wuzznbuddy

Single ended pre driving balanced power

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Does anyone know if there is any disadvantage to using a single-ended RCA output from a pre to drive the XLR balanced inputs of a power amp (a AN P4 balanced, to be exact). The manual for the power amp says it can be connected in this way, but I wondered if I'd be missing out on something if I did this? I've no experience with balanced amps, so am clueless. 

Thanks is advance for any help anyone is able to give. 

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Unless the cable length between pre and power amp exceeds 10m, there will be NO benefit whatsoever from balanced operation. Over 10m, there might just possibly, at a push, be a benefit, which holds up to about 100m. Over 100m, I would definitely go balanced. 

S.

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Does a balanced input not usually need more volts for full power than a single ended one ( assuming you need the higher output that is)

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2 hours ago, wuzznbuddy said:

The manual for the power amp says it can be connected in this way, but I wondered if I'd be missing out on something if I did this? I've no experience with balanced amps, so am clueless. 

You won't be missing out on anything.

Unless the entire system is balanced or the cable runs are far beyond anything normally used in a domestic situation there is no benefit.

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33 minutes ago, omsoc said:

Does a balanced input not usually need more volts for full power than a single ended one ( assuming you need the higher output that is)

No, there's no correlation whatsoever between balanced inputs and input sensitivity. They can be whatever you like. Microphone inputs are balanced and very sensitive. It's just a matter of what gain's available.

S

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if the entire system is balanced (very rare) there are potential benefits. All of wich can equally be acheived through proper grounding in a single-ended set up in domestic use.

No difference in terms of gain, signal strength, voltage, etc.

Simply the circuit topology.

Balanced makes a lot of sense in gigs and the like, where long cable runs for sensitive circuits are the norm and where they run close to lighting cables and similar. If the entire system is balanced, then why not. However, no point.

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I understand that it is not a given but is it not common that a source component that offers both rca and xlr outputs that the xlr output will higher (approx 4V vs approx 2V...very approximately)

:sofa:

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38 minutes ago, omsoc said:

I understand that it is not a given but is it not common that a source component that offers both rca and xlr outputs that the xlr output will higher (approx 4V vs approx 2V...very approximately)

:sofa:

Indeed, but then the corresponding balanced input has a sensitivity 6dB lower than the unbalanced one. 

Output voltage and input sensitivity can be whatever you want them to be. 

S

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13 hours ago, SergeAuckland said:

Indeed, but then the corresponding balanced input has a sensitivity 6dB lower than the unbalanced one. 

Output voltage and input sensitivity can be whatever you want them to be. 

S

This was what I was trying to get at in post 3 (poorly) that if Wuzz was driving balanced amp inputs from unbalanced pre-amp he might not get enough volume from the speakers.

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2 hours ago, omsoc said:

This was what I was trying to get at in post 3 (poorly) that if Wuzz was driving balanced amp inputs from unbalanced pre-amp he might not get enough volume from the speakers.

But why would that be any different from driving an unbalanced input from an unbalance output, or a balanced input from a balanced output or whatever combination you like? There is NO correlation whatsoever between voltage levels and whether balanced or unbalanced. Voltage is voltage, whether it's on one wire relative to ground or one wire relative to the other wire. 

Whether something is loud enough depends entirely on the output voltage level and the input sensitivity, not whether balanced or unbalanced.

S.

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Wuzznbuddy,

You need to be a little careful here as you are driving the Audionote P4 balanced amps. They only have the balanced inputs. They are normally used with the Audionote preamps which have phono and balanced outputs. The audio note preamp balanced outputs are 'generated' via transformers.  Have you got, or know, which pre-amplifier you will be using? It will then be a simple job to say whether there is likely to be a problem. 

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26 minutes ago, SergeAuckland said:

Whether something is loud enough depends entirely on the output voltage level and the input sensitivity, not whether balanced or unbalanced.

This (and connecting to the correct pins in the xlr...)

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In general, correctly made balanced (XLR) connection/cable has an inherent noise rejection of 50dB or more when terminated in truly balanced circuits on both ends. Balanced design successfully/totally reject common-mode (noise) signals as free bonus. Apart from that, I prefer correctly made XLR leads physically as they are sturdy, reliable, well designed, with really flexible cable routing and somewhat more stable/reliable for long distance runs. I've never appreciated that RCA inner hot (signal) connection is made before the actual cold (ground) when accidentally you hot plug the leads.

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...

Edited by JezR

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