The USB Cable Tweak

[Nikhil]

This has been discussed in other forums but I could not find specifics on this tweak when I wanted to try this out for myself. After a little experimenting I have now been using this tweak on my USB cable and the sound benefits are enormous in my setup. I am not the expert on electronics so those qualified more than me are more than welcome to chip in.

Description: The +5V wire on USB cables carries the said voltage to help power general passive devices as per the USB protocol. However for those who are using a computer transport to send data to a USB DAC which has it's own power the +5V is a source of noise (usually due to the computer SMPS) that muddles the sound. When eliminated the extent of the deterioration is quite noticeable.

Sound Benefits: In my setup there was a noticeable difference in bass extension and SPL. The system seemed to have opened up just that much more. Low level detail improved with a little more definition. The difference to me was quite considerable.

Cost: Rs 150 for a simple USB cable + 20 mins time

So here is the USB Pinout for standard USB interfaces:

and here is what a typical USB cable should look like with color coded wires:

The goal is to eliminate the dirty +5V from entering into the DAC.
So using any cable splicing tool, splice open a USB cable and identify the RED Wire.
Just cut the Red Wire leaving the other three Data+, Data- and GND (White, Green and Black) wires untouched.

I have shown this in the picture below:

You may then close the joint with proper electrical insulation tape.
Test before doing this just in case but that's all there is to it.

Note: Cutting both the +5V and the GND may not work. You may need to have the GND wire for the cable to work.


This has been working well with my setup so far with an asynchronous USB connection. If there is anything on here that doesn't pass muster on the electronics side please let me know asap. I've been using this tweak for some months now and I have not had any problems. However I am always open for correction.

Enjoy!

 

[koushik]

Nikhil,

Thanks for sharing the tweak but I have doubt about its working principle.
System (DAC, HDD, Converter) that has its own power supply will not draw the power from the connected USB cable anyway and the connection is off internally. Only the white and green cable is connected to the destination circuit.

So, I am seeing/expecting no benefit from doing this! Open to correction though.

 

[Nikhil]

koshik, I was surprised at the extent of the improvement/change.

I was also a little skeptical but when some senior audiophiles acknowledged that it works I was interested. The main culprit IMO is the power supply on the computer which generates a lot of noise that is still transmitted through the cable. In the AP DAC, Siva has implemented 8 independent power supplies for various circuits plus voltage regulators and chokes. Still the +5V manages to screw up the sound quality.

 

[Audiopolitan]

This has been discussed in other forums but I could not find specifics on this tweak when I wanted to try this out for myself. After a little experimenting I have now been using this tweak on my USB cable and the sound benefits are enormous in my setup. I am not the expert on electronics so those qualified more than me are more than welcome to chip in.

Description: The +5V wire on USB cables carries the said voltage to help power general passive devices as per the USB protocol. However for those who are using a computer transport to send data to a USB DAC which has it's own power the +5V is a source of noise (usually due to the computer SMPS) that muddles the sound. When eliminated the extent of the deterioration is quite noticeable.

Sound Benefits: In my setup there was a noticeable difference in bass extension and SPL. The system seemed to have opened up just that much more. Low level detail improved with a little more definition. The difference to me was quite considerable.

Cost: Rs 150 for a simple USB cable + 20 mins time

So here is the USB Pinout for standard USB interfaces:

and here is what a typical USB cable should look like with color coded wires:

The goal is to eliminate the dirty +5V from entering into the DAC.
So using any cable splicing tool, splice open a USB cable and identify the RED Wire.
Just cut the Red Wire leaving the other three Data+, Data- and GND (White, Green and Black) wires untouched.

I have shown this in the picture below:

You may then close the joint with proper electrical insulation tape.
Test before doing this just in case but that's all there is to it.

Note: Cutting both the +5V and the GND will not work. You need to have the GND wire for the cable to work.

This has been working well with my setup so far with an asynchronous USB connection. If there is anything on here that doesn't pass muster on the electronics side please let me know asap. I've been using this tweak for some months now and I have not had any problems. However I am always open for correction.

Enjoy!

Hello Nikhil,

Thank you for sharing that informative post!

I cannot imagine someone doing such a DIY experiment on a beautiful looking WireWorld Starlight 7 USB cable. ?

In some set-ups, the initial "handshake" that a computer uses to "see" the USB device is sent down the power lines. Therefore the power lines must be present at the moment of connection, or it may not work.

There are some readymade alternatives here, in case cost is no object, such as the ifi Gemini Dual Headed USB cable iFi-audio Gemini & the ifi iPurifier iFi-audio iPurifier to address the very same issues in different ways.

Brgds

 

[Nikhil]

Audiopolitan,

Thanks for the feedback. From what I understand, the power needed comes from the DAC for the handshake etc.
By disconnecting the +5V you are isolating the "dirty" noise from the computer SMPS.

This is primarily targeted to those who are on a budget and/or open to trying out a tweak on a simple USB cable for a VFM solution.
As I have said the cost for trying this out is less than Rs 200/-

 

[haisaikat]

I have ODAC which is powered from USB directly, so probably this will not be applicable in my case, nevertheless a good experiment.

 

[koushik]

I have ODAC which is powered from USB directly, so probably this will not be applicable in my case, nevertheless a good experiment.

You can always tweak to power it from outside.

 

[haisaikat]

You can always tweak to power it from outside.

and possibly invest on upgrading to a more linear power supply in future. No thank you I am happy with the impurities as of now that I am still not aware of since never heard without.

 

[Thad E Ginathom]

I run my ODAC from a powered hub. I don't notice any change in the sound, but I had a situation where power glitch when turning on the powered speakers was causing the PC to drop its recognition of the ODAC. I have no idea if the power from the hub is any "cleaner" than the power from the PC. After buying it )) I discovered that my PC power supply is a pretty good one.

