The "mod your Zhalou" Thread

[aircondition]

Quote:

Originally Posted by udo /img/forum/go_quote.gif Interesting! Did anyone here A/B between Zapfilter and Gold? What about the 780x/7980x used in the Gold? In other words: what is the technical explanation for the improvements heard?

I chose the option with Lars' UWB Regulators (having had good results some time ago swapping a few 7805 in digital equipment with UWBs). These have far less noise and better regulation than standard 7815/7915 just look up the noise graphs on NCD site.

I try to find a technical explanation but I'm no expert. One thing that I assume is superior is the Gold's implementation of dc coupling.. Let me try there are 4 mundorf 10uF film caps on the board, but these are used for +-15V supply decoupling and not DC coupling. In the whole dc supply there is not a single electrolytic cap, just the first smoothing cap after bridge rectifier! Quite unusual isn't it?

DC coupling is done via Vishay SAL128, assumed to be as good as BG NX (never tried BG so I can't verify). Well the best is you can bypass them and adjust via two blue potis the DC output to zero. This implementation I assume is more suited to the integrity of the music signal than ZAPfilters DC servos (which, according to some posts do not work well after some time, as temp.drift etc causes the DC servo to go crazy)

I did not A/B because some day were in between building the Gold into the Zhaolu chassis etc. But sound is just less splashy, much better soundstage, and ambience is to die for.. The reverb tails this thing lets through are something I have never heard before in digital source

 

[udo]

Thanks for your explanation.
Sounds very interesting.
Now if only I could get a nice yet affordable small 5V power supply for the DAC board...

 

[udo]

Hm.
Maybe I could build a 5V PSU for the DAC board based on the NewClassD UWB 5V module?

 

[udo]

OK, so the NewClassD UWB modules appear to be the right choice for a DIY PSU for the D2.5 DAC board.
Assuming the mentioned pin-out for the DAC board is correct we can deduce the DAC board needs two times 5V for analog and digital parts of the DAC.

I am thinking of replacing the transformer in the Zhaolu by one that offers 12V DC after the rectifier diodes and capacitor.
Then I could filter through one 9V UWB module and then through two 5V UWB modules.
The double filtering is the overkill we need.
What do y'all think?

 

[aircondition]

Finally a picture of my zhaolu 2.5A. Enclosure is from a defunct Sony cdplayer, the original Zhaolu enclosure did not provide enough space. Only thing "original" is dac board itself. PSU setup:
1x 5V UWB to dac digital section
1x 5V UWB to dac analogue ref
1x 3V3 UWB via some fiddling injected to output cap of original onboard reg (which is now removed)

It was easy to figure out psu pinout from just looking to underside of board. Most of 10uF ceramic caps are removed and replaced w/ SAL128 RPM solid polymer caps (33uF / 10V) - highly recommened

TOSLINK/SPDIF digital input ceramic caps (originally paralleled 10uF/0.1uF ceramic) replaced with blue Vishay MKP 1837 0.1uF - highly recommended

Smoothing caps on the UWB psu boards are 2x Sanyo SEPC 470uF16V which are on the underside of leftside green psu boards. Earlier I had Panasonic FC, then SilmicII but SEPC is just much superior for digital section. Dynamics, resolution especially. Analogue smoothing cap are 2x SilmicII 470uF

Sound is amazing, it sounds nothing like stock Zhaolu

no kiddin

Minor tweaks are Blutac on crystal, ERS paper on controlchip. highres here: JPG

 

[udo]

Thanks for the pic. The original dac is hard to recognise here.
I see some nice boards for the power regulators, what is the source for these?

I was explained that cascading UWB regulators is not giving any benefit because UWB's act as a switching PSU: they do not care what they are fed, within limits of course. Is this true for audio application ?

I think I must proceed on this path as well. Just fill in some design blanks and then give it a go when funds and time are available.

 

[hifi13]

I am still waiting on my CS4398 board from the Canadian distributor. I am just curious how much different/better it is than the AD1852 board? My DAC is basically 2.5C except the board is AD1852. The original owner just swapped the other opamps. My Canadian distributor wasn't sure if he could find a CS4398 board but might be able to find the opamp itself, how difficult is it unsoldering/soldering all those pins?

