[udo]

If I'd clock the D2.5C with a solution like this:

Would it be effective to power the clock via an UWB regulator?

Where would I get the lowest noise crystal to go on that board?

 

[udo]

This pic

shows 3 UWB regulators at the D2.5A DAC board. How well does that fit with the info from http://www.head-fi.org/forums/f7/mod...ml#post5735503 stating:

1 & 2 - can be left open
3 & 6 - 5V
4 & 5 - supply grounds

?
It looks OK but do you agree?

Does it also work this way for D2.5C?

 

[udo]

The GOLD is now available with UWB regulators in the PSU: NewClassD GOLD.

 

[aircondition]

Quote:

Originally Posted by udo /img/forum/go_quote.gif 1 & 2 - can be left open 3 & 6 - 5V 4 & 5 - supply grounds ? It looks OK but do you agree? Does it also work this way for D2.5C?

This is correct and 2.5C is the same. In picture above pin 1-6 is from left-to-right.
If you want to keep it plain and simple just leave the onboard 3.3V reg intact and make 2x 5V (digital and analogue)
UWBs or whatever low noise supplies to pins 3 & 6, GNDs are 4 & 5 respectively... ignore 1&2

I removed the onboard 3.3V reg and used pin 1&2 for input of clean 3.3 from the third (middle)
UWB reg. I put thin wires to the 3.3V reg output cap (orange drop) coming from the 3.3V UWB reg.

 

[udo]

Hmm.
Maybe install an OCXO instead of TCXO?
Not too expensive: ¡¾×êʯÐÅÓþÍƼö¡¿100£¥ºÃÆÀ·¢ÉÕÆ÷¼þºãξ§ÕñOCXOƵÂÊ¿ ɶ¨ÖÆ-Ó°ÒôµçÆ÷ - ÌÔ±¦Íø
700 RMB is less than 70 Euros at the moment.

 

[brokensound]

Nice to see the Zhalou modding community is still thriving.


________________________
http://www.head-fi.org/forums/f43/fs-omz-2-5a-458677/
http://www.head-fi.org/forums/f42/fs...6/#post6214509
http://www.head-fi.org/forums/f10/fs...1/#post6233704

 

[1stimer]

Just purchased a used Zhaolu 2.5C from the bay, and wanted to check in and bump this monster thread.

Mine has the CS4398 with (2) LT 1057 OPAMPs. I found one of the opamps was kind of loose in the socket, and it wouldn't stay in tight. I do not believes it affects the sound.

I found the detail and liveliness of the LT1057's to be enjoyable, but a little hot and bright for my liking. I was quickly switching between the Zhaolu and my Arcam CD73 for comparison. I could fairly easily distinguish each source blind.

I decided to replace the LT1057's with the included OPA2604's. When quickly switching between this "version" of the Zhaolu and the Arcam the differences were more subtle. The sound was closer to the Arcam, but overall I found the OPA2604 to be a little too mushy, slow, or dull for my liking.

My question is: Is there an op-amp that might give me the detail and drive of the 1057 with not as much "sizzle". I also found the mid bass to be seriously lacking with the LT1057's. When switching to the Arcam a wave of atmosphere and prescence slipped back into the recording which was dearly appreciated.

Any suggestions to better my Arcam CD73?

Oh and thanks for a great site.....I have zero electrical knowledge, and had never even heard of an op-amp before a few weeks ago.

 

[1stimer]

Well....I just bought some OPA2107 to try in the 2.5C....any thoughts

 

[1stimer]

Not much action....guess the zhaolu has fallen out of favor.
So....I'll post my thoughts to help others.

OPA2107> LT1057 and OPA2604

The opamps I ordered were OPA2107AP.

Not sure what the AP stands for.

Hope it's ok to give the ebay seller a plug, as he
sent me a 3rd opamp for no charge.

Should I put this in the power board????????
The 2 I put in when into the analog section.

Ebay sellers ID is audiosector. Again, please remove if this is
frounded upon. I have no relation to this seller...only a satisfied
customer.

 

[udo]

Choosing opamps is a matter of taste tor a certain degree.
They more or less subtly colour the sound which, combined with the rest of the chain, can give so-so or better results.

 

[keyid]

aircondition, I have couple questions if you dont mind me asking.

1. what does the 3.3v, power on the dac section?
The 3v regulator seems to be taking 5v from either 3/4 or 5/6.

2. I metered pins 1 & 2 and they are supplying 30mv. Is this the trigger? If I replace 1&2 with 3.3v then the dac doesnt need this 30mv supply?

