DVD-2900 Power Supply Upgrades?-

Status
Not open for further replies.
Jump to Latest
clm811

clm811

Member
Joined 2002
#1
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).
Click to expand...

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
 

Attachments

  • dvd2900ps1.jpg
    dvd2900ps1.jpg
    96.1 KB · Views: 650
#6
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.
 
#7
outofthebox said:
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.
Click to expand...

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
 
#8
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
 
#9
outofthebox said:
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
Click to expand...

Excellent article.

Thanks,
Dan
 
#12
clm811 said:
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!
Click to expand...

My guess would be start with D901-D904, and C905. I have the same basic components in my Marantz SMPS.

Although I used the ALWSR I would look at NewClassD's UWB regulator for your IC906 and IC908.

Also, how about some blackgates for C934,C937 and C943-44?

Merry Christmas,
Dan
 
#14
I ordered the diodes and caps from Parts Connexion-can't wait to get 'em. 🙂
BTW I got other parts from them in the past & they're a great supplier (fast, friendly & dependable). If you have a question or problem they take care of you!

Will report back once they're installed...

Thanks again for all the tips and Merry Christmas!
-Chas
 
#15
Originally posted by dantwomey
"Although I used the ALWSR I would look at NewClassD's UWB regulator for your IC906 and IC908"
Click to expand...

IC's 906 and 908 appear to be primarily for the video circuitry, while the audio board is powered primarily from IC 912(7809) and also IC 913(7909).

Also, the UWB regulator's rated for max 400mA- max 600mA if a heat sink is employed.

Technical Specs:Maximum Current DX78xx: 630mA;Maximum Current DX79xx: 400mA.
Click to expand...

Anyone think this could deliver enough currrent for the 20-odd IC's on the D/A and analog audio board that follows-especially that positive regulator which also supplies current to the 5v and 3.3v regulators for the DAC?

Perhaps the ALWSR could deliver sufficient current for this app, but could it be directly substituted for the 7809/7909 in this circuit where the input voltage is only approx 12vdc? And how would it be mounted/connected?

I'm also interested in adding such a mod to the Denon once other more basic upgrades are made.

-joe
 
Status
Not open for further replies.
Top Bottom