MHZS - Mystery of the DAC Chip

Well,

I'll start by saying thank you for having the guts to challenge the proprietary DAC chip. I can't figure out what is wrong with my 33E at all. It starts to make static in the left channel. I recently ordered a new KSS-213C which I believe is a drop in replacement for the KSS-213Q to try to fix the issue.

I ordered GE/JAN 5670 tubes and they sound much better than the original tubes. I also ungraded all the Poly caps with Dayton high tolerance caps. Almost all the ecaps to better brand ecaps. Mine sounds great in my opinion, but it has this intermittent static sound in the left channel. I think I'm going to "free" my DAC chip and pull that cover. I live in Texas so I can probably get a new DAC chip if I need one overnight  :wink:

What is wrong with the CD player you are working on?

Blair

One note to those thinking about attempting this. The block of filling that looks like silicone is actually epoxy, and has the poential to remove the DAC chip and resistors completely from the circuit as it did mine when I attempted this. It is okay for me because I think my issue with my player was related to my DAC chip, and I have a new one coming in a few days. I just thought I'd warn you guys before you attempt this. Oh, and the wires there are dead leads to hold the cover in place so you should remove the solder joint before removing the cover if this is desired.

Blair

Hello Kikko,

I am still waiting for a new DAC chip to come in. I should have it by Wednesday or so, but I have replaced almost all the caps with at least a better/lower ESR cap. I replaced all the signal caps with better DAYTON high tolerance caps. I replaced the OPAMP with a better opamp. I also ordered the KSS-213C which is supposed to be a drop in replacement for the KSS-213Q. It is going to be very difficult to resolder that DAC chip, but I'm going to give it my best. Here are a few of my other projects if you are interested.

http://www.villagephotos.com/pubbrowse.asp?folder_id=1535206

Thanks and I'll keep you guys informed if I get this fixed.


Blair

WOW,

Everything looks extremely nice =D>

I don;t have the funds to purchase anything that nice yet. Very nice looking speakers!

I did not get my DAC chip in yet yesterday. It should be here today or tomorrow. It is definitely going to be very difficult to solder. Any advice on this application?

Thanks,

Blair

Hello Kikko,

You just paint a non reflective paint around the lens protion of the laser head? Looks easy enough. I'm really a bit scared of this DAC chip. It is going to be a pain to solder, but hopefully I can get it. That is a neat mod though. I'll try to take a few snapshots of my player when I get this DAC wired in.

Thanks for all the advice,

Blair

Thanks Kiko,

I will definitely try to be careful with it. I paid less than $20 american dollars for two chips, plus I ordered a new laser assembly for 20 more dollars shipped to my door. So far, I only have about $220 USD invested in this so I am not too terribly upset about the project. I can see a Texas Instruments factory from my back yard though   I am really most worried about the alignment of the pads more than the solder part of this project. They did not give you much room for DIY. It is probably pretty intentional. I believe these chips are found in many smaller digital devices as well such as MP3 players and such, but it is supposed to be considered a good DAC chip. If I lift the traces a bit off the board, I have considered dierctly soldering small leads to the chip and casting it in epoxy to make it easier to work with. Sounds like a pain, but that seems to be the logical repair if I lift the traces.

Thanks and I'll keep the progress up to date,

Blair

Kiko,

I have not cast the chip yet. That is going to be a last resort. I did however just order one of these just in case I lift the traces.

http://protoboards.theshoppe.com/proto_chip_jr.html

It looks to be very helpful. We'll see soon   I do have a static bracelet also.

Blair

Kiko,

Yes I have two sets of GE NOS 5670s. Both are new other than the production date. Both make the same static sound, and I checked all the solder joints. I like this hobby. It gives me something to do, and after this, I may never mod another player again but I can say I've done it. Trust me, I've changed everything on this unit besides the DAC chip and a few other control chips that are not in the signal path.

Thanks again,

Blair

[quote:2953a1cf51="Kiko"]Blair,

my position is the same, I like that too. But what I dont understand is why you will never mod again. Is it because your CDP makes this problems? After watching your pics I believe you are in your heart a DIYer and when you buy the next one, or an amp or anything else you will do it again.  :wink:

So I hope it is the DAC what makes this malfunction. What will you do if you change this chip and the intermittant static sound comes again? Where do you bought this CDP? Do they sell spareparts?

Kiko[/quote]

Nice mods! Very cool 8)

It is not that I will not DIY again, but I think I prefer amps and speakers. I bought this player form an individual for 150 USD shipped to my door so it is not a big expense. There are only 2 places in the US that retail these players and both are online stores. They do sell separates though. I am currently in the process of trying to start a US based DIY shop. Mostly tube amps and speakers though. We already own a domain, but are currently working with vendors and web designers on this. I'll keep you in th eloop as it goes along. Thanks for the great pictures again!

