I chose the Cardas HDMI over an Audioquest, then started some critical listening. I had been using the Nuwave DAC with an ARC CDP and the Nuwave was pretty decent. Using the PWT with I2S was superior to S/PDIF coax, and now my system was sounding very good.

After having the PWT for about 2 weeks, the transport failed. I contacted customer service, shipped the transport for repair, and it was returned to me in a matter of days…outstanding! I could tell that the entire transport mechanism had been replaced and upgraded due to the fact that the drawer didn’t wobble anymore and the CD-ROM drive sounded very different when a disk was loaded. In addition, I was told by the PSA rep that the software would be upgraded while at the factory.

So, that’s the backstory, and now the PWT/Nuwave DSD DAC combo doesn’t sound very good. Meanwhile, my $400 NAD CDP sounds smoother and more organic despite presenting some digital “edge.”

The PWT might need some play-in time, but perhaps the problem might be from the change in firmware. How can I tell which version is loaded in the unit? Any other thoughts as to what I might?

With this back story I think something went wrong with the repair. I suggest contacting PS Audio service. Your repaired unit should sound at least as good as it did before.

If you would like, you could try going back to older firmware and then updating again to the newest. I have attached an older version (1.22) and the current version (1.24). The firmware loaded on your PWT might be corrupt.

Please keep us updated.

Many thanks, Elk. I’ll buy a SD card reader tomorrow.

Hello All,

There have been some changes for the better.
Loaded firmware…. PWT-1.22, then 1.24 (1.23 was the version in my PWT). Also, all components are now using shielded stock PC’s into one power strip.

The PWT and DAC present black backgrounds, excellent low-end extension and separation of instruments. The “crunching effect” of the highs is gone, but there is still an overall digital sound to the system. Even my CDP has an “edge” to to it.

I’ve tried two different amps and swapped out my Gallos for speakers with a soft dome tweeter. HDMI and Coax sound very similar, with the Cardas HDMI sounding more full-bodied.

I’m thinking this could be a power issue; possibly the PWT is contaminating the AC. I once had a CDP with high gain that generated noise back to the mains. The harshness seems like some type of interference. BTW, I’m using a single-ended system; tube amp and preamp. Another thought, could there be DC voltage on the line, even though there is no transformer hum?

My last thought is I need a better DAC; perhaps the Nuwave DSD does not control jitter all that well.

You guys have been great. Any comments regarding power, digital noise, or RFI?

Did changing the firmware make any difference in the sound? - just curious.

I do not recall anyone finding the addition of the PWT added power line noise or created other issues. Have you tried listening to your CDP with the PWT disconnected and unplugged?

As the CDP also sounds edgy, my suspicion is the sound has nothing to do with the PWT and either something else has changed or, not uncommon, you have been carefully listening and have now noticed a weakness in your system.

It would be worth paying careful attention to cable dressing if you ave not already done so.

It my be you have a power issue with a great deal of noise on the line and a PowerPlant would help, but this is an expensive solution.

Do you have the ability to power a DirectStream or other excellent DAC to compare?

Hi Elk,

I believe that changing from PWT-1.23 did make a difference, I’m now using 1.24. But I also swapped out my Audience PowerChord (unshielded) for the stock PC. There was a noticeable collapse of the soundstage, but this was to test using a shielded cable.

As far as dirty power, I recently had an electrician upgrade my circuit box and add a subpanel with two 20A dedicated lines grounded to Hubbell receptacles with the addition of a 2nd grounding rod. Maybe I should call him to test the ground and for any DC voltage. Anyway, these new mains are super-quiet.

You’ve brought up a very valid point regarding critical listening and noticing a weakness in my system. As stated previously, Redbook sounds tonally correct providing a black background, but it is now very easy to hear the difference in sound quality of each CD. Female voices with acoustic instruments sound lovely, but Classical with close-miked strings and brass sounds etched. Old Led Zeppelin and the latest remasters both sound very good, but would benefit from changing the stock PC’s.

Have you tried listening to your CDP with the PWT disconnected and unplugged?

No, I haven’t, but you’ve given me an idea to try this and also use the CDP thru the Nuwave DAC. I don’t have access to a DirectStream DAC, but I may try to audition a good DAC from a dealer with a return policy. I tried the Schiit Grundir and preferred the Nuwave DSD (more organic and realistic low-end). I really like using the I2S connection, rather than coax where every cable has a different presentation and jitter becomes a concern.

