Unbalanced to Balanced polarized interconnect - DIY

Hari Iyer

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I had come across this interesting cable wiring last year when i was searching for my DIY tube amplifier built but did not pursue them as i was not keen at that point in time. Now, as i have settled with my DIY tube amplifier and DIY OB speakers (hopefully) i thought of pursuing them now. But unfortunately i could not trace that article as i did not save the link or copied it elsewhere. I have drawn the below schematic from what i could recollect and am planning to build them asap.

Polarized cable-Hari Iyer.jpg

As you can see from the schematic, the electrons (negatively charged e-) on the hot and cold terminals will flow from the input to the output of the cable in one direction as the shield is given a +ve polarity with a battery. The value of the resistors will depend upon your pre-amplifier input impedance and the capacitor is used for allowing RF above 1MHz so that the shield itself dont behave like an antenna. Alternatively the capacitor also allow balance of the cable. The DC will not flow to the cables due to the presence of the capacitor but still have a +ve polarity to allow the electrons (RF) to get pulled toward it creating a direction for the cable. This will enable faster break-in of the cable.

IMO, you will not have to connect the battery for more than a month or a two after the direction of the cable is established. Also the battery will be never drained as their is no current flow anywhere. You should also notice that the H & C is give a battery -ve polarity to make the electrons -vely charged w.r.t. the shield.

This is still in concept stage and work for my coming weekend. Agreed its not a "Moorthy Cable" which has rave reviews in this forum. Hope it will be some where nearby.

Thanks for looking.
 

greenhorn

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from what I can see - the capacitors will charge (depending on the RC value) and reach a steady state pretty quickly. Once they are fully charged, they will have the same voltage as the battery, which would mean that both ends of the wire would be at the same voltage, which would make it no different from a regular cable?
 

IndianEars

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Hari,

I have been using the AudioQuest Coffee USB A to B cables for years now, conecting my PC to DAC.

You may like to read up on these.

The polarising voltage needs to be MUCH Higher than 9 Volts.

The polarising voltage needs to be present permanently, and audible differences are perceived 2 to 3 days after the voltage is first applied.
 

Hari Iyer

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The action is to allow the flow of electrons from source to destination to give them one direction. Charging the capacitors is irrelevant as the capacitors are miniscule at RF frequency. There will anyway won't be any DC on the signal and also ensure flow of electrons towards the destination.

Don't want to get into theory, but built them and see if there is any benefit. Built cost any way is less than 200/- per cable
 

Hari Iyer

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from what I can see - the capacitors will charge (depending on the RC value) and reach a steady state pretty quickly. Once they are fully charged, they will have the same voltage as the battery, which would mean that both ends of the wire would be at the same voltage, which would make it no different from a regular cable?
Alright.
 

greenhorn

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my thought is that if you put a very large resistance across the capacitors, then there would always be some leakage current flowing through the wire from source to destination (but would somewhat shorten battery life). the amount of R across the C would depend on how much bias current you would want to apply to the wire (not looking at bias voltage as it would be minimal)
 

Hari Iyer

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There will be negligent bias current as the DC will be blocked by pF value capacitor, but -9v bias voltage on the H & C w.r.t shield. The charge that flow will be trickle charge good enough for the electrons to get attracted towards the positive polarized shield via the out end as there is again a high resistance and -ve charged "in". This trickle charge then gives direction for the flow of signal (electrons) towards "out".
 

Hari Iyer

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Hari,

I have been using the AudioQuest Coffee USB A to B cables for years now, conecting my PC to DAC.

You may like to read up on these.

The polarising voltage needs to be MUCH Higher than 9 Volts.

The polarising voltage needs to be present permanently, and audible differences are perceived 2 to 3 days after the voltage is first applied.
Indianears, i did not notice any polarizing voltage on the USB cable. Am I missing something? The RF can be returned back to the shield in the same schematic above by removing the Battery and shorting the resistor to the shield without polarising too. That way the noise is not referenced to equipment ground.

I do agree that the voltage should be around 50 volts, then again it would mean using a power supply for that.

This project is more for fun aspect and not meant for any serious manufacturing. If it work well then I may use it for the rest of my life.
 

IndianEars

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Hari,

1. Not sure if you are referring to the AudioQuest Coffee cable. The Link I had mentioned ... The First Bullet under FEATURES, says:

"

DIELECTRIC- "BIAS" SYSTEM WITH RADIO FREQUENCY TRAP​

All insulation between two or more conductors is also a dielectric whose properties will affect the integrity of the signal. When the dielectric is unbiased, dielectric-involvement (absorption and non-linear release of energy) causes different amounts of time delay (phase shift) for different frequencies and energy levels, which is a real problem for very time-sensitive multi-octave audio. The inclusion of an RF Trap (developed for AudioQuest’s Niagara Series of power products), ensures that radio-frequency noise will not be induced into the signal conductors from the DBS field elements. (DBS, US Pat #s 7,126,055 & 7,872,195 B1)

Maybe some other links on the product will also show the Battery Box.



2. Regarding increasing the Bias voltage, small sized 23AE batteries (easily available) provide 12 Volts DC. The Audioquest Coffee uses 4 of these. You can explore for your hobby build.
 

Hari Iyer

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For easy reading, i redrew the same cable with a simplified view for understanding as below,

interconnect cables.png
Since a 9v battery will not be enough, i am planning to replace the B1 with a high value capacitor charged once upon a time. I have couple of 100uF,250V Rubycon capacitor for this duty. Will connect as per above and charge them to around 75 volts. As there is no current bias or flow, the charge will be retained for the rest of its life. Can do away with the battery too and yet have higher voltage in the shield for polarization. Looking for advise / suggestions.

Thanks for looking.
 

IndianEars

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For easy reading, i redrew the same cable with a simplified view for understanding as below,

View attachment 54994
Since a 9v battery will not be enough, i am planning to replace the B1 with a high value capacitor charged once upon a time. I have couple of 100uF,250V Rubycon capacitor for this duty. Will connect as per above and charge them to around 75 volts. As there is no current bias or flow, the charge will be retained for the rest of its life. Can do away with the battery too and yet have higher voltage in the shield for polarization. Looking for advise / suggestions.

Thanks for looking.
Capacitors self discharge.

I doubt the circuit it will hold the voltage for even a day.

Would be great to know what happens in practice
 

Hari Iyer

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Capacitors self discharge.

I doubt the circuit it will hold the voltage for even a day.

Would be great to know what happens in practice
If capacitor is having high impedance due to presence of pF value capacitor and only RF energy passing through makes me more inquisitive. The. RC time constant will be hardly 2uSec , but current drain would be low imo. I shall try this asap and confirm.
 

IndianEars

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Hari,

I am refering to the self discharge characteristic of your 100uF, 250V Rubycon capacitor.

Charge it and keep aside for a day without even connecting Anything to it..... It will have discharged. That is termed as self discharge
 
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