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Review and (unofficial) measurements of Thomann SSSnake Cat Snake 3FB and 3MC (Analog cable snake over Category 5/6/7 cable)

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Rja4000

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I found the use of the very specific J-test signal a bit irritating and misleading, that's all.

I thought that was exactly what it was initially meant for:
Why put the 250 Hz square wave in there if we never see it in the output of the real DAC?
When J-test was invented, it was designed to find jitter induced when long runs of AES or S/PDIF cables were used.
The toggling would cause all the bits to shift from one value to another, exaggerating sources of jitter there.
 
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Rja4000

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Low level SINAD test
Those tests are performed with Low Level signal (5mV rms)

NB: To optimize Low level signal, I follow the methodology I described in this post.

Path is as follows:
1. RME ADI-2 Pro fs R (19dBu range, both channels)
2. Radial Engineering SAT-2 Passive attenuator
3. Radial Engineering JDI Duplex - Passive Transformer DI
4. Y XLR cable, summing the 2 channels
5. "Cable" (or direct XLR)
6. Millennia HV-3C Mic Preamp (Max gain)
7. E1DA Cosmos ADC (6,7V mono)
Measurements are performed with Virtins Multi-Instrument 3.9.5

Measured level just before "cable" is 5,004mV rms
Measured level after mic preamp is around 5,13V rms (Preamp gain measured at 60,2dB)

"Direct"
5mV_Direct.png


Through "cable"
5mV_Cat.png


Comment

This measurement, being very low level, is more subject to random external factors,
so 0.4dB SINAD difference is probably to be considered within testing error.
 
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Rja4000

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Another attempt to
Low level SINAD test
Those tests are performed with Low Level signal (5mV rms)
NB: To optimize Low level signal, I follow the methodology I described in this post.

In this second attempt, I pushed further the preamp gain, by chaining the 2 channels of the mic preamp,
and using the RME as an ADC, allowing up to 24dBu input range


Path is as follows:
1. RME ADI-2 Pro fs R (19dBu range, both channels)
2. Radial Engineering SAT-2 Passive attenuator
3. Radial Engineering JDI Duplex - Passive Transformer DI
4. Y XLR cable, summing the 2 channels
5. "Cable" (or direct XLR)
6. Millennia HV-3C Mic Preamp (Max gain -3dB on one channel, Min=9dB gain on second channel)
7. RME ADI-2 Pro fs R (24dBu range, both channels averaged)
Measurements are performed with Virtins Multi-Instrument 3.9.5

Measured level just before "cable" is 5,004mV rms
Measured level after mic preamp is around 10V rms

"Direct"
5mV_2_Direct.png


Through "cable"
5mV_2_Cat.png


Comments

Here, we see more clearly a difference.
4dB is becoming significant.
It's mainly linked to some mains harmonics though.

Don't forget we compare 2 paths, the later with adding 30m of cable, on a 5mV rms signal.

Noise floor measurements in initial post are probably more relevant than this exercise.

NB: "Measured Level" at 5.1280Vrms is not correct in above graphs
 
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KSTR

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I thought that was exactly what it was initially meant for:
Why put the 250 Hz square wave in there if we never see it in the output of the real DAC? When J-test was invented, it was designed to find jitter induced when long runs of AES or S/PDIF cables were used. The toggling would cause all the bits to shift from one value to another, exaggerating sources of jitter there.
Ah, I see the confusion ;-)
To test for jitter, we have to examine either the D-A converted analog signal or use a jitter analyser directly on the digital output (after long cable, vs. short cable).
Whereas you looked at it after conversion from cable signal to digital source signal which is equivalent to looking on the source signal itself (source file) unless we had significant data corruption (flipped bits).
 

KSTR

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Path is as follows:
1. RME ADI-2 Pro fs R (19dBu range, both channels)
2. Radial Engineering SAT-2 Passive attenuator
3. Radial Engineering JDI Duplex - Passive Transformer DI
4. Y XLR cable, summing the 2 channels
5. "Cable" (or direct XLR)
6. Millennia HV-3C Mic Preamp (Max gain -3dB on one channel, Min=9dB gain on second channel)
7. RME ADI-2 Pro fs R (24dBu range, both channels averaged)
Measurements are performed with Virtins Multi-Instrument 3.9.5
I see more difference in the harmonic profile than expected (expected: none).
That might be an effect of different loading on the DI box (but, why did you need a DI in the first place, hum problems?)
If you put the attenuator after the DI the loading of the source side is effectively constant. Using the pad on the DI should keep HD in bounds.

After years of trying, I think that simple periodic signals looked at in the frequency domain are not ideal for finding extremely subtle changes... time-domain with complex signals has more chances to reveal anything. As noted I did not yet find anything that cables would do other than simple linear effects.
 

tifune

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How much power can safely be run through a device like this? Are 4 passive bookshelves an option? Kef R3 or LS50 for example
 

robwpdx

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Sending audio analog signal over standard Cat 5/6/7 cables over long distance:

Measurements of Thomann SSSnake Cat "Snake" Extenders


Hello

Here is a quick review and some measurements about a... "cable" (kind of).

