[aixer]

nichicon eviro version LOL ..
"PET"
Polyethylene Teraphtalate


dam these caps don't last long
they usaully rate @ about 1000 hours
to 2000 hours, that mean I need to replace me caps each year.

if I use my audio system 6-8 hours a day.

 

[drp]

Aix,

Looks like you found the answer you were seeking.....

I'm not certain how much you paid for your D25, but mine was not cheap (but not as insane as the prices of late). I wanted to maximize the sound with audio grade components--didn't seem to make as much sense otherwise--so ordered the good stuff for all of the mods. The big kids all say that they make a difference, so if interested, get your caps from http://www.referenceaudiomods.com/Me...ry_Code=BG_STD

Two 470 Black Gates in series along with a .1 bypass fit just fine. You'll need to use thin double sided tape instead of foam tape, and I placed black tape on the inside surface of the battery compartment lid. Given the diameter of the 470s, it all just fits (wouldn't dream of chopping the lid). I have a pic of my prototype if interested. However, I couldn't hear a 'real' difference between the 470s and 220s, and the latter leave room for other mods. They're cheaper to boot.

I've been swapping off the Turbo and my D555, another dual dac player; also very sweet. It's close, dude.

D

 

[aixer]

thanks drp, I will probably use the pan FC
for the power supply, btw my search for
caps lead me to that same site

kong

 

[wombatsauce]

I've been interested in this turbo-mod since hearing about it recently. Just wanted to confirm - would this be redundant on a D-555 since it is already using dual DACs?

 

[Duncan]

Quote:

Originally Posted by wombatsauce /img/forum/go_quote.gif I've been interested in this turbo-mod since hearing about it recently. Just wanted to confirm - would this be redundant on a D-555 since it is already using dual DACs?

Dual DAC is one of those old misnomers that pops up from time to time... It doesn't mean that there are two seperate DAC ICs in the unit, but that there is a portion of the DAC given over to each channel...

...No reason that you couldn't do this to a D555 i guess, other than the problem of getting hold of the old PCM chip, and a lack of space inside the unit...

 

[Filburt]

If the D-555 uses PCM66, then 'dual dac' probably does mean two chips since it's a monaural D/A converter that multiplexes to do stereo output when a single chip is available.

 

[drp]

I was trying to dig up an old picture of the D555's DAC arrangement; will keep digging. It actually does have two separate DAC chips. It was a tight squeeze getting one in the D25; would imagine that real estate is the bigger of all obstacles in stacking two in the D555.

If I still had a D555 . . I'd start with the PS caps and see what improvements that makes. I did end up going back to dual 470 ohm Black gates and removed the bypass cap. Sweet sounding. The battery tray is perfect for this. Ditto for the HP cap mod with 2 220 Black Gates.

At the time I had both the D555 and the D25 Turbo, along with a RS XP-7, I actually preferred the D25 Turbo. I sold the D555, but as I type this, the Turbo is sitting next to me in my office desk ready for action. Headphone out to a pair of Yuin PK1s, or line out to a Tomahawk amp, kicks ass. I still love this littlle player and use it often. Can't wait to have it drive a Heed (if it every gets here).

Keep us posted on your progress!

Dave

 

[drp]

I am updating (resurrecting?) this thread to finish the Turbo mod story.

I was also always curious about a post that PeterR made in the original thread about a pin out change to utilize the DAC's ability to truly run as a separate DAC per channel. I actually saved the image to my hard drive and visited it periodically, thinking I should investigate it further. Not having any additional data on the chip, an image of the layout, or the nerve to do the mod blindly (like the first part wasn't…), I left it as it was.

Recently, I was contacted by a new member at Head-Fi (Linear, a very cool guy and welcome addition) who was interested in performing the mod. Being a semi-retired IC designer, he provided some great insight on the modification, and just so happened to have a D25 service manual (image of the PCB layout) and a spec sheet on the DAC, which he kindly shared. I was motivated and armed with the information necessary to complete the Turbo Mod.

Wayward journey skipped; onto the results…..

In a word, transformed. At the moment, I place the line out performance of this modified player on par with a decent entry-level home CD player. Hard to tell as my only reference at the moment is my Opus 21. Comparisons are always subjective and a dangerous business due to how differently we all hear, and there are other members much more suited to this. The only down side is that the line out voltage is low so an amp with decent headroom is needed. Since the DAC is up stream of the chip that amps or sends to line out, the modification is in effect for both outputs. Performance wise, the headphone out (with the HF-1s), seem to handle all but the ultra low bass notes at higher volume levels. The detail is a real eye opener and the imaging better than expected. I spent an entire day with just the Turbo, HF-1, and my CD collection and really enjoyed every aspect of the listening session. This is a perfect transportable solution.

I am completely happy with the modification and would do it all over again, well, if I could find a D25 that I could actually afford. If you have a D25 and performed the turbo mod, or are considering the mod, it is not a true dual DAC player until these pinout changes are performed. The real beauty of the PCM66P chip is that it was designed to operate in single or dual mode with just a few changes.

Oh, and the image that Peter submitted had the channels reversed. I discovered this the hard way; I had to open the unit back up and change the pinouts for pin 20. Much more difficult the 2nd time…. Updated image in below post.

 

[drp]

I'll close this chapter on the dual DAC D25 mod with a basic modification sequence. You can actually perform the modification without cutting any traces, although one spot is very tight; will elaborate in the steps. Even more to the point, you cannot simply cut the traces to pins 19 and 20, because they run under the chip. This is another tidbit I discovered the hard way (your ohmmeter is your friend and savior, especially when a less than careful analysis of the PCB layout is your bane). Since part of the modification includes swapping the power and ground on a few pins, extra caution is needed.

