Balanced outputs vs balanced design

im wondering if a set-up offers single ended and balanced ins and outs can it be fully balanced? my reason for asking is i have a cairn nitro pre and ko2 amp with a fog 3 cd player . great sounding stuff , but they are the very vague with the spec's , and seem to be some of the least reviewed gear ever. but i do love it fully balanced or not.

11-18-07: Jrw40
im wondering if a set-up offers single ended and balanced ins and outs can it be fully balanced?

Can it be fully balanced? Yes
Does having balanced in's and out's mean it has to be fully balanced? No.

Some manufacturers offer balanced inputs and outputs for convienience, but they tie the negative (-) leg to ground inside the chassis and have single ended internal circuitry, not that there's anything wrong with that. However, the appearance of XLR connectors on the rear apron of the unit does not necessarily mean it is a fully differential unit. For it to be fully differential, it must have mirror interior circuitry for both the positive AND negative legs. This can become pretty expensive, and the results are not always audible. Hence I would say that most equipment is single ended, though some single ended gear will have balanced inputs/outputs.

There is little technical info on the internet about Cairn gear, but from what I can find, it looks to be a single ended design with optional balanced inputs and outputs.

Cheers,
John

ELDARTFORD: As for balanced circuitry in the power amp the advantage over single ended is largely theoretical for well designed equipment. It is often said that balanced is quieter because the signal is twice as strong, but there is also twice the circuit noise. Common mode noise, as for hum from the power supply, will be canceled, but there shouldn't be any such noise in a good unit.

Circuit noise is not twice as strong (+6 dB) in balanced designs. Rather, it's +3dB stronger, due to stochastic signals adding up logarithmically. That gives balanced units a +3 dB advantage in noise over single-ended ones. You are also neglecting the benefits caused by reduced distortions caused by cancelling, as well as the improved stability at the power supplies. The advantage is largely theoretical for BADLY designed equipment. In well designed units, the advantage is subtle but real, and I think detectable by ear if you care enough.

Cheers,

The advantage of a fully differential preamp or amplifier is that distortion is canceled at every stage in the device. As a result fully differential products can be lower distortion for a given amount of gain. Noise can be lower too- and the effects of noise and distortion always compound from stage to stage. The more differential circuitry is used, theoretically the more transparent the preamp or amp will be as well.