My (very) mini review of the Singxer SU-1 DDC

[tgb]

On 16/02/2018 at 10:52 PM, rafa said:

Just finished to separate USB 5V from XMOS.

Currently has own independent source of power with LDVO VR. It is significant SQ improvement!

Just to understand : you power externaly the XMOS part with 5V, to cut the 5V PS from the USB slot, right ?

[tgb]

8 hours ago, Energy said:

• 3R3 Inductor and Switch-Mode Voltage Regulator (SMVR) removed.
• Wires soldered into existing eyelet (1V and GND)

       

Hi Energy,

thanks for the photos.

 

In the XMOS part, you power it like that & it works ? 

Only PS @ 1V out of the pin of the regulator you removed and that's enough ? 

Very interesting. Rgds

[oneguy]

@Energy are the rest of the ones you are modifying this complete? What’s the word on the NDK oscillators? Last I heard 3 or 4 weeks ago was NDK was testing them so I am curious if they are are going on soon or not in-house yet. 

[rafa]

11 hours ago, roberto2 said:

I'm not an expert but I think that in this way you loose galvanic isolation and separation between the two sides of the Singxer. 

Once listen the SQ changes and no more doubts

There is no direct connection between power from mainboard and xmos and there is enough filtrating caps to keep it clear.

[rafa]

1 hour ago, tgb said:

Just to understand : you power externaly the XMOS part with 5V, to cut the 5V PS from the USB slot, right ?

correct

[rafa]

@Energy nice idea to put them under the board

[scan80269]

On 2/17/2018 at 3:54 PM, rafa said:

Exactly;

External 9V -> Sparco VR 5V - > main board

External 9V -> LDVO VR 5V -> XMOS

External 9V -> Neutrino

With this power supply topology you may have bridged (shorted) the two grounds on both sides of the isolation barrier, thus defeating the galvanic isolation.  To my knowledge, none of the regulators used here (Sparkos Labs, LDOVR & Neutrino) offer any galvanic isolation capability between input and output (the ground is typically common), so with a common ground between upstream & downstream circuit sections, this box no longer has galvanic isolation for the USB port.

 

Nothing wrong with that, especially if the sound got better, but just need to understand whether you essentially advocate bypassing the galvanic isolation that's part of the original SU-1 design.

 

 

 

 

[rafa]

I realize that. But that's better SQ effect for now. If I found better idea to separate ground I will do it.

[jjh1585]

Hi @scan80269,

 

In a previous post you were trying several regulators at the 5v input. Did you find any one sounded better than the others?

 

Disclosure I used your Sparkos directions for my SU-1. Thank you.

[R1200CL]

New product add on for the SU-1

 

https://ghentaudio.com/part/dc99.html

 

 

[manishex]

My Su-1 isn't working, I've just replaced all the capacitors and the 3.3V voltage regulator.

 

The power on light is not coming on and the powerboard heatsink is getting too hot to touch maybe something went wrong on that board?

 

Both the powerboard and mainboard have the blue lights on.

[rafa]

Disconnect power supply, get the meter and check voltage on power supply. 

Are you sure you connect VR correctly? Caps polarised correctly? Shortcuts?

[manishex]

20 hours ago, rafa said:

Disconnect power supply, get the meter and check voltage on power supply. 

Are you sure you connect VR correctly? Caps polarised correctly? Shortcuts?

Finally found the problem, I'm using the NewClassD 3.3V voltage regulator but copied the pin bending of the Sparkos, hence my "in" is connected to "out" and ground is switched which probably explains why my powerboard voltage regulator overheated. Everything else seems to be fine.

[FIndingit]

Deleted

[rafa]

 

I removed standard VR and added LDVO to Crystek.

And the conclusion is, that nothing get close to SQ improvements as Neutrino did for 44kHz/dsd (22MHz).

 

Before the changes hires, so 48/96/192 sounded better than 44kHz in many aspects. Mostly from sound stage perspective.

Currently with Neutrino 44 get incredible boosted. 3D dimensional. Vocals more natural. But amazing is, it sounds better than hires.

Interesting is DSD didn't get kicked so much. It sound bit better in timing and precision manner but nothing spectacular.

 

Also interesting is the difference between 22 powered by new clock and 24 standard clock get bigger after xmos power upgrade.

New power for 24 crystek didn't improve much.

I am definitely going to replace 24 Crystek with Neutrino some time soon.

 

Last thing will be 24.000Mhz for xmos. How important for SQ is this one.. Is it wort spend even more money?

[Energy]

Interesting modifications. Would be great to see it all assembled with the wires shortened. The wires leading to the NewClassD is probably the most susceptible in terms of possible degradation. And why is your LT3045 soldered to the 24.576 if you are using the Neutrino on the 22.579?

