[FYI] Denon 2900 [Archive]

ben62670

10-20-2009, 07:44 AM

What'd you do Ben? I read something about parts/etc you got to mod your player with or something. Interested in your findings, I've got a Denon DVD2800 that I love as a CDP.

-Freddy

Well I got bored and couldn't sleep so I started digging around in my 2900. Two very easy to remove OpAmps and a slew of crappy electrolytic caps in the signal path. I removed the two OpAmps and installed sockets for an easy swap to better units. I have a bunch of OPA2124's here so no biggy. I like the 2134's dynamics very much, and the mids are a little forward for most peoples tastes, but I like the snap of a rim shot on a drum, and the bite of a live sax. It's kinda funny because I bought this unit intending on modding, and I haven't cracked it for almost a year. For me this is not normal. Well The iron is still going. Just down in the basement scrounging for parts.
Take care.
Ben

ben62670

10-20-2009, 07:45 AM

Did You Upgrade it?

Because I have an extra 3910 if you wanna try that one.

Lets see if I smoke this one first;)
BTW I wanted to call earlier, but lost your number.
Shoot it to me again please.
Thanks lover.
Ben

ben62670

10-20-2009, 08:19 AM

http://i254.photobucket.com/albums/hh83/ben62670/DSCN1616.jpg
http://i254.photobucket.com/albums/hh83/ben62670/DSCN1617.jpg
http://i254.photobucket.com/albums/hh83/ben62670/DSCN1618.jpg
http://i254.photobucket.com/albums/hh83/ben62670/DSCN1620.jpg
Don't light your smoke with a soldering iron;)
At near $50 a carton roll your own is the way to fly:)
PS later I am going to upgrade the caps to better 10ufs. For now I am using 4.7 on the top indaytons, and 4,7uf on the bottom parallel in another flavor.

wutadumsn23

10-20-2009, 09:42 AM

LOL, I was about to ask you if that was something else Ben. Roll your own "cigs" huh? :D

-Jeff

ben62670

10-20-2009, 10:34 AM

I have been trying to refrain from posting, but I am so glad I finally did this. SACD has always sucked on this player. CD has not been very good either. I used to run an Adcom GDA-700 DAC, and then a custom DAC courtosy of GV27, and now the modded 2900. What is special about the 2900? IDK really, but it is very simjple. I had the OPA2134's kicking around and some caps. The original OpAmps were 825's? Before with no matter what setup(except vinynal via my custom phono pre) the soundsatge was too forward. Now I have some depth like tubes(dare I say), and width. The mids have allways plagued my system. Right now it is a hair black(dare I say anything bad), but the dynamics are there, and the highs are there. Symbol hits are good tube like with sustain, and Alsison Kruas has her breath in full effect between notes. I was in the next room getting some juice, and the bass always hit hard, but now I had the weight that I have been missing. I felt the vertical lifting sensation that before was just a hard hit to the chest. The mods are so stupidly simply that most who can read a simple diagram can do it:) I can't wait to get some real caps in there:eek:
Enjoy.
Ben

Edit: BTW I am not claiming to have an ultra high end system at all, but this certainly is a reiteration that mods on mediocre equipment can produce surprising results.

skrol

10-20-2009, 11:50 AM

[IMG]...Don't light your smoke with a soldering iron...

It is not a good idea to use a soldering iron to reheat your coffee either. Yes, I knew an old-timer who used to do this.

Thank you for the mod details. You have peaked my interest and my 2910 may he finding its way to my work bench...as soon as I clear out the other junk that is on my tinker pile.

ben62670

10-20-2009, 12:07 PM

LMK when you are ready. I'll look into it with ya. It shouldn't be very hard to do if you can solder small IC's.

bikerboy

10-20-2009, 12:31 PM

I know you have been talking tubes. Why dont you make a tube output stage ala Lampizator! Get rid of those op amps completely.
http://www.lampizator.eu/LAMPIZATOR/REFERENCES/DENON%201450ar/Denon%201450AR%20lampizator%20tube%20CD%20player.h tml
Have fun.

ben62670

10-20-2009, 12:42 PM

BB I have a tube buffer on the way. I did this because 'I was bored. I was just overly surprised how bad the analog output stage was. I'll get a tube buffer in a week or so;)

ben62670

10-20-2009, 03:57 PM

Damn. Out of the blue comes some serious imaging that wakes me up!
SMB is playing now.
Love Space Cowboy!

