Joemeek twinQ2 Dual Studio Channel - Manual (Page 2)

JM47 Description
The JM47 is a very high quality true capacitor microphone with
FET impedance converter and transformer output. (NOTE, this
is NOT an electret microphone).
The capacitor element is manufactured to the classic ‘centre
electrode’ design which provides smooth extended frequency
response without low frequency boominess. Quality is further
enhanced by using dynamic feedback actually at the capacitor
element. This original technique eliminates distortions which
can occur when using this type of microphone for high volume
levels.
The capacitor membrane is microfine ‘mylar’ with gold sputter-
ing, voltage polarised by phantom power.
The microphone body is made of brass with double screening
of the transformer. Connection is via screened balanced audio
cable with 3 pin XLR connectors.
Care of Your JM47
Although the ‘mylar’ membrane on the capacitor is more robust
than the gold foil used by the German originals of the 1930s, it
is still extremely fine and liable to damage if mishandled. There
are two safety factors that MUST be remembered when han-
dling these microphones:
1) Keep the microphone dry.
2) Avoid wind or air blasts directly onto the capsule.
All electronic equipment should be kept dry, but it is even more
important to avoid any damp conditions when using high quality
capacitor microphones.
Damp can cause partial short circuits in the polarising voltage,
this will cause crackling noises and low output.
The most important instruction for capacitor microphones is
NEVER blow at the capsule. Damage caused by blast of air
on the capsule are often permanent and require the complete
replacement of the capacitor element (capsule).
Never use the microphone in the open air without substantial
wind protection.
Warranty
The JM47 is warranted from defects for a period of 1 year, parts
and labor. Register for your warranty at www.joemeek.com.
Operation
The JM47 is capable of handling very high sound volume levels
so it can be used safely close to musical instrument amplifiers.
If the amplifier sound is very loud, this may overload the micro-
phone amplifier. A 10dB pad switch on the microphone elimi-
nates this problem. It is also a very low noise microphone and
suitable for voice recording to the highest quality.
For voice recording, avoid singing directly into the capsule un-
less an efficient pop shield is used. Occasionally when close
microphone techniques are used in the studio, an excess of low
frequencies occur. The microphone is fitted with a high pass
filter to minimise this effect.
Problems
Should the microphone accidentally become damp and fail to
operate properly (start crackling, or go very quiet) then place
it in a warm and very dry environment for 24 hours. The ideal
environment is an airing cupboard.
The JM47 is extremely resistant to physical damage, but if the
microphone fails to work after being dropped, it should be re-
turned in adequate packing to the supplier. A double test and
inspection system means that manufacturing faults are almost
unknown but should any fault occur, it will be repaired (or re-
placed) free of charge excepting where the fault has been
caused by physical damage.
Connecting Up
Using a high quality balanced and screened audio cable, con-
nect the microphone head to the microphone amplifier input and
switch on the 48V phantom power. NOTE, the microphone will
not operate unless 48V phantom power is provided.
The microphone should be powered up for at least one minute
before it will operate correctly as the polarising voltage on the
capsule needs to stabilise.
Some background noise is possible during the first few seconds
after switch on.
Keep the gain controls on the microphone amplifier or mixer
well down as the output from the microphone is high (as most
capacitor microphones).
Warranty
Using the JM47
The JM47 is supplied with an elastic shock mount system.
Although the microphone is not particularly susceptible to
sounds transmitted through the case, it is advisable to use
this shock mount wherever possible.
To further improve the performance of the mount, it is possible
(but certainly not essential) to remove the wire clips (normally
used to open the microphone holder), this allows the micro-
phone more movement in the elastic mount.
The response of the microphone is CARDIOID, this means
that it is very much more sensitive to sounds from the front
than from the rear. The front of the microphone is indicated by
the JM47 logo. To get the best quality, be sure that the sound
source is in line with the front of the microphone.
To get the classic early capacitor microphone voice sound,
the singer should sing very slightly across the front of the
microphone at a distance of 150 to 200mm from the micro-
phone. The microphone amplifier should be of the highest
quality such as a Joemeek microphone amplifier.
Specification
Cardioid only capacitor microphone with FET impedance con-
verter and transformer output. Power required, 48V phantom
approx. 1mA.
Frequency response substantially flat 20Hz to 20KHz.
Sensitivity approx. -36dBV
Output impedance 200 ohms transformer balanced.
Recommended load impedance 2Kohm.
Signal to noise ratio 74dB.
Dynamic range 126dB
jm47 manual.indd 12/9/03, 2:52 PM 2