 

I find it hard to understand why you chose to remove the 101μH inductor while keeping the other two voltage regulators beside it. You're not really upgrading much if you leave those there.. You're simply adding another regulator into the mix and all that does is silence some incoming voltage from the USB input. The noisy 1.0V and 3.3V voltage regulator is still in place.. Also why are you using a bypass capacitor at the output of the LT3045? What good does that do?

 

I found all the voltage regulator upgrades to offer similar sound benefits. It's hard to distinguish which one was subtly more since I did all of them at the same time. It's intriguing that you say the clock upgrade was what improved the sound quality the most since I am still waiting on the NDK NZ2520's to arrive so that has made me a little more excited. 

 

I will have my XMOS's 24.000 replaced with a Crystek CCHD-575 soon. Photos will be posted as soon as I finish. I'm not too sure if this will offer much improvement but it would be quite nice to match the input oscillator with the output oscillator within my UltraRendu (also CCHD-575).

[rafa]

21 minutes ago, Energy said:

 And why is your LT3045 soldered to the 24.576 if you are using the Neutrino on the 22.579?

 

I don't understand why you asking about this?

[Energy]

3 minutes ago, rafa said:

I don't understand why you asking about this?

 

Never mind. I just noticed you have the LT3045 going into the Neutrino. 

[rafa]

Neutrino 22M has own power.

LT3045 is for Crystek 24M - will be replaced with second Neutrino anyway.

 

I am experimenting with SQ changes so some parts are just for test.

For example coupling cap you asked, make sound smother as just LT3045 make a sound to sharp for my taste.

 

Inductor is removed to cut the power off the USB.

 

The other two regulators., yes. Small steps in time. Another way I won't be able to tell which part makes what SQ change.

[RickyV]

17 hours ago, rafa said:

 

I removed standard VR and added LDVO to Crystek.

And the conclusion is, that nothing get close to SQ improvements as Neutrino did for 44kHz/dsd (22MHz).

 

Before the changes hires, so 48/96/192 sounded better than 44kHz in many aspects. Mostly from sound stage perspective.

Currently with Neutrino 44 get incredible boosted. 3D dimensional. Vocals more natural. But amazing is, it sounds better than hires.

Interesting is DSD didn't get kicked so much. It sound bit better in timing and precision manner but nothing spectacular.

 

Also interesting is the difference between 22 powered by new clock and 24 standard clock get bigger after xmos power upgrade.

New power for 24 crystek didn't improve much.

I am definitely going to replace 24 Crystek with Neutrino some time soon.

 

Last thing will be 24.000Mhz for xmos. How important for SQ is this one.. Is it wort spend even more money?

 

Nice job rafa,

i am amazed at the difference in SQ between the 575 and the neutrino. You sould do the 24 too.

Now the neutrino will be staying you can shorten that clock sig cable, cm not dm.. as short as possible. It directly related to SQ. On newclassd site it says 10 cm max

[rafa]

7 hours ago, Energy said:

I found all the voltage regulator upgrades to offer similar sound benefits. It's hard to distinguish which one was subtly more since I did all of them at the same time. It's intriguing that you say the clock upgrade was what improved the sound quality the most since I am still waiting on the NDK NZ2520's to arrive so that has made me a little more excited. 

Cutting off the USB power was also significant improvement here.

 

I've never used NDK clocks anywhere so I can't say how good are they. Hopefully will give you what you expecting.

Will be great if you replace 24.000 separate then other two to find out improvements.

[manishex]

So I've reconnected my VR, the power light comes on now.

I'm scared I've damaged my VR, the output voltage is 2.47V instead of 3-3.3V... 

This is the NewclassD VR (6.5V minimum input quoted) Rafa gets 3V out fine.  

Should I try to see if it works or play it safe and replace the VR? 

[scan80269]

9 hours ago, manishex said:

So I've reconnected my VR, the power light comes on now.

I'm scared I've damaged my VR, the output voltage is 2.47V instead of 3-3.3V... 

This is the NewclassD VR (6.5V minimum input quoted) Rafa gets 3V out fine.  

Should I try to see if it works or play it safe and replace the VR? 

A 3.3V VR outputting 2.47V is clearly out of spec, which suggests yours has suffered damage.

 

Many devices designed to work at 3.3V have a +/- 0.3V tolerance, and probably won't work properly when given only 2.47V.

 

There's probably no harm in testing whether your SU-1 still has expected functionality, but I'd say the odds are against it.  You will likely need to replace the VR.

 

If you want to be absolutely sure, you can remove the VR from the SU-1 and run it by itself with no load attached.  If the output voltage is still the same 2.47V then it is wrecked.

 

 

[manishex]

I removed the VR and tested at its recommended min 6.5V input, which gave 3.3V out so it's not broken.

 

Lowering the voltage to 5V gives about 2.7V which makes me think using the NewclassD UWB mk2 isn't ideal. 

I haven't tested it in use, maybe I should get a pulsar/sparkos or just test it? 

[FIndingit]

Are those orange "industrial usb connectors", which Intona and Kitsune use (for SU-1 upgrades) available anywhere to buy?