| thomsva |
Last week I made the first steps to modify my Denon DVD2900. I have started at the output stage. The first thing I did was carefully removing the mute transistors from the front channels. The improvement was very clear. A transistor between the signal path and ground seems to cover the smallest details on the recordings. The player now makes a few small pops when turning on the power or changing records. But it’s not very annoying really.
The second thing I did was replacing the coupling caps with polypropylenes. There capacitance is now only 6,6uF compared to the original >220uF. If the cap is too small it will affect bass levels but I have calculated that with a 10k load the –3db point is 2Hz with the new caps, so I think I can live with that. Also this time the improvement was clear. The high frequencies sound cleaner.
Next I will continue working on the output stage. Have a look at TR231 in the pic below. Depending on the state of the transistor the IC215 amplification will be roughly 1 or 2. The wire that changes the state is marked “PCM/DSD”. My guess is that the stage amplification is changed depending on weather the record being played is a CD or SACD/DVDA. As the TR231 could have a similar effect on the sound as the mute transistors I would like to remove it. My logic says that removing TR231 will make the sound level change depending on what format is being played. I can live with that if the sound is improved. Has anyone made similar mods? Any thoughts?
The DVD2900 has two pairs of front channel outputs. I will connect one pair of outputs past the coupling caps directly trough a resistor to the op-amp. This should work as long as the preamp has coupling caps on the inputs. Anyone tried this?
Also more ideas about easy improvements are appreciated!
-thomas |
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| 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/articl...VD_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/DA...DACUpgrade.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 |
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| ergo |
I'm in the process of upgrading one DVD-A11...
I replaced all the opamps in analog stage with OPA2134.
Also all the caps around DAC chips got bypassed as did some other critical caps in analog stage.. look at attached photo.
Next up in list is a Tent XO2 in a few weeks.
Ergo |
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| A 8 |
I am not sure it will be worth the effort changing the clock in these players. The clock that controls the timing is derived from 27MHz (for video) crystal and then uses Clock IC to create the master clocks for audio.
The clock then passes several IC's and many centimeters before it reaches the actual da chips.
Putting a nice clock in and let it pass all that **** seems a waste to me. In my world a good clock needs to be clean close to where it matters.
Perhaps a better approach would be to start by making sure that the existing clock circuit gets the best possible working conditions, then take it from there depending on the results.
I've just dismantled my 2900 for the next level of mods and will start to change decoupling caps for Oscon SVP's on the main board. There are also several existing options to filter ps noise on the pcb that's not being used.
/Michael |
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| thomsva |
Hello again,
I did remove the transistors I referred to in my first message. I also removed the muting transistors for all the other channels as well. So totally I have now removed 26 (!) transistors from the player.
The denon has two pairs of outputs for the front channels. I have the coupling caps bypassed for one of the output pairs. This is possible because the preamp has coupling caps on the input.
q1: The mute transistors are surface-mounted and very small. It took a while to desolder them carefully, but I'm really happy about the result.
So far removing the muting transistors had the biggest impact on the sound quality. Also upgrading the coupling caps was a clear improvement. Bypassing the improved coupling caps didn't change much, only a slight increase in the bass level. That effect could certainly be imaginary.
So what's next? Tampering with the clock is too challenging for me, so I'm thinking about a new psu for the audio circuits.
-thomas |
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| DIAR |
As you know, I achieved the biggest change for better by changing the op amplifiers from output.
I can easily send OPA627+adapter to you for testing (I can send also AD8065 if you like but then I have to listen to old NJM4580 while you're testing :bawling: ;) ) . All you need to do is desolder the old opa and change it to dip8 socket. This enables you to change opa rapidly without any risk of harming the PCB. If you like (I'm sure you won't!) you can install the old opa by just sticking it to the socket. In my opinion, AD8065 is more technical sounding opa and OPA627 is more musical (or should I say emotional). Concidering your equipment, I think you would prefer the latter. I have 5 (!) DIP8 single-to-dual OPA adapters because of the Browndog incidence so I can sell you one of them for a niominal price. You can get OPA626 from RS. I also have 5 AMD single-to-dual which are suitable for AD8065 (however I recommend buying an assembled module from LCAudio).
Any thoughts about this? :D
btw. The easiest way to desolder SMD components is using two soldering irons and heating all pins at the same time. I used that tecnique the second time I removed muting transistors and it was about 100 times easier and safer than using only one soldering iron. |
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| thomsva |
Diar,
Many thanks for the suggestions. I will consider them but I'm moving slowly at the moment. I like my player a lot already.
-thomas |
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| DIAR |
No problem :D It would be interesting to hear your thoughts about the OPA's so if you change your mind and wan't to test before purchasing, send me an email.
Have you considered Jung superregulator to power supply. In some applications Jung superregulator should be the best there is but I've also heard that it isn't a fool proof regulator. You can buy PCB's for low price from here:
http://www.aoselectronics.com/jungsrpcb.html
I'd like to get one of those but I don't know how to adjust the voltage and where to use it :D :rolleyes: |
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| hatchiruko |
[QUOTE]Originally posted by thomsva
[B]Hello again,
I did remove the transistors I referred to in my first message. I also removed the muting transistors for all the other channels as well. So totally I have now removed 26 (!) transistors from the player.
I have a Yamaha CDP and has a digital and analog output (RCA). I removed the mute transistors on the analog side but not exactly sure if the digital side will make any differences. Does anybody have done this? |
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| Lucas_G |
| quote: | Originally posted by thomsva
Last week I made the first steps to modify my Denon DVD2900. I have started at the output stage. The first thing I did was carefully removing the mute transistors from the front channels. The improvement was very clear. A transistor between the signal path and ground seems to cover the smallest details on the recordings. The player now makes a few small pops when turning on the power or changing records. But it’s not very annoying really.
The second thing I did was replacing the coupling caps with polypropylenes. There capacitance is now only 6,6uF compared to the original >220uF. If the cap is too small it will affect bass levels but I have calculated that with a 10k load the –3db point is 2Hz with the new caps, so I think I can live with that. Also this time the improvement was clear. The high frequencies sound cleaner.
