Tube Channel Owner`s Manual
Contents
1. flavor textures experiment with the Tube Channel Overdriving the preamp compressor and equalizer circuitry can add interesting textures when blended with vocals and other instruments Placing signals purposely out of phase can also yield interesting results No harm will come to the Tube Channel with this type of experimentation However 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 Tube Channel EQ Tips mud Electric Guitar ring power bees impact power Bass clack meat Snare Drum crack thud Kick Drum click boxy Drum Overheads sizzle boxy Vocals sibilance air open Piano Organ SS 20Hz 100Hz 250Hz 500Hz 800Hz 1KHz 2 5KHz5KHz 10KHz 18KHz 20KHz What is the best way to use EQ There are two schools of thought on EQ 1 Use as much as you need to make things sound good 2 Don t use any EQ Most people follow the suggestion of if it sounds good it is good You need to use your ears and judge for yourself as their are no steadfast rules for EQing Here are a few pointers to guide you Always tweak the instrument you are EQing while listening to it in the mix EQ ing an instrument when it is soloed doesn t give you a good re2. air band While there aren t very many instruments that contain 18KHz information directly many instruments and mixes contain upper harmonics which can add extra definition and space when boosted Cutting at 18 KHz can decrease hiss and noise High Shift Switch The High Shift switch selects the corner frequency of the High Frequency control In the out position the corner is 18KHz In the in position the corner is 6KHz Note The High Frequency and Hi Mid Frequency controls overlap This feature gives you the ultimate in flexibility For example on cymbals try boosting 18KHz with the High control while cutting 20KHz with the Hi Mid control for a very bright yet noise free result EQ Bypass Switch A Bypass switch is included in the equalizer 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 jacks with no equalization The LED will glow red when Bypass is engaged This informs you that the equalizer is bypassed In its out position the equalizer is active Use the EQ Bypass switch when setting the Tube Channel s output level to achieve unity no boost or cut gain through the equalizer circuit Unity gain is achieved when the active level is the same as the bypassed level Master Output Level Control The Master Output level control sets the output level of the Tube Channel When the
3. Input 1 67k ohms XLR ohm 14 600 ohms XLR 300 ohms gt 15dBu XLR 21dBu 27dBu XLR 22dBu 90dB typical lt 0 1 typical Two Hand Selected Tubes 12AX7A 12AT7 100 125 VAC 25W Export units configured for country of destination T retains a policy of constant product improvement R T reserves the right to make changes in design or make additions to or improvements upon this product without any obligation to install the same on products previously manufactured In other words specifications are subject to change without notice Designed and manufactured in the United States of America Applied Research and Technology Inc 716 436 2720 Phone 22 215 Tremont Street 716 436 3942 FAX Rochester NY 14608 USA We re on line For Product information questions applications tips answers and general discussion with A R T employees look for A R T on the Internet Email us at artroch aol comCheck out our Web Page at http www artroch com Warranty and Service Information Limited Warranty Applied Research and Technology Inc will provide warranty service for this unit in accordance with the following warranty statement Applied Research and Technology Inc A R T warrants to the original purchaser that this product is free from defects in workmanship and materials for a period of three years from the date of purchase A R T will without charge repair or re
4. control is fully counterclockwise there is no output Turning the control clockwise increases the level of the output to a maximum of 10dB of gain When setting the Output Level control refer to the VU Output Level meter or the level meter on your recorder or mixer Phase Switch The Phase switch is provided to reverse the phase of signal leaving the 13 Tube Channel s XLR Output jack The Phase switch also reverses the polarity of the Output jack In the Normal out position the signal is in phase In the Reverse in position the polarity of Pins 2 and 3 and the Tip of jack are reversed and the signal is changed to 180 degrees out of phase with the input signal In multiple microphone applications the placement of the microphones can affect the phase of a signal If two microphones pick up the same signal from different locations the result can be a hollow or frequency shifted sound In some cases it may sound as if an instrument disappears if it happens to be 180 degrees out of phase Depressing the Phase switch can remedy this problem Likewise if a microphone cable is wired incorrectly the signal will be also out of phase Note In single microphone applications switching the phase will produce no audible change in the output signal Output Level VU Meter A backlit average reading VU meter is provided to accurately monitor the output level of the Tube Channel The 0 level is calibrated to 4
