ctong said:
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.
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:
- 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.
mrdon said:
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?
[
As you can see, my complete overall of the power supply did not make the list.
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.
q1 said:
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
mrdon said: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.
q1 said: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.
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.
"Sizzle" and "Pop" in the Left channel Denon 2900
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?
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?
Questions for PS
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
mrdon said:
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
Sizzle
MRDON,
The sizzle sound has something to do with de bleu caps around the (formerly opa275) opamp.
It's an input filter from the dac chip.
I had the same experience and it got worse when playing SACD.
I removed all four of them.
Sorry but I can't give you position numbers because the 2900 is not in my posession anymore.
MRDON,
The sizzle sound has something to do with de bleu caps around the (formerly opa275) opamp.
It's an input filter from the dac chip.
I had the same experience and it got worse when playing SACD.
I removed all four of them.
Sorry but I can't give you position numbers because the 2900 is not in my posession anymore.
I'm having Matt Anker do a custom 6 channel mod on my DVD-2900. The stock clock is being replaced with the Danish "D-Clock" while the D/A and analog power supplies are "beefed up" . The I/V stage(NJM2068) and the Filter opamps (BA25218) are being replaced with AD826's, and the Buffer Opamps (OPA275) replaced with socketed OPA2132 (so these can be swapped out later for another dual opamp as I experiment to see what sounds best in that critical position); the coupling caps are being replaced with Auricaps. The front channel Opamps are then biased into class-A operation. -chas
Another DIYer wrote"I have th CDP-X779ES wich is the non-japanese(?) version of the 777ESA. I have tried a lot of op-amp swapping, and sofar most happy with AD826 in most places, but the "buffer"op-amp is very sensitive , and found a OP2132 worked ok there. Left the OPA27 alone. Next challenge is the clock..."- Arne K[/I
I'm under the impression that the 2132 is simply a tighter-spec'd version of the 2134, which is spec'd for "Audio" (read 'less critical')applications; the improved DC characteristics probably don't matter much in this application. I went with the 2132 because it's what we had on hand.
Any other opinions out there?
-Chas
Another DIYer wrote: I used 2 OPA2132 opamps, but if I had to do it again I would use 2 OPA2134. An OPA2132 costs $6.99 while an OPA2134 costs $2.67. Since there is almost no audible difference between both opamps , I would go with the OPA2134 to save money.-J.Levallois
clm811 said:
I have since replaced the 2134s with 2132s. The latter is simply more open and transparent. I replaced the filter opamps with LM6172.
I also replaced all the caps with Panasonic polypropylene caps.
Overall the 2900 is much better after the mods but still behind the XA777ES on sacd. The limitation is probably the clock, which is not a very good one and is far away physically from the DAC. Given this limitation I would be hesitant to go through the trouble to install 627s.
PS. The 2900 uses soic opams for the IV stage whereas the XA777ES uses 8DIP. Does anyone know whether there is a difference in performance for different packages?
Tweaking Denon 2900
I have replaced all high quality caps in the power supply and removed the video pcb and all connectors that I have never used except the digital and a pair of analog RCA connectors. In the next step, I will stick the Black Hole Pad (BHP) on each cap, transformer and chip. I have tried this to my Promitheus DAC and my SB2 power supply (CI VDC-SB). So far the sound has more focus, decays, resolution and huge soundstage.
Just let you guys know about this important tweaks which cancel out most of vibration going on in the pcb circuit.
I have replaced all high quality caps in the power supply and removed the video pcb and all connectors that I have never used except the digital and a pair of analog RCA connectors. In the next step, I will stick the Black Hole Pad (BHP) on each cap, transformer and chip. I have tried this to my Promitheus DAC and my SB2 power supply (CI VDC-SB). So far the sound has more focus, decays, resolution and huge soundstage.
Just let you guys know about this important tweaks which cancel out most of vibration going on in the pcb circuit.
When you say "still behind the XA777ES", what exactly do you mean?
Are you comparing the 2900 to a STOCK XA777ES?
Besides changing the opamps, what other mods have you done to your DVD-2900?
I believe the stock XA777ES also uses 2132's after the D/A converter, but has a separate audio clock for the DAC and dedicated power supplies for the audio & DAC (where the Denon uses a shared SMPS, which is more noisy).
Perhaps upgrading the clock and adding a dedicated power supply to the opamps will bring the 2900 closer?
Anybody else have experience running separate power to the opamps, and what does this involve(i.e. cutting traces?
)?.Thanks.
clm811 said:
When you say "still behind the XA777ES", what exactly do you mean?
Are you comparing the 2900 to a STOCK XA777ES?
Besides changing the opamps, what other mods have you done to your DVD-2900?
I believe the stock XA777ES also uses 2132's after the D/A converter, but has a separate audio clock for the DAC and dedicated power supplies for the audio & DAC (where the Denon uses a shared SMPS, which is more noisy).
Perhaps upgrading the clock and adding a dedicated power supply to the opamps will bring the 2900 closer?
Anybody else have experience running separate power to the opamps, and what does this involve(i.e. cutting traces?
Thanks.
I have heard the XA777ES and am comparing the 2900 to it from memory. The difference is obvious. I also have a modified SCD-C555ES which is very close to the XA777ES. The 2900 is also inferior.
The problem with the clock in the 2900 is that it is not located on the audio board. The clock signal has to travel a long path and will be susceptible to degradation. So I do not know whether a better clock will make any difference.
I have not tried a new PS. But I did added some bypass caps to the audio board rails. I suppose having separate supplies for the digital and analog parts of the audio board would help.
Another mod I did was to reduce the resistor value for IV conversion. When I was using 2134 for the output stage, the player will clip when the music is near 0db. Reducing the resistor value solved the problem.
The 0db output is about 1.7V rms, 1.4db lower than the standard 2V output. I have not tried to restore the original value after I changed the opamp to 2132.
My SCD-C555ES does not have this problem.
The 0db output is about 1.7V rms, 1.4db lower than the standard 2V output. I have not tried to restore the original value after I changed the opamp to 2132.
My SCD-C555ES does not have this problem.
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