Home Theater > Audio Only Sources
CD PLAYER/DAC MOD
rascal101:
Just wanted to start a discussion on CD player modification ...
Just completed work on two my two entry level cd players:
1. Denon DCD-815
2. Sony CDP-M11
Changes done:
1. Bridge Rectifier, Gen Purpose -> Schottky (SB160)
- To improve headroom on the input of the linear regulator. Also reduces bulk voltage ripple
voltage due to almost zero reverse recovery time (Trr) and low forward voltage (0.7V max).
2. Bulk capacitor, Gen Purpose -> Low ESR (note 1) + decoupling capacitors
(0.33uF polyprelene + 0.47uF metallic polyster)
- To improve headroom and to reduce high frequency ripple & noise
3. E-cap, Gen Purpose -> Low ESR + decoupling capacitors (0.1uF polypropelene or
metallic polyester)
- Same as above. The additional 0.1uF polyprelene or metallic polyster are bypass capacitors
to filter unwanted high frequency noise or signals
4. Decoupling capacitors, Ceramic -> Metallic polyester or polypropelene
- Improve capacitor tolerance and improved cap performance with respect to frequency
5. IC Regulator, Mitsubishi M5290 +/-5V regulator with reset -> Use application notes
(change capacitor values)
6. Replace/Add additional circuit at output section
On Sony CDP: Sony CXD2552BQ (1 bit DAC) + Single op amp circuit -> Use application
notes (differential op-amp = NE5532, buffer + filter op-amp = OPA2132)
On Denon CD: Burr Brown PCM61P (18 bit DAC) -> Add class B push pull discrete circuit
after internal op-amp (pin 9 of IC)
- The sound is a bit warmer after this exercise
7. Differential filter, Nonexistent -> 1uF polypropelene
- Put in parallel with AC inlet to reduce input AC distortion
- Updated 12/12/05, make sure to put a 100k 1/10W discharge resistor parallel to the capacitor
8. DC blocking capacitor, 47uF e-cap -> Used recommendation of Walt Jung on "Picking
Capacitors" article. See note 2.
On Sony CD player:
All connected in parallel: 2x 1uF metallic polyester + 0.22uF polyprelene capacitor
On Denon CD player:
Correction 11/2/05 ... should be 2x220uF ... load resistor 10k
2x 220uF low esr cap in series in parallel to 0.22uF polyprelene series with 0.47uF metallic
polyester capacitor. Placed load resistor of 10k to ground after the output decoupling capacitor.
9. Resistors, Carbon film -> Metal film or Metal Oxide film
- Resistor performance with respect to temp is more stable. Parasitics is better on metal film
or metal oxide film. See note 3.
10. Output filter cap (on RCA jack), 1 nF -> 3.3nF
- Slightly lower bandwidth to elimate high frequency noise
11. Whenever possible, I used metallic polyester caps to replace low cap value electrolytic caps.
-----------------------------------------------------------------------------
Update 11/2/05
Oops ... nearly forgot
12. Removed all output muting transistors and series resistors going to L/R output RCA jacks.
Update 03/02/08
Font, spelling and slight wording adjustments.
-----------------------------------------------------------------------------
I didn't modify the my cd clock on the Sony CD player due to space limitations.
Wanted to try the clock ICs I got from Phaselink Semiconductor ... sayang ...
How does it sound ... Wala na pong sibilance (dahil sa 3.3nF at mga bypass caps sa electrolytic caps),
iyung piano ay pianong piano ang tunog, malinis at walang background noise (dahil sa low esr at
bypass caps), lahat ng instrumento naririnig ko na kahit sabay sabay sila (based on my observation
this is due to the schottky rectifier + DAC modification based on application note) ...
Pictures (modified Sony CDP-M11)
Top View
Top Tilted View
Bottom View
Headphone (modified op-amp fm TI RC4558 to OPA2227)
Changed components
Clarifications or corrections on the above are accepted.
Notes:
1. Low ESR capacitors
- Nichicon "PM" or "HD" series, Rubycon "ZL" series, Sanyo "OSCON" series
2. Picking capacitors article
http://home.comcast.net/~wjungieee/wsb/Picking_Capacitors_1.pdf
http://home.comcast.net/~wjungieee/wsb/Picking_Capacitors_2.pdf
3. Sound of resistors
http://www.sasaudiolabs.com/theory10.htm
4. Capacitor preferences in order:
a. 275Vac X2 polypropelene cap (0.22uF, 0.33uF, 1uF)
b. 250Vac Y2 polypropelene cap (1nF, 2.2nF, 3.3nF, 0.1uF)
c. 400V metallic polyester (0.1uF, 1uF)
d. 63V metallic polyester (1 to 10nF)
5. Updated 06/29/06 - the addition of the polyester or polypropelene caps in parallel with the e-caps
ensures that high frequency signals are coupled to ground. At 10KHz and up, e-caps are typically
at 1/2 of their capacitor value at 100Hz. This means that cut-off frequency extends beyond what
it is designed for which results in high frequency signals just blowing by them.
gutchy:
sir post nmn ng pics...
see some other tweaks you can do to your cd player..
:D enjoy!!! :D
http://www.audiotweaks.com/collection_ascend.htm
http://www.wiredstate.com/forum/viewtopic.php?t=5538
http://www.agoraquest.com/viewforum.php?forum=52&start=60&select_page_number=3
http://translate.google.com/translate?hl=en&sl=ja&u=http://www.kameson.com/audio/CDP-555ESJ.htm&prev=/search%3Fq%3D555esj%2Bsony%26start%3D10%26hl%3Den%26lr%3D%26sa%3DN
http://translate.google.com/translate?hl=en&sl=ja&u=http://www.kameson.com/audio/CDP-555ESJ.htm&prev=/search%3Fq%3D555esj%2Bsony%26start%3D10%26hl%3Den%26lr%3D%26sa%3DN
Garp:
Rascal101,
Nice work but I'm wondering aren't those ELNA caps good enough? Also are those gold or (is it yellow?) caps polystyrene or ordinary mylar?
rascal101:
Sir Garp,
The caps are yellow and they are metallic polyster. The white ones are metallic polyster too. The dirty white colored caps are polysterene (located at the solder side of the PCB).
I wanted to use polysterene but because of their massive size I had contented myself with putting metallic polyster.
The Elna caps are good but since my Sony CD player has been around since 1991 the Elna caps had to go. The life of electrolytic caps are rated for about 5 years only (assuming 24x7 operation). Also, I had higher rated caps 105degC rated compared to the Elna caps which are rated 85degC.
Garp:
Rascal101,
Thanks for sharing your experience. Keep it up :)
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