Next I will continue working on the output stage. Have a look at TR231 in the pic below. Depending on the state of the transistor the IC215 amplification will be roughly 1 or 2. The wire that changes the state is marked “PCM/DSD”. My guess is that the stage amplification is changed depending on weather the record being played is a CD or SACD/DVDA. As the TR231 could have a similar effect on the sound as the mute transistors I would like to remove it. My logic says that removing TR231 will make the sound level change depending on what format is being played. I can live with that if the sound is improved. Has anyone made similar mods? Any thoughts?
The DVD2900 has two pairs of front channel outputs. I will connect one pair of outputs past the coupling caps directly trough a resistor to the op-amp. This should work as long as the preamp has coupling caps on the inputs. Anyone tried this?
Also more ideas about easy improvements are appreciated!
-thomas |
Hi Thomas,
I think removing TR231 seems a good idea.
How about removing everything that follows the OPA275?
DOES ANYONE KNOW whether the output of the OPA275 needs any of the resistors in series or parallel that follow in this scheme? (See picture in first post of this thread)
The 100k resisors on ground together with the 470 pF caps are probably there to prevent oscillation, but are they really necessary? CAN ANYONE COMMENT?
You do need of course one output cap in series to prevent DC ruining you amps (unless you are sure your preamp filters thsi out). 6.8 uF is surely large enough, and in case of using large prolypropyleen (speaker) caps it is wise to try smaller ones. However if you would use Blackgates you could also try 47 to 220 uF. The larger blackgate the more dark and bass-pronounced the sound gets with some lack of fine detail in the treble.
Regards,
Lucas |
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| BerntR |
This was a very interesting thread as I am currently in the middle of a modification process of a DVD 2900. I bought it because I wanted a multiformat player and because it is a very promising modding object. I searched the net and companies like Underwood and Modwright describe their modifications very precise. So I took those as guidlines.
In my setup the DVD 2900 replaced an older Denon CD S-10 modded with clock and analog buffer from LCAudio. I am still happy with the sound from this old horse - but now it is on a new assignment.
Right from the shop - and after some hours of burn-in the DVD 2900 were miles behind the older brother on CD playback. In my ears it sounded ... "dirty" and I frequently turned the volume down after short listening sessions. The comparing was done through the digital output. Regarding sound quality 2 channel digital output is my main priority. But almost any digital improvement will also improve the analog outputs.
As I also have a Tact RCS preamp with digital room correction I am an eager member of the TACT forums over at Yahoo. And one major subject of discussion there has been power supply. Some build separate linear PS and other modify the inboard SMPS The DVD and the RCS both has switch mode PS.
So I started out with component replacement in the power supply. Basically, I used Auricaps on the power input for Hf filtering. Then I replaced the diodes with high speed soft recovery types. Then I replaced every electrolyte on the board with Black Gates. On the input side, I used one PKW type. On the output rails I installed bipolar black gates in super e-configurations where appropriate. (super e: face-to face in order to cancel inductance. This is said to increase bandwith very significantly). For the rest, I basically used standard BG's.
These capacitors require quite a few hours of "idling" before they reach their potential, but the improvement was huge right away. Now it was on par with much more expensive players. Black Gates are quite costly when you replace the lot, but it is cheaper than buying a clock kit and the resulting improvement is worth every cent.
After the SMPS modification I installed an LClock XO3. The improvement was marginal compared to the Black Gates - probably because I'd already cleaned up the power feeding the clock. Or maybe because this clock is feeding another clock generator.
The improvement from similar mod of the Tact unit's smps was at least as huge as in the DVD player and the combination was a taste of magic. I am still running SPDIF outputs here.
I then replaced virtually every electrolyte on the DVD audio board with BG's (N, Nx and Nx Hi-Q types - and the film caps (the blue ones) with a better type. I've not touched the muting transistors nor the output coupling electrolytes as I plan to deal with those later (perhaps a bias adjustment on the output and DC coupling right through the speakers). So I still play through those brown caps - but guess what?
The analog output (which is converted back to digital in the Tact unit - and then back again to analog) is ...ng close to the SPDIF line (which eliminates DA+AD conversion in my setup). Analog has slightly less resolution but the highest frequencies are smoother and more powerful passages are represented in a more relaxed (as in less distorted) manner. Analog and digital outputs are anyway now so close that an A/B comparison is required to sort them out.
This means that the digital signal feeding the audio board must be quite OK by my standards - and that the BG's have improved the sound quality from the DACs and the op-amps by a mile.
So yesterday, I went for the SPDIF output. That had to be the reason digital out wasn't best in all disciplines. I found some alternative circuitry on diyAudio.com - and had a buffer stage available in the house. So I bypassed the circuitry after the 74HC04 with: same value as originial series caps of BG super e combo, R10k/R1k attenuation, BUF 04G with unity gain, a Bybee Purifier and a BNC connector. And now - the digital ouput (which in my setup eliminates two conversions) is finally better than the analog. I haven't compared with good old S-10 after the last steps but I guess that the new dog now performs better than the old horse.
I nearly forgot - I've also damped the cabinet with some damping sheet - and today i replaced the feet with a set of very soft rubber-like consistensy. I don't know how this affects the sound, but I guess it all adds upp.
I am really thrilled by the impact of BG's - and I almost panicked when I realised that they are going out of business next year so I've placed a new BG order. (but no need to panick - there are large stocks "everywhere - or so I'm told)
I don't know if there are any more quantum leaps left in the DVD 2900. I've already reached my satisfaction platau. But due to the very good results so far I am going to replace all the electrolytes on the digital board beneath the transport mechanism. In fact I am going to replace all the electrolytes through the two channel audio chain exept the large 160.000uF bank in the power amp that feeds current to the speakers.
I've spent a few hours on the internet during the process. Black Gates have S/N ratios in the range 140-180 dB if my memory is correct. Some other "high end" electrolytes are also said to perform very well.
