Bout bloody time! LOL
I've currently got /2 to pins 2 & 4.
Looks like Phillips did leave pin 4 for sys clock after all!
Best I get the iron out!
😀
I've currently got /2 to pins 2 & 4.
Looks like Phillips did leave pin 4 for sys clock after all!
Best I get the iron out!
😀
Hi Lee,
I think the general consensus is to focus on the decoupling caps responsible for the MSB first, then spend less priority for the others.
So, pins 13 and 18 first, then 12 and 19 an so on.
I put 1uF caps on 13 and 18. I can't say its a huge mod. Maybe you'll have better mileage, maybe you'll do more and it will drastically improve.
Good news about your divider. I might reinvestigate all that. Is your's a non A? That would possibly explain why MCLK was suitable for pin 4. However, I still remain confused. I'm glad my setup is different so pin 4 is a data input for me, or I'd be investigating this and getting royally muddled.
Cheers,
Phil
philpoole said:
Hi Phil,
So what value's do you use for the rest of the array? I think mine are all 220nF & I think most players used 100nF. What sort of 1uF did you use? Question, questions, and more questions!!
Cheers
Ian
Cheers Phil.
I'll be experimenting with caps later on today. Unfortunately, web-design is the order of today🙁
Mine is an "A" chip though, so I wasn't expecting any improvement, especially not one this large. I can hardly believe the level of detail & separation, still combined with that 1541 smoothness.
Cheers, Lee.
I'll be experimenting with caps later on today. Unfortunately, web-design is the order of today🙁
Mine is an "A" chip though, so I wasn't expecting any improvement, especially not one this large. I can hardly believe the level of detail & separation, still combined with that 1541 smoothness.
Cheers, Lee.
For the other caps, I have 100nF polyester, and the 1uF are polyester or polypropylene. I can never remember. For some bizarre reason, I bought them in Maplins (I think I was close to it one day, so thought I get some to try for this). I don't think they sell them any more. They don't really sell anything any more. You might spot them as the grey caps in the photo I posted earlier in the thread.
Mine are 220n PPS Polyphenylene Sulphide (or summat). They were a decent upgrade from the polyester that were originally in, but it'll be nice to know I'm getting the most from the dac.
Then there's DEM reclocking, but that's for another day.
Lee.
Then there's DEM reclocking, but that's for another day.
Lee.
I'm gonna shove PPS all around as they're quite cheap, good quality and very small - crucial in a CD650.
I've been quiet lately because I've been trying to service and repair my car and do other hi-fi projects. I've also been away.
Soon, however, I'll get a few more bits stuck in there.. it's still singing beautifully and the urge to "repair" a poor soound has gone -- for now.
Simon
I've been quiet lately because I've been trying to service and repair my car and do other hi-fi projects. I've also been away.
Soon, however, I'll get a few more bits stuck in there.. it's still singing beautifully and the urge to "repair" a poor soound has gone -- for now.
Simon
Thomo said:
I'm in total agreement! I was driving both 2 and 4 with the /2 and it was very good.
Knowing Lee had already cut the track, I thought I'd let him go 1st! (my tracks were still in tact!)
I've now got the main clock feed directly onto pin4 (and also to the 7220 & /2 board) and /2 onto pin2.
This is a really straightforward mod that make a very nice difference. It seems to me that there is lots more detail. The fast high freq stuff that CDP's generally don't deal with particularly well are massively improved.
I've also added another 220nF (now 440) to the MSB pins. Not sure if I can hear any difference but then I've not addressed these caps yet.
Ian
Better use 1uf on the msb pin, 0.47 the pin next and 0.22 the rest, MKT 63V.
After dem reclock with 350khz the cap value could be halve for same coupling frequency. Dem freq. with the cap on 16-17 is around 200kHz
Will try the pin 4 mod too on a cd304mk2
After dem reclock with 350khz the cap value could be halve for same coupling frequency. Dem freq. with the cap on 16-17 is around 200kHz
Will try the pin 4 mod too on a cd304mk2
Still on the clock!
Hi Guys,
Looking at the diagram, the SAA7210 also wants the system clock on pin 19!
Thats 4 places that now want the sys clock.
TDA1541a pin 4
SAA7220 pin 9
SAA7210 pin 19
/2 circuit that feeds TDA1541a pin 2
Any idea's on a good clean buffer that could be used to give the 4 outputs without degredation or cross contamination. Or any thought on the fact that the clock is feeding directly to 4 places?
Cheers, Ian
Hi Guys,
Looking at the diagram, the SAA7210 also wants the system clock on pin 19!
Thats 4 places that now want the sys clock.
TDA1541a pin 4
SAA7220 pin 9
SAA7210 pin 19
/2 circuit that feeds TDA1541a pin 2
Any idea's on a good clean buffer that could be used to give the 4 outputs without degredation or cross contamination. Or any thought on the fact that the clock is feeding directly to 4 places?
Cheers, Ian
I woud've thought most clock modules would have a fan out of 4. If not, a TTL inverter or buffer would do the trick (but some would argue add jitter).
Maybe you could seperate out each clock line to each chip, or maybe you could isolate them, each with their own seperate driver at the clock end. I think that's probably clutching at straws though.
Maybe you could seperate out each clock line to each chip, or maybe you could isolate them, each with their own seperate driver at the clock end. I think that's probably clutching at straws though.
mmmm
Surely driving all 4 places from the same clock would also introduce noise and cross contamination?