Parts needed:
1 – PCM66 DAC
2 – small lengths of extra fine wire. I used wirewrap wire that I had from "back in the day."
1 – small piece of bare wire. I used stripped wirewrap wire.

Step one – On the current DAC, lift pins 8, 19, and 20.
Pin 8 – current left channel, which will be handled by the additional DAC. The space between the pin 8 pad and C201 is extremely small, certainly too small for my big fat soldering iron. Additionally, as busy as this area is with another line soldered to a via, I chose to just cut the trace between the pad and C201.
Pins 19 and 20, currently connected to ground, will be rewired to choose which DAC is for which channel.

Step two – Flatten the pins on the new DAC, and then bend them down 90 degrees. See the original thread for tips (I'll try to find and edit this post as well). Leave pins 8 and 20 sticking straight out.

Step three – Mount the new DAC on top of the current DAC and solder all the pins to their corresponding number (1 to 1, 2 to 2, etc.) except the ones lifted in step one (8 and 20), plus, leave pins 5 (NC) and 9 (not used in this player) open. Since pin 8 is not used for this application, leave both pin 8s open.

Step four – Hardware the pad of lower DAC pin 8 (or the connected side of C201) to pin 10 of the upper DAC. This connects the output of the upper DAC, which will be the new left channel.

Step 5 – Hardwire the small bare wire across pin 18, both pin 19s, and pin 20 of the lower DAC. This establishes the mode for one DAC per channel (both pin 19s to +5V; supplied by pin 18), and by connecting pin 20 of the lower DAC to +5V, sets the lower DAC as the right channel DAC. I used pin 17 as an extra solder point since it is also connected to +5V.

Step 6 – Hardwire from the via where the traces for pins 19 and 20 emanate (see image of PCB layout and pic below) to pin 20 of the upper DAC. This sets the upper DAC as the left channel DAC by connecting to GND.

Step 7 – Relax sphincter pressure; you're done with the chip mod. Carefully close up the player. It's a tight fit, so use caution.

Other changes from the original post, which you might entertain:

Op-amp – Not in the sound circuit; not really necessary.
Cap mods – I like the change, but you give up the battery tray and there are (will be) ways to build your own battery once the sequence is fine tuned (another member is working on this).
Copper shield and GND wire on top of DAC. – Subjective; the casing is metal, but there is a ribbon cable running over the top of the new DAC; I suspect pressing firmly against it. I have extra of this copper strip if interested.

Pix

Here are some pix of the mod, which I quickly snapped before sewing up to confirming that the player works, and at this point am not ready to open it back up for better pics with a cleaned up board.

It's a bit difficult to get a perspective on just how tiny the work area and DAC chip are, but the buttons on the D25, shown in the DAC select image, are about 1/8" in diameter. The wire I used is ultra fine solid core wirewrap wire, which is about 20 mils in diameter. This is all ultra fine work and one wrong move could cost you a player that's currently going for big bucks. This is my only disclaimer…..

Channel select pin change – A bit hard to see with the glare from the pad, but the wire is soldered to the left side of chicklet 201.

DAC Select pin change – After cutting trace 19, I then realized and confirmed that the traces run under the chip. I'd also hooked up per the original post, which swapped the channels. This section would have looked better if I had not had to unsolder and resolder a few times. Scary business.

Correct pinout change.

Image of the traces in the battle arena.

 

[mekanoplastik]

i just finished my "Turbo DRP Evo"

and i must admit....it sounds great!! so far i can notice a mush tighter bass and the disappearance of a very faint hissing noise i had on one channel

Thank you



ps..yes...my 500 post

 

[drp]

Holy cow; hello my friend. I could not have asked for a better response than from one of the originators of the initial Turbo mod. I'm so glad you took the plunge and helped qualify this modification.

I use the player just about every day at work, with just the PK2s out of the HP out, and remain amazed at the sound quality.

Cheers and very best regards,

Dave

PS - When you get a moment, would you take a look at the links in your original post? You have a two-part thread, and since the crash, most of the older links point to newer and unassociated posts.


Quote:

Originally Posted by mekanoplastik /img/forum/go_quote.gif i just finished my "Turbo DRP Evo" and i must admit....it sounds great!! so far i can notice a mush tighter bass and the disappearance of a very faint hissing noise i had on one channel Thank you ps..yes...my 500 post

 

[Newzenith]

I just finished the turbo mod to one of my D25 players, it took me about 2.5 hours to complete, and next time will be much faster. Very good results, I only did the duel mono DAC and no other upgrades. I found a NOS BB PCM66P chip on eBay form a Chinese seller for nine bucks delivered.
I did not need to tear out the tab under the board to make room or cut any traces on the circuit board to get the job done; I did however re root the ribbon cable off to the side to help with clearance. 
I will say this job is not for the novice, mostly because of the maniacal work of putting the chip in.
So if you love your D25 and want to take it to the next level and dramatically improve the sound across the board then give this mod a shot, the improvements are not subtle!
This mod brings the little SONY up to modern CD player standards IMHO as far as sound is concerned and I am grateful for your pioneering work and the shearing of the steps necessary to execute the project!
Thank you so much, I would never have figured this out on my own or even known it was possible!
 
I will upload pics soon.
 
Newzenith.