I forgot to add the ressistor to ground after output cap. Im still not using those +15V in series with 4K7 and 5K multiturn pot. to setup the 0V, for now im trying just with cap on the output.
Its just a test project, when (if) I reach all possible improvements ill put it in a nice box. For sure ill choose a wood.
In this moment i like the sound, but there are still a lot off things to do.
I ordered 20 peaces of ELNA silmic II 100uF/35V just to try if that will change something. If not, ill try with Black Gates.
In general, this modified Marantz CD40 can fight against much more expensive players.
Silmic II is very good. I just finished a NAD3020i and a Philips 610 using silmic II and oscon. they sound very good. I like Silmic II and Cerafine a lot. Someone said Silmic II is very much like Black Gate. But I dont know I never had BG to try.
And Oscons seems to work very good at digital power line at the chips.
If you wanna improve the sound a little bit change the wima decoupling to something better. Like naked polyester(MKT-MKH) like in the Naim cd3.
or polyester mylar. Only watch for the width, since the place is very limited. Hard to find a 2,5mm Width and 5-7,5mm pitch.
I know wima is not bad but not very good either.
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Isn't the last stage opamp the filter and amp??
I think the first stage only does the IV conversion but does not amplify.
I believe the 2 stage needed to use it properly.
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Nice boards
I readed somewhere that silmic II is much better then cerafine and a liitle bit better then Black Gate. For sure its subjective. The best way is to try different types and to choose what You like. I have never used Oscons, thanks for suggestions.
I know that WIMA are not so good i will try to find something better, but You are right the space is limited. Its very hard to solder a nice big polipropilens.
I just did the modifications as was suggested, without second stage and without the filters on the first stage. It sound very good, much more natural.
The gain seems to be the same without second stage, at least I cant notice a difference.
With the fet in the off state, that leave the 5m5 in circuit which I thought would effectively take that part of the filter out of circuit. Are you saying that even with this high resistor in series with the other components it will effect the sound?
With respect to the single opamp for I/V direct to the output, working on the basis that less is often more this circuit has a filter and enough output to drive into my amp. I've used this circuit on several players and dacs that I've built.
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An externally hosted image should be here but it was not working when we last tested it.
OK. Thanks UV101 to confirm the IV stage.
I just never seen this solution before and I tought the gain just wont be enough.
I will try next time when I take apart my CD again.
Any suggestion to use opa627?? I got oscillation with the original resistor and cap size in the opamp stage. I have seen with 470 Ohm and 400pf. Is that correct???
To GoranB
As for the decoupling caps I find some on ebay, but I wanna ask for the proper size before I buy them. Or just get them since the cost is only 1,5 EUR.
10 condensateurs MKT 220nF 0,22uF 100V Siemens MKH - eBay (item 280487232827 end time Mar-27-11 01:47:54 PDT)
They have some nice caps and they are cheap too.
The Oscon SP is the good one.
I just never seen this solution before and I tought the gain just wont be enough.
I will try next time when I take apart my CD again.
Any suggestion to use opa627?? I got oscillation with the original resistor and cap size in the opamp stage. I have seen with 470 Ohm and 400pf. Is that correct???
To GoranB
As for the decoupling caps I find some on ebay, but I wanna ask for the proper size before I buy them. Or just get them since the cost is only 1,5 EUR.
10 condensateurs MKT 220nF 0,22uF 100V Siemens MKH - eBay (item 280487232827 end time Mar-27-11 01:47:54 PDT)
They have some nice caps and they are cheap too.
The Oscon SP is the good one.
Thanks Danico for the links. I think here in Poland its also possible to buy what I need, very good prices. Ill order Oscon SP also. What do u think of increasing the values and voltage of the original caps?
On the output now i have two polipropilens 22uF/400V according me they are better then Muse Nichicon Bi-polars.
Yes polipropilens is a good choose. For the size anything above 4,7 will be good for output and the bigger voltage sounds better. Maybe because the better insolution?. I cant tell for difference in size between the same kind of caps. But I know I mostly prefer PIO to Film cap. Again it for personal taste.
As for decoupling on the chip I like to use simple L network.
Inductor and cap. Easy to put on the board. Also I know building on a separate board, like you did is much better.
For now I settled with 100uf, but I wanna try the 47uf size, too. Like in the AN dac. In my case the cd40 had 330uf on the 1541 I put 100uf oscon.
Sound very clear and fast.
Good to hear you have good supply in Poland. Here in Hungary is suck mostly junk everywhere. So I had to get good parts from ebay.
Where could you get Oscon SP?? A had a hard time to find 220uf 16v so I got SA instead. I hope that would make it.
Did you try the DEM reclock mod?? I find a very simple solution and I wanna know if its working or not. I just didnt had the 6v2 zener and know I just put together my cd. I wanna listen today after I did some cap change on that.
Can you try it???
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I will try to check again but I remember that here are distributors for Oscon SP. Ill check later and ill inform You.
About reclock mod i didn't try anything, I would leave it for the end and NOS mode also. I also dont have any 6v2 zener in this moment. But its worth to try this days. Ill tell You about impressions.
Danico
Only, ELNA, Panasonic FC, Black Gate, Nichicon Muse...no Sanyo oscon's
Too bad. Thanks anyway GoranB.
