Clock Me All Night Long

In an all-digital production room, it’s important to have a single master word clock feeding all connected digital devices. Otherwise you’ll likely get clicks and pops, even when all devices run at the same sampling frequency. This is due to the fact that the digital audio data packets are being sent from one device in sync with its clock, and they are being received by another device in sync with its own clock. The exact timing of these send and receive cycles has to line up properly, or the occasional packet will be lost or delayed. This will cause clicks and pops in the audio, and is definitely Not A Good Thing. One digital device must act as master clock, and the other devices should act as slaves to the master. Alternatively, you can use a dedicated word clock generator and set all the digital devices to slave to that.

That’s why the optional sync module on the DN-C680 is a nice addition. After setting the SYNC preset to WORD, I was able to feed word clock from my Aardsync II digital word clock generator into the word clock input of the DN-C680 player, and feed its AES/EBU output to a digital input on my Yamaha 02R console that is also connected to the Aardsync. WORD SYNC lit up in the display, and there were no clicks, no pops, just good sound.

I also tested the video sync input in a similar fashion, using a Horita color sync generator. With the SYNC preset to VIDEO and the DN-C680 playing, turning the Horita box on caused the player to slow down and then come back to speed as it synchronized itself to the incoming video black signal. By the time VIDEO SYNC showed in the display, the player was fully up to speed.

My evaluation unit also came with a built in sample rate converter, which allows the DN-C680 to output digital audio at 48 and 32 kHz sampling frequencies. There is no change in speed when using this feature, as the sample rate converter does the work of changing the normal CD 44.1 kHz signal to the desired rate. I recorded music both at 44.1 and at 48 kHz and compared them. There was no audible difference in the two recordings, which tells me that this is a high quality sample rate converter.

Finalize This

The DN-C680’s ability to play CDRs that have not been finalized is especially handy. Normal CD players don’t recognize unfinalized CDRs, since the CD-burning process saves writing the Table of Contents for the very last step, and normal CD players won’t read a disc with no TOC. Being able to play unfinalized CDRs from a device other than my CD burner is hot.

The Denon DNC680 sounds great, has a ton of cool editing features, and connects to everything. What’s not to like? If you’re in the market for a pro CD player, you need to check this on out for yourself.

The Denon DN-C680 Professional CD Player has a suggested list price of $900, excluding the time code and sample rate conversion options. For more information in the US, contact Denon Electronics at (973) 396-0810. For more information worldwide, visit


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