This is really going to be a list of things I've done to improve the stock second hand Denon dcd920 I picked up for £25 from cash converters. The intresting thing isthat many of these changes are generic and can be applied equally to other devices like DAC's and Minidisc's. This CDP is not cramped with surface mount technology but your normal sized components, though I've done similar to units with SM layouts. Most of the tweaks are to be found on the web but not nessesarily all together. Lets start with the case. Nasty plastic box with feet that were hollow ? Damped top bottom and sides with bitumen damping pads. Removed feet, and stuck 2mm ruber sheet in the base of the unit. This increased thw weight of the unit by about three times and its sounds dead when tapped. Lost, swapped and changed all the sockets for decent PTFE insulated types. Power supply Replaced the stock mains lead with a short length of shielded mains and a female IEC free socket.This allows use of any IEC terminated mains lead. Changed the Diodes for Schottky 11DQ10's with 10n caps. Bypassed all the caps with wima 1uf 63v types. Laser and tray Covered all lead with copper foil and grounded them. Removeed the mounting screws and Placed blu tak under the four supporting feet of the lasser tray assembly. This holds it firmly in place but also isolates the unit fron the rest of the box. Painted the tray green and built a green card "lid" over the top of the assembly. Loaded all exposed non operational bit with blu tac, and the under side of the tray. Used just enough so the tray and assembly wasdamped but not enough to effect its working. Digital section Reclocked with a Net audio unit and Psu. Shielded all Ic's with copper foil and grounded them to the same point. Output section Unplugged the haedphone section, this made a big difference but don't know why? Removed the old Op amp's and replaced with a berylium pined sockets. Op amps swapped for BB opa2604 tweaked to class A, with 10k resistors from output to negative rail. Replaced all resistors in and arround the signal path with Holco's 0.1%. All decoupling caps upgrade to encapsulatd foil types. Main caps swapped for stargets and all bypassed with wima 1uf types. To be do rewire the PCB with silver wire for the audio output fromthe op amps. Removed the muting transistor and associated curcuitry. Well how does it sound.......it now out performs my £1k Quad 77 damn damn damn. Looks like I've got to start work on that one ! The best upgrade penny for penny... the diode swap Cost no object .....reclocking but each change was positive move forward.
