Buffered Pre-out? What is it?

You don't say what make and model of preamp is involved. Buffering in an analog circuit is usually done to make a circuit more tolerant of difficult load situations. (This is different than digital buffering, where data is accumulated in a memory chip and then parceled out to a device or program as needed.)

In your case it sounds like the preferred circuit is the unbuffered one, but that it doesn't tolerate the added resistance or capacitance of a long interconnect. In that case, the extra stage of devices (the buffer circuit) may offer the better compromise in terms of sonic degradation.

Mlsstl, It is an Arcam C-30. And yes, you are correct, the unbuffered out is stated as prefered.

It was more of a general question than a problem with implementation. I am familiar with the concept of digital buffering in the manner you describe. How buffering is applied in the context of a pre-out just had me grasping at thin air (mentally ciruit challenged :>)).

Your thought makes good sense. Do you know what would be used in a buffer circuit that would degrade the sound? Just extra connections?

Just curious.

Thank You! - Jim S.

Buffering lowers the output impedance of the source. Why? Well, sometimes the receiving component has a low input impedance, like some solid state amps. Long cable runs can also load the driving component excessively. So what does it sound like? Reduced dynamics and reduced high frequency extension. The broad rule is that the receiving component should be twenty times the impedance of the driving component. In other words, if your unbuffered preamp has an output impedance of two killaohms, then the amp must show a minimum impedance of 40K ohms. Lower impedance of the driving component and/or increased impedance of the receiveing component is considered better still. Again, there are combinations that sound good and are out of these parameters and there are some rare amps and preamps designed to have exactly the same impedance, but only when used with components from the same manufacturer. But why not then just design for a buffered output. Sometimes it requires more circuitry which adds another stage, some feel the shortest route is the best.