by Dennis Bohn
[Editor: This note specifies the Rane HC6 Headphone Console, but is applicable to other similar products.]
The Model HC 6 Headphone Console is a six channel headphone amplifier, consisting of six stereo amplifiers, two master stereo inputs and six individual stereo inputs. The two master stereo inputs feed a separate left and right bus to each of the six headphone amps (see Figure 1). In addition, there are individual stereo inputs to each headphone amplifier that disconnect that particular amp from the master stereo bus and allows a separate mix to be used. From time to time, we are asked if the HC 6 may be config-ured for use as a balanced line distribution amplifier. The answer is, yes, with a special input jack arrangement.
The requirements for using the HC 6 as a balanced line distribution amplifier are that the input drive must be a balanced (or floating;) mono signal. It will not work with a stereo balancedpair or an unbalanced mono signal.
The trick is to wire a special input jack assembly per Figure 2. What is required is for the tip of the input jack to feed the tip of one of the input males and the RING of the other. And for the ring of the input jack to feed the ring of one and TIP of the other. What this does is drive the two inputs with opposite polarities, such that the left input is driven positive while the right input is driven negative, and vice-versa . This causes all of the left headphone amps to drive the output lines positive while all the right headphone amps drive the other side of the line negative, and vice-versa. Which creates six balanced line drivers, all fed trom the one common input line. So, with this special input jack, the HC 6 is now configured as a one-to-six distribution amplifier.
c. 1983, Rane Corporation.
From Rane Corporation Site. (Republished with permission.)