Hi everybody!
I joinned this forum about 7 months, and following the guide of some guys to complete my fist amp LM3886 3 months ago.
I watching this topic many times and now I decide to modify my CDP.
Now I'm using a nice old Marantz CD 25 -> preamp using OPA2134 -> LM3886 amp -> Pionner CS-A7 speaker.
I will post step by step I modify my CD and I hope you will instruct me to complete it.
Fist, I remove the old oamp LM833 and repalce them by DIL8 socket, that I can change oamp may be OPA2134 or OPA2604.
Second, I found my CD quite hot when it operate, so I attach some heatsink for regulate IC (7812,7912,...)
And follow this topic, I would like to add new DAC chip TDA1541 that I get from old Sony CDP 750.
I remove old DAC chip TDA1540 and replace them by socket, and SAA7030 too.
And I was build a new small board for TDA1541 (not A).
So what I should to complete this modify.
Thank you very much.
P/s: I will post pictures soon, so please help me.
Sorry about my bad English, I just graduate.
I joinned this forum about 7 months, and following the guide of some guys to complete my fist amp LM3886 3 months ago.
I watching this topic many times and now I decide to modify my CDP.
Now I'm using a nice old Marantz CD 25 -> preamp using OPA2134 -> LM3886 amp -> Pionner CS-A7 speaker.
I will post step by step I modify my CD and I hope you will instruct me to complete it.
Fist, I remove the old oamp LM833 and repalce them by DIL8 socket, that I can change oamp may be OPA2134 or OPA2604.
Second, I found my CD quite hot when it operate, so I attach some heatsink for regulate IC (7812,7912,...)
And follow this topic, I would like to add new DAC chip TDA1541 that I get from old Sony CDP 750.
I remove old DAC chip TDA1540 and replace them by socket, and SAA7030 too.
And I was build a new small board for TDA1541 (not A).
So what I should to complete this modify.
Thank you very much.
P/s: I will post pictures soon, so please help me.
Sorry about my bad English, I just graduate.
1540 sounds better then 1541 (my subjective opinion), there is no need for adding new board with it. Maybe is better to build separate dac with 1541 and have both versions. About removing saa7030 everything is very well explained in previous posts, if you really want to use 1541 just look datasheet of 1541 and you will find where to connect digital out from saa7000 and pin 16 must be connected to ground for 16bit mode. Did you completely finished board with 1541? If you build separate board with 1541 dont use opamp, one resistor 33ohm for i/v and one transistor (2sc1775a is my favorite) common base connected will give you much, much better and more analog sound.
Regards, zogu
Regards, zogu
Reading this thread I decided to dig out my old CD101, I did the NOS mod, changed op-amps to LM4562's,replaced lytics on top board with Rubycon ZL's and removed coupling caps.
Its not sounding bad at all
Just need to change the main psu caps and maybe a few other bits and pieces.
BTW this cdp will play any disc I throw at it
Its not sounding bad at all
Just need to change the main psu caps and maybe a few other bits and pieces.
BTW this cdp will play any disc I throw at it
Hi "t"
When you start with PS: Try BYV diodes is PS, really worthwile. I always put a small dot with a marker at the cathode on pcb, then nothing can go wrong. Also some beads to different (digital) chips do wonders. Every chip can be isolated from the other with 47 ohm resistors in the digital signal lines. Scratch the pcb track a litlle, make an interruption and solder a 47 smd res. on it. The decoupling works then for that particular chip and rubbisch/noise doesnt go through whole circuit. Further tips: Search for Guido Tents decoupling guidelines somewhere here on diy in pdf.
When you start with PS: Try BYV diodes is PS, really worthwile. I always put a small dot with a marker at the cathode on pcb, then nothing can go wrong. Also some beads to different (digital) chips do wonders. Every chip can be isolated from the other with 47 ohm resistors in the digital signal lines. Scratch the pcb track a litlle, make an interruption and solder a 47 smd res. on it. The decoupling works then for that particular chip and rubbisch/noise doesnt go through whole circuit. Further tips: Search for Guido Tents decoupling guidelines somewhere here on diy in pdf.
tubee said:
Hi Tubee,
Thank you for the advice, its much appreciated
This old CDP with its pair of TDA1540 dacs is not bad at all
I have a few modified cdp's mainly using TDA1541A and a Pedja external dac using TDA1541S2, also implemented the DEM Reclocking mod, very nice sound!
