HiFi Fever

標題: MHZS - Mystery of the DAC Chip [打印本頁]

作者: Kiko 時間: 2007-7-28 12:20
標題: MHZS - Mystery of the DAC Chip
Hi Friends od Modification,

working on a MHZS CD66 now I find out the mystery of the chip and another really interesting secret about the circuit. I think the CD33 has the same circuit problem.

Please take a look.

It is not a proprietary development, how it is to read in advertisement. It is a BurrBrown PCM 1742KE from Texas Instruments.

After this I studied the signal path in my CD66.

1. Look at: focus.ti.com/lit/ds/symlink/pcm1742.pdf (Page 6).
The analog output is on pin 7 and 8.

2. The signal goes through the cheap and low quality electrolytic Caps on the right side over the DAC. Imprinted is 100uF/16V. In fact, there are two 100uF/25V.

3. The next is the OPA.

4. Following are the two 0.47 uF Multicaps.

5. The 12AX7.

6. Two really cheap electrolytics again.

7. The Relais

Friends, take care by working o the PCBs. The Multicap 1uF has a voltage of 38 V after taking out the PCB (and after more than 3 hours).

The same is on the other PCB. The Voltage at the Pins ( printed is 100V and Ground) is about 52 V after some hours!

So, can somebody tell me why I cannot find the MHZS homepage?

And which tubes are now really good?

Grettings from Germany

作者: Kiko 時間: 2007-7-28 12:30
Some of you have changes the two multicaps. Think about it that the signal flow is about Caps No 2 and No 6. Better to change them first.

作者: Kiko 時間: 2007-7-28 12:48
....... does anybody know whitch value will be correct to change? Caps No 2 are 100uF, caps No 6 are only 10uF and the Multicaps are 0.47 uF. I think they should be all the same value but I'm not really sure.

作者: deicide67 時間: 2007-7-29 04:07
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

作者: deicide67 時間: 2007-7-31 00:40
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

作者: Kiko 時間: 2007-7-31 01:07
Hi,

thats correct.

I didn`t know how the cover of MHZS has been fixed. So at first I have desoldered all solder joints under the cover and then pulled up carefully the cover. Use than a hot-air gun, but don`t blow too long on this epoxy, you will damage the parts around the epoxy. So: max. 20 seconds with 450 degree Centigrade and then carry up 2 Milimeters of this white mass. Thats to repeat several times. You will need with the hot-air gun 2o - 3o minutes until it lookes like at my pix.

And the second: After turning off the machine some caps stay charged and don't discharge itself. I am going to shot some pix and post them in some minutes.

作者: Kiko 時間: 2007-7-31 01:55
Now some tips for your health!

I measured high ( dangerous high ) voltage on cap No 1-please look at my photo. Also there is a high voltage on the connector No. 2. This connector is connected on the left side to No. 3 in my photo.

I took a resistor ( 150 kOhms and 2 Watts ) parallel to cap No.1 and soldered him under the PCB.

Next I do the same under the pins of No. 3, because its easier as to solder under the connector No.2. So you dont worry about the voltage coming out of connector No. 2.

Problem is that the wiring of the 2 Watt resistors is to think and goes not through the PCB. At No. 3 there have to be some small caps to clean the high frequencies, but MHZS or who else has economized this caps ( and the other 50 haw you see on your own board). You can use that solder joints to bring your resistor there.

The result is good. After turning off my voltage falls down to 1 Volt in some minutes.

作者: Kiko 時間: 2007-7-31 02:38
Hi Blair,

you wrote your CDP has this intermittent static sound in the left channel. Not easy to say something about it. Can you change the tubes again and write what has happened?

Sometimes I mod and mod and mod and after starting I must see the machine works not correctly. The best what I can do - if you believe it or not - is to go sleep and don't touch the machine again. ( You must know I mostly mod at late evening and night ).

Next day you think clearer about your work and then pull out the PCB and check all solder joints with a multimeter in all ways. Set up your multimeter on "Ohm", for messuring resistors. Often it has happened this: A line on PCB goes from point A to B to C to D. My soldering joints look very good, but the multimeter says A to B is OK, C to D is OK, too. The solder joints from B and C are only connected to their neighbour A und D, but not together! So a pod or a way on PCB at point B or D is broken. You will see it because the multimeter says Ohms=infinite.

Then I heat the solder again very carefully and meassure again. If the multimeter says again "infinite", you take a small wire and solder this points manually together. That looks not good but it helps.

After many mods in the last years I find out that there is another way to best caps without damaging the PCB. Look at my next pix. Now I am testing much caps and different combinations on the Headphone Amp Xiang Sheng 708b.

I soldered some hard wire without isolation an that pionts where I am not sure which value is the best and let the cabinet open. Then its easy and goes fast to change values and qualities of caps. Every day another value! :wink:

After two weeks I find out what sounds best and pull out the hard wires and everything what I have burned with the soldering iron. Then I calculate my budget and order the really good caps which should stay in.

Thats the way to find out what applies to your music style and your habits. And its economic. I am sure you have enough unused caps there! :wink:

And your result will be very very good, you will see.

作者: Kiko 時間: 2007-7-31 02:53
Some posts before I wrote about bypassing ecaps by a resistor. Here are some pics for the same solution on the headphone amp. The only difference is that in CDP I soldered both sides together and in the amp not, because this big blue caps are not part of PSU, they are part of coupling between main PCB and headphone jack. So there is to cut one side after soldering.

