Singxer SU-2

[joenetic]

One more thing, I am using internal clock now, the effect is very good, I left my 10Mhz clock in my office, I will use external clock after 72hours charge, look forward a super sound

 

[joenetic]

Below is a simplified diagram of how a LVDS receiver can be used to clean up semi-sinusodial signals.
SU2 appears to be using a slightly modified circuit with additional filtering for noise

The voltage at the junction of R1 and R2 is the trigger threshold.
If this voltage changes the duty cycle of the output changes.
This is reflected as a phase change in the complex or s-domain.
Integrated over time, this forms the basis of the phase noise number.

Variations in supply voltage will thus show up as a component of phase noise at the output.
SU2 did not take any additional precautions beyond passive filtering.
I was expecting something better like its own dedicated low noise LDO for this function.

This converter was added as a convenience feature to allow external 10MHz input.
Here is the output of the circuit.
Note the rise time are pretty quick as the input is mostly squarewave in the example
Situation is less ideal with SU2
-FIN1002 specs rise time at 1ns, 10MHz sinewave risetime is 10ns.
-FIN1002 is not operating with optimal input


Additional info here
https://www.ti.com/lit/an/slyt180/slyt180.pdf?ts=1682727261775

Today I cut the 3.3V power trace of FIN1002 circuits, then add LT3045 3.3V regulator on filtered 5V and power the FIN1002 circuit, the sound quality is improved again!

 

[doitttt]

keep it simpel
panasonic-fc 220uf 25 volts sits in singxer su2 as standard
I have replaced the Panasonic SEPG OS-CON 270uf 16volt
then disconnected the power supply
buy this from https://www.ghentaudio.com/products/dc99?VariantsId=14108,14114,14110
used ifi ipower x 5volt connected to , works as well, used superCapacitors
then used external 10mhz clock from cybershaft
it sounds really good
better bass and midrange, as well as a treble that is soft in sound.
i buy later ifi ixpower elite with much more less noise

 

[doitttt]

try Kernel Streaming gives something more in the sound
instead of asio

 

[dfarina]

How would this unit (un-modded) compare to the Denafrips Iris?

 

[doitttt]

Denafrips Iris sound better thanks to opticoubler

 

[fmzip]

@fmzip, board level mods, will need techs familiar with SMD rework to do this one.
Part availability is becoming an issue due to the shortages in the industry.

• IL711S GMR isolators from NVE.
  • These do not use a high frequency carrier wave to transport the signals across the isolation barrier.
  • Much reduced noise and EMC footprint compared to the stock capacitive isolators.
  • https://www.digikey.com/en/products/detail/nve-corp-isolation-products/IL-711S-3E/1635054
• TPS7A20 3.3V regulators replaces ADP151
  • Better power supply rejection
  • Reduced noise
  • https://www.digikey.com/en/products/detail/texas-instruments/TPS7A2033PDBVR/13566866?s=N4IgjCBcpgbFoDGUBmBDANgZwKYBoQB7KAbRABYAGSgJgGZKQBdAgBwBcoQBldgJwCWAOwDmIAL4EwAdmkBOBCGSR02fEVLhp5MGACszNp0g9+wseMkgamgCoAFbtICCNRk3FA
• 47uF tantalum polymer power bypass caps, about 5-10X the size of the existing ceramics
  • -IMPORTANT- these are polarized unlike the stock ceramics, be sure to measure the voltage for polarity before replacing ceramic part.
  • These are generic 10V 0805 parts
  • https://www.digikey.com/en/products/detail/kyocera-avx/F381A476MSALZT/8605509

@b0bb , found the IL711S in my desk today, totally forgot about this post! Thought to check to see if those TI TPS7A20 were in stock which they weren't back in 2021 when you posted this. They are.....

So I think I will do this mod and the Crysteks as suggested on my Kitsune SU-2. I don't recall, do I need an adapter board for this crystal? ITwisted Paer no longer carries the Rhea board from what I see. Do you have a link to one? Are you still using the SU-2/SU/6/LKS DAC or have you moved on to something else?

 

[doitttt]

much better end singxer su6
since the better with a better power supply
as it sets the standard for the sound
https://magnahifi.com/farad-super3-power-supply/
and this
https://www.ghentaudio.com/products/dc99?VariantsId=14108,14114,14110
farad-super3 reviews
https://alpha-audio.net/review/multitest-external-12-volt-power-supplies/
here is also a 5 volt version

 

[Baten]

much better end singxer su6
since the better with a better power supply

what?