I tried 11DQ10 schottky's before in other cdp's but didn't like the results but will give the BYV's a try along with the 47R resistors in the digital supply lines
Cheers,
Leo
Hi Leo
I have modded a CD304mk2, with 1541, kept OS in it (this time) Allmost all caps swapped for Elna Cerafines/Panasonics. Thanks to Kwak 7 clock, divided appropriate clock signals to dac, 7210,7220 and DEM it sounds very good now for a oversampled player. I want to keep dig out, but also the best sound possible with the cdp. Fitted OPA2132 opamps, and a small coil between dac out and opamp to filter some hf. Opamps don't like very fast signals. Some other members here react with bad comments about this coil adding there, but listening tests to me proved a lot. Treble did benefit, less sharp, though soundstage became slightly smaller with coil. The 7220 has now a copper foil grounded shield, this chip broadcasts a lot of rubbish. On the dig out i removed the transformer, and putted a DS8922 buffer in it, advised by EC designs.
After the mods you can hear wat's "in" a CD recording, it's still not analogue but it gets close, very pleasant to listen to it for a longer period. With Nonos i had "listening fatigue" after longer listening periods. Now the depth in soundstage is very obvious. Before it was only +/- 2 Metres,and i thought allways it was normal for CD.
The diodes have to burn in for a while. At first sound is "szising" but after a while it goes over and becomes obviously the noise floor is reduced some dB.
For the 5 V supply i suggest BYV27, (low voltage drop of 1.07 V) and solder them at higher distance from pcb, they can get some warm.
Btw the 47 ohms resistors are not in supply lines, but in the signal lines. So between SAA7220 and TDA1541 WS, CL and DATA get a resistor.
The supply lines profit from beads just before decoupling cap.
I have modded a CD304mk2, with 1541, kept OS in it (this time) Allmost all caps swapped for Elna Cerafines/Panasonics. Thanks to Kwak 7 clock, divided appropriate clock signals to dac, 7210,7220 and DEM it sounds very good now for a oversampled player. I want to keep dig out, but also the best sound possible with the cdp. Fitted OPA2132 opamps, and a small coil between dac out and opamp to filter some hf. Opamps don't like very fast signals. Some other members here react with bad comments about this coil adding there, but listening tests to me proved a lot. Treble did benefit, less sharp, though soundstage became slightly smaller with coil. The 7220 has now a copper foil grounded shield, this chip broadcasts a lot of rubbish. On the dig out i removed the transformer, and putted a DS8922 buffer in it, advised by EC designs.
After the mods you can hear wat's "in" a CD recording, it's still not analogue but it gets close, very pleasant to listen to it for a longer period. With Nonos i had "listening fatigue" after longer listening periods. Now the depth in soundstage is very obvious. Before it was only +/- 2 Metres,and i thought allways it was normal for CD.
The diodes have to burn in for a while. At first sound is "szising" but after a while it goes over and becomes obviously the noise floor is reduced some dB.
For the 5 V supply i suggest BYV27, (low voltage drop of 1.07 V) and solder them at higher distance from pcb, they can get some warm.
Btw the 47 ohms resistors are not in supply lines, but in the signal lines. So between SAA7220 and TDA1541 WS, CL and DATA get a resistor.
The supply lines profit from beads just before decoupling cap.
Hi Tubee,
Thanks again for sharing I've never tried a coil between the dac and op-amp, is it one you made or a type you brought?
for the digital out I was looking at this, the PLL (Phase Locked Loop) synthesizing digital output http://www.geocities.com/koalavilla/audio_tweak.htm I'm not sure if its worth trying something like this, all my TDA1541 based cdp's are NOS apart from the one I use for Pedja's dac, I fitted a newava S22083 transformer on the dacs input but I would like to improve the cdp thats used as a transports output next, the DS8922 sounds interesting.
I use a Tent based XO for the main clock and 163 dividers for the DEM reclocking
Do you hear any small strange noises on parts of some cd tracks with the DEM reclocking installed?