When I put out the amp and want to work on it I push the contacts of the resistor and the cap together, but only with an isolated screwdriver!!! The discharging takes two minutes, the voltage falls from 80 V to 2 or 3 V. After last mod I will take this resistors out, of course.

You go the same way in your CDP, I would recommend it.

作者: deicide67 時間: 2007-7-31 03:08
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

作者: Kiko 時間: 2007-7-31 03:19
Now to the MHZS Mystery Chip 8)

In the description of the manufacturer TI the BB PCM1742KE needs two supplies: 3.3 V for Digital and 5 V for Analog Part. A possibility is to take the 3.3 V from the main 5 V supply. I studied the PCB very carefully and find out thats the way MHZS has gone. BUT: TI recommends in his datasheet ( look here: http://focus.ti.com/lit/ds/symlink/pcm1742.pdf ) to give two separate voltages from two different PSUs to the chip. They write that would be very important to get a good sound quality later. I think I will do that and post the results.

On the other side you will see on your PCB that the cheap ecaps ( in post before ) sit between pin 7 and 8 ( analog signal ) and the OPA.

Now............ the missing small blue caps for high frequency eliminating (about 50!), the missing double PSU, the low quality electrolytics ( 4! ) and and and.........there is much air for new ideas

Now its time to look for new PSU caps. Havent forget them, but only the most important first

作者: Kiko 時間: 2007-7-31 03:29
Hi Blair,

you picture gallery looks very nice!!

I haven`t webspace so I will post some pics here, two of my projects have been really hard but very good. But one thing is not to forget: My experience is that a good clock can make a CDP coming up from a minicar to a rocket!

Changing caps is sure necessary but changing clock is the best I ever have done. On the next pics you will see it on the example TEAC VRDS-20, my last project........4 month work................ :wink:

作者: Kiko 時間: 2007-7-31 11:25
Hi Blair,

I hope you have managed to solder the new DAC. How are the results?

If you have trouble with your pickup try it here, they have everything:

http://www.ersatzteil.justone-schnepel.de/index.html

Now to the pics......at first from the CDP which I used as transport.......

作者: Kiko 時間: 2007-7-31 11:38
the Audiomeca Elixir DAC, a fine thing from Pierre Lurne. Good to see that there are not so much devices on the PCB as somebody would say, and the DAC is a Phillips, the DigFilter is a Crystal and the OP Amp from AnalogDevices. Interesting how few devices but such unbelievebable good sound.

作者: Kiko 時間: 2007-7-31 11:54
The Denon DVD Player DVD 2800 Mk II

The second pic is the origin condition....you buy here a lot of free space for more than 1600 USD...... please ignore the advertising of silicon image......this pic is the only one I have found on the net.

作者: Kiko 時間: 2007-7-31 12:33
oh....I am sorry, this is now the second pic from below .... the forum is sorting pics the other way around......

now the rest.........I think the Vincent ( is the German name, in other countries called SHENG YA ) is to colorless inside........here an original pic ( somewhere between the others, with the white beams ).....

The loudspeakers have been a DIY project from the german magazine Stereoplay. :arrow: http://www.stereoplay.de/stp/home

The order is again not correct.....Sorry :roll:

I brought in some Mundorf caps and coils. As wiring I used Linn K20. Its OK for that price, because there are about 20 meters used for the speakers.

If you have questions feel free and ask

作者: deicide67 時間: 2007-7-31 21:14
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

作者: Kiko 時間: 2007-8-1 01:55
Hi Blair,

thank you very much.

Now I am looking at the little DAC. A real advice I dont have. :? So I take a look on the datasheet. Thats what I have found:

Storage temperature, Tstg –55°C to 150°C
Junction temperature, TJ 150°C
Lead temperature (soldering) 260°C, 5 s
Package temperature (IR reflow, peak) 235°C

So I wish you a quiet hand and luck, dont solder him too hot or too long. And please dont take too much solder, it will be difficult to remove it later if the circuit points glue together.

Later I will handle the lens. The task is to minimize the diffused light of the laser. Its the same procedure as on the TEAC and DENON. You have seen it on the pics? The border of the lens is to colour with black resistant paint. Thats usually the first I do by modding. I will make pics and post them with description. Do you want to do that too? Its independent from your DAC soldering, easy and has a real effect, not vodoo .

Good luck,

Kiko

作者: deicide67 時間: 2007-8-1 02:10
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

作者: Kiko 時間: 2007-8-1 02:48
Hi Blair,

yes it is easy but please dont start it, I have some tips for you.

You need cotton swabs or Q-tips ( whats right now :? ) and pure alcohol. And an usually permanent marker. This work daubts a little bit, so I can show you how it goes easily and fast. :wink:

Blair, dont give up. If you damage the chip, order a new one and go with him to a specialist. Can you tell me how much you payed for this chip? The only problem you can have is that you damage this fine wirings on your PCB. Then nobody could solder in a new chip.

As I have damaged my first PCB ( with the open cover ) a Hongkong dealer told me, both new full assembled PCBs for CD66 and airmail shipping to Europe will be 190 GBP plus customs tax. For your CD33 it would be nearly the same price.