I told you 'bout living in the U.S. of A.
Don't you know that I'm a gangster of love
Let me tell you people that I found a new way
And I'm tired of all this talk about love
And the same old story with a new set of words
About the good and the bad and the poor
And the times keep on changin'
So I'm keepin' on top
Of every fat cat who walks through my door

I'm a space cowboy
Bet you weren't ready for that
I'm a space cowboy
I'm sure you know where it's at
Yeah, yeah, yeah, yeah

I was born on this rock
And I've been travelin' through space
Since the moment I first realized
What all you fast talkin' cats would do if you could
You know, I'm ready for the final surprise
There ain't no way around it
Ain't nothing to say
That's gonna satisfy my soul deep inside
All the prayers and surveyors
Keep the whole place uptight
While it keeps on gettin' darker outside

I'm a space cowboy
Bet you weren't ready for that
I'm a space cowboy
I'm sure you know where it's at
Yeah, yeah, yeah, yeah

I see the show downs, slow downs, lost and found, turn arounds
The boys in the military shirts
I keep my eyes on the prize, on the long fallen skies
And I don't let my friends get hurt
All you back room schemers, small trip dreamers
Better find something new to say
Cause you're the same old story
It's the same old crime
And you got some heavy dues to pay

I'm a space cowboy
Bet you weren't ready for that
I'm a space cowboy
I'm sure you know where it's at
Yeah, yeah, yeah, yeah

skrol

10-20-2009, 04:14 PM

My wife was asking me the other day about the symptoms of lead poisoning.

skrol

10-20-2009, 04:16 PM

I have the shop manual for the 2900 but not the 2910. How similar do you suppose the 2900 and the 2910 are?

ben62670

10-20-2009, 04:17 PM

My wife was asking me the other day about the symptoms of lead poisoning.

Well after bridge painting I would say inhaling crack is close to inhaling lead, but most bridge painters smoke crack. YMMV
Ben

GV#27

10-20-2009, 06:32 PM

ben62670

10-20-2009, 06:36 PM

The 4 output caps are not in series, but are part of the "feedback" loop. I did test this for sure. An upgrade there may be in order. I have not yet pulled one to check the value.
Ben

GV#27

10-20-2009, 06:42 PM

The 4 output caps are not in series, but are part of the "feedback" loop.

I can't see the values on the big film's you installed but they look too big for use in the feedback network unless they are part of a servo circuit to null offset.Do you have schem for it?

ben62670

10-20-2009, 06:50 PM

The ones
I replaced are 2 4.7ufs in parallel to come close to the recommended 10uf caps. I personally think this is way too large, but DIY audio says they are correct? Also the little blues are feed backs for sure. No diagram:(

TouchOfEvil

10-20-2009, 10:08 PM

i got one packed up ready to send ya lol.

ben62670

10-21-2009, 08:05 PM

i got one packed up ready to send ya lol.

Let me play with mine a little first. There are more inexpensive mods that can be done. The OpAmps are going to get some caps added, and the muting resistors are going to be removed when I figure out which ones they are. Also I may look into different opamps. I do want to change out the caps for better pieces on the outputs. I don't understand why the recommended values are so high. There is no doubt that the few mods done so far are significant, but I really want to do the whole package right first shot.
Ben

TouchOfEvil

10-21-2009, 11:02 PM

Let me play with mine a little first. There are more inexpensive mods that can be done. The OpAmps are going to get some caps added, and the muting resistors are going to be removed when I figure out which ones they are. Also I may look into different opamps. I do want to change out the caps for better pieces on the outputs. I don't understand why the recommended values are so high. There is no doubt that the few mods done so far are significant, but I really want to do the whole package right first shot.
Ben

Ya man i'm not in any rush. I have the rotel unit kicking it for me right now but the second system could use a upgraded denon in the future.

ben62670

10-22-2009, 01:54 AM

Give the offset levels a check with your DMM but I suspect it has a differential DAC chip(PCM1791/92?) and with the low offset of the 2134 should allow you to remove the output coupling caps altogether.You may also want to bypass those muting transistors at the output.(Atleast that what they appear to be for in the pic.)