Anyway, it seems that mainstreem hifi electrolytes often has signal/noise of 60db - 100 dB which is very poor compared to most of the other components you can find in this player. They don't do their job very well. Due to limited band with they do not smooth the DC power in an smps very well - and their smaller brethren do a poor job on the audio board. Noisy *******s!
Those on the digital and video board may be struggling hard to keep up with all the digital components in this player. But they seem to be a different - and probably better - kind. I will find out soon.
Has anyone done any serious work on the digital board?
Regards,
Bernt
:att'n: :att'n: |
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| A 8 |
I can recommend doing the main board, for me the difference was significant. My 2900 now beats a heavily modded Pioneer cdp as transport for cd's which was not the case before. It really cleaned up the hights, became more 3 dimensional and with more lowfreq punch.
I changed all decoupling caps to oscons svp's 120uF to 470uF from the drive unit to the audio dsp. I also used the additional filteroption availible on the board for the laser unit.
When you get to the main board it seems there is a lot of space to add stuff but be aware that the discassembly moves down when you eject the disc.
Considering your setup you might want try another mod I've done, get a DIT and tap the digital frontchannel streams just after the Analog devices DSP, this way you get the dsp funktions (if you want to, good for DD and DTS and multichannel tracks) and dvd audio 24/96 through a spdif feed.
Running cd's with this output sounds better then the built-in spdif on my unit. |
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| BerntR |
| quote: | Originally posted by A 8
I can recommend doing the main board, for me the difference was significant. My 2900 now beats a heavily modded Pioneer cdp as transport for cd's which was not the case before. It really cleaned up the hights, became more 3 dimensional and with more lowfreq punch.
I changed all decoupling caps to oscons svp's 120uF to 470uF from the drive unit to the audio dsp. I also used the additional filteroption availible on the board for the laser unit.
When you get to the main board it seems there is a lot of space to add stuff but be aware that the discassembly moves down when you eject the disc.
Considering your setup you might want try another mod I've done, get a DIT and tap the digital frontchannel streams just after the Analog devices DSP, this way you get the dsp funktions (if you want to, good for DD and DTS and multichannel tracks) and dvd audio 24/96 through a spdif feed.
Running cd's with this output sounds better then the built-in spdif on my unit. |
Thanks,
This sounds very promising.
What is a DIT? Could you explain the last paragraph in more detail? I'm in new territory here. |
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| Guido Tent |
| quote: | Originally posted by A 8
I am not sure it will be worth the effort changing the clock in these players. The clock that controls the timing is derived from 27MHz (for video) crystal and then uses Clock IC to create the master clocks for audio.
The clock then passes several IC's and many centimeters before it reaches the actual da chips.
Putting a nice clock in and let it pass all that **** seems a waste to me. In my world a good clock needs to be clean close to where it matters.
Perhaps a better approach would be to start by making sure that the existing clock circuit gets the best possible working conditions, then take it from there depending on the results.
I've just dismantled my 2900 for the next level of mods and will start to change decoupling caps for Oscon SVP's on the main board. There are also several existing options to filter ps noise on the pcb that's not being used.
/Michael |
Hi
You are right abouth the subsequent PLL IC, however, what you don't throw in, doesn't come out....
Especially the LF jitter will improve, when feeding that IC from a better clock
Also cleaning up the PLL IC supply will help, especially at the LF side of the spectrum
(hint: Adding capacitors won't work)
best regards |
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| A 8 |
| quote: | Thanks,
This sounds very promising.
What is a DIT? Could you explain the last paragraph in more detail? I'm in new territory here.
__________________
Regards,
Bernt |
A DIT is a Digitalaudio Interface Transmitter like the CS8405 or 06 from Cirrus logic . CS8405
/Michael |
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| A 8 |
| quote: | Hi
You are right abouth the subsequent PLL IC, however, what you don't throw in, doesn't come out....
Especially the LF jitter will improve, when feeding that IC from a better clock
Also cleaning up the PLL IC supply will help, especially at the LF side of the spectrum
(hint: Adding capacitors won't work)
best regards
__________________
Guido Tent |
Hi Guido,
I agree fully on cleaning up the PLL supply which was why I suggested improving the existing clockcircuits conditions.
It is however not only the PLL IC that needs attention, you have additional logic in the clock path that even share other streams, supply and local decoupling with additional logic so even if you have a nice clock feeding the PLL you'll never get close to the clocks potential without fixing the subsekvent signal path. Even then it is still somewhat polluted by shared signalprocessing, supplies and logic.
In Sweden we have a saying that goes something like "throwing pearls at the pigs..... "
I am sure it will be different though and some might think that is an improvement.
Cheers. |
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| BerntR |
| quote: | Originally posted by Guido Tent
Also cleaning up the PLL IC supply will help, especially at the LF side of the spectrum
(hint: Adding capacitors won't work)
best regards |
Guido,
I would appreciate more than hints on this subject. What will work??
best regards,
Bernt |
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| BerntR |
| quote: | Originally posted by A 8
In Sweden we have a saying that goes something like "throwing pearls at the pigs..... "
Cheers. |
Pigs are underrated. Physically, they are perhaps the animal that's most similar to homo sapiens audiophilis.....
I WANT MORE PEARLS!!
Nøff. |
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| A 8 |
| quote: | | Pigs are underrated. Physically, they are perhaps the animal that's most similar to homo sapiens audiophilis..... |
Bernt,
I just realized how this could be interpreted, Sorry it was really not referenced to you or any other tweaker I was mearly refering to the existing clock circuit as the pig and exotic clocks as the pearls.
Again, I am sorry for the confusion.
/Michael |
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| BerntR |
| quote: | Originally posted by A 8
Bernt,
I just realized how this could be interpreted, Sorry it was really not referenced to you or any other tweaker I was mearly refering to the existing clock circuit as the pig and exotic clocks as the pearls.
Again, I am sorry for the confusion.
/Michael |
Michael,
Don't be. I understood you the first time. I was just trying to make a joke out of it. Not with great success I must admit.
