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Joemeek VC1QCS Скачать руководство пользователя страница 8

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2. THE COMPRESSOR

And now for the part of the JOEMEEK Studio Channel that gives it
character; - the compressor.

The compressor is a photoelectric device where the sound triggers light
emitting diodes which in turn control the resistance of a photo sensitive
resistor. This form of compression used to be common in the 60's and 70's
but has been superseded by so called 'improved' voltage controlled
amplifiers. The advantages of the older system are that distortion is virtually
nil, noise is extremely low while overload margin is extremely good. The
disadvantages are that the design is more difficult to produce cheaply and,
according to those who judge equipment by specifications and not by
listening, the older design is less flexible in operation and ‘more difficult to
use’. JOEMEEK begs to differ!

Using 1990's electronics for the control circuitry, Ted Fletcher has recreated
the compressed sound of the 60's; a sound that was unlikely ever to be
heard again. Totally unlike a modern compressor, it can pull voices forward,
help with internal mix balance, and add 'presence' to the sound as well as
controlling recording volume levels. But its main and unique attribute is its
ability to produce the characteristic 60's compressed exciting sound without
losing the transient sparkles that are such a feature of good digital
recording.

THE COMPRESSOR; TECHNICALLY

To get the best use out of the compressor it is necessary to understand the
basic physics and what it is designed to do.
A LIMITER is a device which stops the output of a signal path going above
a predetermined level.
A COMPRESSOR is a device which reduces the dynamic range of
programme material.

WHAT IS A COMPRESSOR?

A perfect compressor is an amplifier where the input/output ratio is
constant: So using a 2:1 compressor, increasing the input by 2dB gives a
corresponding 1dB increase in the output. Early compressors which used
variable mu thermionic tubes or photoelectric devices only approximated
true compression over a limited range. They had a soft 'threshold' where
compression started and held to a predictable ratio up to a certain level,
then they returned to a more linear amplification allowing transients

VC1Q

CS

Studio Channel

- User's guide

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Содержание VC1QCS

Страница 1: ... If it sounds right it is right Joe Meek 1964 CurrentSense mic instrument pre amp photo optical compressor enhancer de esser Meequalizer JOEMEEK C O M P R E S S I O N C O M P R E S S I O N VC1QCS Studio Channel User s guide ...

Страница 2: ...1 VC1QCS Studio Channel User s guide ...

Страница 3: ... amplifier 10 4 Meequalizer 11 5 The enhancer 11 Using the enhancer 12 Connecting up the equipment 13 Front panel controls 14 Technical specification 15 Digital Upgrade 18 Regulations and safety 19 Warranty Ted Fletcher This instruction book was written by Ted Fletcher the designer of the original JOEMEEK compressor and the whole JOEMEEK range of professional audio equipment Ted worked in the stud...

Страница 4: ...bout a volt This function is not too difficult and the microphone amplifiers on normal professional mixers do it quite well BUT they cut costs and corners The JOEMEEK Studio Channel has an uncompromising approach it uses JOEMEEK s latest current sensing microphone input allowing the use of virtually any microphone type while providing fantastic frequency response and the lowest possible noise and ...

Страница 5: ... meter is reading 3 there is a further 22dB available before distortion takes place Similarly remember that the output level from the VC1Q can be very high so keep the gain settings of following equipment set low This also applies to monitoring settings PHASE SHIFT and QUALITY It s Fletcher Company theory that big sounds are only possible if the recording channel keeps the response and phase of th...

Страница 6: ...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 line input BALANCED AND UNBALANCED The JOEMEEK Studio Channel is designed to be used in the best studios where most if not all interconnections are b...

Страница 7: ...rmal for the needle to move in the red area OVERLOAD MARGIN AND THE VU METER For steady tones the 0 on the VU meter corresponds to 0dBu Where 0dBu is 0 775v RMS on the line output with the output control set at 0 This setting of 0 is to allow for the considerable under read that occurs with all VU meters with music signals It is normal for the peaks of signals to go to 10dBu while the VU meter rea...

Страница 8: ...ll voices forward help with internal mix balance and add presence to the sound as well as controlling recording volume levels But its main and unique attribute is its ability to produce the characteristic 60 s compressed exciting sound without losing the transient sparkles that are such a feature of good digital recording THE COMPRESSOR TECHNICALLY To get the best use out of the compressor it is n...

Страница 9: ...ompressor set the COMPRESSION control to somewhere near full up Set SLOPE to number 4 Set ATTACK to minimum full anticlock you can increase this setting to achieve more interesting compression effects Set RELEASE to halfway the release control at this setting will make the compressor act to moderately control the gain at higher the settings sudden loud noises will cause the signal to remain compre...