So be carefull will it. :wink:

作者: deicide67 時間: 2007-8-1 03:07
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

作者: Kiko 時間: 2007-8-1 03:14
OOOOOOPS, have forgotten somehing:

you must totally discharge yourself, the board and the soldering iron! This chip has a electrostatic sensivity.

So put in one resistor as I told before, meassure all pionts where are ecaps are, everything must be at 0 V. If you use a soldering iron with a transformer station you must discharge him with touching the top shortly with your shockproof socket ( on earth!!). And.....hmmmm......I discharge myself when I sit there ( after going about a carpet where your body charges everytime ) by touching the earth phase of my shockproof socket . But be carefull you can touch the hot wire. I hope you dont make this mistake! Or buy a bracelet for technicions, that a wire to the shockproof socket and you are so connected on earth the whole time you have it on. :wink:

作者: Kiko 時間: 2007-8-1 03:22
HI Blair,

can you make a pic of that and post? If there is some epoxy an the leads, can you use a hot air gun and a screwdriver? The epoxy will be squashier then.

Kiko

作者: deicide67 時間: 2007-8-1 03:41
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

作者: Kiko 時間: 2007-8-1 04:54
Blair,

looks very good what you have found there! And interesting how persistent you are! 8)

Do how have changed the both tubes before pulling up the dac?

作者: deicide67 時間: 2007-8-1 05:22
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

作者: Kiko 時間: 2007-8-1 08:24
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

作者: Kiko 時間: 2007-8-1 09:30
So, now the work on the lens. I recommend to do that on all players, how you have seen above its a good thing for DVD Pl. too.

You need a permanent marker, some Q-tips and little bit of spirit ( ethyl alcohol ) and 10 minutes time.

作者: Kiko 時間: 2007-8-1 09:37
You can pull up the cover so you can better paint 360 degree. Now hold that slide with 2 fingers. The slide is undetermined. Be careful not to break the slide. The mounting suspension is very softly. Paint the lens 3 or 4 times completely around, not only the border, but also not in the middle.

作者: Kiko 時間: 2007-8-1 09:43
If you want to be sure that your painting is 360 degree around you dont need a strong illumination. You have a blue LED there.

作者: Kiko 時間: 2007-8-1 09:49
Make the Q-tip wet with ethyl alcohol, dry him a little bit and touch the lens from above, fix the Q-tip with two fingers and turn him on the upper side. Very easy......

作者: Kiko 時間: 2007-8-1 09:59
Now polish the lens with the other side of the Q-tip. Play a CD. Print forward/backward on your player. Look a the rotation of the CD. Is everything OK you can put the cover back. Something not ok? Does the rotation behave strange? Than take a new Q-tip and make the clear flat of the lens a little bigger. The same procedure.

Dont worry if the CDP wants not to play, that is only a sign that the clear-transparent flat is too small. The CDP is not defective! That has happened here today, too. No problem.

作者: Kiko 時間: 2007-8-1 10:03
So....the cover and the LED are to screw back. Thats all. Costs = 0. The result: More stability and the music is more flowing.

Try it and you will hear the difference 8)

作者: deicide67 時間: 2007-8-1 21:52
[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

作者: Kiko 時間: 2007-8-1 22:57
Hey Blair,

I like your idea. 8) Very fine!

Sometimes I play with the same mind. Is there a homepage I can visit?

作者: Kiko 時間: 2007-8-1 23:11
...deleted message

作者: deicide67 時間: 2007-8-2 02:31
I emailed you. Let me know if you got it.

Thanks,

Blair

作者: Kiko 時間: 2007-8-2 07:18
Yes I have got it. Thank you.

作者: Kiko 時間: 2007-8-2 10:22
hey,

does anybody know good values for caupling caps for mhzs players?

thanks, kiko

作者: alfcat 時間: 2007-8-3 07:50
Hi,

I have heard of marking the edge of a CD to reduce the reflection by the lens. I have marked one of mine many many years ago with a permanent marker as well.

People suggested using Green & Purple; I can't recall what is the reason behind. They said using different colors gives different results.

The Belafonte disc I mark does give a LITTLE difference. I think my set of equipment may be the constraint as this set is just a budget buy.

I have never tried marking the LENS!

Kiko, do you think you can give us a more "close up" look of the lens after marking?

作者: Kiko 時間: 2007-8-3 11:42
Hi Alfcat,

marking the edge of a CD to reduce the reflection by the lens is correct, but the reflection happens on the edge of the CD and on the edge of the lens. Think about your camera, the objective is nontransparent, only the lens is transparent. I heard the lenses of laser pickups had to be build in the same way but the industry searches the cheapest way. The different colors have a reason. The pickup works with 650 nm laser. This is in infrared area.

So the modders try to find a way to absorb the light on the edge and because we cannot see infrared light everybody searches his own way of the best absorption. So some modders believe in purple, some in green. The modding scene has true differences here in Germany.

I have often heard of green as the right colour. You have seen I used black. Thats why I believe that black absorbs best. But if its true I cannot say. I tried that different time and had with black color the best performance. Of course if you believe something else would be better, try it.

Will you please post what you are doing? Will be interesting!

I will post the pics, hope they are better as the last one. They are the best my camera is able. On the last pic the lens seems to be complete black. It is of course not, it is a mistake of my cam!!