5. dual concentric pot there are two controls one outer and one inner The outer control is used to select a frequency while the inner control is used to apply 12dB of gain The Hi Mid control can cover two frequency ranges depending on the position of the Shift x 10 switch These ranges are 200Hz to 2KHz and 2KHz to 20KHz Hi Mid Shift x 10 Switch 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 to 20KHz Note The Lo Mid and Hi Mid Frequency controls overlap in the 200Hz to 2KHz range This feature allows either or both controls to be used in this range This is extremely useful if you want to cut at 200Hz and boost at 350Hz High Frequency Control The High Frequency control adjusts a shelving filter with a selectable corner frequency of either 6KHz or 18KHz The high shelving filter affects all frequencies above the corner frequency when applying boost or cut In other words cutting at 6KHz also cuts 7KHz 8KHz etc 12 The High Frequency control has as range of 12dB The two ranges are selected with the High Shift switch 6KHz is great for adding top end to guitars snare drums and vocals Cutting 6KHz can also help to take the edge off brittle or harsh sounding instruments 18KHz may be used to add sizzle to cymbals and is generally referred to as the
6. way to use EQ essences 19 TUBE REPLACEMENTT ccccccssssssssssssssssssscssscssssssccccccccccceees 20 BLOCK DIAGRAM ccccsssssssssssssssscsssssssscccccccccccsssssssssssssssenees 21 A R T TUBE CHANNEL SPECIFICATIONS 22 WE RE ON LINE cccccccccssccrcssccscsscssccsccsssscccccccscccccccccccccsccees 23 WARRANTY AND SERVICE 23 LIMITED WARRANTY 23 SERVICE E A Ea 23 Features The Tube Channel is a unique product It contains three independent award winning circuit designs one of the finest tube microphone preamplifiers available one of the finest optical tube compressors available and one of the most flexible EQs you ve ever used all in one unit Developed in partnership with studio and live sound engineers the Tube Channel possesses a sound that is not available from any other product on the market at any price The Tube Channel was designed and constructed with the best components assuring a lifetime of quiet reliable performance The Tube Channel offers The award winning A R T SOUND A Tube based mic line preamplifier An Electro optical compressor design A Tube based semi parametric four band equalizer Hand selected preamp tubes VCA less compressor circuitry i e transparent dynamics control Unique tube drive and gain reduction metering VU output lev
7. 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 refer to the output level VU meter or the meter on your recorder or mixer to make sure you won t clip the next piece of equipment in the chain Clip Indicator The Clip LED is located in the equalizer circuit It will illuminate 6dB before the headroom of the circuit is exceeded When this Clip indicator lights the level into the equalizer is too high Turn down either the Preamp Output control the Compressor Output control or the output level of the device plugged into the compressor return insert point Equalizer Circuit The equalizer circuit in the Tube Channel is a tube based semi parametric four band equalizer Each of the bands overlap giving you the ultimate in flexibility The or bandwidth of each of the filters is purposely wide to provide a very musical sound Low Frequency Control The Low Frequency control adjusts a shelving filter with a selectable corner frequency of either 40Hz or 120Hz The low shelving filter affects all frequencies below the corner frequency when applying boost or cut In other words cutting at 40Hz also cuts 30Hz 20Hz etc The Low Frequency control has 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 thos