Blair

I emailed you. Let me know if you got it.

Thanks,

Blair

Alfcat,

WHERE DID YOUR GET THAT

Do they sell them in the US?

Thanks.

Blair

Hello,

I am not at a point where I need to replace my laser yet. I thought it may need replacing, but it was the DAC chip instead. I do have a spare 213c here, but will only install it if necessary. I'll let you know if I try it. The part was cheap enough $12.5 USD.

Blair

Hey Alfcat and Kikko,

Been a little while. I've not changed anythig in my 33 for a while since I got it fixed. I may be not seeing the entire picture here, but from what I see of your damaged board, there is nothing that a bit of wire will not fix. My recommendation is to glue the cap you wish to use where it belongs on the board upside down, and run 28ga leads to the correct locations in the circuit. There should be no harm in this and you should not suffer at all performance wise.

Since my DAC ship solder job, I've been a bit reluctant to try any other mods to my CD player. I've been building a new preamp instead. Good luck guys!

Blair

I'm finished with the preamp. It sounds great! I've been working with tube gear for a while now.

I'm working on some PP monoblocks using 6SL7GTB, and 6SN7GTB driver tubes with a line stage using the 6922 tube. The PP circuit is going to be a quad of SED KT88s.

You can take it with a grain of salt (pardon the american phrase) , but putting a separate power supply on the OP amp may be a moot point. There is plenty of reserve power in that toroid for the opamp, and if the circuit has fast enough diodes, you are going to get about as much out of it as you can. I recommend using your CD 33 as a transport, and begin to mod a DAC for better resolution and soundstage. Plus if it is a DIY DAC, you get plenty of room to play around. I want to build a DAC, but they are really expensive to build here in the US. I can buy a good DAC for about the same as building one.

Hope this advise helps.

Blair

I'm in Dallas Texas.

I have not seen the audionote kits, but if they are the same ones as here in the US, they are a bit expensive compared to simple DIY designs. Your prices and mine are a bit different though.


The LITE audio DAC is a good choice if you are into mods, but there are plenty of kits for full DIY DACs out there. They are about $1,000 USD so a bit out of my price range.

Actually, even as a transport, the 33 is not a great choice. A mid line Toshiba uses a better laser pickup. The DAC chip in the 33 is very difficult to work with also, so you really need to use an external DAC if you are going to tweak the DAC circuit.

Good luck, and if you want to play around with preamps, let me know. There are a bunch of circuits out there I think are very nice and cheap to build. What are you using for amplification? There is a very nice zero gain line stage kit, I really love. It is the first line amp I built, but I still love it.




Blair

Another view:



And an amplifier:



Blair

Yes, I can, but I need to find the schematic. I really do like this line stage because it can be used with a SS amplifier as well. I'm currently working on a different, less expensive power supply, so hang on and I'll send it to you.

Vash

[quote:2761cc1bc4="Kiko"]Alf, Blair? What are you doing now?[/quote]

Hey guys,

I haven't done too much to my player since the DAC fix. That scares me to death :shock:

That little guy is a pain to resolder in place. There are a few leads that run through "dead end" traces as well which helps if you do have to change the chip though.

I have a few extras also. I wish I knew Kiko, I would have sent you one.

I still have the 213C, and plan to paint the lense and see if it is compatable, but again, I am just nervous about the swap because it works again . I have also been really busy with a few small projects I am generating to make some extra cash to support my habbit. I have a few regulated supplies a friend of mine and I are working on for a preamp using 12AU7s or 6SN7s.

I still plan to change out all diodes with UF diodes and all the caps on the PS board first. Typically PSs are the most important thing in sound quality. Clean in = clean output.

I also have a very nice looking open baffle hybrid I'm working on with aluminum bass drivers and a poly mid with a vifa XT25 tweeter. Should be very nice.

Good to hear from you guys.

Blair

[quote:46f0c00836="Koifarm"]First greettings from the Netherlands in Europa.

Use this one.



Connect DAC output to the tubes analog input and you have a perfect DAC in your MHZS player.

Tube input are on right side from C7 en C8. Desolder this side and connect to new DAC board output.

[/quote]


Would the DAC in this link not be just as good? It is cheaper. How would this wire in?

http://cgi.ebay.com/CD-Player-DAC-Upgrade-Kit-BurrBrown-PCM67U-DAC-AE_W0QQitemZ250121862931QQihZ015QQcategoryZ14980QQcmdZViewItem

Thanks,

Blair