Greetings!

作者: alfcat 時間: 2007-8-9 17:14
Hi KiKo,

I haven't got the chance to mark the lens yet. Instead, I discoverd that there are "BLACK" CDs here in Hong Kong. Never heard or seen one before. I think they incorporate the logic you mentioned.

A photo is attached below. The set of CD comes with two discs. The Black (They call it the Purple Crystal) CD and the normally Silvery CD. The contents are the same but the sound quality is indeed different. The Black one is far superior to the silver one.

Will try to blacken the lens later.

Cheers!

作者: deicide67 時間: 2007-8-9 23:30
Alfcat,

WHERE DID YOUR GET THAT

Do they sell them in the US?

Thanks.

Blair

作者: alfcat 時間: 2007-8-10 07:50
Blair,

I don't think these CDs are sold in the US nor Europe. Even my Hi Fi friends are NOT aware of their existence. I discovered them just by chance and so far, there are only TWO I know in existence. One is a female vocalist (shown here yesterday) and the other is a Chinese Orchestra (Drum + other Chinese musical instruments).

Follow this link:
http://modernaudio.hkcdnet.com/main/index.php?main_page=index&cPath=2&zenid=bd7a8f2fc56551100dc08eace4416c7b

The THIRD with the lady and purple background is the first one I mentioned above.

And this link:
http://modernaudio.hkcdnet.com/main/index.php?main_page=product_music_info&cPath=8&products_id=2&zenid=bd7a8f2fc56551100dc08eace4416c7b

Gives you the Chinese Orchestrial one.

You should note that they are NOT expensive at all. Just HK$ 60 & $ 90. Total equivalent to US$ 20 or so. Very worthy of buying.

I listened to both of them. The purple one is far superior to the silver one. My set of equipment is no good for complex performance like an orchestra but still I can more or less locate where the instruments are in the setting.

Unfortunately, I can't find the English Version of the website. The reason, I guess, is because most of the discs are in Chinese. It will be really hard for them to translate the titles and the information into English.

I am not sure whether the company will mail to US or Europe. You may try to drop them an email.

CAT

作者: Kiko 時間: 2007-8-12 08:30
Hi Alfcat,

I know the black CDs. But I know them only for Playstation Games. The PS 2 uses them. Audio CDs in this form have never been sold here in EU.

Cheers!

作者: alfcat 時間: 2007-8-14 20:20
Hi KiKo,

I don't think they are "Black". Perhaps I used the wrong term in my previous post. They are "

URPLE". If you look at the reflection of the photo I posted last time you can see purple light bouncing back from the surface of the CD.

I lent them to a friend of mine for a close listening as his equipment are much better than mine. He also agreed that the purple one sounds much better, tho' he doesn't really like the lady singer way of singing, ha..ha..

It is said the purple CD has error level < 1/1000 mm and the way it is produced has great significance in reducing signal loss due to high spinning speed of the CD. The Purple CD is capable of "neutralizing" the defect of the red laser ... blah blah blah.

Anyway, it is a new toy for us ...

作者: viewer 時間: 2007-9-6 09:32
hi, Vash,

I also have CD-33.
please let me know the sony 213C is suitable for 213Q leaser head??

many thanks.

作者: deicide67 時間: 2007-9-7 04:33
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

作者: alfcat 時間: 2007-9-26 09:26
Dear KiKo,

In your first post in this thread I can see that you have TWO CD66 PCB sitting next to each other

Where did you get the extra PCB? I have ruined my CD 33 PCB (post in CD33 wrecked thread) and I need to consider getting a replacement PCB.

Can you provide me some information please.

CAT

作者: Kiko 時間: 2007-10-1 05:02
Dear Cat,

I must say that has been a great problem. After I have broken the first CDP I buyed a second one. Now I pulled up everything on the PCB to see more and get more information.

I asked different Ebay Dealers if I could bid on the same CDP and if I will be the winner they should put out the PCBs and the rest in the trash, because of saving the expensive shipping. They agreed all.

For the first CDP I payed 132 GBP shipping and import tax, for the replacement PCB about 15 or 18 GBP and no tax, because the PCBs have been marked as repair material.

Sorry that you have ruined your CD 33.

KiKo

作者: alfcat 時間: 2007-10-1 06:56
Dear KiKo,

I took my CD 33 PCB back to Mainland China, to the dealer which me and my friends got our CD 33. The sales there said he will try to get me a replacement board at the minimum charge. He said a brand new PCB cost around GBP 50, which is around HALF the price of the original CD player.

The sales is trying to get me a PCB without the capacitors installed as he knows that I am going to replace all the caps anyway. He hasn't tell me how much it is going to cost me .... but should be less than GBP 50. Have my fingers crossed.

I just feel upset with myself wrecking the CD 33. It is soooo stupid of me trying to rush everything and I lost my temper on doing it. Anyway, it is a good lesson and reminder for me.

One thing for sure, I won't quit DIY .... ha..ha... Will continue after I got my new PCB back hopefully the end of this week.

Thanks for your information. :wink:

作者: deicide67 時間: 2007-10-2 01:06
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

作者: alfcat 時間: 2007-10-3 20:47
Hi Blair,

I am still waiting for the return of my CD 33 PCB. Time comes to a standstill like .... This is indeed a very "long" week for me as I need to wait ....