I didn't realise that I could be interprated as identifying with the pig until now. I guess the next laugh is on me. |
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| Guido Tent |
| quote: | Originally posted by BerntR
Guido,
I would appreciate more than hints on this subject. What will work??
best regards,
Bernt |
Hi
A clean power supply to start with. Get rid of al LM / LT / TL or whatever based circuits. Think in clean current souyrces and discrete shunts, or use voltage followers together with clean references (like buried zeners or LEDs)
Bandgaps are prcise references, but not clean
THEN use decent caps where they are used for: To suppress RF voltage variations caused by the load, rather than trying to flatten the noise gennerated by the supply
cheers |
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| A 8 |
Guido is of course right, however it is really not practical for the mainboard in a player like this. I think it has more then 15 individual regulators. It would be a huge redesign of the powersupply and unless you are really on top of each and every IC and find space for it you are very likely to fail.
The only place I would consider it would be the Audio Board which only needs 4 regulated supplies. I would build a separate supply and get a low noise regulator as Guido suggests.
The main board has a lot of L-C, R-C powersupply filtering built in for most of the IC's so adding HQ Low ESR Caps after the filtering will help to reduce noise on the ps and if you increase the caps values you'll also get better low freq filtering.
I've done it and it sure makes a difference.
/Michael |
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| Htguy |
Hi,
I just bought a dvd 2900 to replace my dvd 3800. So far I have been unimpressed by the audio output of this player for everything but sacd(which sounds great). The 3800 sounds more lively, focused and forward w/o being bright. It seems like the power supply might be a good place to start. Does anyone have a design that might help me make this happen? (Pics, schematics etc? (I am pretty new at this stuff, so please be patient)
Thanks
God bless...
Mark |
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| machinow |
You need a resistor after the OP Amp's output, otherwise it may oscillate. You can keep it's value as low as 30..80 ohms though to minimize the effects of the interconects. Lowering this output resistance usually betters the sound quality of the player even when the mute-transistors are left in place.
PS: In my similar circiuts I put it as close as possible to the OPamp chip to prevent additional parasitic capacitance of the traces which may decrease the phase margin of the circuit. I usually work with SMD parts - SO, 1206 and mostly 0805 passives. |
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| Htguy |
Hi,
I am looking into upgrading my dvd 2900 for audio output and am pretty new w/electronic upgrades like this, so I could use some help.
1) to remove the mute transistors on the analoge outs I remove tr221-228 and replace them with a resistor between the outer solder points? (What value resistor would be best?)
-what about the tr207-214? What do they do? do they get removes as well?
-What about replacing them with relays to stop the poping, but keep the signal clean? (Could run mini relays off their own power supply and use the middle solder point and a transistor to switch the external power to the coil of the relay? Good idea or waste of time?)
2) Upgrading the coupling capicitors replace the radial caps (C361-364) with 10uf black gates? (How much base will I loose?)
-What should I put in place of the blue caps (C371-374)? A black gate alternative? Which one, or better alternative?
3) Are there any other caps that I should replace with Black Gates to make a big difference on the analoge or coax digital output to make them sound better, cleaner, more dynamic, better?
4) is it worth it to upgrade the caps on the main powersupply board to Black gate caps or are Phillips LL caps good enough as long as I up the capacitance? (I am thinking of using 2 caps of the same rating in place of each power filter cap in the power supply I.E. replae one 100uf 16v cap w/2 100uf 16v cap. Reason: two smaller caps recover faster and give better transient power than one larger cap. -->Does this logic hold up in the audio/video realm or not? ??Increased resistance negates effect??
Thanks for your help.
God bless...
Mark |
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| Htguy |
Hi,
I forgot a few things.
1) I want to replace the diodes in the power supply with FRED type.
what ratings should I look for? Anyone have a part number and brand to suggest?
2) anyone have suggestions/ pictures/schematics for upgrading the opamps to better ones? What is the best opamp for this player? (I know the Burr/Brown need an adapter to put 2 to replace the one on the player. what is the best Burr/Brown Part # )
Thanks for your help.
God bless...
Mark |
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| Htguy |
Hi,
Well the SDI mod is working great and the diode replacement really made a difference in the audio performance of the unit. (I just replaced the 4 that make up the bridge rectifier for ac)
Does anyone know if the Burr Brown ops 627 can be soldered in as a pin for pin replacement of the stock opamps?
Thanks
GOd bless...
Mark |
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| A 8 |
| quote: | | Does anyone know if the Burr Brown ops 627 can be soldered in as a pin for pin replacement of the stock opamps? |
Unfortunatly not, the ones in the 2900 are dual channel OP275GP for buffering, NJM2068 for I/V and some BA15218 for hf filtering. Any other SMD dual channel op will fit though.
| quote: | | is it worth it to upgrade the caps on the main powersupply board to Black gate caps or are Phillips LL caps good enough as long as I up the capacitance? (I am thinking of using 2 caps of the same rating in place of each power filter cap in the power supply I.E. replae one 100uf 16v cap w/2 100uf 16v cap. Reason: two smaller caps recover faster and give better transient power than one larger cap. -->Does this logic hold up in the audio/video realm or not? ??Increased resistance negates effect?? |
For the main board you absolutly need to stick with SMD's, partly becouse shorter lead lengts and less ESL but also becouse the critical ones are under the transport where there is not space for anything else. Dunno much about the caps you're referring to but I would suggest Sanyo Oscons, an SMD variant called SVP. I would not double up any caps, the caps I am referring to is as "fast" as you could expect.
| quote: | | Upgrading the coupling capicitors replace the radial caps (C361-364) with 10uf black gates? (How much base will I loose?) |
If you remove the mute transistors I would suggest you just short the dc blocking output caps. |
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| Htguy |
Hi
I made a mistake describing the caps I want to replace. They are the ones on the power supply board not the main board. WOuld it be worth the Black gates for that board? Which ones ar worth the trouble and expense of replacing on that board?
Thanks
God bless...
Mark |
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| machinow |
You'd better use low-ESR caps, as Rubycon ZL series or Panasonic FC. I'm also pretty amazed how good ordinary Rubycon YK behaves in Switched mode PSUs - so I would prefer Rubycon ZL s.
