NAD PP-3 Noise

[meeder]

I bought a NAD PP-3 a while ago and was a little dissapointed by the fact that it had quite a lot of noise and upon viewing the noise profile I could see that there was a strange peak every 1000Hz and a smaller one every 500Hz. The overall noise level was at around -90dB.

I contacted NAD and they told me that the problem was known and that I could send in my PP-3. I received a new PP-3 and the strange noise profile is completely gone. The overall noise level is at -108dB which is allso a lot lower then the old unit.

So if there is anyone with a PP-3 which has a slight high frequency noise you can contact NAD.

[Paul Sanders (AlpineSoft)]

Yes, a few of the early models did suffer from this problem.  NAD's policy is to replace faulty units but I don't think there are many of them out there now.

[Hans]

Hi,
I just purchased a NAD PP-3 with a copy of Vinylstudio in order to convert my vinyl to digital. I use the USB connection to the PC - and the analog line-out connected to a receiver for simultaneous playback. I experience this high pitched noise, but only when I'm recording: When I use the NAD PP-3 to play records (not having connected the PC), the sound is fine. Similarly, the noise is only present when I click on record or check level etc. in Vinylstudio - not if the is PC connected (USB) without recording. The noise is present in the digital file as well as heard through the line-out connected to external amplifier/receiver. Assuming that there might be a feedback loop or something, I have tried to disconnect the line out (connected to the amplifier/receiver) and only have the PP-3 connected to the PC - but this doesn't remove the noise - even when i uncheck the "monitor volume" and do a completely silent recording the noise is still there in the digital version created. BTW: I have an MM cartridge connected accordingly.
Is this the problem you're referring to above as a known issue NAD might deal with, or does it relate to a different problem (since the noise is not present when not recording)?
Also, as far as I understand, using the USB connection, I bypass the soundcard on my laptop, is that correct? So a poor soundcard would have nothing to do with this?
In your helpfile (or somewhere else) you mention that 48kHz sampling accommodates USB - does that mean there's some sort of problem using 44.1 kHz sampling using the USB connection?
Looking forward to your reply - Thanks a lot!

[Paul Sanders (AlpineSoft)]

Hi,

It sounds like a faulty PP-3 to me, but first I would try a different USB cable just in case it's some kind of shielding problem.  If that doesn't work, contact your NAD dealer.  The problem, as I understand it, is that signals on the USB bus interfere with the sensitive analog circuitry inside the PP-3.  That's why you only hear it when recording (or monitoring) as the USB bus is inactive at other times.  Later PP-3's (from the second batch onward) have a redesigned circuit board which eliminates the problem.

Recording at 44.1 kHz is fine, and is what we recommend if you are going to burn audio CD's as this avoids the need to resample the audio in software at burn time.  VinylStudio does use a good quality sampling algorithm however, so if you want to record at 48 kHz for some other reason, that's fine too.

Would you mind emailing me via our website so that I can contact you direct (http://www.alpinesoft.co.uk/contact_us.aspx)?  I'd like to request a sound sample from you so that I can hear the interference for myself.  Thanks.

Sorry, forgot to mention: yes, your soundcard is bypassed on the recording side when using the PP-3, although it will still be being used for output.

[whatsohm]

With respect to this NAD PP-3 thread, I am having the exact same problem with a Maplin pre-amp. Again as above, the line out from pre-amp to the amplifier plays/sounds fine but when line out from pre-amp to iMac - and recording only - I too experience click noises in the high end.
I sample at 24bit @ 48KHz when recording and the noises are intermittent, but when started usually remain constant.
Thinking it was a connection issue, I replaced my cable, but the noises still come through. I then thought it's maybe the software filters but again same result. Until I read this thread I was about to buy another pre-amp.
Did you get results from your customers samples? I would gladly send you on samples if this would help. The below is my setup. Thanks in advance. I don't want to go back to Audacity 

VinylStudio 8.6.2
iMac late 2010
OSX 10.9
Maplin pre-amp
RCA to audio (headphone port)

[Paul Sanders (AlpineSoft)]

Hi,

Yes we did, and it was a high-frequency whine picked up from the USB, which doesn't sound like the sample problem you're having.

Can you make a test recording with Audacity please, to see if we can establish if it's a hardware issue?  We don't know of any problems in our own code, and it hasn't changed in the latest release.  Thanks.

[whatsohm]

Hi Paul, I have done a sample using Audacity as suggested. Where will I send? Thank you for your quick reply.

[Paul Sanders (AlpineSoft)]

Hi,

I wanted to now if it shows the same fault.  Does it?

[whatsohm]

Yes, it sounds like it. I don't know enough about waves to see a difference - except in ampliude, but yes, it is audibly different. This is reason I responded to this thread. The symptoms seemed very similar, albeit from different hardware. After I responded to the thread I listened to 2 sides on "sound level" only, without recording and didn't detect anything.

[Paul Sanders (AlpineSoft)]

OK, can you send me two samples then please, one from Audacity and one from VinylStudio.  If you record to Ogg format, that will keep the file sizes down.  They don't need to be very long, perhaps a minute each, and you can send them to the address you emailed me on.  I'll then post any insights I have back here.  Thanks.

[Paul Sanders (AlpineSoft)]

I got the sound samples, thank you.  You're right, there are clicks on the VinylStudio recording.  I don't think this can be a bug in our code per-se or we would know about it by now, but there may be some difference in the way we set up the device (we do try to set a larger buffer size to minimise the chance of dropouts, perhaps that's upsetting it).

Would you mind trying with VinylStudio V8.5.4, just for safety's sake?  I believe it will behave in the same way as V8.6, but it has been in the field a lot longer and I'd like to be sure.  We did in fact make a minor change in a possibly related area, but I don't actually believe it's relevant.  I just want to be certain.

You can install VinylStudio V8.5.4 from here:

http://www.alpinesoft.co.uk/VinylStudio/backups/V8_5_4/VinylStudio-Installer.dmg

Drag your your existing copy of VinylStudio from Applications to the Trash before installing.  And you can always update again afterwards to get back to the latest version.

Many thanks for your help.

[whatsohm]

I installed the previous version, 8.5.4, as you recommended and have just finished recording 2 sides – one of which had the noises – and I am happy with the results.
With respect to the buffer etc, I think you could be right. The processor and memory of the Mac would have been doing other things – not as intensive as RIPping though. So to conclude, it seems the generation was probably a signal from my Mac. Before I recorded again, as above, my Mac was just restarted and no other apps were running, prior to the installation of v8.5.4.
Do you think the noise/interference could be caused by anything else asides a memory/buffer issue?

Meanwhile, thanks very much for your time and efforts and will keep in touch if anything else comes up otherwise, "no news is good news"

[Paul Sanders (AlpineSoft)]

Hi,

Thanks for this.  It's peculiar as we haven't changed the relevant area of the code at all, but I'm glad you're up and running.  Please let me know if the problem recurs.