I would be interested if you found one too. I just got one, and will probably end up buying another, so I have one to listen to, and one to tweak. Gives me a spare too. For the price, no reason not to.
If you search over at audioasylum, you can find some posts of people who have tweaked the NEC, but nothing too drastic was done to it.
Randy
If you search over at audioasylum, you can find some posts of people who have tweaked the NEC, but nothing too drastic was done to it.
Randy
MultiSpin CDROM
I've just bought one of these drives on eBay for the princly sum of 12.50USD (7.47GBP). Add a few USD on for postage and that is one inexpensive experiment. I have been over to AA and copied any references to tweaks that I found there. I'm intending to run it with a DacKit or DDDac (will be building both and am halfway through the DacKit).
If I find any further tweakage, I'll post here.
Cheers
Jon
I've just bought one of these drives on eBay for the princly sum of 12.50USD (7.47GBP). Add a few USD on for postage and that is one inexpensive experiment. I have been over to AA and copied any references to tweaks that I found there. I'm intending to run it with a DacKit or DDDac (will be building both and am halfway through the DacKit).
If I find any further tweakage, I'll post here.
Cheers
Jon
NEC 6Xi Mainboard ICs
Hi All,
I had my 602 open last night and had to take the 502 inside apart!!
What nice engineering!! I stuck the tack on the cans and stripped the caps. All back together and working fine. I am listening at the moment, through Scott Nixon's DacKit and it sounds very nice indeed!! In fact, almost as good as when I use my 600UKP Arcam as a transport. I can't say if the mods have made any improvement though. Before I bunged it all back together, I listed the ICs on the mainboard. Here they are:
IC101 BH9595FP 545 186Y
IC115 NEC D7225G A9542EP024
IC122 NEC D78330GJ 9537MK002
IC123 SONY CXD1808AQ 536H10E CDROM DECODER
IC124 XLJ6265AF-10LL 543 166
IC128 NPNX NN514256J-45 943 A74222
IC129 NPNX NN514256J-45 943 A74222
IC130 SYMBIOS 53CF92A
IC302 SONY D2559Q 531D83E
IC501 ST B88CB 9535CS (N513A)
IC701 SONY CXA1610M 538D09K
IC702 SONY CXD2510Q 536D52E
IC703 SONY CXA1373AQ 545MB4V
IC711 TA 8407F 9538K
IC712 TOSHIBA TA8192F 9543K MOTOR DRIVER IC
IC719 BA7082F 543 190
I can't find the datasheet for the CXD1808AQ - I would like to see if that is where I can tap the digital signal before it becomes 5v TTL. I am amazed it sounds so good, seeing as the cdrom digital out wires just wander for miles around the back of the mains transformer!!
Anyone got any further with the mods?
Jon
Hi All,
I had my 602 open last night and had to take the 502 inside apart!!
What nice engineering!!
I stuck the tack on the cans and stripped the caps. All back together and working fine. I am listening at the moment, through Scott Nixon's DacKit and it sounds very nice indeed!! In fact, almost as good as when I use my 600UKP Arcam as a transport. I can't say if the mods have made any improvement though. Before I bunged it all back together, I listed the ICs on the mainboard. Here they are:IC101 BH9595FP 545 186Y
IC115 NEC D7225G A9542EP024
IC122 NEC D78330GJ 9537MK002
IC123 SONY CXD1808AQ 536H10E CDROM DECODER
IC124 XLJ6265AF-10LL 543 166
IC128 NPNX NN514256J-45 943 A74222
IC129 NPNX NN514256J-45 943 A74222
IC130 SYMBIOS 53CF92A
IC302 SONY D2559Q 531D83E
IC501 ST B88CB 9535CS (N513A)
IC701 SONY CXA1610M 538D09K
IC702 SONY CXD2510Q 536D52E
IC703 SONY CXA1373AQ 545MB4V
IC711 TA 8407F 9538K
IC712 TOSHIBA TA8192F 9543K MOTOR DRIVER IC
IC719 BA7082F 543 190
I can't find the datasheet for the CXD1808AQ - I would like to see if that is where I can tap the digital signal before it becomes 5v TTL. I am amazed it sounds so good, seeing as the cdrom digital out wires just wander for miles around the back of the mains transformer!!