I will continue to modify the CD 33 once it gets back. I still haven't got the chance to test out the large LED I got from Hi Fi Fever. Also considering adding another power supply to the OPAMP ... but this has to be done at a later stage.

Keep in touch and good luck with your Pre-Amp project as well!

作者: deicide67 時間: 2007-10-3 21:36
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

作者: alfcat 時間: 2007-10-5 18:55
My colleague is persuading me to DIY an Audio Note Pre-Amp. He said it is easy and simple and won't cost me too much even with good components.

I started playing with these toys say somewhat around May this year. Still got a long way to go, learning as I proceed. The first thing I have to learn is Basic Electronics, ha..ha... as I am an Economist, not a pure scientist.

I agree with what you've said. There is plenty of room for improvement with the OPAMP and perhaps even the DAC. I just wish I know more about these gadgets ... ha..ha..

Your suggestion on using the CD 33 as a transport is also a good one. Yet, I have to save up some money before I can go ahead with this DAC project. I guess the LITE ones maybe my choice.

Actually I lived in N. America for almost 5 years; mainly in Canada. I can manage some of the slang and I like watching movies all the time. That helps me a bit in keeping up with the American phrase. Blair, where are you located?

CAT

作者: deicide67 時間: 2007-10-5 21:59
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

作者: deicide67 時間: 2007-10-5 22:01
Another view:

And an amplifier:

Blair

作者: alfcat 時間: 2007-10-9 11:13
Dear Blair,

Interesting work you have there. I haven't make up my mind on the Pre-Amp thing yet as it depends a lot on time available and $$$. I don't want to go into anything that needs US $ 1K or more .... hard to find that spare money.

My CD 33 PCB is back. They charged me US$ 40 for putting everything back on a new PCB. Yet, they also put the burned 2.2/ 2W dead resistor back without knowing about it.

I put the board back and turned it on. It seems okay ... I haven't connect the RCA sockets back so I have no idea how it sounds. Have my fingers crossed.

Since they put all the caps back, I have to go through the process of de-soldering them out and put back my Jensens ... painful.

CAT

作者: SSWONG 時間: 2007-10-9 14:26
CAT,

Good news u can get your new board so soon....and with usd40 is very acceptable price.....

作者: alfcat 時間: 2007-10-11 09:04
Dear WINDWSS,

Yeah, thank God.

I managed to put back most of the capacitors yesterday. Spent almost 2 hours in doing so. Now, I am glad to hear the sound I am used to; though may not be everybody's cup of tea.

Will try to see if I have time to continue with the LED modification next to the laser to reduce reflection later this week or next.

Keep in touch

作者: SSWONG 時間: 2007-10-11 12:47
dear vash,

can you give me some info on cheap & nice pre-amp? (schematic & part list)....especially your zero gain line stage...
Thank you.

Dear cat,
If u plan to buy a DAC then save the money don't mod too much on your DAC part of CD33. Mod the power section enough....
after you had mod with the led teach me how to do it... is the effect is good?

作者: deicide67 時間: 2007-10-11 22:28
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

作者: SSWONG 時間: 2007-10-12 09:53
Dear Vash,

U can send it to my email: sswong@healthtronics.com.my which will be easier & faster.....

what kind of less expensive power supply u studying now?
tube rectifier? i understand that got people use 300B as tube rectifier in China.... so i will try out to use 6N3/2C51 as tube rectifier later.....

ss

作者: alfcat 時間: 2007-10-12 20:46
One think I don't understand. I put back all my previous parts back on the new PCB. However, the S/N ratio dropped to 65db ... which is 10 db less than before ...

作者: Kiko 時間: 2007-10-15 18:16
Hi,

does anybody know where new PCBs from the MHZS Players were sold for changing?

作者: alfcat 時間: 2007-10-15 18:56
Dear KiKo,

I got mine from China. The sales I got my CD 33 said it cost RMB$ 900 to get a new PCB for the Analog Section with everything on.

In Hong Kong, never heard of any place doing this.

CAT

作者: Kiko 時間: 2007-10-16 03:26
Dear CAT ,

thank you very much!

Can you give me the adress or email or homepage of the place you have got it?

And another question I have to you. All manufacturers in HIFI and Audio have their own homepage. Only MHZS has nothing. I have tried everything.... www.mhzs.com, www.mhzs.hk, www.mhzs.cn and and and.....and all metacrawlers I know, but without result.

Who is the mysterious manufacturer? Is it the Bada company? I think it must be possible to order directly from the factory or not?

KiKo

作者: alfcat 時間: 2007-10-16 09:09
Dear KiKo,

I did the same, NOTHING related with MHZS whatsoever found. This CD comes not from a well known company nor there is a big firm behind its production.

Another active member here, Viewer, had just purchased and modified a second hand CAYIN CDT-15A or so. That one has some support, I think. You can check out what Viewer did in my other thread "Interesting S/N Ratio for the CD 33".

The shop I got the CD 33 has NO web page or so. It is not a big store at all. Kind of like the Variety Store next to our neighbourhood (I mean the scale & way of operation). Some said the Bada CDs are very similar to the MHZS but there is no proof that they came from the same source.

