Well it was inevitable really, after finally getting my hands on a Creek CD60 I'm now keen to see how good it can be after some upgrading. The Creek CD60 was a high end player from the early 90's. It features a Philips CDM 4/14 swing arm laser mechanism and a TDA1541A S1 (single crown) DAC chip. Like many players with the TDA1541 it also has the accompanying SAA7220 digital filter chip. The SAA7220 has dual role within the player. Firstly it performs the 4x oversampling and subsequent filtering of the digital data and secondly it also acts as the clock distribution device. Unfortunately the SAA7220 is a very noisy chip and injects a lot of noise (jitter) into the clock signal which it feeds to the other devices. Carrying out a NOS conversion and removing or bypassing the SAA7220 is therefore a relatively simple way of eliminating the problems associated with the noisy SAA7220 chip. A excellent explanation of the benefits of a NOS conversion can be seen here: [URL]http://www.net-audio.co.uk/tda1541nos.html[/URL] Those of you who are familiar with this forum may have already seen my thread about upgrading an Arcam Alpha 5. A key move in the modification of my Alpha 5 was the conversion of the player to a non-oversampling mode by fitting a NET Audio Super non-oversampling kit. This kit is specifically developed for the Alpha 5 and involves removal of the SAA7220 digital filter chip. Of course by removing the SAA7220 you also loose the digital filter function it performs within the player. As a consequence unwanted sampling artefacts are not filtered out and remain in the audio signal and consequently are passed along to the rest of the equipment in your system. Advocates of non-oversampling argue that this is not a problem since this noise is at frequencies above the human hearing range and therefore doesn't adversely affect the sound. However other people believe that non-oversampling is a very bad idea and that the digital filtering function of the SAA7220 must be retained. A compelling argument for this is that whist this ultra sonic noise can't [B][I]directly [/I][/B]be heard by the human ear it most definitely is felt by the rest of the components in your system and consequently adversely effects the overall performance of the system. Back-to-back listening tests between the CD60 in standard form against the modified non-oversampling A5 show that whilst the Creek can't match the A5 for all-round listening pleasure it does do certain things in a superior way and this is what has spurred me on to see how good the CD60 can be made with a bit of tweaking. With my Creek CD60 I intend to carry out a series of upgrades whilst retaining the SAA7220 P/B chip and its 4x digital oversampling function. Hopefully I'll then be in a position to make some worthwhile listening comparisons between a well sorted non-oversampling player vs an equally well sorted player which retains oversampling. I'm going to try to be a little more focused in the upgrading than I was with the Alpha 5 project I intend to cover one topic at a time. I'd like to point out to anyone following this thread that the service manual/schematics for the Creek CD60 can be downloaded from the Creek website here: [URL]http://www.creekaudio.com/old-products/[/URL] I hope you enjoy following my progress.
