PWT reads CDs that other optical drives do not

Most of my listening is via LAN streaming to the DirectStream DAC but I continue to buy many legacy CDs partly to access rare or discontinued material but also to provide a backup for albums in my NAS music library. I play the CDs via the PWT before ripping them to the library. I’ve recently had a couple of cases where a CD plays perfectly via the PWT but does not rip completely or rips with errors when it is read by a computer optical drive. We have 2 iMac systems with Apple optical drives, in one case internal the other an external superdrive. The former is little used and the latter is the 2nd replacement following failures to read DVD-RW discs (no problems with CDs), whereas my PWT is 11 years old and works perfectly. I’ve tried ripping using iTunes, XLD and Max software - all produced the same errors.

Given the excellent performance of the PWT drive (scratch tolerance etc etc) I’d welcome advice and recommendations for an external optical drive that could match this performance.

I’m aware that the PWT uses buffering when reading discs and makes multiple read attempts but I assumed that the hardware-software combinations I’ve tried should be able to achieve similar performance.

This is my first guess for why the PWT seems to have no problem reading them. I don’t know if it’d help but you could try one of the discs that cleans the drive? You mentioned they’re quite new, so maybe this wouldn’t be helpful.

Could simply be that the PWT is correcting for the errors (I.e. masking them) as CD players are designed to do, but the comp drives are trying to grab bit perfect and can’t.
Are these second hand CDs by any chance?

“Are these second hand CDs by any chance?”

Yes and no: the recent 2 examples were (1) I bought new in 1990 and (2) second hand.

So to re-phrase my question then. Is it possible to get a USB connected external CD reader that corrects for errors?

All drives will (I believe) attempt to correct the errors.
The player that plays them fine will likely also be hitting the same errors, but it’s audio error masking will be hiding it as best it can.
Also worth pointing out as Jamesh alludes to - that one drive might have a cleaner lens than another…

I have exactly the same happen - with old CDs bought new and second hand ones more often.

I always use the the software from dbPoweramp (yes, strange name…) which reads many times if needed an also uses a checksum from a public database to verify the result. Has never failed to do its job even with the very simple and cheap reader in a computer of some kind.


I use EZ CD Audio Converter Pro ($39.99 on Microsoft Store). It gives me better control over error correction, loudness, album data search, and even album art search and embedding into files. It solved issues with some CDs ripped on Unit Core & Uniti Serve. It does much more than what I want it to do though, like converting DSD to Flac or Wav etc.

Another vote for dbPoweramp. I have been using it for about a year and it is very useful. You can also use it with HDCD discs, so they are ripped properly.

The PWT does not use conventional error correction like other drives. It re reads until it gets it right. Everything gets stored in a buffer and than output to the DAC.


If you happen to have a CD with one annoying bad track, for example, dbPoweramp will fix it since it uses AccurateRip. They say that: ”AccurateRip™ furthers Audio CD ripping by verifying ripped tracks against an Internet database, making sure they are error free.” So thousand of other rips of the same album based on a better quality CD than your own one, will attribute to the bit perfect result of your rip. That has sometimes saved my day.

But ripping to file for later playing, and using the CD in a player are two different use cases. Should not really be compared.

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I often play CDs via a USB CDR drive attached to my Auralic Altair G1 - while playing it rips it in FLAC to the internal SSD. The Altair will try multiple times to read a CD, just like any ripping software. In fact, AFAIK, it buffers it to a FLAC file even if not ripping to SSD. There are a few CDs that I know play perfectly well in my PWT that just don’t work in the USB CDR drive - I wondered if there’s some copy protection in the CDR, or maybe the Altair ripping software is more sensitive to scratched CDs than the PWT. I am creating a little stack of problematic CDs that I will use dBPoweramp to rip when I move the USB CDR back to the home PC. I will know then if its the CDR or the software.

Thanks to all responders to my original post. All very helpful.
I’m currently investigating the hardware aspect. So far my problem CDs not only play faultlessly on the PWT but also on a Panasonic DVD recorder and a Pioneer Blue Ray player. Thus looks like the problem lies with the Apple Superdrive and internal optical drive. More detail to follow…

I have been ripping cds with my computer for many years now. I have always had two drives in my computer. In the old days one was always a Plextor. And the other a Pioneer or ASUS. Usually one was a CD drive and the other a DVD drive. I use dBpoweramp always. If one drive has trouble reading a disc it was not unusual that the other drive would work. Now that I have Blu-ray drives I have better luck than with older drives.

Clean the disc’s and use good software.

I have used my PWT so little that I don’t have an opinion other than my belief that they use high quality computer drives.

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