I only have the Chinese Address of the company. Unlike firms in Western Countries, this address may also be a FAKE. If you need anything, you may drop me a note and see if I can ask the sales I know to arrange for you. Last time he told me that he did this as a favour for me (to get a new PCB). Yet, each time we go there, we bring him a lot of business ... ha.ha.. and I think he doesn't mind to continue giving us favour.

CAT

作者: Kiko 時間: 2007-10-29 19:20
標題: Finished...
Hi

I have finished the CD66 , but there is no clock modification yet. This will come later.

At first take a look at the high resolution pics of the PCBs. I have studied them and investigated some weakness of MHZS Players.

Here they are:

作者: alfcat 時間: 2007-10-29 19:34
Dear KiKo,

Long time no see. Glad to see you back.

The photos are missing. Hi Fi Fever allows upload to 1M only. I think your Hi Res photos have to be in different sections of the PCB.

Awaiting for your report.

CAT

作者: Kiko 時間: 2007-10-29 19:43
Hi Alf,

fine to hear from you!

Thank you for the tip.
Now I will start to arrange and to resize the pics. Awaiting your comment after upping them.

作者: Kiko 時間: 2007-10-29 20:16
At first some pics of not assembled PCBs. If you look for a circuit path it will be very helpful. Please ignore the marking.

作者: alfcat 時間: 2007-10-29 21:03
Dear KiKo,

These photos are very useful. Although I am just an amateur, these photos give me / us a better understanding of the layout of the whole thing.

As I scan through the photos, your CD 66 uses 12AX7 instead of the 6N3?

Vash, t, WINDWSS and I are looking at the readings we got from the tubes. Please also check out our other thread"

http://www.hififever.com/forum/viewtopic.php?t=952&postdays=0&postorder=asc&start=700

Got to pick up my wife now ... ttyl

CAT

作者: Kiko 時間: 2007-10-30 19:38
Hi Alf,

thats right. The CD 66 uses 12AX7 instead of the 6N3. The rest of the circuit is nearly the same. Espetially the Digital board with heater PSU.

作者: arnaudb 時間: 2007-10-30 22:04
Hi everybody,
This is my first msg on this board, i'm from France and we (mhzs french owners) are reading your posts with great interest. Firstable, thank you all for all your posts about mhzs players tweaks. We (french mhzs community ;-) ) are working on some tweaks too. If we find something new, i will post it on this forum. So Kiko, thank you so much for your pcb pictures (very usefull !), and could you please tell us more about your findings about mhzs weakness ?

作者: leo 時間: 2007-10-31 01:16
There are lots of weakness on the standard MHZS players

the implemented regulation and decoupling of the supply rails is poor, the op-amp after the dac section is a waste of time, the standard clock circuit is noisy, the SPDIF output is not very good etc etc

BUT these cdp's are cheap and fun to tweak :wink: with some careful thought and added improvements the MHZS cdp's can be made to sound very good

Any idea's to add a better quality internal dac chip instead of the supplied PCM1742?

作者: Koifarm 時間: 2007-10-31 01:40
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.

作者: Kiko 時間: 2007-10-31 08:59
Hallo,

nice to see how much guys from different countries are interested in this CDP and forum. I want to thank you for your response!

Here my point of view:

The Digital board is ok, you can increase the performance on classic ways.

I changed some elCaps to Panasonic FC, added some film Cs above the diodes and changed the input Cs of the filter for PSU. Just nothing in particular. After finishing you can add some damping material; here I used a rubber mat from a store which is selling sport articles. In earlier times I used tar-bitumen roof sheeting, but it makes a lot of dirt. Certainly bitumen is better and more heavy, can be well performed on the chassis, but the sand falls out of the bitumen and after a while it doesnt look. The free positions between the small film caps amazed me, so I studied the circuit paths for checking their functions. The conclusion is very easy - there is one high frequence filtering film cap in a line with 2 free places for other small film caps. Finance seems to be the reason for omitting them. Dont worry about that, I have seen it also on other very expensive equipment! The price doesnt matter, the manufacturers seem to produce the first prototypes fully assembled in best quality and on mass production they save their money. MHZS is doing the same........

Of course there is to paint the lens of the laser, you can read it on earlier pages of this thread. On this board there is not so much to do.

作者: Kiko 時間: 2007-10-31 11:25
Now, the DAC board is a little bit harder. The most intersting things I found out after taking a look on the bare board.

1. The circuit paths are a totally chaos. For example:

You surely remember the 4 elCaps in a row, in front of them the 4 voltage regulators and in front of them the other 4 elCaps? At first it seemed to be so: 1 elCap to 1 volt. reg. and following is the next one elCap. If you believe it you are wrong. This is absolutely different. I will try to write the paths in some pics with an image editing prog.

2. The heater run very hot. The mounted voltage regulators run inexactly.

3. Read: http://focus.ti.com/lit/ds/symlink/pcm1742.pdf, the DAC needs Dual-Supply Operation: 5-V Analog, 3.3-V Digital. You have a cheap 2 Zener solution here, but TI says, you need a separate supply for the Digital input if you want to have a good sound.

You can see the connection diagram on page 25. The important facts here as copy:

"The PCM1742 requires a 5-V analog supply (VCC) and a 3.3-V digital supply (VDD). The 5-V supply is used to power the DAC analog and output-filter circuitry, while the 3.3-V supply is used to power the digital filter and serial interface circuitry. For best performance, the 3.3-V supply should be derived from the 5-V supply using a linear regulator, as shown in Figure 28."

