The true experimental tweak thread

[Cornan]

That says it will accept high-speed devices but reduces the speed to "full" nonetheless. Your DAC may not like this, and it certainly won't allow more than 96 kHz operation.

 

Thanks, I just re-read it and realized that I got it wrong. I'll need to move on to other solutions.

[Cornan]

Thanks Cornan. I understand now it is contamination of the mains you are primarily concerned with.

 

Where do you place your meter probes to check for galvanic isolation please?

 

Yes, correct! I used my multimeter in continue-mode, put the black probe to the black DC output and the red probe to the IEC input ground pin. Nothing. When I will get my DC cable I will also check it again between black DC output to my routers chassi ground.

[Cornan]

@mansr

This is just a hunch, but I just thought of one thing looking at this usb to male RJ45 8p8c adaptor:

 

 

If you have seen my previous post about my 100Base-TX ethernet wire you see very clearly that this adaptor have the very same configuration with pin 1/2 & 3/6. How about making a USB to ethernet cable with this configuration?

It would look something like this:

 

USB A plug>RJ45 socket connected to Rj45 plug>USB A plug all wired like the RJ45 8p8c adaptor.

 

Since you said that most RJ45 sockets contains a ethernet transformer this could be an interesting experiment.

 

 

BUT...is it a really bad idea or is there a chance that this would work considering that my DAC does´nt require 5v power (which this RJ45 8p8c adaptor will not provide either)?

 

Ps. I´ll guess that a ethernet socket with built-in ethernet transformer would looks something like this tough (and would require external power to work) Ds.

 

[Liam]

Yes, correct! I used my multimeter in continue-mode, put the black probe to the black DC output and the red probe to the IEC input ground pin. Nothing. When I will get my DC cable I will also check it again between black DC output to my routers chassi ground.

 

Thanks :-)

[JohnSwenson]

If I cannot find anything simple and useful for data isolation I think I will order the USBISO-AA to give it a try USB to RS485 converter shop

 

[ATTACH]32745[/ATTACH]

 

It works at high speed.

 

Since I am just after the data isolation this might be a valuable option for EUR60 +VAT & freight.

 

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This device is NOT high speed, in the data sheet it specifically says it is a Full speed only device.

 

There are a bunch of these isolators on the market, they all use the same Analog Devices chip which has been around for many years. Several of these companies say they are "USB 2.0" trying to make you think they work with high speed when in fact they don't. Strictly speaking it is true since the USB 2.0 spec includes low speed and full speed. Many people are a bit confused about this and think that USB 2.0 means high speed, high speed is part of USB 2.0, but so is low and full speed as well.

 

On the other device up-thread, it almost certainly is the same chip and the transformer symbol on the case is just to give the idea of galvanic isolation not that it actually uses a transformer.

 

The USB bus has to be bidirectional even after enumeration, even though we think of the audio protocol as one direction, it is not. Every so often the host asks the DAC if it is still there, the DAC then responds with a packet letting the host know it is alive. If the host doesn't get this it will drop the connection. So you still need a bidirectional isolation even while the music is playing.

 

The only way to know when to switch the direction of the isolator is to actually follow everything that is going on bus, ie a USB protocol engine. This is not trivial. Getting it right is NOT easy and has been one of the reasons such devices have been very scarce. The Intona is one of the few devices that has actually done this. And they still didn't get it right for audio at first.

 

I'm not trying to disparage you from trying things, but this is just not something you are going to be able to do without a LOT more knowledge of USB and electronics.

 

It is HARD.

 

John S.

[Cornan]

This device is NOT high speed, in the data sheet it specifically says it is a Full speed only device.

 

There are a bunch of these isolators on the market, they all use the same Analog Devices chip which has been around for many years. Several of these companies say they are "USB 2.0" trying to make you think they work with high speed when in fact they don't. Strictly speaking it is true since the USB 2.0 spec includes low speed and full speed. Many people are a bit confused about this and think that USB 2.0 means high speed, high speed is part of USB 2.0, but so is low and full speed as well.

 

On the other device up-thread, it almost certainly is the same chip and the transformer symbol on the case is just to give the idea of galvanic isolation not that it actually uses a transformer.

 

The USB bus has to be bidirectional even after enumeration, even though we think of the audio protocol as one direction, it is not. Every so often the host asks the DAC if it is still there, the DAC then responds with a packet letting the host know it is alive. If the host doesn't get this it will drop the connection. So you still need a bidirectional isolation even while the music is playing.

 

The only way to know when to switch the direction of the isolator is to actually follow everything that is going on bus, ie a USB protocol engine. This is not trivial. Getting it right is NOT easy and has been one of the reasons such devices have been very scarce. The Intona is one of the few devices that has actually done this. And they still didn't get it right for audio at first.

 

I'm not trying to disparage you from trying things, but this is just not something you are going to be able to do without a LOT more knowledge of USB and electronics.

 

It is HARD.

