There perhaps needs to be clarity and (dare I say) agreement over what 'truly balanced' actually is, circuitwise. There seems to be different opinions.
Recently I have contributed to a debate concerning the Audio Research Ref Phono 3SE. This is described by AR as 'fully balanced'. Yet a glance at the back plate reveals phono inputs only.
When AR were questioned as to how the amplifier can be fully balanced, they said:
The REF Phono 3SE does not have balanced inputs. We create a balanced signal after the inputs using a phase inverter. What turntable are you using that has balanced outputs? The outputs of the Phono 3SE are balanced and will feed your line stage with a balanced signal, pin two is positive, pin 3 is negative, and pin one is ground.
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Summary: The phase inverter does not increase the gain of the unit, it simply maintains a balance signal through the circuitry. This does provide CMR but we have no published specs on that to share.
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Summary: The REF Phono 3 uses a phase inverter circuit which converts the single ended inputs to balanced so the unit is fully balanced through the unit at at the XLR outputs
All very strange.
'The Ref Phono 3SE does not have balanced inputs'.
Why not? Many of AR's other pre-amps have balanced inputs using XLRs. What magic is the ;phase inverter circuit' and even if it works, why bother?
'What turntable are you using that has balanced outputs?'
Very strange response, entirely off-message. Turntables don't have 'outputs'. At this level everyone uses separates. The output is from the cartridge and can be connected balanced or not, at choice. I am afraid the responder is a marketing man, not an engineer, and knows little.
So is this amp 'fully balanced' or not?
Best to steer clear. As I did, and bought the vdH Grail SB that can be run fully balanced or single ended - has to be one or the other from input to output.
Can someone help please. AR don't seem to be able to.
IMO AR is not the same company since Mr Johnson left the stage. Pity.