There is no "clean" 3,3 V supply. The 2 Zener near the DAC produce 3,3 V but in a very noisy way. So I redesigned the complete PSU on this board.

4. All electrolytics in signal path have to be removed (4 pieces , see above) with anything you want - or can pay.

5. A new clock is a good thing.

6. Except the elCaps I changed all resistors in signal path and the tube area for better ones. Some of them are non-magnetic Vishay-Dale Mil Spec  CMF-55, but not all, because they are hard to find here and the most powerful are 1/10 W. Furthermore not all needed values have been available. The other resistors are some of 1, 2 or 3 W metalloxide film from Yageo. The empirical formula is not to take lower power rating but the same value. Minimum power is the power of the old resistor.

7. I had one greater problem in redesigning that you maybe will have too. Please read this now very carefully and avoid this problem:

For the DAC I used a Linear Technology LT1584CT-3.3 / 7A linear regulator. This one has a stability of 0.05 %, is very fast and has a constant voltage of 5 %. Costs are 20 USD.

7 A is absolutely to much for the PCM1742, but it was the only one I could get without lead time. Then I made a great mistake. I connected him where the other linear regulator is connected , the LM 317 - on the big resistor 2,2 Ohms 2W near the two cooler. I have done it because I wanted a single path for the 3,3 V. And I thought, that a 5V regulator can share the same input as a 3,3V. After this procedure it got curious. Player has no  more signal! The solder joints seemed to be all right, so I have searched the error for weeks!

.............and then I found it. It was the expensive regulator. It had not 3,3 V on output, it had 3,85 V! But why?

At the end of the big resistor (where the LM317 is connected) there is an input voltage of more than 20V! So the 3.3V regulator and the LM317 share a 20V input? I couldnt believe. At first I thought the 2W 2,2 Ohms resistor is broken and I had a short-circuit. But it was not so. What was the reason?

The reason is that a Linear Technology LT1584CT-3.3 should not be connected on such high input. I found the answer here:

http://www.farnell.com/datasheets/84158.pdf........"input below 7V".

But why has a single 5V regulator (LM317) an input of 20V?

The answer is on the other side of the PCB. The bigger elCap is not only connected to this 2 voltage regulators, no, this cap is also connected to the 7812 regulator on the other side. This regulator produces this voltage only for the delay at the output.

Again studying the datasheet of the PCM1742 I found the answer on page 2:

" ABSOLUTE MAXIMUM RATINGS: Power supply voltage, VDD –0.3 V to 4 V,

and RECOMMENDED OPERATING CONDITIONS:

Digital supply voltage, VDD = 3 MIN, 3.3 NOM,  3.6 MAX. Here is the problem! This DAC dies at 3.85 V input!

The next problem is - by pulling up (slowly and carefully) the cover of the broken DAC the circuits paths were demolished. Between the cover and the chip is epoxy and the chip, the epoxy and the cover are stucked together.

After a longer time I got a new DAC, a new SMD adapter and a new regulator (for 20 USD again :shock: ).

This time I made no more experiments: the 3.3 V regulator I connected directly on the output of the 5 V regulator (on the same cooler of the LM317). The changing of the DAC is really a hard thing and I dont recommend that if it is absolutely not necessary.

The new high precision 5V regulator is a 1,5 A one instead of the old LM317 with 1 A. The heater runned very hot with 1 A, so I searched a solution for it, because I expected now overheat on the 5V regulator. This is a simply 20 W resistor. Pulling out the 2,2R I build in an 6,8R. Now the heater is a little bit cooler, the resistor a little bit warmer. I wanted that the heater is only handwarm, but he isnt yet. At least I added a second 6,8R in serial and an approx. 5R on the other regulator, the 7808 at the top of the pic.

It is a little bit better, but I will take greater values and conduct some experiments. For the 7808 10V input is enough, for the 5V regulator 8V. Its a simple thing to increase the resistors. Better a hot resistor than a hot regulator.

Its ready now! Now its a really good thing! I will try to explain that all with the pics tomorrow.

Have a nice day

Greetings to our new friends, coming to us from Holland and France. I am your neighbour. Coming from Germany. Pics will come tomorrow......

作者: Kiko 時間: 2007-10-31 14:14
Alf, Blair? What are you doing now?

作者: alfcat 時間: 2007-10-31 17:15
Dear Friends,

It is so nice to see people coming from all parts of Europe and our friend Blair from USA. I guess it is really hard to find a chance for people of different parts of the world to come together like this.

Although I am not the operator, I sincerely welcome you all to share your interesting experience.

I am a bit busy right now as this is the quarterly examination period at my college. I have to set a number of papers (not to mention marking them). For this week or two, I may not be able to contribute much but will continue the DIY thing by mid Nov.

For the time being, I will continue to read your posts and give some comments if possible.

Keep in touch guys and happy DIYing.

CAT

作者: deicide67 時間: 2007-10-31 22:10
[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

作者: alfcat 時間: 2007-11-1 20:38
Dear friends,

I have a plan to build an AudioNote 7 pre-amp before Christmas. My friend told me that the material cost will be around HK$ 2K (approx. US$ 230).

Just hope I can spare the time after the half yearly examination.

