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Preview: Rubycon Black Gate™ F vs. Nichicon Muse | XMOS Capacitor Oscilloscope and FFT Comparisons

Update 7/15/18:

I just stumbled across by far the most detailed document I have ever seen on Black Gates™ and it is by Jelmax (the creators of the technology)!


See the 107 page PDF here: Blackgate_Tech_Note_Compilation.


 

 

33747763_195808574381684_5023781851236401152_o.jpg
Stock Set Up of the Singxer SU-1 clone, the FUN01, with stock Nichicon Muse capacitors.

 

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FUN01 w_Black Gates Installed Labels_sm
FUN01 upgraded with Rubycon “Black Gate™ F” Capacitors of the same capacitance and voltage values as the stock Nichicon Muse capacitors.

 

FUN01 w_Black Gates Installed Labels Backside_sm
Soldering the FUN01 was far from the easiest of the boards I have worked on, probably due to a protective layer applied (such as modified silicone). I overcome this usually with MG Chemicals or ChipQuik Flux and quality solder. You can also try scratching the surface of the pads/solder with something mildly abrasive before starting to solder (an X-ACTO knife works too).

 

Cable used between the FUN01’s Coax output and the Siglent SDS 1202X-E : Ghent Audio’s E03 (Choseal 4N-OFC (99.99%) 75Ω Coax) along with a standard BNC-to-Phono adapter (RFB-1139 RF Industries)

All oscilloscope captures are made over I/O = CAT6/LAN using EasyScopeX Ver: V100R001B02D01P20 and my Siglent SDS 1202X-E 200 MHz 2Ch Digital Super Phosphor Oscilloscope.

 

Nichicon Muse (DSD256 11.2MHz Close Up | FFT Normal)

Digital Coax Before Black Gates FUN01_Nothing Playing_BW limit Full 75ohm load IIR 47K
Close up capture of FUN01’s Coax Signal with the FFT in dBVrms (using Nichicon Muse) | ES9038Pro Settings: FIR = “Hybrid”  & IIR = 60k | Scope  @ 200mV/div & 20nS

 

Rubycon Black Gate™ F (DSD256 11.2MHz Close Up | FFT Normal)

Digital Coax After Black Gates FUN01_Netflix Playing_BW limit at Full load at 75ohm_close up of wave shape_IIR at 70K
Close up capture of FUN01’s Coax Signal with FFT in dBVrms (using Rubycon Black Gate™ F) | ES9038Pro Settings: FIR = “Hybrid”  & IIR = 60k | Scope @ 144mV/div & 20nS

Rubycon Black Gate™ F (DSD256 11.2MHz Extreme Close Up | FFT Normal)

Digital Coax After Black Gates FUN01_Netflix Playing4_BW limit at Full load at 75ohm_close up of digital steps to make wave rise and fall_no measures_IIR at 70K
Zoomed in on one of the peaks and troughs of the wave in the image shown above (with Black Gates™), to show the waves are in fact a digital representations of an analog waveform. Note: the higher the sample rate the more steps/samples we will see per period, the converters used in the scope also play a crucial role here (DAC and ADC). | Scope @ 28.4mV/div & 10nS | Zoom Window : 2nS

 

It is known that often when going from high to low or vice versa, transients can carry over where they shouldn’t causing small ripples in the beginning of a new step. This phenomena can cause pre-ringing or post-ringing if the sound is in the audible range.

This mechanism creates a sort of digital signature to the incoming signal that you could almost compare to a sort of HW fingerprint, due to how HW dependent this action is in the digital realm. The FUN01 (SU-1 clone) uses a technique of varying the pulse width depending on the frequency called a variable time window. At least, that is what I believe from my observations and my studying the material. Sub-band coding is another way you can optimize the digital domain to filter out the most noise, but I believe the XMOS chipset uses variable pulse sizes instead of sub-band coding.

 

FUN01 w_Black Gates Installed Labels 2_sm
Another angle after the upgrade. Notice how many Black Gates™ are on the digital side vs. the analog side of the board (separated by the split in the ground plane). The digital side (1 cap) is on the left and the analog side (5 caps) on the right.

Nichicon Muse (DSD256 11.2MHz @ Med Time Scale | FFT Averaged 253 Times)

11_2MHz DSD Coax Signal Before Black Gates™ FFT Averaged 350 times.png
11.2MHz DSD256 Coax Signal Before Black Gates™ | FFT Averaged 350 times | FFT @ 20dB| Scope at 5mV/div & 20uS

 

You can easily see the 11.2MHz signal showing on the FFT (only peak past 5MHz). There seems to be a fair bit of noise, but all at or below the dBVrms of the 11.2MHz signal.This is with Nichicon Muse capacitors still in place.