Anyone got any further with the mods?
Jon
Hello!
As to NEC 602 mods...
The best ones involve building a totally
analog +5 & +12 VDC power supply
Adding some sort of SPDIF output buffer
(either 74VHC04 and/or pulse transformer)
BNC true 75 ohm output jack
Case/drive/chassis damping
Replacing any small onboard electrolytics
with better units where they will fit
Isolation foot system under the drive housing
Vents for better air circulation inside the drive
(ever notice how WARM the CD caddy gets after
an hour or two of playing?)
The power supply & output interface upgrades
are probably the most productive, and DO
really improve the sonics of this CDROM drive.
Enjoy!
fastcat
As to NEC 602 mods...
The best ones involve building a totally
analog +5 & +12 VDC power supply
Adding some sort of SPDIF output buffer
(either 74VHC04 and/or pulse transformer)
BNC true 75 ohm output jack
Case/drive/chassis damping
Replacing any small onboard electrolytics
with better units where they will fit
Isolation foot system under the drive housing
Vents for better air circulation inside the drive
(ever notice how WARM the CD caddy gets after
an hour or two of playing?)
The power supply & output interface upgrades
are probably the most productive, and DO
really improve the sonics of this CDROM drive.
Enjoy!
fastcat
Excellent............
Hi Fastcat,
thanks for the ideas. I saw the SPDIF buffer on a link posted in another thread (loads of options here: http://www.andrewkilpatrick.org/mind/spdif/#faq ).
Looks like they are simple enough for even me to do!!
I have a plan for the power supplies (super-regulated), and I want to use those I construct in later projects.
The 75 ohm output should be a doddle. I will have a look at the board in the back of the main case (just near the transformer), because that may well have a reasonable TTL / SPDIF circuit on it that can be upgraded.
I have just obtained another from eBay at the massive cost of 5 UKP(!!), so I'll have a reference. I'll be interested to see what we can do with this kit!!
Cheers
Jon
Hi Fastcat,
thanks for the ideas. I saw the SPDIF buffer on a link posted in another thread (loads of options here: http://www.andrewkilpatrick.org/mind/spdif/#faq ).
Looks like they are simple enough for even me to do!!
I have a plan for the power supplies (super-regulated), and I want to use those I construct in later projects.
The 75 ohm output should be a doddle. I will have a look at the board in the back of the main case (just near the transformer), because that may well have a reasonable TTL / SPDIF circuit on it that can be upgraded.
I have just obtained another from eBay at the massive cost of 5 UKP(!!), so I'll have a reference. I'll be interested to see what we can do with this kit!!
Cheers
Jon
Jon:
When you were looking around inside the NEC 602,
did you notice what chip was outputting the TTL +5V
SPDIF signal, and if there was any sort of attempt in
the output circuit to get the proper 75 ohm output
impedance? Or did the wires simply come off the
rear internal connector and go to the RCA with no
output circuit or 75 ohm impedance matching?
Thanks!
Fastcat
When you were looking around inside the NEC 602,
did you notice what chip was outputting the TTL +5V
SPDIF signal, and if there was any sort of attempt in
the output circuit to get the proper 75 ohm output
impedance? Or did the wires simply come off the
rear internal connector and go to the RCA with no
output circuit or 75 ohm impedance matching?
Thanks!
Fastcat
Jon:
Since you will be looking at the inside of another
602 unit, can you tell which of the chips that
you listed in a posting is the one outputing the
TTL digital signal? There is always the issue of
the chips ability to put out sufficient current for
the resistor network (330/100 ohm) that sets
a correct 75 ohm output impedance.
All this is assuming that there are no digital
output resistors currently in the NEC that DO set
the 75 ohm impedance (previous posters on
another website seem to think that there are
NO resistors present). I have not yet torn down
one of my NEC transports to verify this. Posting
digital snapshots sounds like a good idea!
Fastcat
Since you will be looking at the inside of another
602 unit, can you tell which of the chips that
you listed in a posting is the one outputing the
TTL digital signal? There is always the issue of
the chips ability to put out sufficient current for
the resistor network (330/100 ohm) that sets
a correct 75 ohm output impedance.
