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Audiophile Ethernet Switch
Audiophile Ethernet Switch
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Old 8th August 2019, 08:01 PM   #141
analog_sa is online now analog_sa  Europe
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Audiophile Ethernet Switch
Bought a Dlink today. Looks exactly like the Aqvox switch minus the expensive goo. Has two onboard switchers for 3.3v and 1.1v. Apparently none of the modders consider removing the switchers important.

Due to the high price of OCXO/TCXO i would like to first get some sonic incentive. I am also unconvinced that changing just the oscillator in the switch without also changing the oscillator on the ethernet card will have any effect.

Despite this reservation will make a simple experiment: a little board with a cleanish 3v3 supply and a Crystek 957 24.576MHz. Looking at modded switches it appears some are indeed using audio frequency oscillators instead of proper 25MHz.

It would be nice if the switch could also incorporate an Ethernet filter but i have no idea about the RC values. Suggestions?

It is also easy to cut off all but two pairs to a particular port and force it to 10Mbit operation. This will allow for easy comparison against the unmolested ports.
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Old 8th August 2019, 09:15 PM   #142
analog_sa is online now analog_sa  Europe
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Audiophile Ethernet Switch
Quote:
Originally Posted by analog_sa View Post
Looking at modded switches it appears some are indeed using audio frequency oscillators instead of proper 25MHz.
This is clearly wrong: the difference is too big to make any sense. So, this experiment, unless i buy a useless for audio 25MHz OCXO just won't happen.
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Old 9th August 2019, 04:53 PM   #143
Faboz is offline Faboz  France
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Quote:
Originally Posted by analog_sa View Post
Bought a Dlink today. Looks exactly like the Aqvox switch minus the expensive goo. Has two onboard switchers for 3.3v and 1.1v. Apparently none of the modders consider removing the switchers important.
Hello sa,
Sounds like the switchers have not been replaced, but I would say upgraded on the AQVOX. Looks like a diode has been implemented on D5 and D6. This is an non implemented option by Dlink, even if the PCB is ready for it.
I cannot read the ref of the lite-on semi switcher, but looks like a Schottky Diode has been installed between SW pin and GND pin of the Buck Converter. Don't know if the adjacent selfs and capacitors have been upgraded. Could you please provide the ref of the switchers? Check the LSP5526 data sheet for the diode option.
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Old 9th August 2019, 07:35 PM   #144
analog_sa is online now analog_sa  Europe
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Audiophile Ethernet Switch
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Could you please provide the ref of the switchers?
Not sure what are you asking me.

You are certainly right about the diodes, only there is no way to know if those were not on the boards Aqvox used in the first place. Too many board revisions to know for certain. And is this not some trivial minutiae?

The 3v3 reg is easy to replace with linear but i don't have anything suitable for 1v1 in my drawers.

Generally think this is clutching at straws.
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Old 9th August 2019, 10:49 PM   #145
Faboz is offline Faboz  France
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I was refering to the PN of the switchers, which is confirmed to be LSP5526 from LITEON.
Regarding the diodes, if you look at your Dlink board D5 and D6 are empty places where optional diodes could be installed. Looks like AQVox soldered a component at this place (look at first page picture), I assume it is a shottcky diode as advised as optional for LSP5526 LITEON Synchronous Buck Converter datasheet.
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Old 9th August 2019, 11:01 PM   #146
analog_sa is online now analog_sa  Europe
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Audiophile Ethernet Switch
As i already wrote, there is no way to know who soldered those diodes. Perhaps it was Dlink in another version of the board. You seriously expect these diodes to elevate the sonic performance? If this would make any difference, the logical approach would be a switch to linear regulation.
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Old 10th August 2019, 06:08 AM   #147
Faboz is offline Faboz  France
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Originally Posted by analog_sa View Post
As i already wrote, there is no way to know who soldered those diodes. Perhaps it was Dlink in another version of the board. You seriously expect these diodes to elevate the sonic performance? If this would make any difference, the logical approach would be a switch to linear regulation.
The regular Dlink do not have the component in D5 or D6.
It is for sure a modification made by Aqvox. If Dlink would implement this, they would have put a B130 SURFACE MOUNT SCHOTTKY BARRIER RECTIFIERS as advised by LITEON scheme. (done automatically by a SMD machine). If you look at the picture from AQvox, the component in D5, D6 has been added to the board as an add on.

I have no clue if the add on component used by AQVOx on the LSP5526 is a Diode or not. It is hidden with black resin. Im talking avour diode since it is an optional scheme advised by Liteon to improve the device performance
"
Optional Schottky Diode
During the transition between high-side switch and low-side switch, the body diode of the low side power MOSFET conducts the inductor current. The forward voltage of this body diode is high. An optional Schottky diode may be paralleled between the SW pin and GND pin to improve overall efficiency. Table 3 lists example Schottky diodes and their Manufacturers.

Does this help in leakage current management? I dont know, Would current leakage blockage be helped by a capacitor or additionnal self at this place in the circuit, I dont know neither. This is where some electronic experts could provide some good advise. Blocking current leakage should help in sonic performance.
Attached is the recommended circuit application with optional diode.

This is by comparing regular Dlink and AQvox picture boards that I have seen the physical differences. This is investigation phase
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