It is a full differential DAC. I am not sure what model, but it sounds good. Well I have played around some tonight, and decided to bypass everything after the last OpAmp straight to the Jack with just a 100r in the signal path to reduce an chance of oscillation. Bass is a little harder hitting, the mids are a little more forward, but not in your face like before the mods started. It is nice to have this player. Thanks much GD:) The way this is setup is nice with 2 pairs of front outs. One set is with the caps... all in the ciruit, and the other is strtaight from the output pins. This is very cool for doing an easy comparioson. Time for some better OpAmps. Also I did mod the power caps on the board near as possible to better the power the OPA's get. Maybe I will bias the OpAmps into class A next. Also the PS is SMPS which I have never been a fan of. Maybe I will build a toroidal PS for just the analog section.
Ben

Face

10-22-2009, 03:52 AM

Time for some boutique caps. ;)

Let's see some more pics.

ben62670

10-22-2009, 04:00 AM

Time for some boutique caps. ;)

Let's see some more pics.

You know what. The capless output is great on some material, but on other material the cheap caps sweetened it a bit. I am thinking some 4.7uf AuriCaps may be in order. It is very easy to switch between outputs and have the best of both worlds. The soundstage is freaky(in a very good way). I need a little more gain with my passive pre, and I think I am going to add a tube stage in here. It is already on order:)

Face

10-22-2009, 04:12 AM

The best cap is no cap.

Is your pre direct coupled?

ben62670

10-22-2009, 04:16 AM

My Pre is an alps 100k pot and the signal is sent to the custom active XO. The XO has DC protection if I remember correctly, but I measured near nill DC offset from the Denon outputs. The cheap caps I am using seem to have a little better sustain, and imaging. It takes away from the digital edge. This is by far the closest to tubes yet. The caps are still doing the roller coaster of burnin, but I am going to bite the bullet and get some decent caps.
Ben

Face

10-22-2009, 04:21 AM

I've heard Auricaps in electronics and they were ok. Smooth, a little laid back and soft.

ben62670

10-22-2009, 04:24 AM

I heard them in some tube gear and was very pleased with them. Dynamic and yet smooth.

buymesome

10-22-2009, 04:25 AM

Hey ben could you post a pic of the faceplate?

Face

10-22-2009, 04:27 AM

Hey ben could you post a pic of the faceplate?

http://lmgtfy.com/?q=Denon+2900+faceplate

ben62670

10-22-2009, 04:33 AM

Hey ben could you post a pic of the faceplate?

I didn't mod the faceplate:D

Face

10-22-2009, 04:53 AM

You need these:
http://img202.imageshack.us/img202/3162/clarity20cap20mr20450.jpg (http://img202.imageshack.us/i/clarity20cap20mr20450.jpg/)

ben62670

10-22-2009, 04:54 AM

I may do it:)

Face

10-22-2009, 04:59 AM

If you want a little more highs and great transparency, go for MR's. For something a little more neutral, a little less transparent, and a lot cheaper, ESA's.

ben62670

10-22-2009, 05:06 AM

$77 each for the MR's:eek: ESA's $18 much more in my budget.

ben62670

10-22-2009, 06:42 AM

Time for some boutique caps. ;)

Let's see some more pics.
like this? Circa 1990?
http://photos-g.ak.fbcdn.net/photos-ak-snc1/v2347/115/85/1365012852/n1365012852_30369931_7453977.jpg

ben62670

10-22-2009, 11:45 PM

comfortablycurt

10-23-2009, 12:01 AM

http://lmgtfy.com/?q=Denon+2900+faceplate

So...I clicked on that link, and where does it lead me? The google search was performed, and the very first hit was this VERY thread...Crazy.

ben62670

10-23-2009, 12:34 AM

One of the best things I like so far is the imaging is very pronounced at low volume levels sounding very full and airy. Never before have I had this at this low of a volume setting. Very pleased so far.