Страница 10: ...iven hard before the gain has been controlled by the light cells The cells catch up and overcompress momentarily giving a tiny dip immediately following the start of the note This is best demonstrated when recording drums With Slope set to maximum and attack and release to fastest Used sparingly this can contribute to musical drive Slower attacks are used where the compression needs to be less obv...

Страница 11: ...l and readjust the microphone amplifier gain 4 I can t make the compression gentle enough It takes practice The setting of the Attack control close to fastest is quite critical as is the compression control Also longer release times lead to a less noticeable compression effect 3 THE GAIN MAKE UP AMPLIFIER The JOEMEEK compressor is essentially a passive piece of electronics That means that under co...

Страница 12: ...lving lift and cut of up to 15dB at 8KHz When using the equaliser bear in mind that lifting any EQ will increase the volume level in the channel and so can reduce the overload margin Be prepared to turn down the input gain to compensate 5 THE ENHANCER WHAT IS AN ENHANCER An enhancer or exciter adds a particular type of sparkle to sounds particularly voices It appears to create brightness from soun...

Страница 13: ...rmonic after the syllable that created it CAUTION If in any doubt at all leave enhancement till the mixdown its easy to put on but impossible to take off NOISE IN THE ENHANCER Under many normal conditions of use the enhancer has the effect of amplifying selected narrow frequency bands in the upper mid range The danger is always to overuse the enhancer This has the effect that any noise sounds part...

Страница 14: ... whether balanced or unbalanced The line input is disabled when mic is selected by the mic line switch and vice versa INSTRUMENT INPUT FRONT PANEL The instrument input is high impedance unbalanced and is suitable for any instrument output or line level signal from unbalanced equipment INSERT POINT This is used to insert another effect or outboard equipment into the Studio Channel The microphone li...

Страница 15: ...rumbles A green LED shows that it is in circuit PHASE SWITCH reverses the phase of the VC1 any input This is useful to correct for some microphone placements in the studio INPUT GAIN is a rotary control which sets the electronic gain of the front end of the VC1 It operates on mic in and line in COMP SWITCH switches on the compressor and the blue LED COMPRESSION is a rotary control that sets the am...

Страница 16: ...ng effects EQUALISER MeQ switches the Meequalizer into and out of circuit An LED shows when the EQ is in circuit LF gives low frequency lift and cut MF give mid frequency lift and cut Mff sets the frequency of the mid control HF gives high frequency lift and cut OUTPUT sets the main output volume level of the VC1 It does NOT change the reading on the VU meter it is connected after the meter TECHNI...

Страница 17: ...ic predominant AMPLITUDE FREQUENCY RESPONSE Line in 6Hz to 20KHz within 0 5dB Mic in 8Hz to 20KHz within 1dB High pass filter 3dB down at 75Hz 12dB per octave FILTER Push button high pass filter switch and indicator operates at 75Hz at 12dB per octave OUTPUTS High level balanced 50 ohm 4dBu for 0VU variable Max balanced output approx 26dBu Insert Tip and Ring jack socket 400 ohm 10dBu output 22K o...

Страница 18: ...ency controls 8K and 100Hz Mid frequency cut boost control Mid frequency centre control 1KHz 4KHz Bypass switch with indicator Cut boost levels approx 15dB POWER 3 4 Watts IEC socket for power cable Reversible fuse holder for 230VAC and 115VAC power input HOUSING 2U rack mounting totally enclosed aluminium case depth approx 250mm weight 1 5Kgs VC1QCS Studio Channel User s guide ...

Страница 19: ...io Channel VC1Q Controls The VC1QD offers simple operation A basic rate selection of 44 1 48k on a pushbutton and a x2 pushbutton enabling higher sample rates Headroom is plentiful with full 24bit resolution Capturing highly dynamic material is no problem AES EBU connection is also no difficulty as the output from the upgrade module is transformer balanced Output S PDIF 24bit at 44 1 48 88 2 96KHz...

Страница 20: ...an Common Market the CE symbol on the rear of the unit indicates compliance In the United States of America the compressor utilises UL approved components and complies with UL requirements WARRANTY In the unlikely case of a breakdown please return the unit in its original packing through the supplier The unit will be attended to immediately and returned to your supplier If any breakdown occurs exc...

Страница 21: ...by FLETCHER Electroacoustics Ltd St Mary s Barton Road Torquay Devon TQ1 4DP ENGLAND Tel 44 0 1803 321921 Fax 44 0 1803 321922 e mail sales joemeek net DECLARATION OF CONFORMITY This analogue audio processing equipment conforms to the standards and requirements of the European Economic Community The EC Harmonised standards that have been applied are a Electrical equipment safety Regulations 1994 S...

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