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using the 'Superbal' electronic circuit designed by Ted Fletcher in the mid
70's. The circuit gives excellent rejection of electrical interference.
On the front of the unit there is an unbalanced 'instrument' input designed
with gain and impedance specifically for guitars or basses. Use of this
socket disables the rear inputs (both mic and line).
BALANCED AND UNBALANCED
The JOEMEEK Studio Channel is designed to be used in the best studios
where most (if not all) interconnections are 'balanced'. Balanced operation
means that the audio is carried on two wires working in opposite phase.
Then should any interference appear on the 'line' , it will be effectively
cancelled out.
Both of the main inputs (Microphone and Line) and the four main outputs
(two per channel) are balanced to get best advantage from true balanced
operation; but unbalanced operation (for line level signals) will NOT
degrade the performance due to a new type of balanced output stage.
OPERATING THE MICROPHONE AMPLIFIER
·
Press in the 'MIC/LINE' switch. (in for MIC and out for LINE).
·
Turn the INPUT GAIN knob down to minimum then, If you are using
a capacitor microphone, plug in the microphone, then switch on the
phantom power by pressing in the 'Phantom' switch. (Do it in that
order). NOTE.Some phantom powered microphones take several
minutes to reach correct working conditions. Remember to switch on
at least 5 minutes before using the microphone.
·
Turn up the INPUT GAIN until sound registers on the VU meter (VU
switch in). Do not let the VU needle hit the end stop too hard or
overload may possibly happen. The meter electronics has been
adjusted so that it is normal for the needle to move in the red area.
OVERLOAD MARGIN AND THE VU. METER
The 'TwinQ' is set up so that when the output gain control is set to '0' and
the meters are indicating '0', then the output is '0' dBu (0.775V rms).
Moving the output gain control to maximum will give an additional 4 to 6 dB
of level output, the meter reading will stay the same. This system; called
'input' metering, makes the 'TwinQ' very flexible for driving into different
types of mixer/recorder which may require different input levels.
6
VU METERS
.
'VU' (or Volume Unit) meters were designed originally so that the indication
on the meter was a good measure of the perceived 'loudness' of the sound.
While this type of meter is very popular in professional studios, and is very
easy to use, it must be remembered that while it shows 'loudness', it does
not necessarily show peak level or 'overload' point. The VU meter tends to
under-read (show a lower level than is actually present), on signals that
have a high transient content (speech particularly). Typical under-reads
are; piano 6dB, guitar 2dB, human voice singing 4 to 7dB, human voice,
speech 10 to 14 dB. While the 'TwinQ' has been designed with enormous
overload margins specifically to allow for perfect transient response, (even
when operated heavily 'in the red' the 'TwinQ' will not distort), this may not
be so for the next equipment in the recording chain, so be careful to watch
for overloads in any equipment following the 'TwinQ'.
Both microphone and line input amplifiers are 'CS' type. 'CS' stands for 'Current
Sensing'.
Conventional microphone amplifiers amplify the voltage generated across the input
impedance of the amplifier. The sound is heavily affected by cable quality, length,
capacitance and many other factors. The Current Sensing amplifier directly
converts the coil current into usable audio so that the sound from the microphone
amplifier is exactly the same as the sound at the microphone head; without the
distortions and losses of cable, connectors and odd impedances.
THE INSTRUMENT INPUT
Each of the channels has a jack socket on the front panel labelled
'instrument'.
This is a high impedance high gain input designed specially for 'passive'
(without pre-amplifier) instruments like Fender Jazz/Precision bass, most
Fender guitars, Gibson guitars, in fact, almost any musical instrument.
Some instruments (Yamaha basses etc) have built-in pre-amplifiers and
they sometimes work better when plugged into the rear 'line in' jack socket
where the amplification is lower.
The Instrument input is capable of amplifying very low-level signals so
please take care to keep the volume control to minimum when plugging or
unplugging instruments.
twinQ
CS
Dual Recording Channel
- User's guide