 

John S.

 

Thanks John!

 

I have already noticed that is is not properly hi-speed with the help of @YashN and @mansr!

 

You told me about these problems ones before, but I am a quite stubborn guy when I have an "obstacle" in front of me!

 

Even though many people have posted great reviews about the Intona it is really a step back in my point of view. Since I already use unshielded twisted pair data wires, no 5v and GND lift on my USB cables plus a battery powered Regen in-line I am not all that interested to add another USB powered device in the chain...but I am still interested to know if a passive type of data only isolation could improve things. Anyway, it seems to be a dead-end without really deep knowledge in the subject.

I will concentrate my efforts on my coming experiment with a twisted pair SAT cable instead plus see if I can find some other use for my coming optocouplers (maybe on my twisted pair SAT cable? ?)

 

 

 

 

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[scan80269]

Thanks John!

 

I have already noticed that is is not properly hi-speed with the help of @YashN and @mansr!

 

You told me about these problems ones before, but I am a quite stubborn guy when I have an "obstacle" in front of me!

 

Even though many people have posted great reviews about the Intona it is really a step back in my point of view. Since I already use unshielded twisted pair data wires, no 5v and GND lift on my USB cables plus a battery powered Regen in-line I am not all that interested to add another USB powered device in the chain...but I am still interested to know if a passive type of data only isolation could improve things. Anyway, it seems to be a dead-end without really deep knowledge in the subject.

I will concentrate my efforts on my coming experiment with a twisted pair SAT cable instead plus see if I can find some other use for my coming optocouplers (maybe on my twisted pair SAT cable? ?)

 

Hi Cornan,

 

Like John said, there is no simple way to passively isolate USB 2.0 (D+/D-) signals, due to the definition of USB 2.0 (covering Low Speed (1.5Mbps), Full Speed (12Mbps) and High Speed (480Mbps) using bi-directional mostly-differential signaling. Products like the Intona and Corning optical USB cable use custom logic on both sides of the isolation barrier, and are way too complex for DIY. These active isolation designs are the only ways to meet USB 2.0 specification compliance, and the complexity is unavoidable.

 

Ironically, USB 3.0 SuperSpeed (5Gbps) and SuperSpeed+ (10Gbps) use unidirectional true differential pairs (SSTX+/SSTX-, SSRX+/SSRX-) for signal transmission, which have similar architecture to other high speed differential links such as Ethernet, PCI Express, SATA, MIPI CSI & DSI, DisplayPort, HDMI, etc., and implementing galvanic isolation is possibly much more straightforward compared to USB 2.0, and may not require much more than pulse transformers built with the proper electrical specs. Unfortunately, digital audio streaming has yet to catch up to USB 3.0, but perhaps one day...

 

By the way, what is a SAT cable?

[Cornan]

Hi Cornan,

 

Like John said, there is no simple way to passively isolate USB 2.0 (D+/D-) signals, due to the definition of USB 2.0 (covering Low Speed (1.5Mbps), Full Speed (12Mbps) and High Speed (480Mbps) using bi-directional mostly-differential signaling. Products like the Intona and Corning optical USB cable use custom logic on both sides of the isolation barrier, and are way too complex for DIY. These active isolation designs are the only ways to meet USB 2.0 specification compliance, and the complexity is unavoidable.

 

Ironically, USB 3.0 SuperSpeed (5Gbps) and SuperSpeed+ (10Gbps) use unidirectional true differential pairs (SSTX+/SSTX-, SSRX+/SSRX-) for signal transmission, which have similar architecture to other high speed differential links such as Ethernet, PCI Express, SATA, MIPI CSI & DSI, DisplayPort, HDMI, etc., and implementing galvanic isolation is possibly much more straightforward compared to USB 2.0, and may not require much more than pulse transformers built with the proper electrical specs. Unfortunately, digital audio streaming has yet to catch up to USB 3.0, but perhaps one day...

 

By the way, what is a SAT cable?

 

Hi scan!

 

Thanks! A pity they made USB that difficult to isolate! ?Anyway, I have left that path now and will see what comes out with a twisted pair SAT cable which is a coaxial satellite cable with F plugs like this one that my router needs as input:

 

 

I want to see how it turns out if I change it to this cable

 

 

and these plugs

 

 

BTW. Thanks for the tip regarding 100Base-TX Ethernet cables! It sounds great in my setup with a couple of these Ethernet cables

 

 

connected to my uphill & downhill FMC (TP-Link MC100CM). Very happy with the result!

 

Micael

 

 

 

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[Cornan]

One silver soldered twisted pair silver wire satellite cable ready!

 

Unfortunately all too late at night to install it and test it without waking up the rest of my family, so the actual trial as my router input cable (instead of the coax SAT cable) will have to be done tomorrow evening.

 

Quite happy with the result though! [emoji16]

 

 

 

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[Middy]

looks good mate

 

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[Cornan]

looks good mate

 

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Thanks Middy!