But what are the stock ones??? They should be similar. To filter the supply better you may only need to enlarge the capacitors after the filter inductors at each Vout. |
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| Htguy |
Hi
Thanks for your input. I am wondering what ERS stands for (IE low esr caos?) I am pretty new at this and don't know a ton of terms.
Also, how does one tell if a dioide in soft recovery or not? (there are fast switch, fast recovery... and I can't tell which is soft recovery. What is the rating I should look for and what is a good range for a soft recovery diode for power supply rectifying? (IE, is a higher "trr" time mean soft recovery? (200ns instead of 35ns?) If not what is the abreviation of the rating I should look for?
Thanks
God bless...
Mark |
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| 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. |
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| WTS |
| DOes anyone ever do any improvements for the video side of the dvd players. |
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| Htguy |
Hi,
So far the only video improvements I have seen is an SDI output. I would love to see some way of making video improvements, but I think it is a tough thing to do (that is apart from making the power supply better so teh video circuits perform better.
Has anyone tried hooking the sdi pins right to the mpeg chip rather than the video card ribbon connector? Does it make the video better? |
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| WTS |
Hi HTguy,
Thats what I was referring to though, was just improving the supply and maybe the clock for the video. Or does nobody here use the players for video, just audio. I've done enough pooging in audio, I'm now into getting a better signal for my 8" crt projector.
Anyone care to jump in, I know this is a audio forum, but it is a DVD player(s) we're talking about here.
Thanks |
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| A 8 |
I've probably done more to the videosection then anywhere else in my unit.
When I first got it I thought the picture was way to soft and a little "nervous"so I got going on it.
I've changed all the decoupling caps to shielded oscons (in the component/PS signal path), replaced the video op amps, replaced the dc filtering caps to film types and increased the PS filtering (coils and caps) going on the board.
The picture is now rock solid, with a bit more details, much sharper and less noisy. The only issue I still have with it is a slight ringing which got marginally better after the mods but still not where I want it. |
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| WTS |
Hi A8,
That sounds great, so what opamps did you go with. What coil/cap(values) combo did you use. Did you anything to the clock circuit.
Thanks
Walter |
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| Htguy |
Hi A8,
Do you have pics of the video mods? What opamps did you use? Where are the video opamps? Were all these mods done on the video board or on the main board? I am using SDI output, so I am guessing that most of these mods would not effect that data stream, right?
Thanks
God bless...
Mark |
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| A 8 |
Hi Guys,
I am not the one to document stuff, I tend to focus on a issue at a time, figure out whats needed and get it done.
However browsing through my files I think I've used a MAX4216 opamp, 200Mhz, -75dB THD@5Mhz, not becouse its the best but becouse it was what I could get that would be a drop in replacement. Its still better then the TOKO 15420 originally mounted. Be aware though that these opamps are VERY, VERY sensitive to layout and decoupling. You can easiliy end up worse then you are.
If I really wanted the best I would try to change the layout and cut down to one opamp per feed, then use the MAX4108 single channel, 400Mhz, -93dB@5Mhz or the BB OPA843 with a similar spec.
I did this a few years back using a BB OPA620 on an Pioneer 717 with really stunning results.
When it comes to filtering and decoupling I don't have the specific values but there are many options on the video board not used to filter ps lines, use them with good coils (very high resonance freq) togeather with oscons and you'll lower the noisefloor significantly.
For the ps entering the board you can easily cut the cables, add coils directly on the cables with a set of high value, low esr caps to keep the overall esr down and at the same time lower incoming noise and smooth off any 50Hz residues.
I've done the clock curcuits by changing the decoupling on the clock curcuit(s) and basically all the digital processing that I found relevant to audio and video performance.
The video board is easy, its the first thing you see above the audio board and the DA is marked AD7300, the opamps are three in a row and marked 15420.
Hope it helps with your inspiration.
/Michael |
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| WTS |
Hi Michael,
Thanks for your input. I'm not modding a 2900, I was just looking for mods that have been done and what improvements where the result. I would think that reworking the clock would make just as big an improvement as it would to the audio side, do they use the same clock for both audio and video as a rule in most players.
Thanks |
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| Htguy |
Hi Guys,
I am looking to make my SDI output even better, so I want to connect it right to the Mitsubishi mpeg decoder
(It says
m32r/e
m32102s6fp
302b100
on the chip. My usual sources for datasheets is coming up blank. So I need help finding the pinouts for this chip. Thanks guys.
God bless...
mark |
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| q1 |
Back to audio :-)
I did replace the 2 op275 with 4 pieces BB OPA627BP and 2 adapters. (total cost 26 usd) like Diar did. Thx for the advice by the way!!!
The is really a large improvement!!! WOW!! What a sound stage, speed, micro dynamics. Now we can hear what SACD is capable of.
Did anyone replaced the NJM2068 for I/V and some BA15218 for hf filtering??
yes? any advise? |
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| q1 |
Back to audio :-)
I did replace the 2 op275 with 4 pieces BB OPA627BP and 2 adapters. (total cost 26 usd) like Diar did. Thx for the advice by the way!!!
The is really a large improvement!!! WOW!! What a sound stage, speed, micro dynamics. Now we can hear what SACD is capable of.
Did anyone replaced the NJM2068 for I/V and some BA15218 for hf filtering??
yes? any advise? |
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| Htguy |
Hi,
Ok so I am ready to start some audio board mods and I noticed the 2 op275's am I right in thinking that those two havet o do with the digital outputs, or do they serve some other purpose?
Can I replace the njm2068 opamps with dual BB opa627 without causing myself anytroubleS?
Thanks
God bless....
Mark |
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| Htguy |
One more thing,
I amnaged to trace the yuv2-9 feeds back from the video board to the top side of the main board through a set of 22ohm mini resistors and then they go to the underside of the main board and come out behind the IC marked TruSurround (data sheet seems to indicate that this is the mpeg decoder.) Is that correct? Is that the mpeg?
Would it help my picture quality to out my sdi feed before those resistors, or would that cause me problems?
Thanks
God bless...
