19" wide and 1 3/4" high, telephone interface that compliments the remote broadcast telephones to get the most from
ordinary dial-up telephone lines. Has low and high frequency equalizer controls. Works
very well for on-air talk shows and for recording audio in production studios.
The ZH-2 Telephone Hybrid will accept mix-minus (send) audio input levels from -42 DBM to +20 DBM on
an active balanced/unbalanced input. Audio output is also active balanced and is
adjustable from zero to +20 DBM at clipping. Caller frequency response
is 300 Hz to 3 KHz +/- 1.0 DB. The front panel low and high frequency
equalizers offer +/- 8 DB at 300 HZ and 3 KHz to make the
caller sound more natural. Audio distortion is 0.2%
or less and noise is at -80DBM. Trans-hybrid null is 10 to
25 DB depending on the telephone line. A receive filter improves
recovered audio signal to noise. The filter response is -24 DB at 60 Hz,
-9 DB at 100 Hz, and -35 DB at 10 KHz as referenced to 1 KHz.
This is an analog product. It connects to a telephone line either with
an internal high-quality line transformer, or with a capacitor in series
with that transformer. This capacitor is also internal. These two
configurations allow the hybrid to terminate and hold a telephone line or
bridge onto a line, which might be held by another device like a
telephone. Connections are made via a screw terminal strip at the rear
of the hybrid.
There is a
"conference" feature, which was put in the original design, to allow two
hybrids to conference/exchange audio between two telephone lines.
However, it does not work as well as expected so it is not recommended that hybrids
be connected in this manner.
in .pdf: Main
Circuit add-on The Ducking Circuit is included in all hybrids sold
nowadays. February 15, 2017 update:
The threshold point of the ducking circuit can be desensitized by 11 dB when
a 1 meg ohm/1/4 watt resistor is added in parallel with R1, a 3.3 meg ohm
resistor, on the Ducking Circuit board. This will decrease the chance
of accidental caller gain reduction when there is room noise in a broadcast
studio while the announcer's microphone is turned on.
ZH-2 Telephone Hybrid carries a one-year parts and labor warranty. If
you get a unit and decide it is not right for your situation, you may return
it for refund, minus the shipping costs, within 30 days of purchase. A
refund assumes the unit has not been damaged or modified in any way.
$199.00 plus shipping and tax.