Have you ever researched digital power cables that address the noise issue I’ve mentioned? I read about them on the Audiogon forums; JPS is well thought of…

Many thanks for your comments thus far, Jim.

Just a wild idea (I’ve never owned a PWD): but I’ve noticed that the digital filter settings that some prefer for lite jazz, a few performers, etc. don’t always do well for classical or some other more complicated performances. With classical, orchestral, big band, etc. I definitely prefer a sharper filter setting to keep down the aliasing which can definitely add some harshness.

Quick question regarding firmware updates. My system is not connected to the internet and I have both the ps audio pwt and pwd2. They are both at least 4 or 5 years old and the firmware has never been updated. If I update to the latest firmware this could possibly improve sound quality? I was under the impression that firmware updates were more for the touchscreen and other operations not involving sound quality. Thanks

Lovecountry, both the PWD and PWT are upgraded with SD memory cards. To do this go to the “Resources” tab at the top of the page and you will find out how to do it. The “Downloads” sub-tab has the two files, one for the PWD and one for the PWT. The “How To” sub tab has a video on how to do it, you will have to scroll down a little to find the one titled “How to Update Using an SD Card”.

Ted Smith said

Just a wild idea (I’ve never owned a PWD): but I’ve noticed that the digital filter settings that some prefer for lite jazz, a few performers, etc. don’t always do well for classical or some other more complicated performances. With classical, orchestral, big band, etc. I definitely prefer a sharper filter setting to keep down the aliasing which can definitely add some harshness.


Thanks for posting. I’m not using a PWD, it’s a PWT; the memory transport. My DAC is the Nuwave DSD and does not have any filter settings.

Duh, I didn’t read things carefully enough, sorry.


I have a couple of observations. I’ve been playing my CDP w/o the PWT IEC plugged in, and to my ears, it sounds fine for a budget unit. When the CDP is plugged into the same receptacle as the PWT and DAC, there is a bit of harshness in the mids and highs. Now this is not based on any scientific evidence, only my observation. It would be better to perform this exercise with an independent listener.

One thing I can say for sure is that the NAD CD sounds significantly better when run thru the Nuwave DAC via coax.

Now this is interesting, I found this info in the Nuwave DSD manual:

Once everything has been connected, use a high quality AC cable to power the NuWave DSD. DACs in particular are quite sensitive to AC power and produce a bit of line noise themselves. Make sure you have a high quality, shielded power cable to power the NuWave DSD, such as a PS Audio AC Series cable.
The power supply in the NuWave DSD takes the AC from the home’s wall outlet and converts it to DC, like battery voltage. Musical signals are then used to modulate the DC to feed your preamplifier or power amplifier. The quality of the DC power modulated by the musical signal is critical to the sonic success of the system.
Use of high quality power cables and appropriate power conditioning, like PS Audio’s AC regenerating Power Plants is essential for great sound.

This must be due to all the switching inside the DAC. The transport isn’t processing voltage in the same manner. It’s the DAC that can generate line noise. In any event, I will need to use some high quality shielded cables.

The problem in my system may still lie outside the digital devices. I have a Blue Circle passive conditioner which does a great job of cleaning the AC and produces a very low noise floor, but does not regenerate voltage into DC.


Recently I added a Synergistic Research PowerCell 12 UEF SE in my system. One of the benefits is no more digital harshness, glorious 3D, detailed, yet smooth organic sound. My favorite instrument is piano (I have a grand piano sitting right outside my music room), now the piano timbre and tone from my system is one step closer to the real thing. Adele’s Daydreamer could be nasty if your system is harsh, now is very listenable.

lovecountry said If I update to the latest firmware this could possibly improve sound quality?
I would not expect it to. Here I suggested changing firmware as the sound had changed and it was possible the installed firmware somehow became corrupt. Unless there is a specific reason not to do so, I tend to install the latest updates.
davinci75 said The problem in my system may still lie outside the digital devices.
It may be, but your is a frustrating situation.

I would like to upgrade to balanced power conditioning when funds allow. For the short term, I ordered an Emotiva line conditioner which eliminates DC offset, filters high-frequency line noise and can indicate improper grounding.

I’m also looking for a used DAC with FPGA.

Just wanted to say thanks for the help, some great members on this forum.

Quick update…I’m using a large gauge shielded PC on the DAC. I have all digital components into one dedicated line, amp & pre into the other, and there has been an improvement in SQ. Also changed some tubes, now it’s smoother with much less “digititis.” I still think I can do better than this DAC as far as jitter control.

I am delighted to learn there is progress.

Have a good weekend.