8. A R T APPLIED RESEARCH AND TECHNOLOGY TUBE CHANNEL USER S MANUAL BEA TURES essscssccsiccscsveseusissedeusasssdeveasesbusessascnsacessunsscevsesessecssausesseves 3 OVERVIEW ccsccsscccsscsccssscseccsscscccssscscesssssscsssscscesssscssessscsessssees 3 WHY USE AN EXTERNAL PROCESSING CHANNEL 3 DESIGN NOTES 4 SETTING 5 UNPACKING 5 AC POWER 5 AUDIO CONNECTIONS E E E 5 INSTALLATI N pe n a E E E E A teen E E E 6 SAFETY FPRECA TI NS 6 POWERING u r 6 FRONT PANEL CONTROLS amp INDICATORS 7 PREAMP ties 7 Gain 1 7 7 Phantom Power 7 Tube Drive Gain Reduction 1 8 Preamp 8 OPTICAL COMPRESSOR 9 Slope SWit hy 9 Died tales 9 Compressor Bypass Switch cccccscccssccesseeeneesescecesseeeseeenneeesaeees 9 Compressor Threshold and Output 10 C
9. ass toms guitar amps voice etc The two sweepable parametric bands and selectable shelving bands have been optimized for musical instruments The two sweepable bands overlap each other and also the high and low shelving bands providing you with the ultimate in flexibility This EQ design gives you all the control you need to effectively alter and dial in great sounds from even the poorest of sources Setting Up Unpacking Your Tube Channel was packed with care at the factory The shipping carton was designed to protect the unit during initial shipment Please retain this carton for use in transporting the Tube Channel or in the unlikely event that you need to return your Tube Channel for servicing AC Power Hookup The Tube Channel has an internal power supply designed to operate at 100 to 125VAC 50 to 60Hz Units manufactured for use outside of the United States have been modified to comply with the required electrical specifications Under no circumstances should the power cable be altered If the cable becomes cut or damaged discontinue use and have it replaced before operating the Tube Channel Audio Connections Audio connections to and from the Tube Channel are balanced XLR Pin 2 Hot Pin 3 Cold Pin 1 Ground and unbalanced 14 Tip Hot Sleeve Ground The insert points between the preamp and compressor and the compressor and equalizer are 4 Tip Hot Sleeve Ground unbalanced connecto
10. controls to provide an appropriate level into the next stage of your system The Tube Channel is ideal for use as a DI box Plug the instrument into either input and use the XLR 1 4 or both outputs to connect to your recorder board or PA system Experiment with different input level settings for different textures In most cases the Tube Channel offers superior performance to the on board preamp on your console To use the Tube Channel instead of your on board preamp simply connect the output of the Tube Channel to the line input of your mixer s input channel Note you can connect the XLR output jack of the Tube Channel to the XLR input of your mixer however most affordable mixers do not allow you to bypass their internal preamp when using the XLR jack You will cause no harm to either unit when doing this but you will probably experience slightly higher noise This is due to the fact that you are now preamplifing your mixer s preamp 17 Note Be certain that you do not connect the Tube Channel s XLR Output to a mixer input that has Phantom Power applied The Tube Channel has enough gain to be used in front of a power amplifier To use the Tube Channel as a instrument preamp simply plug the instrument into the Input jack and connect the Output jack to the input of the power amplifier See Loop Connections for further hook up options and for using single circuits in the Tube Channel Special Effects For industrial metal or just
11. d control sets the point at which the compressor circuit will act on the input signal Turning this control counterclockwise lowers the threshold adding more compression to a signal Turning this control clockwise raises the threshold Setting the Threshold control is dependent on the Preamp Output control or the output of the device plugged into the compressor return insert point The easiest way to set the threshold control is to start with the control fully clockwise After setting the Preamp Output control slowly turn the Threshold control counter clockwise lowering threshold until you see the yellow OdB Threshold LED light in the gain reduction display Now adjust the control either lower or higher until you have the amount of compression you desire Use the Gain Reduction meter as a visual guide to the amount of compression applied Compressor Output Level Control inner 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 change in level when 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 attenuated by 20dB Turning the control clockwise increases the level to maximum of 20dB of gain While