Edit: BTW even with the caps not burned in yet the sound stage is better with them than without:confused:

GV#27

10-23-2009, 01:18 AM

Burr-Brown 24-bit, 192-kHz DSD-1790 Audio DACs .... I am hoping they are not voltage outs.They don't appear to be a regular BB product so are likely a custom version of the V-out DSD/PCM1791 or I-out 1792.You should be able to determine if it's a V or I out by the number of op amp stages following the DAC.Even with the integral I/V convertor the DSD/PCM 1791 is a VERY good chip.

ben62670

10-23-2009, 01:23 AM

I couldn't find any data on the chip either. I wanted to steal the signal straight off the chip, and tube it from there. From what I have read the filter stages are more for presenting good numbers and you can omit them without harming anything.

GV#27

10-23-2009, 01:43 AM

From what I have read the filter stages are more for presenting good numbers and you can omit them without harming anything.For the most part thats true there is a lot of hi frequency noise involved with the noise shaping process of delta sigma DAC's.Combatting this noise is the purpose of the LPF.Assuming a V out you could run your tube directly from it but keep in mind the tube itself will add gob's of noise and distortion:eek::D j/k.

If the DAC has a I out you might be able to use a simple resistor for I/V conversion before the tube stager.

ben62670

10-23-2009, 01:50 AM

...
If the DAC has a I out you might be able to use a simple resistor for I/V conversion before the tube stager.

This is where I was looking. A 100r is suposed to be sufficient for the tube into. The only thing that I need to figure out is the fact that the DAC is balanced out. Not sure if I am supposed to use just the vcc+ or sum both after the tube stage? I have been doing a lot of reading.

GV#27

10-23-2009, 01:54 AM

This is where I was looking. A 100r is suposed to be sufficient for the tube into. The only thing that I need to figure out is the fact that the DAC is balanced out. Yes it will have balanced (differential)outputs.
Not sure if I am supposed to use just the vcc+ or sum both after the tube stage? Sorry can't help on that one.

ben62670

10-23-2009, 02:02 AM

I'll figure it out and share:)
Thanks again.
Ben

ben62670

10-25-2009, 01:53 AM

Well I have about $30 in parts in this thing so far, and all I can say is WOW. The sound stage is better than ever. Room filling with some depth. The upper mids are not exactly to my taste. A little hot. I am going to hunt down a better OpAmp solution, and change the output caps. The biggest disappointment is I can't figure out why manufactures don't use ever so slightly better components in the final stages:confused: When I first received this player I was pretty disappointed. It did not sound much better than my 400 disc Sony DVD/SACD/CDP. I now know why this player is very high up on the list of players to mod. I hesitate to write this, but I never thought I would bother to upgrade a player instead of using a separate DAC. I still like the idea of a separate DAC with multi digital sources. I may be seeking another 2900 for a second system in the future.

Edit: Listening to YES 90125. Awesome on SDA's

ben62670

10-26-2009, 08:17 AM

Well I have been looking into an OPA627 solution. Also the voltage is +9/0/-9. I wish it were a little higher, but it does make for safer biasing into class A. I am very happy with the 2134 sound, but everyone likes the 627 much more. It figures because it cost 10 times as much. Also some 4-4.7uf AuraCaps are going to be used. Like I said I can't complain about anything, but I am a freak, and I must mess with it. Well maybe the vocal mids are slightly dark, but they were previously too hot and forward.

Edit:

If Wile E. Coyote had enough money to buy all that ACME $hit, why didn't he just buy dinner?

ben62670

10-26-2009, 10:41 AM

They don't appear to be a regular BB product so are likely a custom version of the V-out DSD/PCM1791 or I-out 1792.You should be able to determine if it's a V or I out by the number of op amp stages following the DAC.Even with the integral I/V convertor the DSD/PCM 1791 is a VERY good chip.

Quote from SACDmods
This player is among the best that I have to offer. With the modifications listed below, the Denon DVD-2900 reaches a level of performance that pretty much equals my modified Sony SCD-C555ES, a feat that I thought could not be repeated. The 2900 features balanced current output DACs like the 555ES, and it is therefore a perfect candidate for the ZapFilter analog output stage. The player features Texas Instruments/Burr Brown's latest DSD DAC, the PCM1790. The 1790 features a wider dynamic range than my favorite, the PCM1738

GV#27

10-26-2009, 01:30 PM

So it's a current output device.It must be a custom for Denon variant of the 1792 as used in your eval board because it appears there are no data sheets available from TI/BB for it.

