Denon DCD-2700 CD Player Mod Thread

[Bratwurst7s]

My first serious CD player was a Denon DCD-1290. I had searched out that model because it looked like it had some pretty good specs, good build quality, were available for decent prices and one can still find lasers for them. I was very happy with that player. Details of that adventure can be found here...

http://audiokarma.org/forums/index.php?threads/dennon-dcd-1290-cd-player-mod-thread.688774/

After I had been using the 1290 for a while I became aware of the DCD-2700 and decided to buy one when I could find one for a decent price. I not only found one but was so pleased with it that I found a second one to give my son to replace the DCD-1290 that I had given him.

This thread will detail my exploration of the DCD-2700. It's been fun.

Cheers,
James

 

[Bratwurst7s]

Right off the bat I realize that I didn't take any "before" photos of the un-opened player, so we'll have to start with some with the cover removed, but before any work was done.



In outside appearance the 2700 is nearly the same as the 1290. Some different labelling on the front, and the case is 3cm deeper. But inside they are quite different animals.

The DCD-2700 first shows up in the 1993-1994 catalog. I don't know exactly how long they were produced.

Specs:
Frequency Response = 2 ~ 20,000hz
Dynamic Range = 100db
S/N Ratio = 117db
THD (1khz) = 0.0018%
Channel Separation = 110db (1khz)
Wow & Flutter = "Under Measurable Limits" = +- 0.001%
Output Voltage = 2v (Fixed Output), 0~2v (Variable Output)
Case measurements = 434mm W x 122mm H x 360mm D
Weight = 9.2 kg
Remote Control Unit = RC-240
Original Price = 2,500 DM (MSRP)

This unit uses 4 x Burr Brown PCM-1702 DAC's, has dual digital and analog outputs. The variable output level is motor driven (which also controls the headphone output level). The Laser is a Sony KSS-240A. Chinese production copies of the laser can be found for ca €25, and NOS lasers are running ca €60 on the 'bay.

Over the next few days I'll be posting the journey of what's been done to the players so far.

Cheers,
James

 

[loudnoises]

Looking forward to this, i use a dcd-520, always liked the denons

FWIW i have read in multiple places that there aren't any real NOS lasers left. Supposedly, the NOS you see is rejected product that didn't meet specs when they were current. This jives very nicely with the reality that replacement lasers were almost as expensive to purchase as the completed unit, sometimes more expensive. Sony did not want a repair market, they wanted you to buy new. You might do best if you can find a NIB player that uses the same laser, but digging into fixing my cdc-635, the recommendations seem to be to go towards the best new laser you can get as the tolerances for current production models is better than the remaining unused NOS lasers. Grain of salt.

 

[unfairlane]

First, upgrade the clock-unit. Then; there are four op-amps after the four 1702-dacs, you can take the signal (balanced if from all four) directly from (leg 7?) the op-amps and skip the following "filter". Then; you can upgrade the trafo. Think big.

 

[Bratwurst7s]

Well, I don't have the resources to think too big at the moment. So my progress in the direction of actual "modding" has been pretty modest. But I'm not done, I'll be slowly trying things out in the future, step by step.

I was able to find an original service manual on the 'bay. I had to buy it from a fellow in the USA and it took a long 6 weeks to get here, mostly because of Customs here. But it was well worth buying, alone for the full size schematic.

Of course I did hook the player up after unpacking it and tested that it did indeed work. First impression was that shows a lot more bass/mid-bass than the 1290. But as it was it didn't have the "sparkle" that the 1290 did.

My plan was to first do some basic maintenance. Clean & lube the mechanism, then recap the power supply. Then go through the digital section, recapping and adding heat sinks. After that replace the signal path resistors with 1% metal film, and lastly recap the analog section and replace the op-amps. Then just use it for a while and decide what I want do do next. Probably replace the voltage regulators with high precision ones, and then replace the clock. We'll see.

Anyway, the mechanism is totally different than the one in the 1290 & 890. More complex.