12. dBm with a 600 ohm load on the output using either the XLR or 4 connector Use the VU meter for a visual reference to the signal level leaving the Tube Channel Note When using the Tube Channel into a mixing console or recorder always reference the meter on the mixer or recorder when setting output levels All meters are not necessarily calibrated the same and it is always best to look at the level entering the last piece of equipment in the chain Power The Power switch supplies and removes power from the Tube Channel The Tube Channel should be turned only after all monitor levels are turned down or off to protect against any thumping caused by high gain settings Likewise the Tube Channel should be turned off after turning all monitor levels down The Output Level VU meter will illuminate when power is turned on Rear Panel Connections Input and Output Connections The Tube Channel s XLR connectors follow the AES standard Pin 1 Ground Pin 2 Hot Pin 3 Cold The unbalanced 4 phone jacks are typical Tip Hot Sleeve Ground Input One input jack per channel should be used at a time However because of its design the Tube Channel can be hard wired without having to disconnect the XLR inputs when using the 14 jacks If no load is placed on the XLR input no instrument or microphone connected the 1 4 jack will function as if there was no
13. ding on the characteristics of the input signal Use the fast setting when the signal has repetitive consistent characteristics kick drum snare vocals etc Use the auto setting when the signal has varying characteristics long decaying notes alternating with quick notes mix material etc 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 This informs you that the compressor is bypassed In its out Norm position the compressor is active Use the Bypass switch when setting the compressor s output level to achieve unity no boost or cut 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 Threshold and Output Controls The compressor s Threshold and Output controls are ganged together on a dual concentric pot The outer control is the Threshold level and the inner control is the Output level Compressor Threshold Control outer control The Threshol
14. e in bass guitars and kick drums Cutting 40Hz can also help to clean up mixes that sound muddy or loose in the low end 120Hz is generally the low end for vocals guitars and toms Boosting 120Hz can add weight or beef to a week vocal and cutting it can thin out a signal that takes up too much room in the low end Low Shift Switch The Low Shift switch selects the corner frequency of the Low Frequency control In the out position the corner is 40Hz In the in 11 position the corner is 120Hz Lo Mid Frequency Control The Lo Mid control is a dual concentric pot there are two controls one outer and one inner The outer control is used to select a frequency while the inner control is used to apply 12dB of gain The Lo Mid control can cover two frequency ranges depending on the position of the Shift x 10 switch These ranges are 20Hz to 200Hz and 200Hz to 2KHz Lo Mid Shift x 10 Switch The Lo Mid Shift x 10 switch determines the range over which the Lo Mid frequency control will cover In its out position the range is set at 20Hz to 200Hz In its in position the range is set at 200Hz to 2KHz Note You ll notice the Low Frequency and Lo Mid Frequency controls overlap meaning they cover the same frequencies This is intentional and is one of the powerful features of the equalizer circuit Hi Mid Frequency Control Like the Lo Mid Frequency control the Hi Mid control is a
15. el metering Bypassable compression and equalization circuitry XLR balanced inputs and outputs TS unbalanced inputs and outputs A Custom extruded aluminum chassis unbalanced insert points between the preamp and compressor and between the compressor and equalizer 48V phantom power Phase reversal Over 70dB of gain Detented rotary controls Compression and limiting ratios Selectable release time settings gt 90dB dynamic range An Internal power supply A three year warranty The Tube Channel was Designed and manufactured in the USA Overview Why use an external processing channel The shortest signal path is the best way to get a signal to tape In most cases the shortest path is mic to preamp to compressor to EQ to tape deck The signal doesn t even go through the mixer This isn t a new concept but it has become more relevant with the availability of affordable mixing consoles As their name implies most affordable mixers excel in signal routing and mixing capabilities However they are not necessarily your best option for the actual recording of tracks While their onboard circuitry is nearly always clean and quiet the simple truth is that the Tube Channel has a better sounding and more flexible collection of circuits Mixer manufacturers need to make trade offs to keep prices down while keeping performance up Imagine the price of your mixer if each channels EQ cost over 200 and we re not talking about