I did manage to sneak in silently and add it between me service providers outlet and my router. No luck! I cannot connect to internet. I will have to double check my jack connections tomorrow ones more. It is all a long shot. If the connections is OK I guess my experiment is a failure and twisted pair cable is just not suitable for SAT cable. Fun experiment in any case. Let's see tomorrow! ?

 

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[mansr]

Thanks Middy!

I did manage to sneak in silently and add it between me service providers outlet and my router. No luck! I cannot connect to internet. I will have to double check my jack connections tomorrow ones more. It is all a long shot. If the connections is OK I guess my experiment is a failure and twisted pair cable is just not suitable for SAT cable. Fun in any case. Let's see tomorrow!

 

I don't think that cable will work. Twisted pair and coax are not generally interchangeable.

[Cornan]

I don't think that cable will work. Twisted pair and coax are not generally interchangeable.

 

It certainly seems so right now. How about stripping a coaxial wire and use the dielectric core with a GND wire twisted around it. Would that work as a coax?

I am looking for a solution to get rid of the shielding!

 

 

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[mansr]

It certainly seems so right now. How about stripping a coaxial wire and use the dielectric core with a GND wire twisted around it. Would that work as a coax?

I am looking for a solution to get rid of the shielding!

 

Why on earth would you want to get rid of shielding?

[Cornan]

Why on earth would you want to get rid of shielding?

 

Because cables sounds better without it IMO. Atleast in my setup!

 

 

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[mansr]

Because cables sounds better without it IMO. Atleast in my setup!

 

That's a hell of a generalisation.

[Cornan]

That's a hell of a generalisation.

Not for me. This have taken me 30 years to realize. All my cables have been shielded in the past. For every shield that I have removed it have changed the sound for the better. However, it is not just a matter of removing the shields. It is very much dependant on system grounding (less is more), how you power your devices, length of cables and how well it is isolated (distance & galvanic isolation) IME.

 

My personal goal is to have all my ICs and power cables unshielded in my system. Just my SAT cable and my router ac power cable left to reach that goal.

 

 

 

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[Cornan]

Here is my system typology that I recently posted in another thread. It gives a rough idea about my plans.

 

[mansr]

Here is my system typology that I recently posted in another thread. It gives a rough idea about my plans.

 

[ATTACH=CONFIG]32789[/ATTACH]

 

Don't worry about the router. All the connections to other equipment are isolated, so any noise coming in on the cable shield has nowhere to go anyhow.

[Cornan]

Don't worry about the router. All the connections to other equipment are isolated, so any noise coming in on the cable shield has nowhere to go anyhow.

 

Thanks mansr! I am not really worried. I am more intrigued to know if it will make a difference...for better or worse (it is easy to swap back if it turns out worse)!

 

When I look at my own system I am quite clear that I want a DC blocker between my lab psu and the wall outlet as well. My SAT DC blocker and my mains ALT DC blocker are both close to the wall inlets and have made a good improvement on the sound, so I guess another ATL DC blocker could potensially be a good thing to ensure that the router is not affected by DC noises from the mains.

[Cornan]

Yesterday when I was sneaking silently trying my experimental SAT-cable I noticed one thing.

 

My service provider have a inlet like this one

 

 

To get more space (and be more silent) I removed the RF TV cable which is side-by-side to my SAT inlet (but is called DATA). When I noticed that it did´nt work I wanted to connect the original SAT-cable again but by accident started to plug in the SAT cable to the TV socket. Took me a second to realize my misstake...but I also noticed that I actually got a picture as well (with the shielded cables).

 

Bottom line: It made me wonder if there is something that could be done inside that wall inlet to isolate the TV signal and the data signal? Anyone got a clue were to start?

[mansr]

Bottom line: It made me wonder if there is something that could be done inside that wall inlet to isolate the TV signal and the data signal? Anyone got a clue were to start?

 

It's the same wire. Data is modulated on a different carrier frequency than TV (up to about 1 GHz). This is RF, so cables do matter. It must be coax with the correct impedance, or it will not work (as you found out).

[r_w]

Knowing you, the answer is probably yes, but have you tried shielding connected at just one end of (all of) your DIY cables?

 

;-)

 

 

Because cables sounds better without it IMO. Atleast in my setup!

 

 

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[mansr]

Knowing you, the answer is probably yes, but have you tried shielding connected at just one end of (all of) your DIY cables?

 

;-)

 

That won't work too well with the coax running to the cable modem.

[Cornan]

Knowing you, the answer is probably yes, but have you tried shielding connected at just one end of (all of) your DIY cables?

 

;-)

No, I have just tried shielding at one end on USB cables and on copper Ethernet cables. On ac power cables I have tried with disconnected shields in both ends (actually conductive GND wire with unconnected shielding foil). On all these cables it sounds best with unshielded cables in my setup...but still think that shielded plugs is beneficial to the SQ.

 

 

 

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