Denon DVD2900 tweaks

[mrdon]

Originally posted by ctong

How does ad8066 compare with opa134 or 627?

Well first of all the AD8066 is a dual opamp and the opa134 and opa627 are singles. There is an opa2134 that is a dual version of the opa134 but there is no such dual for the opa627. To make the latter work in the 2900 you need to put two singles on a browndog adapter.

Secondly, these three opamps are all fantastic opamps each with a different emphasis and presenation. In regards to sound differences...to my ears the opa2134 is missing some midrange warmth, the opa627 is too warm, and the AD8066's warmth is in-between the two with the added benefit of the Analog Designs snap and detail. I personally prefer the AD8066 after replacing the stock op270's with opa627's and after that AD8620's.

Again, these impressions are merely subjective as God has created each of us uniquely with unique hearing and has given us audio systems to enjoy, some of which are on the warm side of neutral and others which are on the bright side of neutral.

[mrdon]

After a few days of burn-in and listening, I've been reflecting on all that I modded in my 2900 over the last year. This morning I thought about what if I was given another 2900. What would I now mod? Another way of phrasing it - given all that I did what's the best bang in regards to time, effort and cost. Here's my list:[list=1][*]Upgraded Power Cord[*]Dutch Mod coupled with replacing certain resistors in output path with Riken Ohm's [*]Auricap tweak[/list=1]

As you can see, my complete overall of the power supply did not make the list. The PS overall included replacing stock capacitors on the PS board with ones 20% larger in capacitance (ala Bob McNiece on the Toshiba 4960). The only exception to this rule was the large cap which I doubled. This work on the PS improved the sound of the 2900 a little but not that much that warrants the time, effort, and cost it took. I think now I would simply replace the x-rated safety caps with Auricaps as well as double the capacitance of the big cap.

Another item that did not make the list is replacing the clock. The reason it did not is that I did not even consider it as I simply couldn't afford it.

[ctong]

Originally posted by mrdon


Well first of all the AD8066 is a dual opamp and the opa134 and opa627 are singles. There is an opa2134 that is a dual version of the opa134 but there is no such dual for the opa627. To make the latter work in the 2900 you need to put two singles on a browndog adapter.

Secondly, these three opamps are all fantastic opamps each with a different emphasis and presenation. In regards to sound differences...to my ears the opa2134 is missing some midrange warmth, the opa627 is too warm, and the AD8066's warmth is in-between the two with the added benefit of the Analog Designs snap and detail. I personally prefer the AD8066 after replacing the stock op270's with opa627's and after that AD8620's.

Again, these impressions are merely subjective as God has created each of us uniquely with unique hearing and has given us audio systems to enjoy, some of which are on the warm side of neutral and others which are on the bright side of neutral.

Hello mrdon,

Thanks for the info. I installed an opa2134 in my sound card a few days ago and I really like the results. I have been using opa627s in my headphone amp but have not done any comparisons between the two op amps. It will be interesting to try the ad op amps. I just bought two ad797s, which are used in one of Mark Levinson's DACs. I will try them in my headphone amp. Do you or anyone else have any experience with this chip?

[BerntR]

[
As you can see, my complete overall of the power supply did not make the list. The PS overall included replacing stock capacitors on the PS board with ones 20% larger in capacitance (ala Bob McNiece on the Toshiba 4960).

IMO, a competent upgrade of the 2900 SMPS can move this player up a league or two. I seriously doubt that it is possible to bring out the potential in the player without addressing the PS.

But it takes more than bigger caps to make the move. While bigger caps may help, other factors are far more important.

I'm not en expert on caps and diodes, but I received qualified help to select the right components in key areas. And I was - and still am - extremely happy with the result.

[singleended40]

Originally posted by q1
Hi Tomas,

Thx for the information.
I also replaced the output capacitors by 10 uf mkp audyn capacitors. Sounds better indeed!

muting transistors is a good suggestion. did not see them yet. I have no scheme...:-( how they look like?

Got the idea on this dutch site:
http://www.soundevolution.nl/article...D_2900_SE.html

Also a new clock is placed inside and better op-amps.

A new clock which can be obtained here:
http://www.tentlabs.com/Products/DAC...ACUpgrade.html

I did not do the clock my self yet. But I expect a huge difference. Because i have the same clock in my CEC transport. And the was WOW!!

Hope to hear from you.

Rene

Hi,

Would you please describe more specifically the replacement of two output caps with Audyn 10uF but ?volt? It looks like in the pictures that shown the replacement of two (2) original medium caps and four(4) small caps for two big Audyn caps. Is that okay I can replace with two (2) Sonicraft 10uF/1200VDC but in what indicated letter/number on PCB?