3. Are the UWB regulators shunt type? I couldnt find details on their site. There seems to be couple other 7805/3 replacement options.

 

[keyid]

Also, would this diagram be correct to get two +5v & +3.3v? Im planning to create the rectifier on a diy circuit board or p2p.

In my zhoulo, the r-toroidal has three primarys - green (18vac), black (0vac) & green (18vac) and two secondary 8vac yellow. I am not to sure on an current rating from the toroidal and output after the regulator. Thanks for the help

 

[keyid]

hey 1stimer,

I tried many opamps before adding a zapfilter, the one that I liked most were the LM4562. They were not muddy and slow like 2604 and gave it a lively presentation without any sibilance. Though I did hear some initially but after couple hours it disappeared with the LM4562.

On the power section, you can replace the opamp with 2604 as its a dual opamp. I find on the power section 2x opa627 or ad823 to be good, one of the sellers said opa637 was best but havent tried. I dont like that fact that the opamps in the power makes a discernable change and is the reason im trying to replace the power board. Also, be careful when pulling on this opamp as it can be easy to break a lead pin on the opamp.

Also, if you havent already; it is recommended to bypass the caps on the output board for better sound. You will need a soldering iron or someway (soldering is recommended) to attach a piece of wire across the four caps. If you do this, you must remember the proper orientation of the opamp (see notch on the opamp & socket) and not put it in backwards or it will kill the output board. Attached is a diagram I posted before somewhere in this thread.

Quote:

Originally Posted by 1stimer /img/forum/go_quote.gif Not much action....guess the zhaolu has fallen out of favor. So....I'll post my thoughts to help others. OPA2107> LT1057 and OPA2604 The opamps I ordered were OPA2107AP. Not sure what the AP stands for. Hope it's ok to give the ebay seller a plug, as he sent me a 3rd opamp for no charge. Should I put this in the power board???????? The 2 I put in when into the analog section. Ebay sellers ID is audiosector. Again, please remove if this is frounded upon. I have no relation to this seller...only a satisfied customer.

 

[aircondition]

1. Most chips on the board are using 3.3v, which is (in stock configuration) converted from pins 3&4 (aka 5V digital supply) using the one and only stock onboard regulator down to 3.3v
As I could not imagine a secure way of mounting my external 3.3 supply's cable to the tiny pads left after removing the onboard 3.3v reg, I figured that I could attach external 3.3 supply to pins 1&2 on the underside of the board - from there run thin wires to the original 3.3V reg's output cap.

2. Good question, see the picture where I cut pin 1&2 original traces so 1&2 can be solely used for "mounting" and re-routing 3.3v supply to regulator's output cap. It is working this way. The measured 30mA -- don't know what this does trigger. I'll look into it later.

3. UWBs are not shunts but design by Lars clausen (same person who's designed your marvellous Zapfilter). (Paul Hynes whatever) shunt are probably even better, haven't had the chance to try one. Keep in mind, 780x UWBs can provide up to 630mA, shunts have typically much lower current capabilities, but I think they would work in this application. Measure ^_^

Quote:

Originally Posted by keyid /img/forum/go_quote.gif aircondition, I have couple questions if you dont mind me asking. 1. what does the 3.3v, power on the dac section? The 3v regulator seems to be taking 5v from either 3/4 or 5/6. 2. I metered pins 1 & 2 and they are supplying 30mv. Is this the trigger? If I replace 1&2 with 3.3v then the dac doesnt need this 30mv supply? 3. Are the UWB regulators shunt type? I couldnt find details on their site. There seems to be couple other 7805/3 replacement options.

 

[aircondition]

You have made a clearly arranged diagram

- for clarification, a transformer's primary is in fact always where you write "AC input". So in fact the primary is always where the 115V or 230V power resides. The transformer's secondaries are its output, depending on how the trafo is wound this can be multiple.. In case of zhaolu, the Rcore has just like you mentioned:
Two 18V secondaries (center-tapped as there is only one black GND wire shared between them)
One 8V secondary (8V and its GND)

I hope that I am right, as I don't have the stock Rcore trafo but have used instead higher rated standard 230V primary , two times 6V secondary transformator from Talema (see link).

Quote:

Originally Posted by keyid /img/forum/go_quote.gif Also, would this diagram be correct to get two +5v & +3.3v? Im planning to create the rectifier on a diy circuit board or p2p. In my zhoulo, the r-toroidal has three primarys - green (18vac), black (0vac) & green (18vac) and two secondary 8vac yellow. I am not to sure on an current rating from the toroidal and output after the regulator. Thanks for the help