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Kenwood CD player

S

SLTHORP

AK Subscriber
Subscriber
I am wanting a silver faced Kenwood CD player to go with my KA-7100 and KT-5500, I am only finding them from Japan so will need a power transformer.
I have found a DPF-7002 which has the same DAC and laser unit as the DP-7090.
Also found a DP-1001
Does anyone have any experience with these silver faced Japanese units? Are they any good?
 
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The DPF-7002 must use the Burr Brown PCM1702.
They are an R2R-ladder type of DAC.
Similar to the Analog Devices AD1865.

Recommended.
 
Evonimos said:
The DPF-7002 must use the Burr Brown PCM1702.
They are an R2R-ladder type of DAC.
Similar to the Analog Devices AD1865.

Recommended.
Click to expand...
The DPF-7002 has the same DAC and laser unit as the DP-7090, 8 x PCM1702 - KSS-213B, and the DP-7090 is VERY highly regarded.
The DPF-7002 I would think should sound about the same, but is not upgradable like the DP-7090, but it can be used a stand alone DAC for 1/2 the price.
Not sure if I will go with the 7002 or the 1001, the 1001 is less money but maybe not quite as good sounding? Not sure, any advice appreciated.
 
I found a couple modified Kenwood DP-1001 CD players on Ebay, and am including the description of the work done on each unit below. I would really appreciate feedback in reference to sound quality improvements as a result of the upgrade. Both units are in Japan so a transformer will have to be used.
Again, please, any feedback is greatly appreciated.


Modification/maintenance status, unit 1.
Cleaning the interior and exterior, disassembling the front panel and cleaning the FL display tube,
Disassemble the CD mechanism and replace the tray opening/closing belt.
For the pickup, I carefully selected one with minimal deterioration from among the many KSS-240A's I had on hand, and to improve reading performance, I replaced the capacitor in the pickup, oiled and greased the pickup assembly, and greased the loading and chucking mechanism. Replace the D/A section LPF operational amplifier with Nisshinbo Micro Devices (formerly New Japan Radio) MUSES8820, and the analog section operational amplifier with Nisshinbo Microdevices (formerly New Japan Radio) MUSES01D (installation IC socket is round pin DIP8P), CD control board. Replaced electrolytic capacitors in important parts of the main board and all electrolytic capacitors on the DAC board with audio grade products (Nichicon FG, MUSE KZ, Toshin UTSJ, Sanyo OS Con), changed the block capacitors from 3300μF x 2 to 8200μF x 2, the 7 rectifier diodes were replaced with SBDs (Schottky barrier diodes), the connection between the D/A section and the main board was changed to a MOGAMI shielded cable, and the low-pass filter capacitor was replaced with a WIMApolypropylene film capacitor (tested). The crystal oscillator is removed and connected to the TCXO unit using a high frequency cable.We added a power transformer for the operational amplifier (linked to the main power switch using a relay), installed a power supply unit that generates positive and negative voltages, and supplied ±15V to the operational amplifier on the main board and DAC board, which were modified to use a separate power supply. As for the operating condition, it has been connected to an amplifier and tested for CD and CD-R listening.The CD tray opens and closes smoothly, the CD mounts quickly, and there are no problems with all operations. There is no decrease in brightness or unevenness in the cleaned FL display tube, so I think it can be used comfortably. 　
Thank you for your consideration.
Kazuki



Modification/maintenance status unit 2.
Cleaning the interior and exterior, disassembling the front panel and cleaning the FL display tube, disassembling the CD mechanism and replacing the tray opening/closing belt, and carefully selecting a pickup with minimal deterioration from among the many KSS-240A's I have on hand to improve reading performance. Therefore, I am replacing the capacitor in the pickup section.Lubricating and greasing the pickup assembly section, greasing the loading/chucking mechanism, used the Analog Devices' low-distortion, ultra-low-noise operational amplifier ADA4075-2ARZ for the D/A section LPF operational amplifier, and Burr-Brown operational amplifier for the analog section. Replaced with the OPA2604AP (OPA2604AP, an operational amplifier with a reputation for high sound quality, is unfortunately no longer manufactured by the manufacturer, and is a rare stock item) (the mounting IC socket is a round pin DIP8P), and the 4 electrolytic capacitors in the D/A section were replaced with Sanyo's OS CON's, replaced the analog section capacitor with an audio capacitor, replaced the low-pass filter capacitor with Soshin Dipped Silver Mica, and modified the master clock by removing the crystal oscillator and connecting it to the TCXO unit with a high frequency MXSU cable. As for the operating condition, it has been connected to an amplifier and tested for CD and CD-R listening.
The CD tray opens and closes smoothly, the CD mounts quickly, and there are no problems with all operations, so I think you can use it comfortably. 　

