I found a couple modified Kenwood DP-1001 CD players for sale, and am including the description of the work done on each unit below.
I would really appreciate feedback in reference to sound quality and overall improvements as a result of the upgrades. 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
I would really appreciate feedback in reference to sound quality and overall improvements as a result of the upgrades. 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