Mark |
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| Htguy |
Hi,
I just got done upgrading all the opamps in the FR and FL of my 2900. I used BB opa2134 and the sound is great. The imaging is better by far and soundstage is also better! (It actuall sounds like the voice is coming from front center even w/o a center speaker!)
It is well worth the effort.
God bless...
Mark |
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| AR2 |
Hello,
Is there anyone who has schematics for this Denon?
I would appreciate it a lot.
Thank you
AR2 |
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| annex666 |
I,d really like to get my hands on the scematics as well.
I recently bought the player (Dec 2004) and would like to modify it at some point, probably starting with the power supply (as this is easiest to build and test off-board and then replace when I know it works!)
Keep up the good work all
;) |
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| Htguy |
Hi,
I finally decieded to bypass the opa 2134s I put in my 2900. I am wondering what is the best place to ground them to? (i noticed that the metal tabs to the chassy are isolated from what appears to be the ground plane via what look like smd resistors, but I can not find any continuity through them, so they seem to not connect at all.
Do I just tie my caps into the other side of the ground plane away from where the mounting tabs are?
Thanks
God bless....
Mark |
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| Htguy |
Hi,
I replaced the op275 with opa627 and tested w and w/o bypass caps and the 627 really does like to be bypassed for best performance.
anyone else have thoughts on doing a clock upgrade on these players? Would it make my SDI ouput better? How about audio? (Based on the circut, I am guessing I would get more in the video end than the audio end due to the IC circuits after the clock)
God bless...
Mark |
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| ergo |
I have installed the Tent XO2 in DVD-A11 and it did give an impovement and according to owner it did improve the sound more than video.
Take care also to improve the bypassing on PLL IC and also a buffer inverter after the PLL IS that feed different parts of a player with clock.
****
As for suggestion that the upgrade is not worth - I think it is. The output clock from PLL will still be much better feed from a pure and low jitter clock source than the original version. Also the clock circuit is mostly inverters for buffering and the added jitter there is still very small compared with original jittery clock.
Ergo |
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| Htguy |
HI ergo,
Thanks for the info.
God bless...
Mark |
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| mrdon |
| Can the "Swenson mod" for the Toshiba 3960 and 4960 also be done to the Denon 2900? I did this in my 4960 recently and it made a vast improvement and you don't need to replace opamps. ;) According to John Swenson the mod can be done to the 2900 if the DAC used in the 2900 is a voltage out DAC and not a current out DAC. Any ideas? Thanks! |
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| mrdon |
| I have just read through this entire topic and frankly it would be nice if someone organized all this modding info with PCB placement numbers, cap and resistor values, maybe even a photo or two. :) I am a newbie at all this so that is why I am asking. |
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| Htguy |
Hi,
The opamp bypassing mod will most likely not work on teh 2900 in that it has a set of opamps to do current to voltage conversion. The dac in it is a BB dsd1790 which is similar to the dsd 1792 and dsd 1796 dacs. try going to ti.com and do a part search for those part numbers and down load the data sheets for those two dacs and then read them over and see what you find.
God bless...
Mark |
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| D.A.R.R.Y.L. |
Hi All,
I am looking to replace the clock as a starter. I have the schematics in pdf format and have the clock ordered. I was wondering about where to connect the new clock? Guido always suggests to remove both the clock and the two adjacent caps. I saw some professional mod where, as far as I could see, only the clock was removed. What are your takes on this?
What i also do not understand is why in the original state the clock signal is fed to pin 8 of the sm8707EV clock gen? In the datasheet of this IC pin 8 is for xto and 7 for xti. Pin 7 isn't even connected!!
So what would you recommend? Only remove the original clock and hook up the new tent XO? And onto which points?
My thougts would be to only cut the trace between r169 and pin 8 from the ic105 (sm8707ev clock ic) and hook up the + of the clock there on pin 8. And hook up the - to the ground somewhere near pin 8.
It would then be very easy to restore the old clock circuitry by only reconnecting the rightside of r169 with pin 8 again. Correct me if I am wrong here. Thanks in advance!!
 |
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| BerntR |
How to connect an extarnal clock is thoroughly described in the datasheet of the clock generator. If you go with that you'll be fine.
I believe pin 7 is connected, but that the trace goes under the ic between the pairs of legs. But you will have to check that for yourself. |
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| D.A.R.R.Y.L. |
| Has anybody else experienced strange clock behaviour with installing a new clock? Like not starting up anymore after 3 days of proper functioning. |
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| mrdon |
I am naming this mod procedure the Denon Dutch Mod as I got the idea through this Dutch modding website and through assistance from diyaudio forum member D.A.R.R.Y.L. who happens to live in Holland. :D
These are the steps:
1. Months ago I replaced the two opamps (IC216 and IC21?) on the top of the audio board and the one underneath the board marked "IC213"with AD8620's. You can also use BB OPA627's on browndogs. It all depends on your ears and your system. (Note: I have found the AD8620 midrange is too light for my ears, so over the weekend, I am going to try AD8066's which some say provide the detail of the AD8620's and warmth of the BB opa627's.)
2. I removed all the two-channel output caps from the top of the audio board using a hot iron and soderwick. They would be
C369 and C360 (Blue film caps)
C366, C355, C367, and C357 (4- 2.2uf/50V caps)
C421 and it's mate (2- 220uf/50V caps)
3. I replaced all these caps with 2 - 10uf/200V Auricaps (Actually I used OEM Auricaps from RTI). I am sure Solens, Audyncaps, Multicaps, Sonicaps, etc... are good and cheaper equivalents. I soldered the negative leads to the negative pads of C357 and C355. I soldered the postive leads to now shorted C369 and C360 (where the Blue film caps used to be).