 

[aircondition]

Quote:

Originally Posted by udo /img/forum/go_quote.gif Thanks for the pic. The original dac is hard to recognise here. I see some nice boards for the power regulators, what is the source for these? I was explained that cascading UWB regulators is not giving any benefit because UWB's act as a switching PSU: they do not care what they are fed, within limits of course. Is this true for audio application ? I think I must proceed on this path as well. Just fill in some design blanks and then give it a go when funds and time are available.

The boards for the power regulators are the bare pcbs from audioupgrades.co.uk

In this thread it is mentioned that a second UWB (dexa=NewclassD) is not really necessary for better performance. Just read more of the thread to fully understand what greg stewart did to his Juli@

. Of course you can always measure on an oscilloscope the noise spectrum, but i don't have one.

@hifi13 I think you are mixing things up

If you want to swap opamps (these come after the dac chips, they are used in the analog output stage), its easy because they are built into sockets. Just be careful when you remove them, to not bend the tiny legs. Second, i have followed the whole thread here, it is not certain which board is really better as it depends more on the rest of your chain or which sound you prefer. In fact, some users here have reported the AD1852 board to be better, especially if you are ready to invest in a better output stage- then its more easy to discern differences. Personally I feel that you can gain more sound quality if you try to improve the power supply and output stage of any DAC chip first

For an easy start, just swap some electrolytic caps on zhaolu psu board with Panasonic FC or Elna Silmic and you will be very surprised. I suggest diggin through this whole thread before thinking about a AD1852 -> CS4398 board change. Caps etc are much less expensive also. I'll be happy to guide you

 

[udo]

Thanks for posting about the UWB question.
I do not see a technical explanation yet.
I was thinking that an UWB regulator damps noise by x dB, so two UWB's should damp the double amount. (plentiful...)

Any tech here that can explain why this is right or wrong?

 

[hifi13]

Quote:

Originally Posted by aircondition /img/forum/go_quote.gif The boards for the power regulators are the bare pcbs from audioupgrades.co.uk In this thread it is mentioned that a second UWB (dexa=NewclassD) is not really necessary for better performance. Just read more of the thread to fully understand what greg stewart did to his Juli@ . Of course you can always measure on an oscilloscope the noise spectrum, but i don't have one. @hifi13 I think you are mixing things up If you want to swap opamps (these come after the dac chips, they are used in the analog output stage), its easy because they are built into sockets. Just be careful when you remove them, to not bend the tiny legs. Second, i have followed the whole thread here, it is not certain which board is really better as it depends more on the rest of your chain or which sound you prefer. In fact, some users here have reported the AD1852 board to be better, especially if you are ready to invest in a better output stage- then its more easy to discern differences. Personally I feel that you can gain more sound quality if you try to improve the power supply and output stage of any DAC chip first For an easy start, just swap some electrolytic caps on zhaolu psu board with Panasonic FC or Elna Silmic and you will be very surprised. I suggest diggin through this whole thread before thinking about a AD1852 -> CS4398 board change. Caps etc are much less expensive also. I'll be happy to guide you

Hi aircondition,

Yes I heard back from my distributor and the board will cost me $100 so I think your idea of replacing some caps might be a better idea at this point. Which caps were you referring to on the psu?

 

[udo]

I will be getting a D2.5C again for the next upgrade run.

 

[LockerMannz]

2009 LockerMannz

 

[glitch39]

Quote:

Originally Posted by aircondition /img/forum/go_quote.gif Yes, zapfilter does seem to be NLA. The former designer of the Zapfilter Mk2, Lars Clausen, has started a new company (NewClassD). He designed another linestage - "GOLD" NewClassD GOLD I have this hooked up to a heavily modified Zhaolu DAC 2.5A board, and the sound is even better than Zapfilter, which i had previously there. The sound is very musical and detailed without being harsh at all. This is audio heaven! I can definitely recommend this product for all seeking the best sound out of Zhaolu, even if it seems a bit expensive to use.

Looking at the GOLD, it does not offer balanced like the zap II.

 

[aircondition]

Quote:

Originally Posted by glitch39 /img/forum/go_quote.gif Looking at the GOLD, it does not offer balanced like the zap II.

Right, but according to NCD website it is planned to offer a upgraded Gold that offers balanced output. I do not have balanced input on my amplifier, so it was not my concern.

Of course you may think "a pity, a downgrade to Zapfilter".. But from sound quality my ears tell me opposite-

 

[udo]

I do not need balanced output for a NAD C320BEE.
D2.5C ordered.