I am planning to replace the LC clock (from parts connexion) but do not know how to replace the CLOCK PS. Anyone had experience please help me step by step. I would appreciate your time and effort. Thanks in advance.

Regards,
Tan

[singleended40]

[QUOTE]Originally posted by mrdon
[B]The modding of my 2900 is officially complete.

Tonight, I finished my PS upgrades by removing the .1uf/250V and .22uf/250V x-rated safety caps and replacing them both with .47uf/600V Auricaps (ala "auricap tweak").

At what position of PS do you remove the .1uF/250V and .22uF/250V x-rated safety caps by replacing with two .47uF/600V?

I just removed two tiny 220uF/16V and replaced with two BG 220uF/63V. The sound is smoothing out very nice.

[singleended40]

Originally posted by q1
Hi all,

Nice to read all the new replies :-)

Maybe it is a idea that everybody who is getting this messages post a list of all the modifications he made to his 2900 and what the results were?

I own 2 pieces of denon 2900. 1 for to play DVD+ SACD's and 1 for the pc room as cd/sacd player only (second hand for 575 euro)

What I did is nothing complicated:

- Removed the output capacitors - 1 piece both channels +/- 3 mv DC / 1 with one channel 50mv* DC. : --> Better soundstage and bass response.


- Removed the muting transistors: --> better soundstage.

- Silver wire and 70 ohm resister connected from op275 to output terminal. --> Better bass response.

- Disconnecting power and signal cable to video board improve sound as well (1 use one as music player only)
--> Better bass response.


Future plans:

- Improve powersupply with Black Gates?
- Replace op275 with 2 x opa627BP with a adapter. (order placed on ebay 4 for 20 usd!!)
- TentClock?

Does anyone know why there are 2 op-amps (op275gb) needed in the signal way? what would happen when we disable one half of the op275? I would not mind when sound would improve and output voltage would decrease.

Best regards,

Rene

* Maybe this will improve with other op-amps.

Hi q1,

Would you be more specific about what you replaced and removed parts in 2900? I am in the process of mod my 2900. So far I just replaced the PS caps to a better one (Rubycon 100uF/450V and two BG 220uF/50V).

Where are the output caps and muting transistors located? Would you please show me step by step with your pics if it is possible? Thank you and appreciate your time and effort.

[mrdon]

Would you please describe more specifically the replacement of two output caps with Audyn 10uF but ?volt? It looks like in the pictures that shown the replacement of two (2) original medium caps and four(4) small caps for two big Audyn caps. Is that okay I can replace with two (2) Sonicraft 10uF/1200VDC but in what indicated letter/number on PCB?

C366, 355, 367, and 357, c421 and mate are bridged by the 2X10uf poly caps. The bridge begins at the the negative pads of C357 and C355 where the negative leads of the Auricaps are soldered. The bridge ends at the postive leads of the now shorted C369 and C360 (where the Blue film caps used to be). Here the positive leads of the poly caps are soldered.

Of course you can use two (2) Sonicraft 10uF/1200VDC.

At what position of PS do you remove the .1uF/250V and .22uF/250V x-rated safety caps by replacing with two .47uF/600V?

At the front of the PS pcb, there are two rectangular black capacitors. Those are the ones to remove and replace with the Auricaps.

[mrdon]

I am experiencing a "sizzle" sound from time-to-time in the left channel. It comes and then goes.

Another issue, which may be related, occurs when I switch tracks - a "pop" comes out of the left channel only.

Could the left channel opamp be oscilating?

Or could it be a mute transitor going bad?

[singleended40]

Originally posted by mrdon


C366, 355, 367, and 357, c421 and mate are bridged by the 2X10uf poly caps. The bridge begins at the the negative pads of C357 and C355 where the negative leads of the Auricaps are soldered. The bridge ends at the postive leads of the now shorted C369 and C360 (where the Blue film caps used to be). Here the positive leads of the poly caps are soldered.

Of course you can use two (2) Sonicraft 10uF/1200VDC.



At the front of the PS pcb, there are two rectangular black capacitors. Those are the ones to remove and replace with the Auricaps.

Hi mrdon,

I did not complete this part. However, I replaced the two small tower caps in between the four small caps with two big O BGs (same capacitance but higher voltage, is that okay?). Therefore, I had to remove a Video PCB. What should I do next or replace some of the small caps with BG Non-polarized in this Audio PCB @signal path. Is worth to do this?

I also replaced the two secured mica caps with two Auricap .47 630V but have not increased the capacitance value of main PS cap to 220uF. I heard some of the dull sound, is this happened to your? Do you also recommend to replace all other caps in PS to higher grade caps like UCCs, Nichicons or BGs? Thanks.

What else do I need to replace in term to make the sound improving?

Regards,
Tan