I'll try the BYV27's thank you
Cheers,
Leo
Thanks again for sharing
I've never tried a coil between the dac and op-amp, is it one you made or a type you brought? for the digital out I was looking at this, the PLL (Phase Locked Loop) synthesizing digital output http://www.geocities.com/koalavilla/audio_tweak.htm I'm not sure if its worth trying something like this, all my TDA1541 based cdp's are NOS apart from the one I use for Pedja's dac, I fitted a newava S22083 transformer on the dacs input but I would like to improve the cdp thats used as a transports output next, the DS8922 sounds interesting.
I use a Tent based XO for the main clock and 163 dividers for the DEM reclocking
Do you hear any small strange noises on parts of some cd tracks with the DEM reclocking installed?
I'll try the BYV27's thank you
Cheers,
Leo
Hi Leo: Matter of fact, today i heard for the first time some extra noises besides the normal music. And when i listen careful it is gone. Did DEM in the simple way, clock divided by 4 and then by 16 to get 176.4kHz. This is fed to dac with coupling cap. Ecdesigns has a more complicated schematic with a lot of beads caps and a transformer to filter spikes. This could remove those extra noises. I will try this schematic when the noises re-occur.
If i want a analytic sound: i use Tent XO
For a deep bass and natural, analogue like sound: Kwak
The coils with H shaped ferrite core where scavenged from a PC, and had a value of a few uH's. I unwinded the coils to about 8 windings left.
You can also make a "pigsnose" coil, with 3 / 4 or so windings to see if you like it. When you have fast opamps, a small coil can be used. Slower opamps tend to slew with hf.
I know of the CS8402 for dig out.
BTW if you want the best, don't use Spdif but I2S, as 3 buffered output signals clock, WS and Data. Northstar uses I2S too.
Hi Tubee,
I found the noises do not last long, just a second or two also at the start of a track, its a faint noise and not too bad.
I use a 470pf Evox PFR coupling caps after the last 163 going to pin16, pin17 is left unused, I may try ECC DEM reclocker and added filtering next (some excellent work on his thread btw)
Elso's Kwakclock7 is very good, I prefer it with the TDA1541A and prefer Guido's with the TDA1541S2
I'm tempted to try Elso's clock in the CD101
Plenty of things for me to try I2S is the best but the dac is not close enough to the transport, maybe buffering will help
Cheers,
Leo
I found the noises do not last long, just a second or two
also at the start of a track, its a faint noise and not too bad.I use a 470pf Evox PFR coupling caps after the last 163 going to pin16, pin17 is left unused, I may try ECC DEM reclocker and added filtering next (some excellent work on his thread btw)
Elso's Kwakclock7 is very good, I prefer it with the TDA1541A and prefer Guido's with the TDA1541S2
I'm tempted to try Elso's clock in the CD101
Plenty of things for me to try
I2S is the best but the dac is not close enough to the transport, maybe buffering will helpCheers,
Leo
Hi Leo
Ecdesigns problably has also on this a solution, he indeed is a inspirement for a lot of us.
The Dem noises lasted not long either here too, few seconds. Used a KS 470pF cap to p16. Have been thinking it over tonight, couldn't sleep anyway.
Maybe a 2meg resistor to accros pin 16- 17 will do it, now the cap discharges due to its own leaking current, with a resistor added a small (erroring) bias voltage over the cap flows away faster. Only an mind storm of me, best is to ask the experts on this.Another thing i forgot to mention yesterday:
The diode mod is done best when you remove the original caps accros them. My theory: They TRESPASS HF noises from mains right into your system, instaid of filter diode noise away. To filter away the diode noise itself can be done by adding two 1W 1ohm resistors before the diodes in the AC line. A (few) nice film caps over the PS near lytics can't do wrong too.
I looked at the BYV's with scope: compared to 1N400* they have a more round top, no sharp edges/transisions anymore.
Btw in the 5V PS of 304 are 2 lytics, inbetween i added a reasonally big ringcore coil to create a CLC supply. Glued core at some points on caps/pcb.
Hi Tubee,
The 2m resistor across pin16 and 17 may work, it won't hurt to try
I removed the diodes and built a few rectifiers on small pieces of vero board using different diodes to allow comparing easier, once I find the types I like I'll solder them onto the pcb properly theres short wires coming from the pcb which can be soldered onto the vero board. I already fitted MSR860 which I had spare, these are better than the standard types but I'll order some more types including the BYV's.
I've several different diy amplifiers, one of them uses CLC supply (6800uf 10uH 6800uf 10uH 6800uf) on each rail, it works well with that amp so will try something similar in the cdp too.