All this is assuming that there are no digital
output resistors currently in the NEC that DO set
the 75 ohm impedance (previous posters on
another website seem to think that there are
NO resistors present). I have not yet torn down
one of my NEC transports to verify this. Posting
digital snapshots sounds like a good idea!
Fastcat
I need more light..........
..because where I am, I can hardly see the details!
The big electrolytics are:
Rubycon Electrolytics
16V 470uF
6.3V 470uF
6.3V 220uF
Black Gate N & Nx are available in these values. Also available in Std at 16v only. There appears to be enough room on the board to fit the larger caps.
On the board in the external case (that has the RCA Audio and Digital connectors, and the dip switches on the back (1,2,3,4), there are links (?) with insulated uprights, ceramic caps and resistors. The digital + (black) and digital - (grey) go from th eback of the cdrom, via plain wire, to pins 1 and (a space, then) 2 on this board. Audio R, Gnd, L (Orange, Red, Brown) go to pins 5, 4, 3. Pin 1 goes to C613 (ceramic disc - marked B 103K CM59), through link L608 to the Dig +. Pin 2 goes to R611 (brown, black, space, gold - 10R or could be violet, black = 70R 5%. Can't really make it out under the lamp, and I don't have my multimeter here!!!!) that joins C613 downstream of the cap. Upstream of R611 goes through L607 to C612 (missing). The other side of C612 would have gone to downstream of L608 (as mentioned earlier) and then to the Dig +. However, as C612 is missing, the trace goes directly to LJ601. This rises to be the RCA Dig -.
Incidentally, both Audio + go through C611 / 612 respectively (small brown ceramic with an underlined 151) and then to RCAs. Audio gnd goes through a larger green disc ceramic (?) marked 473 underlined, then Z).
There are smd caps around the TTL output on both sides of the board, and are numbered (for example) 221, 195, 102. But no obvious 75 ohm.
Similarly, I had real difficulty following the traces from the TTL back to the chip. Double-sided board make it difficult for my untrained eye!!!
If anyone is willing to open their 602 and have a look to verify what I've found, and to take thing further, then I'd be really interested to hear!!
More when I get it - Suffice to say, the digital camera will be out very soon (not with me at the moment) and I'll get some relevant photos posted.
Cheers
Jon
..because where I am, I can hardly see the details!
The big electrolytics are:
Rubycon Electrolytics
16V 470uF
6.3V 470uF
6.3V 220uF
Black Gate N & Nx are available in these values. Also available in Std at 16v only. There appears to be enough room on the board to fit the larger caps.
On the board in the external case (that has the RCA Audio and Digital connectors, and the dip switches on the back (1,2,3,4), there are links (?) with insulated uprights, ceramic caps and resistors. The digital + (black) and digital - (grey) go from th eback of the cdrom, via plain wire, to pins 1 and (a space, then) 2 on this board. Audio R, Gnd, L (Orange, Red, Brown) go to pins 5, 4, 3. Pin 1 goes to C613 (ceramic disc - marked B 103K CM59), through link L608 to the Dig +. Pin 2 goes to R611 (brown, black, space, gold - 10R or could be violet, black = 70R 5%. Can't really make it out under the lamp, and I don't have my multimeter here!!!!) that joins C613 downstream of the cap. Upstream of R611 goes through L607 to C612 (missing). The other side of C612 would have gone to downstream of L608 (as mentioned earlier) and then to the Dig +. However, as C612 is missing, the trace goes directly to LJ601. This rises to be the RCA Dig -.
Incidentally, both Audio + go through C611 / 612 respectively (small brown ceramic with an underlined 151) and then to RCAs. Audio gnd goes through a larger green disc ceramic (?) marked 473 underlined, then Z).
There are smd caps around the TTL output on both sides of the board, and are numbered (for example) 221, 195, 102. But no obvious 75 ohm.
Similarly, I had real difficulty following the traces from the TTL back to the chip. Double-sided board make it difficult for my untrained eye!!!
If anyone is willing to open their 602 and have a look to verify what I've found, and to take thing further, then I'd be really interested to hear!!
More when I get it - Suffice to say, the digital camera will be out very soon (not with me at the moment) and I'll get some relevant photos posted.