If people are really going to worry about this sort of thing, then I think they should invest in the appropriate test equipment (which might be cheaper than the education to use it, especially for maths dunces like me). People love picking up rumours and turning them into absolutes. Before worrying about the noise created by one's PC power supply, how about finding out if there is any? Some might get a shock (figuratively, I hope!) and some might find they were worrying unnecessarily.

But hey, am I saying don't try this unless you buy an oscilloscope first? No way! Nothing wrong with tweaks, and as long as they are not expensive. You can find green-edged CDs among my collection .

If I had a self-powered DAC, I might have tried it. Cost of a USB cable only ...or at least, only one if one has a delicate hand with the knife, to cut the outer insulation only!

There's also USB isolators available. Oh! Come to think of it, I've got one, from HiFiMeDIY --- but I had some difficulty with the PC recognising the DAC through it. Then I forgot about it

You can always tweak [ODAC] to power it from outside.

I think that I won't mess with mine. One USB cable is a reasonable risk; one ODAC is not :lol:.

and possibly invest on upgrading to a more linear power supply in future. No thank you I am happy with the impurities as of now that I am still not aware of since never heard without.

And me too... I get such a sense of transparency and cleanliness from my ODAC/iCAN that I am very happy with it, and feel that upgrades should now be at the headphone end.

Of course, I'm not saying that it couldn't be improved.

BTW, ifi make a big fuss about their wall-wart for the iCAN: they claim that it is exceptionally low noise. I'm not arguing! In fact, as long as it wasn't at silly-audiophile prices, I could be in the market for a super-low-noise multi-voltage multi-output wall-wart eliminating power supply.

And another thought from my butterfly brain... ifi make a USB power purifier.

 

[Nikhil]

If I had a self-powered DAC, I might have tried it. Cost of a USB cable only ...or at least, only one if one has a delicate hand with the knife, to cut the outer insulation only!

A half decent electrician can do this job for less than 50 bucks.

 

[Thad E Ginathom]

It would be a good test! of course, they might fail.

I'm, let's say, better-than-average at such things, so, sure, I'd do it myself

 

[reignofchaos]

My amr dac does not require the ground wire to be present either. Works with just the data lines.

 

[rud3dawg]

An interesting idea and experiment Nikhil!!! :thumbsup: :thumbsup: I would definitely like to try the same with my DAC hyeah: but in a few weeks ...

right now am on hiatus but really excited to try this , Wonder if a locally purchased USB cable would out do an expensive cable after this surgical modification which I would love to do by myself (Will definitely buy spares incase of accidents )

 

[Nikhil]

Wonder if a locally purchased USB cable would out do an expensive cable after this surgical modification which I would love to do by myself (Will definitely buy spares incase of accidents )

Great to see you on here after a long time dawg!

It's a little unfair to compare this tweak on a standard USB cable with an expensive cable but still the results will surprise you. Expensive cables usually do a much better job with the materials used for the wire and connectors which make the comparison a little skewed.

However I still think this tweak (isolating the +5V) does a massive job of improving sound.

 

[koushik]

koshik, I was surprised at the extent of the improvement/change.

I was also a little skeptical but when some senior audiophiles acknowledged that it works I was interested.

Nikhil, I am great believer of tweaking/modding as I got so much great results doing small changes here & there.

I am NOT trying to disregard your findings. I am just trying to figure out what may be the probable reason.

The main culprit IMO is the power supply on the computer which generates a lot of noise that is still transmitted through the cable.

Current will not flow through the cable if no potential differences is applied. So, if the wire is not connected to the circuit on the other end, it is not possible for charge to flow.

Only an ammeter can check if the DAC is connecting the incoming power to any part of the circuit or not. Just connect an ammeter between the 2 ends of the wire which you have ripped off.

- Koushik.

 

[Nikhil]

Current will not flow through the cable if no potential differences is applied. So, if the wire is not connected to the circuit on the other end, it is not possible for charge to flow.

Only an ammeter can check if the DAC is connecting the incoming power to any part of the circuit or not. Just connect an ammeter between the 2 ends of the wire which you have ripped off.

- Koushik.

Koushik, I have got the cables checked with a multi-meter for connectivity etc.
The whole purpose of the tweak is to disconnect the 5V wire.

Not able to get what you want me to answer here.

 

[Santy]

What koushik probably wants to ask is if no current is flowing through the wire what's the point of disconnecting it?

 

[Nikhil]

My amr dac does not require the ground wire to be present either. Works with just the data lines.

ROC I think its the Gemini cable design that allows you to do this not the AMR DAC. I suspect the signal cable has a ground connected in the cable.

 

[Nikhil]

What koushik probably wants to ask is if no current is flowing through the wire what's the point of disconnecting it?

Aha! Ok ... I think that along with the current the "wire" carries RF noise from the computer SMPS.
By disconnecting the wire the noise gets eliminated/reduced to a large extent.

 

[Audiopolitan]

Audiopolitan,

Thanks for the feedback. From what I understand, the power needed comes from the DAC for the handshake etc.
By disconnecting the +5V you are isolating the "dirty" noise from the computer SMPS.

This is primarily targeted to those who are on a budget and/or open to trying out a tweak on a simple USB cable for a VFM solution.
As I have said the cost for trying this out is less than Rs 200/-

Hello Nikhil,

Indeed your DIY suggestion is an affordable and practical tweak. One that every audio enthusiast should essentially try and experience for themselves. The pleasure is in the learning. I was only sharing potential hiccups (as shared elsewhere) and possible alternatives.

In fact, Im currently gathering materials to make my own USB cables. I will surely be terminating one of them without the 5v power cable. I may be able to add more to this conversation once Im successful with it. Whenever that will be