Because the rectifiers for the cdp are now on vero I can easily try damping resistors on their input.
Cheers,
Leo
The 2m resistor across pin16 and 17 may work, it won't hurt to try
I removed the diodes and built a few rectifiers on small pieces of vero board using different diodes to allow comparing easier, once I find the types I like I'll solder them onto the pcb properly
theres short wires coming from the pcb which can be soldered onto the vero board. I already fitted MSR860 which I had spare, these are better than the standard types but I'll order some more types including the BYV's.I've several different diy amplifiers, one of them uses CLC supply (6800uf 10uH 6800uf 10uH 6800uf) on each rail, it works well with that amp so will try something similar in the cdp too.
Because the rectifiers for the cdp are now on vero I can easily try damping resistors on their input.
Cheers,
Leo
Hi Leo.
If possible i allways put a small or big L in PS, in tube pre i added a TL lamp coil! And in tube stage of poweramp i have a very very old 11H L. The core type isn't EI but has only 1 arced airgap, impregnated with tar! Fabricated by "Robot Amsterdam". After this coil the PS is split up in stereo.
Good idea to swap sorts of diodes to decide for best sounding ones.
Have a nice time with your mods, nice to fill up those dull Xmas days.
If possible i allways put a small or big L in PS, in tube pre i added a TL lamp coil! And in tube stage of poweramp i have a very very old 11H L. The core type isn't EI but has only 1 arced airgap, impregnated with tar! Fabricated by "Robot Amsterdam". After this coil the PS is split up in stereo.
Good idea to swap sorts of diodes to decide for best sounding ones.
Have a nice time with your mods, nice to fill up those dull Xmas days.
Hi Leo
I tried AD823, OPA2132, LT1469 and OP275. I liked the OPA2132 most of them, not distorted in dynamic passages, and good low level information. But (very slightly) some laid-back soundstage/mids.
Oh, and i build Pedja's AD844 I/V stage, but til now never got a tone out of it. Have to check it all.
For a pair of LM4562 i had to pay $17.45 for the high interest in this chip and shipping costs. So better is then to wait when they are available and order right away a half dosen or so.
Bass of 1540 is deep, because of produced subharmonics. Ask Bernard for this!
see: http://www.diyaudio.com/forums/showthread.php?postid=665926#post665926
I tried AD823, OPA2132, LT1469 and OP275. I liked the OPA2132 most of them, not distorted in dynamic passages, and good low level information. But (very slightly) some laid-back soundstage/mids.
Oh, and i build Pedja's AD844 I/V stage, but til now never got a tone out of it. Have to check it all.
For a pair of LM4562 i had to pay $17.45 for the high interest in this chip and shipping costs. So better is then to wait when they are available and order right away a half dosen or so.
Bass of 1540 is deep, because of produced subharmonics. Ask Bernard for this!
see: http://www.diyaudio.com/forums/showthread.php?postid=665926#post665926
Yes i have it, after some searching, Guido Tent's decoupling tips: http://www.tentlabs.com/Products/Components/XO/assets/Supply_decoupling.pdf
Hi Tubee,
Pedja's AD844 common base I/V stage is excellent! I've tried a few output stages with the TDA1541A including 6C45PI and ECC88, my favourite is Pedja's, its one of the reasons I decided to build his dac which I'm very happy with .
I first built it on vero board and tried it in my cdp, the layout is a little picky but I got it working fine after some time spent on it, to my ears it was much better than any classic I/V op-amp type.
For classic op-amp I/V my favourite dual so far is LM4562, for single op-amp I liked OPA626BP with a 1k feedback resistor.
The Philips is still sounding nice but not as good as my modified TDA1541A based cdp
Thanks for the link, I'll have a read now
Pedja's AD844 common base I/V stage is excellent! I've tried a few output stages with the TDA1541A including 6C45PI and ECC88, my favourite is Pedja's, its one of the reasons I decided to build his dac which I'm very happy with .
I first built it on vero board and tried it in my cdp, the layout is a little picky but I got it working fine after some time spent on it, to my ears it was much better than any classic I/V op-amp type.
For classic op-amp I/V my favourite dual so far is LM4562, for single op-amp I liked OPA626BP with a 1k feedback resistor.
The Philips is still sounding nice but not as good as my modified TDA1541A based cdp
Thanks for the link, I'll have a read now
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