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Use the Auto setting when the signal has varying characteristics (long decaying notes 
alternating with quick notes, mix material, etc.) 

Type Switch 

This switch covers one of the more unique features of the Pro Channel.  In the “out” 
position (Optical), the Pro Channel’s compressor employs the award-winning Vactrol®-
based compression element from our Pro VLA.  Switching to the “in” position engages 
the dual-triode variable-mu control element.  This circuit is capable of considerably 
faster attack and decay times than the optical circuit.  However, when the Attack & 
Decay times are set to very long time constants, the shared detector circuit will 
dominate, and the two types will behave in a very similar manner.  Experiment with the 
two types to become familiar with how they react to different source material. 

Compressor Bypass Switch 

A Bypass switch is included on the compressor circuit to enable you to remove the 
compressor from the signal chain.  When set to its “in” (Bypass) position, signal is 
allowed to pass from the preamp circuitry to the equalizer circuit with no compression.  
The LED will glow red when Bypass is engaged.  In its “out” (Norm) position, the 
compressor is active.  Also, when the compressor is bypassed the gain reduction LED 
display (under the VU meter) will still operate, but at a much dimmer level.  This is to 
remind you that the compressor is out of the signal path, but still gives you an indication 
how much compression will result when the compressor is engaged.   
Use the Bypass switch when setting the compressor’s output level to achieve unity gain.  
Unity gain is achieved through the compressor when the active level is the same as the 
bypassed level.  Toggle the switch between Active and Bypass while adjusting the 
Compressor Output level.  Once the levels are the same (use your ears and the VU 
Output Level meter), you’ve reached the unity setting for the compressor. 

Compressor Output Level Control 

The Compressor Output level control sets the output level from the compressor circuit.  
Typically, the output level of a compressor is used to add gain to compensate for the 
amount of compression applied to a signal.  The output level is set to achieve unity gain 
(no apparent level change when the compressor is active or bypassed).  

See Compressor 

Bypass Switch for more details on achieving unity gain.  

 

When the control is fully counter-clockwise, the output is off.  Turning the control 
clockwise increases the level to a maximum of +20dB of gain.  While you can use the 
compressor to add gain to a signal, it is better to add gain 

before

 the compressor for the 

best signal to noise ratio.  If you want to use the compressor to add more gain, use the 
VU meter to monitor the Pro Channel’s output level, or use the meter on your recorder 
or mixer to make sure you won’t clip the next piece of equipment in the chain. 

- 11 - 

Содержание Pro Channel

Страница 1: ...HNOLOGY Inc 215 TREMONT STREET ROCHESTER NEW YORK 14608 USA 716 436 2720 Voice 716 436 3942 Fax Internet http www artroch com E mail art art com Pro Channel Professional Tube Mic Preamp Compressor Equ...

Страница 2: ...Pro Channel PROFESSIONAL TUBE MIC PREAMP COMPRESSOR EQUALIZER USER S GUIDE...

Страница 3: ...S INDICATORS 7 PREAMP CIRCUIT 7 Gain Control 7 Gain Switch 8 Phantom Power Switch 8 Phase Switch 8 Tube Drive Gain Reduction Display 9 Preamp Output 9 COMPRESSOR CIRCUIT 10 Threshold Control 10 Ratio...

Страница 4: ...VU Meter 15 VU Meter Switches 15 Power 15 REAR PANEL CONNECTIONS 15 INPUT AND OUTPUT CONNECTIONS 15 Input 16 Output 16 LOOP INSERTS 16 Preamp Compressor Loop 16 Compressor EQ Loop 16 Loop Connections...

Страница 5: ...s A solid state input circuitry Both electro optical and variable mu compressor designs Tube based semi parametric four band equalization with selectable frequency ranges and Q Three hand selected tub...

Страница 6: ...ign Notes The Pro Channel is a multi purpose tool for audio engineering and recording Enclosed in a two rack space 2U chassis are three independent circuits featuring a tube based analog preamplifier...

Страница 7: ...rotect the unit during initial shipment Please retain this carton for use in transporting the Pro Channel or in the unlikely event that you need to return your Pro Channel for servicing AC Power Hooku...

Страница 8: ...o produce a thump on power up and power down Note Like all tube based equipment the Pro Channel needs to warm up before being used Allow one to two minutes for the tubes to reach proper operating temp...

Страница 9: ...leaking from a tire when phantom power is disconnected but some can make some very nasty low rumbles and whines as well Another Note MOST dynamic microphones should not be affected or damaged if they...

Страница 10: ...g for a range before it turns into a distortion box After some use you ll find that the sweet spot of the Pro Channel is when this light flashes fairly regularly and the top red LED flashes occasional...

Страница 11: ...ery mild and musical compression ratio which is ideal for smoothing all types of signals At its maximum position the compression ratio is greater than 10 1 This is typically called hard limiting as it...

Страница 12: ...is to remind you that the compressor is out of the signal path but still gives you an indication how much compression will result when the compressor is engaged Use the Bypass switch when setting the...

Страница 13: ...s as range of 12dB Two ranges are selected with the Low Shift Switch 40Hz or 120Hz 40Hz is great for enhancing sub low frequencies such as those in bass guitars and kick drums Cutting 40Hz can also he...

Страница 14: ...h The Hi Mid Shift x 10 switch determines the range over which the Hi Mid Frequency control will cover In its out position the range is set at 200Hz to 2KHz In its in position the range is set at 2KHz...

Страница 15: ...qualizer circuit to enable you to remove it from the signal chain When set to its in Bypass position signal is allowed to pass from the compressor circuitry to the output tube section with no equaliza...

Страница 16: ...hand switch is set to Output the left hand switch has no effect Another Note The internal level monitoring points correspond to the level at the Send jacks of the two insert loops If you are using eit...

Страница 17: ...ack is inserted The loops may also be utilized to re patch the compressor and equalizer circuits in a different order i e signal flow preamp to equalizer to compressor Preamp Compressor Loop A loop is...

Страница 18: ...microphone instrument or line level source To use the Pro Channel as a mic or line preamplifier only simply press the Bypass switches to bypass the compression and equalizer circuitry Plug a microphon...

Страница 19: ...rument can be fixed by simply isolating the bad frequency and pulling it out After you determine approximately where the problem area is in the instrument highs lows mids isolate the track and boost o...

Страница 20: ...ever be sure to have output and monitoring levels turned DOWN before testing the sound Remember you have a great amount of gain available in the Pro Channel Grounding Connecting several pieces of equi...

Страница 21: ...Block Diagram 20...

Страница 22: ...s 3sec program dependent Maximum Compression 30dB optical 23dB vari mu EQ Frequency Bands Low Shelf 40Hz 120Hz selectable Low Mid Sweepable 20Hz to 200Hz 200Hz to 2KHz Shift out in Low Mid Q Wide Narr...

Страница 23: ...paid delivery to the factory service department or an authorized service center accompanied by proof of purchase date in the form of a valid sales receipt EXCLUSIONS This warranty does not apply in th...

Страница 24: ...ization RA number 4 Pack the unit in its original carton or reasonable substitute The packing box is not recommended for a shipping carton Put the packaged unit in another box for shipping Print the R...

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