CAT

作者: alfcat 時間: 2007-11-1 20:40
Dear Koifarm,

The DAC board you are using -- LITE AC-AH, I think it is no longer available at DIY Gene ... sigh

作者: leo 時間: 2007-11-1 21:18
I have built some discrete regulators to try for the dac :wink:

作者: arnaudb 時間: 2007-11-2 01:50
I would be very interested by the results you get with your regulator...
Question : Is it a 5 ou 3.3v reg ? Do you get 3.3 from the 5v reg as BB suggests in their 1742 documentation ?

作者: Koifarm 時間: 2007-11-2 02:36
Dear alfcat

I just have ordered one for another forum member to Modify his MHZS 66.

He had enough of the noise that the original DAC produced.

作者: deicide67 時間: 2007-11-2 03:11
[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

作者: Koifarm 時間: 2007-11-2 03:37
Dear Vash.

That DAC can you also fit in the MHZS players.

I do not know how it sounds. But the other DAC sounds musical. (very analog). No noise. I do not use the opamp output section of the DAC board. Less is better i expierenced.

The power supply for the two dacs you can take from the MHZS player. The analoge outputs from the dac connect as writen in the other reply.
The digital input is another story i must look inside my player to tell you where to connect.

作者: leo 時間: 2007-11-2 05:54
[quote:67d1b01e5d="arnaudb"]I would be very interested by the results you get with your regulator...
Question : Is it a 5 ou 3.3v reg ? Do you get 3.3 from the 5v reg as BB suggests in their 1742 documentation ?[/quote]

That one in the picture is set for 5v output but I can build another and adjust it to other voltages

You may have noticed I currently use modified super regs in my CD33, it will be interesting to see how these cheap easy diy ones compare.

作者: leo 時間: 2007-11-2 05:57
If anybody wants to wire in another dac simply tap into the I2S lines , of course the dac you use should be I2S compatible

作者: alfcat 時間: 2007-11-2 20:36
Dear Koifarm,

Strange, that board was NOT available yesterday at DIY Gene. Today, it is!

If I use that board, I will by-pass all the analog part, is that correct? In that case, it will be the same as having an External DAC connected through the coaxial out.

Please correct me if I am wrong as I don't know Electronics at all.

作者: Koifarm 時間: 2007-11-3 00:48
Alfcat,

If you connect the output from the DAC board to the cinch of the player then it is like a external DAC. But the trick is to use the good parts of the MHZS player.

The analoge buffer opamps on the DAC board you must not use ( like passive filter in the MHZS player ). The analoge outputs from the TDA chips you must directly connect with C7 and C8 as in the above reply from me. Then you do not use the bad opamps and you use the tube output of the MHZS player . The one we like.

作者: arnaudb 時間: 2007-11-4 06:08
So t. what about your home made regulator, is it better with them ?
And what about the sound difference with them (more detail, focus,...) ?
Thx !

作者: leo 時間: 2007-11-4 10:45
[quote:d2ec9dd10a="arnaudb"]So t. what about your home made regulator, is it better with them ?
And what about the sound difference with them (more detail, focus,...) ?
Thx ![/quote]

I like it, its much better than a standard 3pin regulator.
I set the CRD to 4.7mA in the discrete regulator to lower impedance, the type of capacitor on the output has quite a big influence, I'm using Sanyo SEP polymer, the discrete regulator likes low ESR unlike standard 3pin regulators :wink:

Anyway sound is more focused with better separation of instruments, improved background details

作者: arnaudb 時間: 2007-11-4 17:48
Excellent t. !
Could you please post schematics and pictures of your regulator ?
It would be great ! ;-)

作者: alfcat 時間: 2007-11-5 08:41
Dear Koifarm,

I understand your logic but I need further help from you as I am a dummy in this field.

The LITE DAC-AH board got several connectors which I highlighted in YELLOW circle in the photo that comes with this message. What and Where should I connect these to? I think one should be the INPUT source, one the OUTPUT and the next should be POWER. But there is still one left?

I used KiKo's CD 66 PCB as a reference as it has high resemblance with the CD 33 PCB. Can you point, by means of arrors or so, where should I connect those items mentioned above.

It would be better if I use a separate Power Supply for this board, is that right?

CAT

作者: arnaudb 時間: 2007-11-6 05:02
I've worked on kiko's pcb pictures ;-) I think that we can do better but if it can help a bit...

作者: leo 時間: 2007-11-6 23:44
Hi alfcat, the best way to connect that sort of separate dac pcb would be I2S instead of spdif so it bypasses the CS8412/4 input receiver which would result in a much better performance, unfortunately this way is harder and unless you know exactly how to do it I seriously would not attempt it :wink: it can result in a damaged board.
I do not have a LITE dac but judging by the picture it seems that two top right hand connectors are for the PSU/transformer and the top left connector looks like its for another psu/transformer using a centre tap secondary

The sockets on the bottom right are the spdif input

The bottom left connector looks like its the signal Left,Right and ground output

作者: leo 時間: 2007-11-6 23:45
[quote:bf0e3f0b1b="arnaudb"]Excellent t. !
Could you please post schematics and pictures of your regulator ?
It would be great ! ;-)[/quote]

I will try and find the schematic, there is no other pictures so it needs to be built on a piece of matrix board

歡迎光臨 HiFi Fever (http://hififever.com/dz/)