4. I secured the rather big Auricaps to the board with Silicone.
Experience shows that Auricaps take a number of hours to break-in but I noticed immediate positive results from this upgrade. More micro detail, less harsh highs, bouncy bass, slightly warmer midrange. |
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| D.A.R.R.Y.L. |
Hi Don,
I second that!!! I have used a Solen 9,1µF 400VDC and rerouted to new improved rca sockets from Monacor. Very nice results. |
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| mrdon |
The RTI Audio Film Caps (a.k.a Auricaps) have been in the 2900 for three days now and it appears that the auricap midrange bloom is in process! At least for now, they have managed to compensate for the AD8620's light midrange presentation. This could lead to two rather scandalous conclusions:
1. Auricaps are not neutral.
2. AD8620's provide nice midrange with the right caps. |
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| mrdon |
Over the weekend, I replaced every electrolytic cap in the power supply with Panasonic FC's, increasing the capacitance by 20% over stock except the large cap after the diodes which I increased by 100%. I also replaced the 5 stock diodes with FRED's. It still is breaking in but the results are very good. Darker background, tighter bass, and cleaner highs.
This morning I replaced the two AD8260's (IC216 and IC21?) with two AD8066's each coupled at V+ to V- with .47uf/50V BG PK's. I also replaced the Marinco Cryo'd AC plug I had removed. Of course, it is still breaking in but the results are gorgeous. With the PS upgrade, the Auricap "Dutch" output mod and the AD8066's opamps the Denon 2900 sounds stunning! I highly recommend it.
I am going to let things burn in over the next week. My future plans are to replace IC213 with an AD8066, replace the two X-rated caps with Auricaps, and possibly try the Kwak Klock v.7 as a replacement to the stock clock. |
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| BerntR |
| quote: | Originally posted by mrdon
This morning I replaced the two AD8260's (IC216 and IC21?) with two AD8066's each coupled at V+ to V- with .47uf/50V BG PK's. I also replaced the Marinco Cryo'd AC plug I had removed. Of course, it is still breaking in but the results are gorgeous. With the PS upgrade, the Auricap "Dutch" output mod and the AD8066's opamps the Denon 2900 sounds stunning! I highly recommend it.
|
Experimentation on SMPS in Tact gear suggests that Auricaps on PS input filtering and ERS sheet underneath the PS improves the sound as well.
Can you descibe what new opamps did to the sound? |
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| mrdon |
| quote: | Originally posted by BerntR
Experimentation on SMPS in Tact gear suggests that Auricaps on PS input filtering and ERS sheet underneath the PS improves the sound as well.
Can you descibe what new opamps did to the sound? |
Thanks for the confirmation on the impending Auricap tweak!
In comparison to the AD8620, the AD8066 in my revealing tube system makes the midrange bloom. |
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| Htguy |
hI,
I broke two of the muting transistors on my dvd 2900 when I was trying the remove the muting trans. mod. In my setup I did not like the result, so I want to put them back, but I can't get any of them in the USA. I have tried several other similar transistors, but no luck.
Does anyone have some they would like to sell to me?
Please email me at htguy1@yahoo.com
Thanks
God bless.. |
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| A 8 |
Removing the mute transistors have in my experiance always improved things.
There must be something else wrong if you think it sounds worse.
If you want to keep them, there should be many that can do their job, just google on the name and try to find the specs, go to the nearest vendor and he should be able to find you a set that works. |
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| Htguy |
Hi A8,
Good to talk to you again. The mute trans did make a noticable improvement, but I can't stand the poping noises that result, so I want to put them back. I have tried several different replacements, but no lick at stopping the poping, so I am hoping someone who has taken them off can sell me thiers and save all the trouble.
God bless....
Mark |
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| A 8 |
Its a simple task, they just short the signal to ground and it does not take a exotic trans to do it.
Perhaps there is something else wrong. You could easlily measure the base voltage ie the pin that's not to ground or signal, just to confirm the control logic is ok. |
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| Htguy |
Hi A8,
All the other channels work just fine, so the logic is still operating, but the new 2 transistors must need different value resistors around the transistors. (and I don't have the expertise to refigure those need's)
God bless....
mark |
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| Htguy |
Hi,
Do someone know what the package type is on th muting transistors is? (I think it is a SO-323 type, but I am not sure)
God bless...
Mark |
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| batam |
Hi,
I'd like to know if it is possible to change something to give the unit more "punchy" bass (not the extreme low frequencies, but more like 80Hz), something that really punches you.
Does the changing of some caps would make any difference ?
Which ones ?
Thanks for your replies. |
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| BerntR |
| I would think that you have to look for the punch in the power amp, the speakers and perhaps the room . It's more likely to be found around 150Hz than below 100 Hz. |
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| mrdon |
| quote: | Originally posted by batam
Hi,
I'd like to know if it is possible to change something to give the unit more "punchy" bass (not the extreme low frequencies, but more like 80Hz), something that really punches you.
Does the changing of some caps would make any difference ?
Which ones ?
Thanks for your replies. |
You could try a couple things with the power supply.
1. Replace stock IEC cord with a 4-way braided cable made out of 12 awg teflon coated, silver plated copper and terminated with a Marinco 5266 AC plug on one end and a Marinco IEC 320/15 at both ends. The braid will provide cleaner power and the Marinco plugs will provide tighter bass.
2. Upgrade every power supply cap with Panasonic FC caps (or Black Gates if you can afford them) with 20% increased capacitance over stock. There are only two exceptions. Increase C905 (the big PS cap) from 100uf/400v to 220uf/400uf and maintain the capacitance on the x-rated caps, which you could replace with Auricaps of the same value if you understand the potential risks involved. :hot:
3. Upgrade 5 stock diodes (D901, 902, 903, 904, 906) to 4amp/600v TO220 FRED's.
These two upgrades will provide easier flow of power when those low notes demand it.
You could also try the "Dutch Mod" which will provide cleaner, tighter, more realistic bass.
I've done all these mods to my 2900 and I am VERY HAPPY! |
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| ctong |
| quote: | Originally posted by D.A.R.R.Y.L.
Hi All,
I am looking to replace the clock as a starter. I have the schematics in pdf format and have the clock ordered. I was wondering about where to connect the new clock? Guido always suggests to remove both the clock and the two adjacent caps. I saw some professional mod where, as far as I could see, only the clock was removed. What are your takes on this?
What i also do not understand is why in the original state the clock signal is fed to pin 8 of the sm8707EV clock gen? In the datasheet of this IC pin 8 is for xto and 7 for xti. Pin 7 isn't even connected!!
