alex108n said:
Yups, I've got a DCD-1015 and a DCD-1550AR.
I don't know how far you want to go with it.
The simplest way is to focus on the analog output section,
improvements there are rather simple and really audible.
1) who needs that variable output? --> remove R712 and R713
2) Denon likes to use a very bad headphone amplifier, changing volume changes the sound of the fixed output. Loose that headphone-amp by means of removing R912 and R913
3) the mute circuit is not needed when using good opamps remove TR706 and TR707
4) coupling caps C710 and C711 (100µF/50V), change them to high quality audio types (don't know why Denon uses 100µF, 22µF is more than enough and allows you to choose better caps)
5) IC 309 and IC 310 are the I/V and filter stage, Denon fits NE5532... Not really bad, but there are much better opamps these days... take them out and change them into something better, plenty of examples at this forum
6) optional: C325 and 326 (100µF/50V) are used to equalise the power supply, change them into low ESR types. C318 and C319 are decoupling caps of the opamps mentioned in (4), 1µF, better change them into a low-esr-type too.
This will really make an audible difference.
You don't have to stop there, but the next level takes a lot of work and less improvemment, since the PCM61P DAC is simply not the best performer.
You could change the master clock (16.9344MHz) to a Flea powered Tentlabs XO, but I only would do that if you intend to use the DCD-1015 with an outboard DAC.
In that case, you need to change almost every decoupling cap on the board and make severe changes tot the psu.
The DCD-1015 uses one power-supply for everything,
+8V and -8V unregulated for the motors
and +5V and -5V regulated for everything else.
Needless to say that every capacitor in the psu-section is of
utmost importance.
There's also a -33V section (display-unit), no need to do something there.
One little warning:
DO NOT TOUCH VR300 AND VR301 unless you have the proper equimpent to adjust it.
(It's the MSB-adjustment of the PCM61P)
Good luck with the modifications!
OneyedK, Just came across this thread. Thanks for the great info because I have one of these and thought for a few bucks, to make it sound better, why not!
One question please. For the life of me I can't find R912 and R913 to disable the headphone amp. Where the heck are they? Thanking you kindly in advance.
One question please. For the life of me I can't find R912 and R913 to disable the headphone amp. Where the heck are they? Thanking you kindly in advance.
One question please. For the life of me I can't find R912 and R913 to disable the headphone amp. Where the heck are they? Thanking you kindly in advance.
It's been a while since I've seen the innards of my 1015,
but I had a quick look at the schematic and they are connected to
the fixed output of your Denon.
I have to replace the drawer switch of the 1015 one of these days,
so if I do, I'll take a picture of the exact location.
Difficult to comment on that, since I simply removed the dac+analog board of the 1550.
It's a different beast...
The way headphone amp and variable output are coupled (fully buffered)
makes me think that the audible improvement will be less that with the 1015.
There could be some tonesuck by the mute circuit, so you could remove that.
Improving the coupling caps might be very well audible.
Basically steps 1 to 4 can be done on a 1550 (different part numbers),
step 5, not so much, Denon fitted OP275's in a well designed circuit,
different (even "better") op-amps could give you a circuit that sounds worse.
--> this circuit seems designed around the actual OP275 instead of a theoretical op-amp (no such thing in the 1015).
And step 6, the 1550 is full of 78xx regulators, before you start, please read the following article:
Simple Voltage Regulators Part 2: Output Impedance
--> the 1015 has a discrete regulator that actually benefits from lower esr caps, so don't worry...
The rigid drive of the 1015 matches very well with the PCM61P dac, it is worth
the effort to do the "mods" and end up with a extremely good CD-player.
An outboard DAC doesn't improve the sound all that much.
(sound is a little bit "harder" than with the 1550)
The better drive of the 1550 can give you much better performance
with an outboard DAC, so I believe it is wiser to leave the 1550
as it is and spend some money on a different DAC.
I only made some (poorly documented) "upgrades" to the power supply,
replaced the drive (still available from Denon after all these years!)
and gave the digital board a capjob (some caps were ready to burst).
My sample had brown Teapo caps, my friends 1550 had red caps from a
different make (don't remember).
Worse in what way? Bright, dull, shrill, warm, less open? Have you heard it in the Denon 1015? If not, what circuits have you heard it in? I'm curious because I am just starting to experiment and I would appreciate a broader description.
What is better about the 1612?
OP-Amp comparison:
http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf
OPA2604 is actually sounding quite bad... many treads about the sonics on headphone forums.
Wery OP-Amp tutorial:
OpAmps
The 1612 Op amp is one new "hot" amp... have not heard it myself, but i have ordered some.
Good luck!
http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf
OPA2604 is actually sounding quite bad... many treads about the sonics on headphone forums.
Wery OP-Amp tutorial:
OpAmps
The 1612 Op amp is one new "hot" amp... have not heard it myself, but i have ordered some.
Good luck!
LOL, it's been more than 3 years since I made the change.
So commenting today about a change that long ago would be crazy.
But we're still using it, bass is very accurate now and the player produces a very balanced sound. (you know how the stock 1015 sounds, bass is strong there, but I wouldn't call it accurate, and without precision the soundstage collapses.)
But I can say WHY I chose OP271.
I wanted:
The same (or almost) slew rate as the 5532. (you don't want to make the sound of the 1015 any colder)
Better phase margin like the OP275 (but couldn't use it for the reason above, Denon used a different circuit in the 1550 to prevent the cooldown).
Higher gain bandwidth product 5GHz instead of 10MHz seemed sufficiënt.
The same (or almost) input resistance as the 5532 (300k), OP271 has 400k.
--> you never know if Denon adjusted the citcuit for such a value.
Before you change the op-amps with wild brand new megaspec beasts, take a look at the circuit and make sure you're not killing it's sonic properties.
Opamp decoupling is Rubycon ZLG, and coupling caps are Sanyo, but I forgot the type...
I have a pair of 6204 at the moment. I just started burning it in with the new parts and I'm going to let is settle down and then do some comparing. Any suggestions?
I'm guessing you mean OPA2604?
How do they respond to the rather low power supply voltage of the Denon?
I tried them in other projects, but with less than 20V (+10 -10), I found them rather harsh sounding.
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