Cheers,
James

 

[Bratwurst7s]

The top clamp plate is easy to remove, just remove the 2 screws and it will pop off when the little finger clamps are unhooked. The drawer is removed by pulling the 2 screws on the rear edge, one of them holds a small drawer travel stop in place. Then you can remove the tray by sliding it out the front of the frame. Watch out when removing the tray, there are 2 small teflon spacers under the front edge, one on each side, as well as a flat spring on the left side that stabilizes the tray by pushing it lightly towards the right. I tend to immediately clean each part as I remove it and lay them out on a clean rag in the same position they were in, kind of an exploded view of the mechanism as it's disassembled. This makes it easier to rebuild it, at least for me anyway.



Cheers,
James

 

[Bratwurst7s]

The laser/spindle motor mounting frame can be removed after removing the 2 hinge pin holding screws. One can see from the various photos that there is a lot of old grease throughout the entire mechanism. I use plain old dishwashing soap and warm water to clean everything.



Cheers,
James

 

[Bratwurst7s]

The tray closed switch and loading motor are also easy to remove. One screw holds the switch PCB in place. It has a wire spring under it. After pulling the screw just pop the 3 plastic holding clips out of the way one after the other and the pcb will be free.



Cheers,
James

 

[Bratwurst7s]

Carefully remove the loading tray drive belt and then the 2 screws that secure the motor and now that entire assembly is removed.



Cheers,
James

 

[Bratwurst7s]

The loading tray motor turns a set of gears that also drive the cam plate that lowers/raises the laser frame. They are held in place with cast in plastic clips (on the mounting shafts) and a screw.



Cheers,
James

 

[Bratwurst7s]

Mounted on the inside front of the mechanism frame is a wide L shaped plate/frame that is driven by the loading tray gears. It has cam slots in it that the shafts in the front end of the laser holding frame fit into. The left/right sliding action of the cam plate lifts/lowers the laser frame. To remove the cam plate slide it all the way over towards where the drive gears were mounted until the retaining clips reach the cutouts that allow the plate to be lifted off of the main frame. Note! The fit is very fine. You will have to carefully pop the cam plate up out of the main frame. Break anything here and you are done! Don't force it, it takes a little bit of feel but it will be possible with care.



Cheers,
James

 

[Bratwurst7s]

So now everything is clean and other than the laser frame the mechanism is ready to be re-assembled. I use Rivolita SKD 4002 synthetic grease for everything that needs to be greased. And a light machine oil with teflon for the motor bearings. The motor bearings each get one (1!) drop of oil. The tray drive belt gets cleaned in dishwashing soap. Then I re-assemble the basic parts of the tray drive and frame. The laser frame comes next.



Cheers,
James

 

[Bratwurst7s]

And dang. It seems that I only have one photo of the laser/spindle motor frame. OK. The plate that holds the laser can be removed from the plastic frame by removing the 4 screws in each corner of the plate. Important! Under each of the screws is a coil spring. They are not all the same! Mark their positions and Do Not Mix Them! They have different spring rates to dampen oscillations of the laser plate. They Must go back into their original positions.

After cleaning everything I use a small amount of Rivolita grease on the plain flat sliding surfaces and a few drops of light teflon oil in the brass bushings in the laser frame that slide in the guide rail. Then everything gets re-assembled and the mechanism is finished.



Cheers,
James

 

[Bratwurst7s]

While this unit doesn't have 2 or more transformers like some of the top dogs of the late '80s early '90s did it does at least have separate windings for the digital and analog sections, and is completely separated from the main pcb.

Mounted directly on the transformer pcb are:
2x 2200µF/50v Elna main filter caps (25mm dia x 50mm)(C-701, 702).
2x 2200µF/25v Nipon Chemi-Con KMG (12 x 35mm)(C-703, 704),
1x 47µF/63v NCC SMF (C-705)(!Note! Shown in schematic as a 4.7µF/63v!),
1x 0.1µF/50v NCC SMF (C-706).

