Buzz Audio qsp-20studio mic preamplifier - Manual (Page 4)

④
Instrument Inputs
Tip (T) = Signal + (hot)
Ring (R) = Signal ground (shield)
Sleeve (S) = Signal ground (shield)
The QSP mic input is intended for use with microphones only, and connection of
other sources is not recommended. It is important that the pin 1 (shield) is used
and terminated at both the microphone and QSP ends of the cable.
The pin1 connection of the Line out is not part of the audio path, and is
provided to shield the interconnecting cable. Leaving pin 1 free at one end of
the cable can help reduce earth loops with other equipment.
The ¼” jack sockets are intended for use with instrument pickups. You can also
connect the output from keyboards and drum machines, but watch the output
level as these devices can potentially overload this input.
Please Note, inserting a jack into the ¼” sockets automatically selects this input
to the channel as labeled, and the rear mic input is disconnected.
4] Controls and Indicators
As you’ve no doubt guessed by now, there are four identical preamp channels
provided in the QSP, we will discuss the operation of Channel 4.
GAIN
This 41 position stepped pot sets the amount of gain (or volume) applied to the
microphone or instrument input, and is adjustable from 22dB to 70dB.
0dB/-20dB
This switch introduces a 20dB pad at the microphone input for use when you
have high level inputs coming from your microphones (such as from micing up
drum kits) and you need less gain than that provided on the GAIN control.
Please Note – the 0dB/-20dB switch is placed right at the input of the QSP’s
amplifier stages and it does cause a click on the output when activated. Turn
down the GAIN control or MUTE the channel before operating this switch to
minimize the volume of the click.