So what would you recommend? Only remove the original clock and hook up the new tent XO? And onto which points?
My thougts would be to only cut the trace between r169 and pin 8 from the ic105 (sm8707ev clock ic) and hook up the + of the clock there on pin 8. And hook up the - to the ground somewhere near pin 8.
It would then be very easy to restore the old clock circuitry by only reconnecting the rightside of r169 with pin 8 again. Correct me if I am wrong here. Thanks in advance!!
|
DARRYL,
Would it be possible for you to post the Denon 2900 service manual? I am considering replacing th op amps. If the forum policy does not allow
posting service manuals, would it be possible to send it to me via private email?
Thanks
CT |
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| ctong |
I am planning on replacing the IV converter op amps for the RL channels
(JRC2068). I would like to use OPA627 but I cannot find any adaptor that goes from 2DIP to a dual SOIC. Does anyone know any such adaptors?
If there is no such an adaptor, what is the next best thing? One candidate is OPA2134, which I will also use for the post filter/amp. Is opa2132 better for IV convesion? Thanks. |
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| BerntR |
Darryl,
Did you replace the clock and if so - what was the result.
I replaced it with a LCaudio kit, but I am not convinced that it improved things.
First of all, I didn't hear an immediate improvement. On the other hand I got distortions in the picture indication some sort of jitter. But that was with a dedicated power supply. When I fed the clock with the players own PS, the distortion disappeared.
One other matter that complicates things is the chip that you depicted. It's a clocking device. And everything that is sound related is fed a secondary clock signal from this chip. The question is - how much does it help with a better clock with this device in the clock chain? In my case - where I hade invested heavily in PS improvement before the clock was installed - I suspect that the upside of replacing the clock wasn't very big.
But I would like to hear your result. |
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| singleended40 |
Hi All,
I got a modded plan from mrdon. So far I just replace the 100uF/400V with a Rubycon 100uF/450V but I have questions for the rest of mod of the PS capacitors. Should I replace them (I mean all of capacitors) with Rubycon ZAs/ZLs or BG Non polars? I have been told that I replace the superclock with its PS the sound will dramatically change. Therefore, if anyone had done it I would appreciate your share with how to do step by step since I am newbie in this DIY forum. Thanks in advance. |
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| ctong |
As a practice run to modifying the 2900, I replaced the front channel op amps on my Audigy 4 pro sound card, a JRC4556, with an opa2134 (I have never worked with surface-mount components before). The improvement is tremendous. Gone is the muddy and strained sound. The sound card uses CIRRUS 4398 DAC, therefore has a lot of potential. The performance far exceeds the stock 2900 in both cd and dvd-a.
I am very much encouraged by the performance of 2134. But I cannot find any infomation about the PCM1790. If it is comparable to 4398 then 2900 has a lot of room for improvement. I did find a way to use opa627 for IV conversion but it is very pricy and I have no idea whether the extra benefit is sufficiently significant to worth the cost. |
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| mrdon |
The modding of my 2900 is officially complete. :nod:
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").
On the audio board, I replaced the AD8620 I had placed in IC216 with an AD8066 to match the AD8066's in the output path.
I also replaced the stock output path resistors R312, 313, 314, 315, 318, and 319 with Riken Ohms.
In addition to my "Dutch Mod," these last few items have dramatically improved the sound. More detail, tighter bass, more air around notes, and the blackness is just beautiful. Surprisingly, the redbook playback (the 2900 weakness IMHO) has really improved. |
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| ctong |
| quote: | Originally posted by mrdon
The modding of my 2900 is officially complete. :nod:
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").
On the audio board, I replaced the AD8620 I had placed in IC216 with an AD8066 to match the AD8066's in the output path.
I also replaced the stock output path resistors R312, 313, 314, 315, 318, and 319 with Riken Ohms.
In addition to my "Dutch Mod," these last few items have dramatically improved the sound. More detail, tighter bass, more air around notes, and the blackness is just beautiful. Surprisingly, the redbook playback (the 2900 weakness IMHO) has really improved. |
How does ad8066 compare with opa134 or 627? |
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| mrdon |
| quote: | 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. :nod: |
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| 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:- Upgraded Power Cord
- Dutch Mod coupled with replacing certain resistors in output path with Riken Ohm's
- Auricap tweak
As you can see, my complete overall of the power supply did not make the list. :whazzat: 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. :) |
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| ctong |
| quote: | 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. :nod: |
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? |
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| BerntR |
| quote: | [
As you can see, my complete overall of the power supply did not make the list. :whazzat: 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. |
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| singleended40 |
| quote: | 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/articl...VD_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/DA...DACUpgrade.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:whazzat: |
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| singleended40 |
[QUOTE]Originally posted by mrdon
[B]The modding of my 2900 is officially complete. :nod:
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. |
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| singleended40 |
| quote: | 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.:bigeyes: |
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| mrdon |
| quote: | | 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.
| quote: | | 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. |
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| 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? |
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| singleended40 |
| quote: | 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 |
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| Menno Keizer |
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. |
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| ctong |
| I replaced the IV opamps with opa2132 and the outputs with opa2134. The improvement is significant. However, it is still not as transparant as the sony XA777ES. Has any one tried to replace the filter opamps (BA25218)? Also any comparisons between opa2132 and 2134? |
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| clm811 |
| quote: | | "I replaced the IV opamps with opa2132 and the outputs with opa2134. The improvement is significant. However, it is still not as transparant as the sony XA777ES. Has any one tried to replace the filter opamps (BA25218)? -CTong" |
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 |
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| clm811 |
| quote: | | ...any comparisons between opa2132 and 2134? -CTong |
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 |
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| mrdon |
| Unless your system is on the bright side, I wouldn't recommend the opa2132/34 family. Save your pennies and replace the 2 op275's with 4 opa627's and don't look back. |
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| ctong |
| quote: | Originally posted by clm811
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 |
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? |
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| singleended40 |
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. :idea: |
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| clm811 |
| quote: | | I replaced the IV opamps with opa2132 and the outputs with opa2134...I have since replaced the 21 |
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