Thank you for your consideration.
Kazuki
 
Unless the original XO was poor quality, I see little benefit in using a TCXO. You are very unlikely to notice the small frequency drift on a non-compensated XO, and any variability/noise in the oscillator loop, or noise pick up in the cabling is likely to degrade jitter performance.

The secret to low jitter is a clean oscillator (including choice of xtal cut & oscillation mode), as close as possible to the DAC, with clean PSU for oscillator and oscillator input buffer on the DAC, to prevent electrical noise becoming timing noise.

What sound quality improvements do you think you have achieved? And, by doing all the changes at once, how are you going to determine which was responsible?
 
cpt_paranoia said:
Unless the original XO was poor quality, I see little benefit in using a TCXO. You are very unlikely to notice the small frequency drift on a non-compensated XO, and any variability/noise in the oscillator loop, or noise pick up in the cabling is likely to degrade jitter performance.

The secret to low jitter is a clean oscillator (including choice of xtal cut & oscillation mode), as close as possible to the DAC, with clean PSU for oscillator and oscillator input buffer on the DAC, to prevent electrical noise becoming timing noise.

What sound quality improvements do you think you have achieved? And, by doing all the changes at once, how are you going to determine which was responsible?
Click to expand...
I am just interested in whether the changes as a whole will achieve sound quality improvements over stock, the op amps the capacitors, the cables, etc. It seems like the person that did the work knows what he is doing, I just want a good refurbished/restored/upgraded CD player that sounds good to go along with my completely restored KA-7100 and KT-5500.
 
SLTHORP said:
It seems like the person that did the work knows what he is doing
Click to expand...
Right; I misunderstood your post; I thought, from the first person descriptions of the changes, that you had done them. Now I understand that 'kazuki' is a third person who has done the work.

Hard to say if that person knows what they are doing, or is blindly following things they have seen suggested on the internet; the replacement of silicon rectifiers with SBDs isn't necessarily an improvement, for instance.
 
I decided to purchase an un-modified Kenwood DP-1001, I may decide to have it modified later. Right now a step down transformer is needed in order to connect it to
USA AC power, and I am looking at a Hammond 169C line transformer to be mounted inside the unit to feed the existing transformer the 100V that it requires. However I am not
able to read schematics and such so could use some help with wiring it. Attached is the wiring diagram, it shows 2 black wires on one end and 7 color coded wires on the other end, so I have no idea how this would be wired with the black and black/white wires to the existing transformer. I would like to bring the AC power from the wall jack into the rear of the CD player to the input side of the line transformer, and connect the output side of the line transformer to the existing transformer input voltage wires which are black and black/white. Can anyone help?
 

Attachments

You will need to replace the power transformer to accept the proper voltage at its primary winding and have a matching output voltage (to the original), at its secondary.
If you live in a country where the grid voltage is 220VAC you will need the primary winding to be rated as such.

Example for 220VAC grid:

If existing transformer is 100VAC primary / 24VAC secondary (10Watt), you will need a replacement transformer that will be 220VAC primary / 24VAC secondary (10Watt).
 
Evonimos said:
You will need to replace the power transformer to accept the proper voltage at its primary winding and have a matching output voltage (to the original), at its secondary.
If you live in a country where the grid voltage is 220VAC you will need the primary winding to be rated as such.

Example for 220VAC grid:

If existing transformer is 100VAC primary / 24VAC secondary (10Watt), you will need a replacement transformer that will be 220VAC primary / 24VAC secondary (10Watt).
Click to expand...
The transformer in this unit is proprietary, it cannot be replaced.
 
rjsalvi said:
Passive components are those which do not generate power. Examples of these are resistors and capacitors.

What I'm about to say is important to the conversation, but not meant to be critical...if one cannot read a schematic, it can create a serious issue(s) which at the very least, could blow a component fuse, or trip a house circuit breaker. Any mistakes in wiring may cascade into burned components and then your CD player becomes a door stop. There's also a possibility that adding another transformer internally to the CD player, could introduce noise/hum into the audio signal.

OR, you can pull the transformer out of the unit I linked to and try to add that one to the CD player. You'll still need to be able to read a schematic to figure out if you can do it.
Click to expand...
I have thought about whether noise would be introduced so that is why I found an isolation transformer such as the Hammond 169C, thinking it would help in that regard.
 
rjsalvi said:
Edit: Maybe discussion regarding the x-former would be better suited to the Kenwood forum, instead of the DAC forum...
Click to expand...
Or, given that it's a CD player, the 'Digital Sources' forum... Or the DIY forum, since it's a mod. But not the DAC forum, certainly...
 
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