DVD-2900 Power Supply Upgrades?-

[clm811]

I'm interested in replacing the diodes in the analog power supply with FRED-types, and the critical caps with superior types (BG).

For instance, Underwood lists the following in their Level-1 mod:

The power supply is upgraded with 6 BlackGate FK and NX series electrolytic caps and all critical analog supply diodes (generic stock quality) are replaced with ultra-fast soft-recovery FRED-type diodes (1 Telefunken and 5 IR Hexfreds).

Which parts in the schematic(attached) are the likely candidates?

Several posts here mention replacing the caps and diodes PRIOR to the Switching Power Supply, but wouldn't replacing the diodes and caps AFTER the SMPS make more of an audible difference?

Any advice/comments will be appreciated

-chas

p.s. I will post second half of schematic below

[clm811]

Attached is second half of PS schematic, showing more diodes & linear regulators for audio stages.

[clm811]

Anyone out there... have DVD2900,
or modified similar?

[dantwomey]

SMPS's are complex and hard to work on so when I looked at my Marantz universal player I focused on better regulators and caps after the SMPS portion of the supply.

Here's a couple of my posts:

DV7600 Power Supply



Upgraded Regulators

Regards,
Dan

[clm811]

Thanks, Dan, for the insights into your Marantz mod-

Anybody else out thare modded (specifically Denon) their DVD/SACD Player's SMPS?

[outofthebox]

I did mod my Denon 2900 extensively (including PS mods) about four years ago or so. I am still a happy user of the player.

I did the mods in stages. Starting from the SMPS diode bridge and Caps and the IEC Inlet and the mains supply cable and the Mains fuse. Eventually ended up building an offboard PSU for the analog stage completley bypassing the SMPS for the analog output stage. I still recall that the first diode and caps mod on the SMPS had a profound impact on the lower frequencies and in the imaging , soundstaging dept.

Went on to add a LC Audio Clock module and used an off board power supply for that too. Had also added a DC jack for powering the LC Audio clock from a 12v SLA.

Let me know if you need to ask anything specific.

Best of luck with your mods.

[dantwomey]

Originally posted by outofthebox
I did mod my Denon 2900 extensively (including PS mods) about four years ago or so. I am still a happy user of the player.

I did the mods in stages. Starting from the SMPS diode bridge and Caps and the IEC Inlet and the mains supply cable and the Mains fuse. Eventually ended up building an offboard PSU for the analog stage completley bypassing the SMPS for the analog output stage. I still recall that the first diode and caps mod on the SMPS had a profound impact on the lower frequencies and in the imaging , soundstaging dept.

Went on to add a LC Audio Clock module and used an off board power supply for that too. Had also added a DC jack for powering the LC Audio clock from a 12v SLA.

Let me know if you need to ask anything specific.

Best of luck with your mods.

Which diodes and caps did you use on the SMPS? Just guessing I would think that something like the MUR860s would be a good choice for the diodes and a Blackgate WKZ or the Jensen four pole for the main cap.

Regards,
Dan

[outofthebox]

Mouser part number: 583-1N4946-B. 1 amp/600 volt ,Fast/Soft recovery diode with axial leads.
Mouser part number: 583-FR205P-B: 2A/600 Volt, fast recovery diode, axial leads.

are two options for you for the diodes.

I used FR205.

Since I live in a 230V country so cap options were limited for me If you can get hold of a Blackgate at that voltage rating and a decent price I think it would do nicely.

I used a Nippon Chemi Cap with double capacitance value of the original eventually.

Here is a useful link for you:

http://www.soundstage.com/maxdb/maxdb200006.htm

cheers!
Amit

[dantwomey]

Originally posted by outofthebox
Mouser part number: 583-1N4946-B. 1 amp/600 volt ,Fast/Soft recovery diode with axial leads.
Mouser part number: 583-FR205P-B: 2A/600 Volt, fast recovery diode, axial leads.

are two options for you for the diodes.

I used FR205.

Since I live in a 230V country so cap options were limited for me If you can get hold of a Blackgate at that voltage rating and a decent price I think it would do nicely.

I used a Nippon Chemi Cap with double capacitance value of the original eventually.

Here is a useful link for you:

http://www.soundstage.com/maxdb/maxdb200006.htm

cheers!
Amit

Excellent article.

Thanks,
Dan

[clm811]

Amit,

In the first schematic above, please specify

http://www.diyaudio.com/forums/attachment.php?postid=1361350&stamp=1196154733

which part numbers shown did you change?

Thanks in advance for being specific.

Happy holidays!