NuForce CDP-8 CD player Manufacturers' Comment

Manufacturers' Comment

Editor: Thank you for taking the time to review our CDP-8 CD player. We are humbled by Wes Phillips' very positive response to the CDP-8, and by the company he chose to compare it with. Both Benchmark and Ayre Acoustics are companies we really respect.

We are also embarrassed and chagrined by the poor jitter measurement. We had felt that the basics of performance were addressed by design, and have been applying our effort at listening and making decisions based on listening. Like Wes, we had not noticed any significant degradation in the sound, so we had no reason to look for jitter issues. The measurement was a surprise to us. However, we have recently made a small change to reduce EMI-RFI radiation that also seems to have effectively eliminated the jitter. We have attached plots we have made showing before (with the same jitter) and after (with very little jitter). The change is a small one, and we will be happy to install it in units returned to us. We will also provide a corrected unit for you to evaluate.

Much more interesting is the apparent low impact of the 124Hz jitter on the sonic performance. There have been other reports that low-frequency jitter is less audible, and this may be another example of that. However, since it is an identified possible issue, we have addressed it; it is not present in current production.— Jason Lim, NuForce

NuForce, Inc.
382 S. Abbott Avenue
Milpatis, CA 95035
(408) 890-6840

TakisJK's picture

... (Normally, a CD player constantly varies its speed, from 200rpm at the innermost data spiral to 500rpm at the outermost data spiral, in order to provide the DAC with a steady datastream.)...

I think this is wrong. The truth is exactly the opposite.

The first track on a cd is in the inner spiral and the last one in the outermost, so the cd spins at higher rpm on the 1st track and reduces speed as the time elapses and the laser moves away from the center.
The angular velocity is going down so that the linear velocity remains constant (at any point on the disc the laser reads, any given moment)

John Atkinson's picture
Yes, you are right TakisJK. I will amend the text accordingly. - JA
dcolak's picture

@John Atkinson: WP liked it so much because it was 2.2dB louder.

It's an old trick.