Actually, this is a full range of accessories Thomann (one of the major music stores in Europe) is saling under its own SSSnake brand.
Here is a link to the range.

View attachment 204388View attachment 204389

I purchased 2 components: A 4 Female XLR "stage box" ("3FB") and a 4 Male XLR "splitter" ("3MC").
Price of those is quite low (below 30€ each)
Connection between the 2 boxes is done through standard RJ45 Category 5/6/7 cable.

I've performed following measurements using a 30m Cat5e UTP cable I had at hand.
This would not allow Phantom power transport (you need a shielded cable for that), but that's enough to transport audio signal.

(For facility, I'll call the assembly of the 2 Thomann connectors + the UTP cable "the cable" below.)

To assess performance, I measured some key values first "Direct" (from DAC to ADC through a set of XLR cables) then through the Cat5e cable.

Measurements are, as usual (for me), performed using
1. RME ADI-2 Pro fs R as a DAC (both output merged into 1 mono channel)
2. E1DA Cosmos ADC (from @IVX, Grade A, set to 6.7Vrms range, measured in Mono) as an ADC for SINAD and noise measurements
3. RME ADI-2 Pro fs R as an ADC (both input merged into 1 mono channel) for High frequency measurements and Frequency response
4. Virtins Multi Instrument Pro 3.9.5 as a measurement software
Performances of this is not supposed to match with Amir's Audio Precision, but as we will compare 2 measurements with just adding the "cable" we want to test, that should make no real difference. As you'll see, the performance of the test set up should be good enough to get a good idea of the added "cable" transparency.

SINAD dashboard
Direct

View attachment 204405

Through "Cable"
View attachment 204404

Noise floor
Direct
View attachment 204406

Through "Cable"
View attachment 204407

32 tones
Direct
View attachment 204402

Through "Cable"
View attachment 204403

Frequency response (96kHz sampling rate)
Direct
View attachment 204398

Through "Cable"
View attachment 204399

1kHz Square wave @768kHz sampling rate
Direct

View attachment 204401

Through "Cable"
View attachment 204400


Bottom line

I don't know for you guys, but, for me, I don't see any difference to speak about...


(Spoiler: I tested another similar device, from another brand, for which this is NOT true)


Important notes
Those devices exist in various brands.
(But this one is exceptionnaly cheap).

They all use the 4 twisted pairs you find in each Cat 5/6/7 cable to transport 4 separate balanced signals.
But they don't all use the same pairs for the same channels. And, more importantly, some brands are reversing phase on some pairs.
So mixing such "connectors" from different brands at the 2 sides of the Cat cable may be done, but you'd better check what impact that has.

Wiring for the Thomann SSSnake brand may be found here.

Phantom power may also be sent if you use a foilded/shiedled Cat 5/6/7 cable (the phantom power will use the shield)
DMX signal may also be transmitted.
I suppose that AES/EBU digital audio may also be sent using those extenders.
I didn't check any of those though.
Dave Rat is a live sound engineer for live shows. He has been experimenting with twisted pair Ethernet for analog audio and demos it on his YouTube.

Regarding Ethernet, I was the network engineer and led a team of system admins for a large, about 2500 person building of a global Fortune 50 company. Our building hosted global finance, the global research lab, a manufacturing floor, and the first software tools group for the company. This would have been about 1986? The finance group was amazing, they could close the global quarterly and annual books in, I think, 24 hours.

I brought in the first 10BaseT system to the company. There were a few groups running proprietary Synoptics twisted pair Ethernet, but we installed one of the first production 10BaseT networks in the world just as the spec was being approved. It worked fine, though I had very bad interactions with the facilities group that installed the actual wiring. There is a conflict between who was in charge of the project the physical wiring group - facilities contracting, and the building systems group - my group, that was technical. The finance group moved into my building in mid-Ethernet project, with zero impact on their operations. It really pissed off the facilities group that I rearranged the project around finance.

 

robwpdx

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How much power can safely be run through a device like this? Are 4 passive bookshelves an option? Kef R3 or LS50 for example
You see 23, 24, and 26AWG. 24 is about 90 Ohms per Kilometer and is max speced for 3.5 Amps. But given how close the conductors are and the insulation thickness, I would derate the 3.5 Amps.

The LS50 has a sensitivity of 85 dB at 1 Watt, and 87 dB for the R3. That is low sensitivity. Mid 90s dB per Watt is high sensitivity. Theoretically by Ohm's law you can get 98 Watts with 3.5 Amps into 8 Ohms, but I wouldn't do it to the amplifier. (check my math, correct as necessary)
 
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