Incorporating DAC-AH into CD 33

Dear Koifarm, t and KiKo,

I tried to incorporate the DAC-AH into my CD 33 tonight. By looking at the previous posts and tried my best to understand them, I HOPE I have the connections right.

Please point out any mistakes I made by looking at the photos that follow. I turned the CD 33 on for a while, the sound was VERY impressive. Unfortunately it is already 12:xx midnight and I can't turn the amp on at the normal volume ..... can't totally tell how good the improvement is.

Please advise me on this modification, my friends. Many thanks!

Dear Alf,

you dont need any advise, that looks very good and logical in my eyes.

In this matter I have some questions:

To picture No. 1: Are the signal cables together with power supply cables in the multicore cable? If yes I would separate the signal cable from the other.

To picture No. 3: You dont need the RCA input jack if you dont want to use this cable in future. You can desolder it if you want to use a simple short but shielded internal cable.

To picture No. 4: Thats the best way too. The isolation of the caps from the input site is absolute correct in my eyes.

Good work, my =D>


.......tomorrow you can terrorize your neighbours further ....\/  :-({|=

Dear alfcat it looks good.

Cut the traces like picture below and the opampsection is decoppled.



You now do not have connect any powersupply to the opamp section.

To fit the board better in the player, i cut/saw the board so that the opamp section comes off. Now the board is smaller.

Dear KiKo,

No wonder you have that doubt in Photo 1. They looked like they are together as a multi-core cable, ha..ha.. And they shared similar colors too.

I have the Power Supply cable and the signal cables separated. It is because I am just temporarily testing the arrangement out only. Will position the Transformer better today and extend its cable so that it won't affect the signal part.

Photo 2. True, I don't need the jack in the future. It is just that I can't find a suitable cable at that moment and I really would like to test it out before it gets too late at night .... So I just use that cheap RCA jet.

I am now longing to get back home asap tonight .... I think the CD 33 sounds "incredible" last night. Really want to try it out thoroughly tonight before getting too late.

Thank you very much for your help! :wink:

Dear Koifarm,

Thanks for your advice / help / sharing through out the modification on this part.

I don't have a saw but it will be easy for me to get one. I do agree that if I cut the board smaller, it will be a better fit into the CD 33.

Just one more question. Do we make use of the OPAMPS in the CD33 under this arrangement? If not, can I just take the 2 opamps out from the CD 33 as well?

CAT

You do not use the opamps anymore. So you can remove them.

Dear Koifarm,

I figured that it is pretty hard to fit the DAC-AH board into the CD33. You successfully did that? If so, can you post me a photo or two for reference?

I tried to put the transformer lying on the side wall close to the AC input and the DAC-AH board on top of the Power Stage PCB. It is hard to fit it there as the heat sink and the Sanyo caps are tall. Even if I fit the board insdie, I won't be able to put the cover back ...

Hi alfcat,

did you do the DAC -AH 輸出反相 ???
any feeling after correction ??   

thanks.

Dear Viewer,

I haven't. Just realised that I MISSED setting an examination paper and now I have to rush and finish it before tomorrow. Will try that on Tues or Wed.

Many thanks

CAT

alfcat, it is not possible to make some photo's because i did the mod for a friend in Germany.

I used a small torriod transformer with sec. voltage of 2 x 9V. Because i cut of the opamp section in do not need more supplies.

I mounted the DAC board upside down above the MHZS DAC right in that corner.

Dear Koifarm,

I cut the PCB as you suggested but I use back the original Transformer from LITE. The Transformer was mounted on the sidewall of the CD33. All the wires are now directly soldered onto the board.

The sound is MARVELOUS!  :shock:

Thanks so much

CAT

Hi, alfcat,

can you post your present cd-33 for member sharing........

thanks.

Dear Viewer,

The setting now is temporary as I still need to solve the problem of fixing the board right.

Will post the photos next week as I also need to solve the problem of over-heating as the DAC board is pretty hot inside the CD 33.

CAT

Nice work alfcat. I am glad you like the board.

The heat you can lower with a smaller transformator with lower output voltage as the original transformator. The voltagestabilizers on the DAC board then have not to dissipate much power.

I am still busy with my shanling cd-t100se. I am now trying other tubes. The 6N6P. And make the output symmetrical with only tubes. This will be the best sounding CD player i ever have modded.

I have now 2 weeks off from work so i can spend a lot of time on modding.

Dear Koifarm,

I have some spare 3M Nexcare Cold / Hot pad. I think I will place one in between the CD 33 Analog section PCB and the Inverted DAC-AH board.

First, the pad will absorb the heat without problem. Second, it is an insolated board so it will be quite safe. Third, it can act as "shock absorber". I will experiment it later tomorrow.

Still thinking of a good way to "mount" the board upside down safely ...

CAT

Dear all,

I finally have the DAC-AH settled inside the CD-33. Let me post the photos I promised in earlier days.

Hope you all enjoy.

Thanks again to Koifarm! :wink:

CAT

Oke alfcat finaly you got the DAC into the MHZS player.

I like the jensen capacitors they sound perfect. When you have time discribe the sonic changes beyond the origanal player. And how about the noise?

Dear Koifarm,

I played some CD this morning and I realised that there is some static sound in the RIGHT channel. It is not always there, only once in a while. I won't be able to hear it unless I stay next to the speaker.

It is a very mild static sound and each time it goes for a few seconds (less than 5). Since I didn't test the CD for long this morning, it seems to be occuring RANDOMLY.

What could be the problem?

For the sound quality, I have one song of a Chinese Lady with a night outdoor scene as a background. You can hear crickets, tiny little frogs calling while the lady is singing in the foreground.  Before putting the DAC board in, the foreground and the background is quite separated. You WON'T feel like you are sitting outside on a grassy land with the stars and the insects surrounding you. After the modification, I really feel like lying outside on a starry night, resting my back on the grass land while the insects play their songs together with the lady singer. The background covers / fills the room while the lady is like singing in front of you. You can hear the "end sound" of the words clearly and the instruments sound much better. My distance from the speakers is around 10 ft., that is why I normally won't be able to hear that "static" noise.

CAT