I listened my cd and find the bass a little bit less dinamic and its just didnt go deep enough. But it could be I got my hearing still on my friend Philips 610's sound that I just finished. He got my opa2604 and I switched back to the lm833. Probably I remeber listening the cd40 with the opa2604.
Tomorrow I gonna build a separate power supply for the 7220 and 7310.
that would clear things up.
I will try to find those Oscon's here and I will send it to You.
Im running my CD40 for 24 hours in hope that the new caps and the modified output will make an friendship
The best thing You can do is separated trafo for digital (separated rectifiers and LM regulators for every single IC), trafo for servo and trafo for audio. The top end will be adding a trafo for display and display controller. After this, You can go with NOS mode and tube output.
Im running my CD40 for 24 hours in hope that the new caps and the modified output will make an friendship
The best thing You can do is separated trafo for digital (separated rectifiers and LM regulators for every single IC), trafo for servo and trafo for audio. The top end will be adding a trafo for display and display controller. After this, You can go with NOS mode and tube output.
I will try to find those Oscon's here and I will send it to You.
Im running my CD40 for 24 hours in hope that the new caps and the modified output will make an friendship
The best thing You can do is separated trafo for digital (separated rectifiers and LM regulators for every single IC), trafo for servo and trafo for audio. The top end will be adding a trafo for display and display controller. After this, You can go with NOS mode and tube output.
Thanks for your offer. Right now I just will go with the Oscon SA version.
But if you can find somewere just let me know.
Yes I plan to do a separate section for the 7220 and 7310. Later I do the dac. I dont think I will have enough time to do the servo, but I know is important too.
What can you recommend for the transport?? Thinking of the box.
I mean without ripping it off. I just wanna keep it that way.
I bought this cd just to have a taste for the TDA1541 sound. It got me
I want to put more effort and money to start the DAC-END.
It just collecting dust now.
Thanks for your offer. Right now I just will go with the Oscon SA version.
But if you can find somewere just let me know.
Yes I plan to do a separate section for the 7220 and 7310. Later I do the dac. I dont think I will have enough time to do the servo, but I know is important too.
What can you recommend for the transport?? Thinking of the box.
I mean without ripping it off. I just wanna keep it that way.
I bought this cd just to have a taste for the TDA1541 sound. It got me
I want to put more effort and money to start the DAC-END.
It just collecting dust now.
About transport I can only suggest according my experience.
The first thing i did was to put it out from the cd player to not be in the same nasty plastic vibrating box with all that electronics and trafo. I took out CDM4/19 composite version and mount it on the greay 5kg heavy brick. As the flat cable is pretty short, i used another one from another CD40 to make it longer. So, cd transport mechanism was out of the box on that ugly brick connected to the board by two flat cables in series. I notticed a huge improvement in details and sound stage. (in that time the marantz board was not tweaked) I readed somewhere that vibrations of standard mounted cd mechanism loos 30% of details becouse of weak maded box. (I dont know if that is true, for sure not for expensive players).
I wasnt sure that using the double lenght of flat cable has some bad influence , so, I decided to make a metal case (leyers of metal and damping material) and to put back the CDM4/19 in another wooden box with all electronic and to start with tweaking the board. That way my cd40 is so ugly in this stage of tweaking. The tweaking of transport as You can see from pictures ive sent is not still finished. Im using a metal clap to keep the cd's. CDM4/19 is fixed on metal with its original amortisators (they are glued) the metal case is also fixed to the wooden case with rubber and glue.
If You have some old CD player try to take the transport mechanism out and use just a clap to keep cd's. You will notice the difference.
Few days ago i bought 2 old telefunkens for 10 Euro just for fun and for tweaking. Ill see if I can improve those low end level comercial players.
About Oscons You need i i will search instantly. I would also like to buy them. I will let You know about.
You can damp the upper and down covers of the player. Also dampen the plastic part wath keeps the cd's on their place. Side of box also. You can mount a wooden parts, side to side and back to front of the box. I didnt do any of this. But it cant be bad for sure.
For really noticable improvements you should do a hard tweaking of cd mechanism and box. Buy some second hand cd40/50/60 and try.
Here the price of an old cd40 is about 20-50 EURO.
When i moved in Poland an year ago i had a few months free because i was looking for a job. I used that time for buying cheap second hand players and to explore the tweaking. I bought also an Marantz PM44SE (50 EURO) just to listen to something. Few months ago i bring my reference system which i was using in my motherland. Now the differences are more noticable.
Best regards
Goran
Thanks for the very well detailed info.
I did just bought this cd secondhand a little less then a $100. Here the prices a little higher because not too many of them. Although the used market on the local hifi forum seems to be very slow, so I could pickup some good player cheaper. But I didn't plant to buy this one either.
Anyway I planing to leave aboard so I cant get into a big project like yours.
I just wanna do the the very basic and important tweaks.
Just for fun and to learn new things.
10 years ago when I bought my first "real" High-End after a couple of months I went to San Fransisco, so I didnt even listen them too much.
Now I am back and since I got no job here I had to find something to do.
I finished all my gears upgrades, only this cd40 and the DAC-END left.
I might just do dumping the old case. I have been thinking about a wood sidepanel with coper underneath and something rigid at the bottom.
Best regards
Bardos
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