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The "mod your Zhalou" Thread - Page 143

post #2131 of 2140
ah, thank you for the correction. That talema is nice price and encapsulated too. After your pm im thinking of using this hammond transformer, based on recommendation from a user in a diyaudio thread. Though I may have to somehow mount it upside down in the case. 48va max, secondary w/ parallel ouput of 6.3vax @7.6A.

Digi-Key - 229D12-ND (Manufacturer - 229D12)
http://www.hammondmfg.com/pdf/5c0013.pdf

Attach is new wiring diagram with the above transformer and combined 5v and 3.3v.
LL
post #2132 of 2140
Interesting updates here. Thanks for sharing.

What is the AC voltage of the proposed transformer at the secondary side?
post #2133 of 2140
The most recent proposal posted for the UWB setup:

Does the two UWB modules for digital 5V and 3.3V sharing of the GND without any extra parts cause issues?
Or can we take an extra step to protect 5V and 3.3V from each other?

If this is unnecessary, please explain.
Thanks.
post #2134 of 2140
for the hammond its 12.6vac & 6.3vac when wired in series.

Quote:
Originally Posted by udo View Post
Interesting updates here. Thanks for sharing.

What is the AC voltage of the proposed transformer at the secondary side?
post #2135 of 2140
i believe it works fine in the wiring setup as that is how aircondition did his. I think its because ground can be shared and the 5v & 3.3v are not shared. Only the input voltage 6.3v & ground is shared.


Quote:
Originally Posted by udo View Post
The most recent proposal posted for the UWB setup:

Does the two UWB modules for digital 5V and 3.3V sharing of the GND without any extra parts cause issues?
Or can we take an extra step to protect 5V and 3.3V from each other?

If this is unnecessary, please explain.
Thanks.
post #2136 of 2140
Based on Aircondition's recommendation for the dac board, I replaced most of the 10uf with 128 Sal-RPM, replaced the 10uf & .1uf caps around the spdif with MKP 1837 0.1uf and the 100uf caps with 47uf blackgates nx; its quite a nice improvement. Highly recommend doing this. Even just replacing the two 100uf cap with blackgates was a nice improvement.

Now my aim is to replace the dac's power supply. Im thinking of using salas shunt regs or the discrete shunt regs, as I can use the existing R toroidal. Cant get lars/Newclassd to sell his uwb regs.
post #2137 of 2140
Did another little mod on the dac board. All the screws on the dac board are connected to ground through the case. Unscrewed and disconnected all connection to the case except to for one point. Soldered wires from each screw to one screw/ground connection, which I think creates a simple star ground? Also took out the opamp on the power board as my output is powered by zapfilter. I hear more details in the music.
post #2138 of 2140
Quote:
Originally Posted by keyid View Post
(...) its quite a nice improvement. Highly recommend doing this. Even just replacing the two 100uf cap with blackgates was a nice improvement.

Now my aim is to replace the dac's power supply. Im thinking of using salas shunt regs or the discrete shunt regs, as I can use the existing R toroidal. Cant get lars/Newclassd to sell his uwb regs.
Happy to hear that you've got really audible success in replacing the 10uF ceramics etc. IIRC the effect will be again much more pronounced when you make the "clean" linear supplies. The zhaolu stock 5V regulators for VDD etc. are really what's holding it back it seems. What's up with NCD, in the past Lars/Brenda have been rather quick in delivering the goods? I have heard that ATM they get many requests for their new NCDX class-D amp and they are a very small company.. Shunts would be great, UWB was just a suggestion - they just have that bright and happy blue LEDs

That star ground seems like a very good idea. Will try to something similar using a copper sheet - thanks for the suggestion
post #2139 of 2140

I finally broke down and bought a Zhalou 2.5c DAC.  No mods other than some opamp rolling.  I put in a pair of browndogged OPA602's on the analog board and OPA2107's on the headphone amp since my other headphone amps (PPA2) are in for repairs.  The Zhalou headphone amp seems to do better now, but no big change otherwise.  The headphone amp has some crazy gain though which is annoying.

 

The board is chock full of Elna capacitors, and a few Nichicons.  Good parts if they're legit.  The decoupling caps I believe are 47uf Elna RB2 (shiny blue) bypassed by a 1uf film cap.  I've seen other designs use polarized 100uf for the same purpose.  I believe the positive side would face the DAC board.  I've got all sorts of fancy 100uF's I could swap out there.


Edited by whitelabrat - 9/14/10 at 12:45pm
post #2140 of 2140

I cam across the link with a simple heater circuit to change a crystal into an OCXO.

 

qh40a

 

Would that be interesting to put in the D2.5C?

Or the CD/DVD player?

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