The clock is happily driving 3 of the 4 places at the moment and I have to admit I see no reason why it wont drive 1 more.
I guess its just working out whats the lesser of 2 evils! I might start a seperate thread and see where that goes!
Surely driving all 4 places from the same clock would also introduce noise and cross contamination?
The clock is happily driving 3 of the 4 places at the moment and I have to admit I see no reason why it wont drive 1 more.
I guess its just working out whats the lesser of 2 evils! I might start a seperate thread and see where that goes!
Well, I've done that mod too now. Clock direct to SAA7210.
Large improvement again. I didn't think it could get smoother, but in a back to back comparison, it sounded positively ragged compared. Another fantastic tweak to be made Simon. (are you still around)?
Cheers all,
Lee.
Large improvement again. I didn't think it could get smoother, but in a back to back comparison, it sounded positively ragged compared. Another fantastic tweak to be made Simon. (are you still around)?
Cheers all,
Lee.
SimontY said:
Yes, I can believe that !
With all the extra regulators etc., your cdp must generate a lot of excess heat.
I have not heard of water-cooled players before, though, so it must be a first.
Andy
SimontY said:
Does that mean you can make your own resistors based on the length of the radweld!😀
Started looking into the DEM reclock.
It appears that you need /4 clock both inphase and 180deg out of phase.
I'll be trying this out fairly soon and post the findings. If you're interested in researching this mod check out the 1541 NOS thread. It makes for heavy reading but its very informative.
on another note, I got my tube buffer stage yesterday and the valves have just arrived. Its a copy MF stage with cryo treated valves. It runs from a 12vac source so none of the high voltage messing that normally goes with tube stages. No time to fit this weekend 😡 but i'll let you know how I got on as soon as its in place of the DOS.
Ian
Hi Guys,
Been busy!
I wanted to try out the valves stage. Its a chineese copy of the MF valve buffer stage. The std components are OK but it could really do with some FC's on the power supply, decent diodes and mundorf dc blocking. I'm sure I'll deal with that over the coming weeks! 😉 I've already got mundorf supreme's for DC blocking on the DOS which can replace the main output caps on the board.
In order to hook it in, I needed to seperate the Burson from the DOS. I'd previously glued them together! Having seperated them, I set about getting the Bruson into position to act as I/V. I used the 2 SPowers for the DOS to power the Burson. I also re introduced the 2n2 cap accross the 1k8 feedback for the I/V. My only filtering was on the DOS which was now removed! I thought I'd better put back a filter!!
Having got the Burson back in and running, I thought I'd try the player with just a Burson acting as I/V. The sound was very detailed but seemd to lack some weight. It seems that alsthough it will drive its borderline. Its a bit like putting attenuated leads on the wrong way round. Its still detailed but becomes very thin!
I set about hooking in the valve stage. 12vac on, heaters alight and led's on! hooked in the output by replacing the on board caps with my supreme's and gave it an input.
It started a bit thin again but after 2 or 3 minutes, the sound became much fuller. I out this down to new valves caps etc. I guess the burn in will be even longer on this stage than the DOS.
40 minutes in and it is definately becoming more balanced. I'd certainly not be dissapointed with the sound but I would say at this point, the DOS has the edge, poss abit more detail as well. I'll give this a good soaking and report back. One thing it does do very well already is accoustic guitars. Newton Faulkner sounds awesome. It also has bags of punch and no problem with low freq attack!
Overall poss about what I expected! 😀
one other thing I should have mentioned, I'm using National, cryo treated valves. Nothing too fancy but should be much better than MF put in to start!!
Been busy!
I wanted to try out the valves stage. Its a chineese copy of the MF valve buffer stage. The std components are OK but it could really do with some FC's on the power supply, decent diodes and mundorf dc blocking. I'm sure I'll deal with that over the coming weeks! 😉 I've already got mundorf supreme's for DC blocking on the DOS which can replace the main output caps on the board.
In order to hook it in, I needed to seperate the Burson from the DOS. I'd previously glued them together! Having seperated them, I set about getting the Bruson into position to act as I/V. I used the 2 SPowers for the DOS to power the Burson. I also re introduced the 2n2 cap accross the 1k8 feedback for the I/V. My only filtering was on the DOS which was now removed! I thought I'd better put back a filter!!
Having got the Burson back in and running, I thought I'd try the player with just a Burson acting as I/V. The sound was very detailed but seemd to lack some weight. It seems that alsthough it will drive its borderline. Its a bit like putting attenuated leads on the wrong way round. Its still detailed but becomes very thin!
I set about hooking in the valve stage. 12vac on, heaters alight and led's on! hooked in the output by replacing the on board caps with my supreme's and gave it an input.
It started a bit thin again but after 2 or 3 minutes, the sound became much fuller. I out this down to new valves caps etc. I guess the burn in will be even longer on this stage than the DOS.
40 minutes in and it is definately becoming more balanced. I'd certainly not be dissapointed with the sound but I would say at this point, the DOS has the edge, poss abit more detail as well. I'll give this a good soaking and report back. One thing it does do very well already is accoustic guitars. Newton Faulkner sounds awesome. It also has bags of punch and no problem with low freq attack!
Overall poss about what I expected! 😀
one other thing I should have mentioned, I'm using National, cryo treated valves. Nothing too fancy but should be much better than MF put in to start!!