Denon 2900

ben62670

Well I have dove in. Very simple. Even for me:)

kawizx9r

ben62670 wrote: »

Well I have dove in. Very simple. Even for me:)

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

buymesome

You bought 1?

ben62670

kawizx9r wrote: »

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

Lasareath wrote: »

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

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

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

-Jeff

ben62670

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

ben62670 wrote: »

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

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

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.html
Have fun.

ben62670

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

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

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

skrol

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

ben62670

skrol wrote: »

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

Systems

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.)

ben62670

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

Systems

ben62670 wrote: »

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

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

i got one packed up ready to send ya lol.

ben62670

TouchOfEvil wrote: »

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

ben62670 wrote: »

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

GV#27 wrote: »

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

Time for some boutique caps.

Let's see some more pics.

ben62670

Face wrote: »

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

The best cap is no cap.

Is your pre direct coupled?

ben62670

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

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

ben62670

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

buymesome

Hey ben could you post a pic of the faceplate?