[joenetic]

I used a no brand name Chinese 25W 5V LPS cost about USD30. I found LPS, alkaline batteries and super cap all have same sound quality or different is too small I cannot notice, but it is much improvement, very close to Digione, I used coaxial output only, you can check Digione's jitter test result is better than stock SU6 : https://www.audiosciencereview.com/...measurements-of-allo-digione-rpi-s-pdif.5418/

 

[b0bb]

@b0bb, did you find significant improvement in SQ after replace isolators to IL711S?

Stock SU-2 compared to SU-6, the ability to resolve details is much less. The new isolators address this shortcoming to some extent.
I have only used the 47uF Polymer Tantalum caps with the TI regulators, have not tested it with the stock ADP151

 

[joenetic]

Stock SU-2 compared to SU-6, the ability to resolve details is much less. The new isolators address this shortcoming to some extent.
I have only used the 47uF Polymer Tantalum caps with the TI regulators, have not tested it with the stock ADP151

Thanks for your reply, today I changed four 3.3V LDO with your recommended TI one, with LPS power, the detail is same as Digione, but SU2 is more wet sound or analog sound, not as dry as Digione which is very analytical, I like SU2 more than Digione now, next I will replace two Taiwan TCOX with my old Crystek SMD TCOX, see if there has further improvement, 47uF polymer tantalum capacitors are on the way, I sure will change them later, thanks for your finding and recommendation.

 

[joenetic]

@b0bb Today I changed the SU2 stock Taiwan VCXO to Crystek VCXO CCHD957, I didn't find any difference in SQ, is it because the system only use these set of VCXO when running external clock?

 

[b0bb]

@b0bb Today I changed the SU2 stock Taiwan VCXO to Crystek VCXO CCHD957, I didn't find any difference in SQ, is it because the system only use these set of VCXO when running external clock?

That agrees with my observations tracing the circuit on the SU-2 board

 

[joenetic]

After I replaced capacitors to 47uF Polymer Tantalum caps, it seems not big difference, next step I will replace two big 3.3V regulators with LT3045.

 

[joenetic]

I replaced two big 3.3V regulators with LT3045, there has noticeable improve in SQ, more precise sound!

I ordered a 10Mhz clock, I connected it to SU2 today, I keep using all original vcxo in SU2, external clock brought SU2 to another level, the bass is so fast, so tight, and very clear, sound is much more 3D, also more forward, excellent sound now.

 

[joenetic]

That agrees with my observations tracing the circuit on the SU-2 board

Today I put Crystek 45Mhz VCXO and keep stock 49Mhz VCXO in SU2, use 10Mhz clock source, same sound file, I playes it in 44.1khz and 48khz, I didn't find different in sound quality, detail, 3D image, I thought 44.1khz has better sound quality, but it hasn't, I checked with Singxer about how SU2 use the cheap VCXO but they weren't willing to tell me.

 

[b0bb]

Today I put Crystek 45Mhz VCXO and keep stock 49Mhz VCXO in SU2, use 10Mhz clock source, same sound file, I playes it in 44.1khz and 48khz, I didn't find different in sound quality, detail, 3D image, I thought 44.1khz has better sound quality, but it hasn't, I checked with Singxer about how SU2 use the cheap VCXO but they weren't willing to tell me.

If you are using CVHD950, this unit is not 100% compatible with the stock VCXO, the VCO control loop has to be recalibrated to make full use of the Crystek part.
This is requires specialized test instruments.

 

[joenetic]

If you are using CVHD950, this unit is not 100% compatible with the stock VCXO, the VCO control loop has to be recalibrated to make full use of the Crystek part.
This is requires specialized test instruments.

I used CCHD957.

 

[b0bb]

I used CCHD957.

That is not a VCXO, it should not be used in place of the Taitien VCXO, it can be used to replace the Accusilicon, however you are unlikely to see an improvement at 44.1k.
The payoff of the CCHD957 vs Accusilicon comes at the highest sample rates like 768k and over the I2S output.

The Taitien VCXOs are the ones labelled "Actual Clock" in the picture below.
CCHD957 is the same size as the Accusilicon Reference Clocks and very much bigger than the VCXOs

 

[joenetic]

That is not a VCXO, it should not be used in place of the Taitien VCXO, it can be used to replace the Accusilicon, however you are unlikely to see an improvement at 44.1k.
The payoff of the CCHD957 vs Accusilicon comes at the highest sample rates like 768k and over the I2S output.

The Taitien VCXOs are the ones labelled "Actual Clock" in the picture below.
CCHD957 is the same size as the Accusilicon Reference Clocks and very much bigger than the VCXOs

I replaced Taitien 45Mhz VCXO with CCHD957, of course I soldered a connector between the PCB and CCHD957. Why CCHD957 cannot replace Taitien VCXO?

 

[b0bb]

I replaced Taitien 45Mhz VCXO with CCHD957, of course I soldered a connector between the PCB and CCHD957. Why CCHD957 cannot replace Taitien VCXO

VCXO allows the frequency output to be changed, this allows the XO to correct itself by referencing a more accurate timing source like the 10MHz input.
CCHD957 frequency output cannot be changed, this defeats the purpose of having the 10MHz reference.

 

[joenetic]

VCXO allows the frequency output to be changed, this allows the XO to correct itself by referencing a more accurate timing source like the 10MHz input.
CCHD957 frequency output cannot be changed, this defeats the purpose of having the 10MHz reference.

I see, I thought CCHD957 is VCXO, thanks! Then what make me confuse is the sound quality of CCHD957 + 10Mhz clock is same as Taitien + 10Mhz clock, since CCHD957 clock cannot be fine tuned, I was listening to CCHD957 clock even I switched to 10Mhz clock, but the sound quality of is same as Taitien + 10Mhz clock. Anyway it is fun to play with SU2.

 

[b0bb]

I see, I thought CCHD957 is VCXO, thanks! Then what make me confuse is the sound quality of CCHD957 + 10Mhz clock is same as Taitien + 10Mhz clock, since CCHD957 clock cannot be fine tuned, I was listening to CCHD957 clock even I switched to 10Mhz clock, but the sound quality of is same as Taitien + 10Mhz clock. Anyway it is fun to play with SU2.

You just got a taste of the performance potential of the CCHD957.
It also provides insight as to why Singxer never bothered with an external 10MHz input for the SU-6 which uses the CCHD957