Also part of the power supply but mounted on the main pcb:
1x 330µF/16v NCC SMF (C-403),
4x 220µF/50v Elna Silmic (C-391, 392, 393, 394).

At the point that I re-capped most of the PSU I didn't replace the main filter caps because I couldn't decide on what I wanted to use. As things turned out the last thing that I've done to the player (as of 10 Feb 17) was to replace them. Now I'm glad about that because it allowed me to hear the difference when just those 2 caps were changed, after having done everything else. It was an eye opener. More on that later.

To replace the rest of the above I used:
C-703, 704: 2200µF/35v United Chemi-Con KYB,
C-705: 47µF/100v Panasonic FC,
C-706: 0.1µF/63v Wima MKS2,
C-403: 330µF/25v UCC KYB,
C-391~394: 220µF/50v Nichicon KZ Muse.

The voltage regulator transistors on the main PSU pcb were turned down and mounted to the case originally but without any kind of thermal transfer compound. I added sil-pads to them.



Cheers,
James

 

[Bratwurst7s]

 

[Bratwurst7s]

The digital drive section was originally completely equipped with Nippon Chemi-Con SMF elcos. They were replaced with a combination of Panasonic FC and Wima MKS2 elcos and film caps, and one Nichicon ES Muse BP cap.

C-113 (6.8µF/50v): 6.8µF/50v MKS2,
C-122, 123 (0.22µF/50v): 0.22µF/63v MKS2,
C-135 (10µF/35v BP): 10µF/35v ES Muse Bi-Polar,
C-170~173 (47µF/16v): 47µF/25v FC,
C-207 (1µF/50v): 1µF/63v MKS2,
C-208 (33µF/35v): 33µF/50v FC,
C-216 (0.33µF/50v): 0.33µF/63v MKS2 (I actually used a Panasonid ECQ film cap here but they are no longer available),
C-245 (100µF/50v): 100µF/63v FC,
C-351 (220µF/25v): 220µF/35v FC.

Cheers,
James

 

[Bratwurst7s]

 

[Bratwurst7s]

The small pcb mounted on the volume drive motor has 2 caps on it.
C-503 (470µF/16v SMF): 470µF/25v Panasonic FC
C-504 (2200µF/16v SMF): 2200µF/16v UCC KYB



Cheers,
James

 

[Bratwurst7s]

The Analog/DAC section was populated entirely with Elna Silmic caps (all 50v) with the exception of 8x 10µF/50v Elna ASF caps. I replaced them entirely with Nichicon KZ Muse except for all of the 10µF caps which were all replaced with Wima 10µF/50v and 4.7µF/50v MKS2 film caps,.

C-225~232 (10µF/50v): 10µF/50v MKS2,
C-341~344 (22µF/50v): 22µF/50v KZ,
C-333~340, C-381~388 (100µF/50v): 100µF/50v KZ,
C-343~350 (10µF/50v): 4.7µF/50v MKS2,
C-347~350 (470µF/50v): 470µF/50v KZ,
C-391~394 (220µF/50v): 220µF/50v KZ.

Just before the output, and directly in the signal path, are 4 coupling caps on each channel arranged in series/parallel pairs. Now in the DCD-1290 those positions were entirely populated with Silmic 470µF/50v in some players and 100µF/50f in others that I've had. I tried several different caps in them but for some reason never thought about using pairs of different values with one pair to improve the highs.

So when I looked at the schematic for the DCD-2700 the coin finally dropped when I saw that on those output coupling cap positions there were a pair of 470µf in series (back to back), paralled with a pair of 10µF also in series. So in effect 1x 235µF bi-polar with 1x 5µF bi-polar in parallel. I substituted Wima 4.7µF/50v for the 10µF Silmics. In the end I later went back to all 5 of the DCD-1290 players that I've re-capped and changed them all to this configuration also.



Cheers,
James

 

[Bratwurst7s]

BTW, there are no muting transistors to remove in this player. Instead there is a relay, so no sound degradation from muting.