I have recently modified a Sony NS900 DVD/SACD. It uses the same DAC as the NS500 and the same topology for the analog section but with JRC 2114 ("improved" 5532") and a dedicated power supply for the analog section
I did the following mods:
1. replaced the puny transformer for the analog power supply and put the analog stage into an "always on" configuration.
2. upgraded the opamps in the two channel analog section to BB OPA627
3. replaced mylar caps in filter with polypropylenes & micas
4. replaced carbon film resistors with metal films (left the SMD resistors alone)
5. modified the power supply by replacing 12V zener with well-bypassed LM431 and replacing error amp (JRC 4580) with BB OPA2604
6. eliminated the coupling caps (Elan Silmic in the 900) at the output
I also removed all opamps for multichannel operation and headphones since I'm not using any of this now. I haven't gotten around to getting rid of the transistors used for muting yet.
The stock electrolytic caps are a combination of Elna Silmic and Nichicon Fine Gold, mostly bypassed with stacked metal film polyesters. Except for removing the coupling caps at the output I left the other electrolytics alone.
My modified CAL Audio CL-15 creamed the Sony on CDs, not surprising considering the price difference and mods. But the Sony SACD bettered the CAL in most respects except dynamics.
In the NS500 thread, there is a comment about lack of dynamics in the 500. Since the 900 shares the same DAC as the 500 and it is also low on capacitance in the power supply, I am hoping that someone has some insight into the lack of dynamics. Is it a result of the DAC and/or can more C in the power supply help out? Any other suggestions out there? The power supply uses a dual opamp as error amp with pass transistor. It also uses Schottky's as the rectifier diodes.
Thanks in advance to all those out there who can help out with this.
Phil
I did the following mods:
1. replaced the puny transformer for the analog power supply and put the analog stage into an "always on" configuration.
2. upgraded the opamps in the two channel analog section to BB OPA627
3. replaced mylar caps in filter with polypropylenes & micas
4. replaced carbon film resistors with metal films (left the SMD resistors alone)
5. modified the power supply by replacing 12V zener with well-bypassed LM431 and replacing error amp (JRC 4580) with BB OPA2604
6. eliminated the coupling caps (Elan Silmic in the 900) at the output
I also removed all opamps for multichannel operation and headphones since I'm not using any of this now. I haven't gotten around to getting rid of the transistors used for muting yet.
The stock electrolytic caps are a combination of Elna Silmic and Nichicon Fine Gold, mostly bypassed with stacked metal film polyesters. Except for removing the coupling caps at the output I left the other electrolytics alone.
My modified CAL Audio CL-15 creamed the Sony on CDs, not surprising considering the price difference and mods. But the Sony SACD bettered the CAL in most respects except dynamics.
In the NS500 thread, there is a comment about lack of dynamics in the 500. Since the 900 shares the same DAC as the 500 and it is also low on capacitance in the power supply, I am hoping that someone has some insight into the lack of dynamics. Is it a result of the DAC and/or can more C in the power supply help out? Any other suggestions out there? The power supply uses a dual opamp as error amp with pass transistor. It also uses Schottky's as the rectifier diodes.
Thanks in advance to all those out there who can help out with this.
Phil