Rubycon Black Gate™ F (DSD256 11.2MHz @ Med Time Scale | FFT Averaged 267 Times)

Digital Coax After Black Gates FUN01_DSD256 11.2MHz_BW limit at Full load at 75ohm_all measure on_FFT measured 126 avg  horiz_IIR at 70K FFT at 20dB 20uS.png
Digital Coax After Black Gates FUN01: DSD256 11.2MHz (BW limit at Full) | Load at 75ohm | FFT measured 248 avg | IIR at 70K |FIR: Hybrid| FFT at 20dB| Scope @ 5mV/div & 20uS

You can see that the image above in the FFT part has similarities and differences to the FFT shown with the Nichicon Muse capacitors, this one has been averaged over almost the same number of periods. I noticed the additional signals showing up out near 10Mhz so I took a closer look with the FFT on a 10dB scale instead of 20dB and here is what I saw after I reset the FFT average.

Rubycon Black Gate™ F (DSD256 11.2MHz @ Med Time Scale | FFT Averaged 56 times)

Digital Coax After Black Gates FUN01_DSD256 11.2MHz_BW limit at Full load at 75ohm_all measure on_FFT measured 126 avg  horiz_IIR at 70K FFT at 10dB 20uS.png
Digital Coax After Black Gates FUN01: DSD256 11.2MHz (BW limit at Full) | Load at 75ohm | FFT measured 248 avg | IIR at 70K |FIR: Hybrid| FFT at 10dB | Scope @ 5mV/div & 20uS

Looks pretty good now, I believe it must have been from bumping the cable or something earlier that caused that harmonic to pop up.

Rubycon Black Gate™ F (DSD256 11.2MHz @ Med Time Scale | FFT Average 213 Times)

Digital Coax After Black Gates FUN01_DSD256 11.2MHz_BW limit at Full load at 75ohm_all measure on_FFT measured 2k avg  horiz_IIR at 70K FFT at 10dB 20uS Cursors On.png
As you can see, this is precisely where the  highest (in dBVrms) signal across the frequency spectrum (FFT) is originating, right around 11.2 MHz (Notice the count number and the Standard Deviation is in mdBV)

When playing with the settings in foobar2000, I found out that using DSDTranscoder to convert DSD or FLAC into any DSD that your DAC can handle, in my case DSD256, created a completely different waveform on the FFT than the native DSD decoding does and I wanted to make sure to show this (below).

Rubycon Black Gate™ F (DSD64 2.8MHz @ Med Time Scale | FFT Averaged 195 Times)

Digital Coax After Black Gates FUN01_DSD256 11.2MHz_BW limit at Full load at 75ohm_all measure on_FFT measured 195 avg  horiz_IIR at 70K FFT at 10dB 20uS Cursors On.png
Digital Coax After Black Gates FUN01: DSD64 2.8MHz (BW limit at Full) | Load at 75ohm| FFT measured 195 avg | IIR at 70K | FIR: Hybrid| FFT at 10dB | Scope @ 200mV & 20uS | Cursors On

 

 

Now here is a look at some FLAC (48kHz – 16-bit) for contrast.

Rubycon Black Gate™ F (48kHz 16-bit FLAC @ Med Time Scale | FFT Averaged 302 Times)

Digital Coax After Black Gates FUN01_48kHz16bit LPCM video_BW limit at Full load at 75ohm_close to before measurement__all measure on_FFT measured 305 avg at 2uS horiz2_IIR at 70K
Digital Coax After Black Gates FUN01: 48kHz 16bit LPCM (BW limit at Full) | Load at 75ohm| FFT measured 305 avg | IIR at 70K FIR: Hybrid | FFT @ 20dB | Scope @ 144mV & 1uS

Rubycon Black Gate™ F (48kHz 16-bit FLAC @ Med Time Scale | FFT Averaged 302 Times)

Digital Coax After Black Gates FUN01_48kHz16bit LPCM video_BW limit at Full load at 75ohm_all measure on_FFT measured 100 avg at 4211 horiz2_IIR at 70K FFT at 10dB
Digital Coax After Black Gates FUN01: 48kHz 16bit LPCM (BW limit at Full) | Load at 75ohm | FFT measured 4211 avg IIR at 70K | FFT at 10dB | FIR: Hybrid | Scope @ 148mV/div & 1uS

 

Hallman Labs View All

Electrical Engineering student (Jr year) with a background in IT. Such as dealing with large scale network infrastructure upgrades at Lowe's HQ and former lead hardware tech for the NC Government. My specialty has shifted over to audio hardware and vintage hardware re-certifications along with treble bleeds.

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