Cheers
Jon
there are some pictures overe att headfi of the named player..
anyhow it would be simpler to get the datasheet for CXD2510 (i think that is the ic used in the NEC if memory serves me.. and just cut the trace where Digout is concerned
anyhow i also hope to be able to present some pictures of my modded nec later this week)
/micke
anyhow it would be simpler to get the datasheet for CXD2510 (i think that is the ic used in the NEC if memory serves me.. and just cut the trace where Digout is concerned
anyhow i also hope to be able to present some pictures of my modded nec later this week
) /micke
To ALL:
Check out this link for NEC 602 CD-ROM SPDIF info:
http://www4.head-fi.org/forums/showthread.php?threadid=54211
The questions behind all this is which chip output
configurations work best for SPDIF output on NEC?
Fastcat
Check out this link for NEC 602 CD-ROM SPDIF info:
http://www4.head-fi.org/forums/showthread.php?threadid=54211
The questions behind all this is which chip output
configurations work best for SPDIF output on NEC?
Fastcat
HiFi:
What do you think makes a good SPDIF output
circuit for the NEC? I have seen the 74VHCU04
inverter chip type where the digital gets cleaned
up through 1 inverter, and is then fed to 3-5 paralled
inverters for current output capability, although some
(including Jocko) think that increases jitter. And then
the capacitor and the 2 resistors/ 75 ohm BNC jack.
What is your experience with all this?
Fastcat
What do you think makes a good SPDIF output
circuit for the NEC? I have seen the 74VHCU04
inverter chip type where the digital gets cleaned
up through 1 inverter, and is then fed to 3-5 paralled
inverters for current output capability, although some
(including Jocko) think that increases jitter. And then
the capacitor and the 2 resistors/ 75 ohm BNC jack.
What is your experience with all this?
Fastcat
Fantastic!!
Hi All,
the Head-Fi link is excellent!!
I wonder if my photos are necessary, given the quality of those posted over at Head-Fi.
However, in the interests of getting the whole picture (pun intended ), I will take requests for shots of the 602 gubbins as required. I'll make sure I take the camera with me this time!!
I have decided which of my 602s is the mod "mule" and which is for "best". I stand by (next week) with screwdriver and camera at the ready!!
Cheers
Jon
How about a run of the uber board for the SPDIF output?
Hi All,
the Head-Fi link is excellent!!
I wonder if my photos are necessary, given the quality of those posted over at Head-Fi.
However, in the interests of getting the whole picture (pun intended
), I will take requests for shots of the 602 gubbins as required. I'll make sure I take the camera with me this time!!I have decided which of my 602s is the mod "mule" and which is for "best". I stand by (next week) with screwdriver and camera at the ready!!
Cheers
Jon
How about a run of the uber board for the SPDIF output?
CXd2510Q data sheet
Hi,
Here is the data sheet of the CXd2510Q.
http://www.sony.co.jp/~semicon/japanese/img/sonyjd01/a6800932.pdf
Could you tell me whether it is possible to pull the I2S signal out from it? I am considering making an inbox non-oversampling dac similar to the one in this link (marantz CD-63):
http://diyparadise.com/nonosdac.html and
http://diyparadise.com/rm20dac.html
Thanks in advance for your kind help!
Best wishes,
Russell
Hi,
Here is the data sheet of the CXd2510Q.
http://www.sony.co.jp/~semicon/japanese/img/sonyjd01/a6800932.pdf
Could you tell me whether it is possible to pull the I2S signal out from it? I am considering making an inbox non-oversampling dac similar to the one in this link (marantz CD-63):
http://diyparadise.com/nonosdac.html and
http://diyparadise.com/rm20dac.html
Thanks in advance for your kind help!
Best wishes,
Russell
Sorry, no english version.
Thank you for your reply.
I am afraid that only the japanese version is available from Sony on the web. Thanks for your kind help anyway.
I guess I probably would need to convert the TTL signal to RS422 format and then feed it to the CS8412, though it seems rather redundant.
Best wishes,
Russell
Thank you for your reply.
I am afraid that only the japanese version is available from Sony on the web. Thanks for your kind help anyway.
I guess I probably would need to convert the TTL signal to RS422 format and then feed it to the CS8412, though it seems rather redundant.
Best wishes,
Russell
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