 

[b0bb]

@b0bb , found the IL711S in my desk today, totally forgot about this post! Thought to check to see if those TI TPS7A20 were in stock which they weren't back in 2021 when you posted this. They are.....

So I think I will do this mod and the Crysteks as suggested on my Kitsune SU-2. I don't recall, do I need an adapter board for this crystal? ITwisted Paer no longer carries the Rhea board from what I see. Do you have a link to one? Are you still using the SU-2/SU/6/LKS DAC or have you moved on to something else?

The IL711S is a worthwhile improvement as the isolator does not use a high frequency carrier for the data, less noise injection into the clean side.
Less likely to aggravate the 9038Pro in the LKS

Try the link below for the XO SMT adaptor, not as good as Rhea, they are a little bit wider.
https://www.audiophonics.fr/en/comp...rs-brackets-for-xo-clocks-set-x5-p-17063.html

The LKS + SU2 is still being used, SU6 is a spare. I have not found anything that can replace it at the moment and not for the lack of trying.
I also have the SMSL D300 with the Rohm BD34301EKV running in DSD direct mode. This is one of a handful of DACs that allows complete bypass of the internal DSP processing, digital filtering done externally via HQPlayer. It comes close to the LKS

 

[b0bb]

what?

I have both the SU2 and SU6.
The SU2's power supply holds it back, stock dynamics is muddy presentation lacks focus.
Soundstage is very narrow in stock form.
Add a supercap supply and this improves dramatically.

I did a mod with a small LTC4425 supercap demo board on the SU2, the changes were substantial enough to push the SU6 into the role as a spare.

SU6 is competant but the Xmos USB interface used there is getting old.
Singxer has not followed up with a replacement.
SU2 replaces SU1 lower down in the food chain

 

[Xoverman]

I have both the SU2 and SU6.
The SU2's power supply holds it back, stock dynamics is muddy presentation lacks focus.
Soundstage is very narrow in stock form.
Add a supercap supply and this improves dramatically.

I did a mod with a small LTC4425 supercap demo board on the SU2, the changes were substantial enough to push the SU6 into the role as a spare.

SU6 is competant but the Xmos USB interface used there is getting old.
Singxer has not followed up with a replacement.
SU2 replaces SU1 lower down in the food chain

Hey B0bb,

whitch supercap demo board did you use ? Analog Devices ? nice to hear from you again

 

[b0bb]

Hey B0bb,

whitch supercap demo board did you use ? Analog Devices ? nice to hear from you again

It is from Analog Devices.
Mouser sells it: https://www.mouser.com/ProductDetail/Analog-Devices/DC1589A?qs=ytflclh7QUVER2OaQD/T0A==

It comes with a 1.2F supercap, quite adequate for the job.

The onboard 1A regulator is a bottleneck, it should be replaced with something that can supply larger currents to cope with the current charging spikes from the supercap
Replaced mine with a 3A unit from Belleson, it has very quick current delivery.
Upgraded diode rectifier to 8A schottkys for the same reason.
Removed transformer, my SU2 is using DC input from Sotm SPS-500 supply.

I experimented with the 15F caps leftover from my SU6 mod, minor incremental improvement.

 

[fmzip]

The IL711S is a worthwhile improvement as the isolator does not use a high frequency carrier for the data, less noise injection into the clean side.
Less likely to aggravate the 9038Pro in the LKS

Try the link below for the XO SMT adaptor, not as good as Rhea, they are a little bit wider.
https://www.audiophonics.fr/en/comp...rs-brackets-for-xo-clocks-set-x5-p-17063.html


The LKS + SU2 is still being used, SU6 is a spare. I have not found anything that can replace it at the moment and not for the lack of trying.
I also have the SMSL D300 with the Rohm BD34301EKV running in DSD direct mode. This is one of a handful of DACs that allows complete bypass of the internal DSP processing, digital filtering done externally via HQPlayer. It comes close to the LKS

Thanks Bob, I received these today. The board didn't come with any instructions on mounting the resistors. Can you tell me if my assumption is correct on the attached images please?

 

[b0bb]

Use a 100nF smd ceramic in topmost position.
You do not need to place anything in the area with the red X.
The other side is for mounting the crystal.
Triangle is pin1