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Balanced source output to unbalanced RCA input

Hari Iyer

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Now-a-days many of the mid to high end cd players / blu ray players come with a balanced xlr output and also with the associated RCA output. In the RCA section one of the cold point is directly grounded and there by some loss of the signal could result, Most amplifiers (like mine) have only a unbalanced RCA input to drive. So how do one connect the balanced output to unbalanced input?

- get a balanced to unbalanced audio isolation transformer - this is one of the best option, but again confusion on what should be the turns ratio, primary and secondary impedance, frequency response, noise etc. Could not find much information about how far the characteristic impedance need matching. Jensen transformers are as expensive as 400+$. Cheap Chinese audio transformers are available for as low as 1$ Lol

- get a balanced to unbalanced active converter - will have its own distortion because of quality of power supply, components and opamp used and will not be as good as the transformer option.

So what options do our FM use in such a situation?
 
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Hari Iyer

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Thanks keith for the link. Most connectors option from xlr to rca looks like a compromise to me. Any idea about balanced to unbalanced transformers? cant figure out the impedance matching scheme. most xlr have an output impedance mentioned as 10kohms. Does that mean that i need a 10k:10k balanced audio transformer? suggest.
 

tuff

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@Hari Iyer I don't know much on the technical end as you guys do, but when i was looking for something to connect from RCA to XLR, i read a highly recommended product called ART Clean box pro. It lets you correct input levels also.
 

Hari Iyer

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@tuff, thanks for the link. Looks like this is an active balanced / unbalanced line converter. I am not looking at an active solution because of the quality of the power supply and internal components used. Also they will not be as good as the transformer based solution imo. I am not able to figure out the characteristic impedance matching figures currently for the xmer option..
 

jls001

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@tuffAlso they will not be as good as the transformer based solution imo. I am not able to figure out the characteristic impedance matching figures currently for the xmer option..
Order a pair of bal-unbal transformer converters from Promedia. They use Neutrik transformers. Approx Rs 3500 per piece.

Or if you have any IC that is actually a balanced cable but using RCA-RCA, simply convert it to XLR-RCA following the Rane Notes examples.

I have both above options. I honestly find no sonic difference between the two.
 

Hari Iyer

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@jls001 thanks for the suggestion. If i have to do the suggestion from Rane Notes examples, i can very well connect the RCA out from the source to the amplifier. That way i can avoid the xlr fully. I would rather prefer the option suggested by @tuff instead. The transformer suggestion though nice is a bit pricey. I have contacted my telecom friends if they can find me some suitable audio transformer from their scrap. Let me see if i am lucky.
 

saikatbiswas82

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Thanks for the same.
Looking at the table of connections "Figure 4. Interconnect chart for locating correct cable assemblies" I was hoping to find directional unbalanced rca to rca connection. Unfortunately it was not there. In case anyone have any link on this, could you please share?
 
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jls001

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hmm, whats that. Never heard that before.
First tell us why you need balanced to unbalanced.

I'll tell you mine --- my power amp is balanced ONLY and the rest of my chain is unbalanced, hence I genuinely needed it.
 
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jls001

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Thanks for the same.
Looking at the table of connections "Figure 4. Interconnect chart for locating correct cable assemblies" I was hoping to find directional unbalanced rca to rca connection. Unfortunately it was not there. In case anyone have any link on this, could you please share?
Assuming you're using a balanced cable to make RCA-RCA cable, short the shield and return wire at source end and shield floating (unconnected) at destination. The purpose of such construction is to break ground loop (in case the interconnect link is responsible for creating a ground loop). Don't expect improved sonics.
 

prem

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The entire chain has to be balanced to obtain benefits. Hari you have a SET. So makes no sense
 

Hari Iyer

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Jousha, Prem, thanks for your suggestion. I look from the schematic point of view of the balanced output in the Marantz blu-ray player ud7007 which i ordered today. If i consider the unbalanced rca option, the hot is connected to the rca hot and the cold is grounded. the other half of the cold is fully ignored. That eventually means i am loosing an entire 50% of the signal technically. The balanced to unbalanced transformer helps me to resolve this issue imo. Am i missing something here?
 
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arj

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Now-a-days many of the mid to high end cd players / blu ray players come with a balanced xlr output and also with the associated RCA output. In the RCA section one of the cold point is directly grounded and there by some loss of the signal could result, Most amplifiers (like mine) have only a unbalanced RCA input to drive. So how do one connect the balanced output to unbalanced input?

- get a balanced to unbalanced audio isolation transformer - this is one of the best option, but again confusion on what should be the turns ratio, primary and secondary impedance, frequency response, noise etc. Could not find much information about how far the characteristic impedance need matching. Jensen transformers are as expensive as 400+$. Cheap Chinese audio transformers are available for as low as 1$ Lol

- get a balanced to unbalanced active converter - will have its own distortion because of quality of power supply, components and opamp used and will not be as good as the transformer option.

So what options do our FM use in such a situation?
If your equipment is not designed balanced, you do not get much benefit as they only connect one of the lines to the ground at that end and hence it becomes a SE cable. very few manufacturers..I believe Electrocompaniet is one using an internally balanced design.

For digital connections though a balance cable can bring benefits but for analogue better to go Single Ended and save on the money


Jousha, Prem, thanks for your suggestion. I look from the schematic point of view of the balanced output in the Marantz blu-ray player ud7007 which i ordered today. If i consider the unbalanced rca option, the hot is connected to the rca hot and the cold is grounded. the other half of the cold is fully ignored. That eventually means i am loosing an entire 50% of the signal technically. The balanced to unbalanced transformer helps me to resolve this issue imo. Am i missing something here?
In balanced it is the same signal on both but one is reversed. When they subtract one from the other in the end, the noise gets deleted.

so you lose the benefit of balanced since it is grounded
 
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Kannan

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@Hari Iyer the only caveat is the 6db loss as only the hot signal is used on the RCA end. You can either leave '3' open or short '1' and '3' at the XLR end.
If you have noise issues, connect the body of both the equipment.
 

Hari Iyer

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Many thanks to all FMs for sharing their thoughts on the balance / unbalanced connection.

Arj, as mentioned by you, the xlr has the cold reversed from the hot. So the hot still carries all the information of the signal. Like as mentioned by Prem unless the amplifier input is balanced there is no point in pursuing with only the active converter. I still am curious about the balanced to unbalanced isolation transformer but unfortunately the Chinese transformers look very basic and could suffer from FR issues. But as jls001 has already tried those stunts in the past, i will go by his wisdom and settle with connecting only the humble RCA unbalanced to RCA unbalanced for the time being. Maybe if i am able to source a high end transformer from my telecom contacts i can try some antics.
 

arj

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yes i have seen those, my understanding was that its to remove dc and any RFI from the line. but thats just an assumption and would like to know the actual usage from anyone who knows !
 

Hari Iyer

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since my source and preamp is going to be very close to each other (around 50 cm cable will be required to connect them), i am not expecting any noise with the RCA connection. i believe, balanced connections are most preferred if the cable length are too longer than normal and there could be stray noise pickup and / or probable impedance mismatch issues. In my case i am not going to face these issues. Make sense to stick to time tested traditional method of interface.
 

jls001

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yes i have seen those, my understanding was that its to remove dc and any RFI from the line. but thats just an assumption and would like to know the actual usage from anyone who knows !
Converts impedance correctly. This is why pro guys use it.

Being a transformer it stops any DC signal that may be riding in the signal path. Excellent ground loop breaker.
 
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