I discovered CDP ground plane. What should I do with it?

[Elso Kwak]

Originally posted by DIAR
Here's a picture of the Oscons that I used to replace the original SMD electrolytic caps. I had to remove the old caps because there wasn't any other good place for the caps. I tried to keep the cap leads as short as possible. Is the lenght of the leads critical?

Tomorrow I get MSR860 diodes for power supply.

Hi DIAR,
I don't think the lead length is critical but I always keeps the leads as short as possible leaving room to solder.
The D1NS4 and the D1NS6 diodes f.a. used in the power supply are Schottky recitifiers. Be carefull when replacing these as the MSR860s have higher voltage drop.

[Peter Daniel]

While I found MSR860 to work better than MUR860 in digital circuits, I never really compared them to anything else.

The results are fine in a DAC, but recently somebody suggested BYV26C diodes as better alternative. I didn't try them yet.

I once replaced original rectifiers in CD-94 player with MUR860 and quickly returned back to the original parts as they sounded much better.

[DIAR]

It's good that you mentioned the difference in diode voltage drops. MSR860 has 1,7 V voltage drop and D1NS6 only 0,58 V.

I'll have to find out somehow wheather I can use diodes with higher voltage drop or not...

[Elso Kwak]

Originally posted by DIAR
It's good that you mentioned the difference in diode voltage drops. MSR860 has 1,7 V voltage drop and D1NS6 only 0,58 V.

I'll have to find out somehow wheather I can use diodes with higher voltage drop or not...

Hi DIAR, Well under the load they have in the player I think the MSR860 has 0.6V voltage drop and the 1DNS6 about 0.3V. So the difference would be 0.3V. Maybe I am too cautious as that is not a big difference.

[DIAR]

Thanks Elso !!!

This is not the first time I Interpret data sheet wrongly

I measured some voltages in the power supply and they are a bit higher than what is claimed in service manual. I'm quite sure that small difference in voltage drop is nothing to worry about!

Here are the data sheets for both diodes:

http://www.onsemi.com/pub/Collateral/MSR860-D.PDF

http://semi.shindengen.co.jp/en/d1ns6.pdf

[DIAR]

I changed the diodes to MSR860. They fitted nicely and there seems to be no problems with the higher voltage drop

I'll let the diodes burn in a while before making a judgement.


I must admit that somewhere along the way the sound has got worse in some areas. For example ambience and echoes aren't that clear as they have been. Also the sound is somewhat restless and fatiguing now. I believe one of the mods to blame might be the LM317 regulator. The first LM317 regulator module I made sounded very good but actually didn't work perfectly. Sometimes I heard pops but the ambience and feeling of precence was wery strong. I made another regulator module which was smaller and used smaller polypropylene caps but the sound wasn't as good as with the malfunctioning regulator. It amazes me that a misoperating component can actually sound good.

Does anyone have an idea what might cause restless and hard sound (as if the upper mids are a bit hard and emphasized). Of course The player might be a perfect source ( ) and it is the other equipment that is causing listening fatigue (Densen Beat B300XS, DACT CT2 passive preamp and Dynaudio Audience 52).

Other mods and tweaks that I have done (random order).
- I've chaged original OPAs to OPA627 and AD8065 (stereo and 5.1 front channels outputs)
- Changed 100 uF Elna Silmic coupling caps to 2*47 uF Black Gate Hi-Q NX (Super-E-Caps) (for stereo output only)
- Changed power supply diodes to MSR860
- Changed 7805 regulator to LM317 (with the resistors, caps and protection diodes)
- removed muting transistors
- Added a few ferrites to power supply cables
- Changed the power cord to IEC plug and DIY power cord
- Made a low impedance 1. stage line filter
- I use 2*0.47 uF huge polypropylene caps between hot and neutral (so called Auricap tweak)
- Changed a few DAC power supply bypass caps to Os-Con
- Damped the enclosure with thick rubber sheets
- Damped the oscillators with rope caulk
- I use different combinations of bicycle inner tube platform and DIY rollerblocks and Cerabals etc. I change the combinationg from time to time.


It's very difficult to hear all the changes that the mods are actually causing. Some areas might get much better and some might get just a little bit worse which is unnoticeable. After piling many of these degradations the effect becomes very noticeable but it is impossible to say which mods ware responcible for the degradation of sound.

Actually one reason might be the acoustics of my listening room. I previously concidered it to be very good (it is) but now I'm starting to notice that there is much to improve. Maybe the fatiguing sound is result of unwanted reflections and echoes.

[diyer]

Perhaps too high a value of coupling capacitance in the signal path, that would roll off the lows a little.

The problem with so many mods done at once is it's hard to work out exactly what form of success you've had at each stage. One might have detrimented another.

Don't chase your tail on this as you'll never be happy, but don't doubt your other gear at the same time - chances are it's still just the way it was before you started modding, after all, you've done nothing to the other gear.

You can always undo it all, backtrack, and start again, perhaps with more testing between each modification. Or just undo one mod at a time and see what happens....

Good luck

diy-er

[Elso Kwak]

Originally posted by diyer
Perhaps too high a value of coupling capacitance in the signal path, that would roll off the lows a little.


diy-er

Hi diy-er,
Perhaps you mean a too low value will roll off the lows.........

[diyer]

Yes, that's it, freudian slip....

Too small or too low a value..... Thanks