As for the OPA627 it being a single you will need an adaptor to get two of them into the 8 pin DIP footprint.Aswell I understand the DIP versions are hard to source.Going SMD with the apropriate dual SMD-DIP adaptor might be your only option if you want to use them.I'd avoid the cheap 627's on epay as they are likely counterfits.

Why the coupling caps if your offset is low enough to eliminate them?

ben62670

10-26-2009, 11:28 PM

Yep yep and yep. I have two R+L jacks on the outs. I usually prefer no caps, but adding the caps makes some music sound a little better. The 627's are as you know surface mounts, and require the adapter. Thanks for the heads up on the flea pray chips. I can get some from digikey. I may make a custom board to take the signal after the IV conversion, and do a power supply on that board for a more acceptable +12/0/-12 instead of 9v+-. Also the PS in Denon's is SMPS and It would be easy to drop a toroid in there:) Thanks again for that eval board it is a great learning device for this project:)

GV#27

10-27-2009, 12:19 AM

but adding the caps makes some music sound a little betterSo the colourations they add are of the ear pleasing variety.:D
Also the PS in Denon's is SMPS and It would be easy to drop a toroid in there:)It looks like you have enough room to add a Talema toroid and filter caps in front of the SMPS like I did with one of my Pio's.See pics in post #31 in this link. http://www.polkaudio.com/forums/showthread.php?t=55733&highlight=pioneer+dv563&page=2

Thanks again for that eval board it is a great learning device for this project:)Your welcome.Basically you will have the same circuit to work with in your Denon as in the eval board but the added advantage of not having to use the SPDIF connection so potentially less jitter.

ben62670

10-27-2009, 12:43 AM

I have a 15-0-15 avel for it. I need to get off my butt and get some boards made that are fairly universal. I only have 2x3"s for the boards to work with so it makes it tough to get everything on there I want, and it is $65 for 3 boards... I am toying with the idea of the LM4562

ben62670

10-27-2009, 03:46 AM

Looking at the PS I am thinking of totally removing it. From what I see it is all +9/0/-9 and 5vdc. A couple toroids and I think I would be on the way to even more improvement. Again the very least a +12/0/-12 PS for the anolog section.
Ant thoughts?

GV#27

10-27-2009, 07:44 PM

Looking at the PS I am thinking of totally removing it. I would leave it in there.The display,transport, transport logic controls etc. are powered by it. IMO your best bet is to have a fully isolated supply to power everything in the analog stage after the DAC chip.(I-V,LPF / output buffer). You could place the the raw supply externally in a bud box if there is not enough room to fit it into your chassis.

ben62670

03-24-2010, 02:04 AM

Well I picked up a second player seeing I was having major read issues with mine. I received the second one and it read everything. I put it in my system, and had issues reading disks. Well come to find out my little 30vdc tube buffer was making the players have problems. Now I have two good players that have been modded. It's a good thing really because I want to setup a system in my bedroom. Live and learn.
Ben

billbillw

03-24-2010, 07:13 AM

Two 2900s is not a bad thing. Great little unit there. I kinda wish I still had mine. Glad you figured it out.

ben62670

03-24-2010, 05:54 PM

Thanks Bill. I hope this helps anyone else who gets stuck in a similar situation. BTW it is sounding so good.

ben62670

03-01-2011, 01:44 PM

I have my OPA627's in for a customers upgrade, and I am going to do mine also. The customers 2900 is getting the Clarity ESA 10uf caps:smile: I can't wait to here those.

Outfitter03

08-05-2011, 10:04 AM

I have my OPA627's in for a customers upgrade, and I am going to do mine also. The customers 2900 is getting the Clarity ESA 10uf caps:smile: I can't wait to here those.

I am patiently waiting too Ben. Hope this crisis in your life will soon pass. Sent several emails over the last 2 months just to touch base. Not pushing, just wanted to touch base and make sure this is still on the back burner.:smile:

ben62670

08-05-2011, 11:46 AM

I am patiently waiting too Ben. Hope this crisis in your life will soon pass. Sent several emails over the last 2 months just to touch base. Not pushing, just wanted to touch base and make sure this is still on the back burner.:smile:

I responded too. Those caps burnin like sonicaps. I prefer it without the big10uf cans, but that depends on what I am playing. I kept going back and forth between units. The cable cooker I built helped speed things up. That will be going out soon.
Ben