16. hannel s preamp At this level the tube is producing an output signal that most would term warm Whatever you would like to call it is fine simmering toasty etc You ll find the output signal has an enhanced bottom to low mid quality with smooth high frequency detail The last LED is labeled Clip This LED will light approximately 6dB before audible distortion occurs If this light flickers don t panic The unique design of the Tube Channel allows the tube to distort well before any other gain stage When a tube goes into distortion it is a gradual process and tends to sound pleasing for a range before it turns into a distortion box After some use you ll find that the sweet spot of the Tube Channel is when this light flashes fairly regularly You may very well find a clipped level is suitable for some applications Note Use the Tube Character Array to aid in setting the Gain Control Preamp Output The Preamp Output control sets the output level of the preamp section of the Tube Channel In most situations be leaving this control set around 12 o clock or its 0 setting The Preamp Output control has a range of no output from its fully counter clockwise position to additional 16dB of gain when turned fully clockwise When setting up the preamp circuit start with the Preamp Output at its 0 level Once you get the Gain control set the way you want it to sound use the Preamp Outpu
17. hannel will result in voiding the warranty 20 55 9 04 6 amp IPPON LNO _ 3 fo Oa Aossaiduiog oe anas gt Boponped u9 Ane ees 1 eqny oA HOV lt 1 dwog 0 A NI dip A v ule ony A A yseyy dwog y 2 SSVdAd T lt y e i a N 2 E 5 O 7 LNO Ag Jossaidwo9 dwuyaig 1055 lt jouueyy NVAOVId Y90174 Tube Channel Specifications Dimensions Weight Maximum Gain XLR to XLR 14 to V4 Phantom Power Compression Ratio Attack Time Release Time EQ Frequency Bands Low Shelf High Shelf Low Mid Sweepable High Mid Sweepable Gain Frequency Band Equivalent Input Noise Dynamic Range Impedance Output Impedance Maximum Input Level Maximum Output Level CMRR THD Tubes Power Requirements 5 25 D x 19 W x 1 65 H 8 0 Ib 81dB 63dB 48v DC switchable 2 3 1 comp 6 1 lim 6 5ms 200ms fast 70ms 1sec auto 40Hz 120Hz Selectable 6KHz 18KHz Selectable 20Hz to 200Hz 200Hz to 2KHz 200Hz to 2KHz 2KHz to 20KHz 1 1 12dB 129dBu XLR to XLR A wghtd gt 90dB no weighting
18. hone s documentation to see if phantom power is required to power it Phantom power is turned on and off with this switch and supplies power to pins 2 and 3 of the XLR input jack Note It is best to have phantom power turned off when connecting microphones to the Tube Channel Note Be sure to turn down or mute the output of the Tube Channel when engaging or disengaging phantom power Additionally when disengaging allow 30 45 seconds for the power to completely dissipate Most microphones will make a sound like air 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 are plugged into the Tube Channel when phantom power is turned on we haven t run across any However if the mic doesn t need it don t use it Some things are best left untested Tube Drive Gain Reduction Display Four LEDs display how the tube gain is affecting the input signal These LEDs are calibrated with the tube circuitry to give you an accurate representation of the tube s output signal Note these LEDs measure the signal level before the output level control Use this meter as a visual guide for setting the Gain level The first LED is labeled Cln The tube is producing a clean output when this LED is lit The next two LEDs are labeled warm This is the optimal operating range for the Tube C
19. ircuit The Preamp Send jack is located directly after the Preamp Output level control This jack may be used to send an unbalanced signal directly to an input of a recorder mixer or other piece of outboard equipment The Compressor Return jack is located directly before the Threshold Control of the compressor circuit This jack may be used to connect the output of a piece of equipment to the input of the compressor circuit in the Tube Channel Since there is no input level control to the compressor in the Tube Channel the piece of equipment in the insert loop should have level matching capabilities 1 an output level control Compressor EQ Loop A loop is provided between the output of the compressor circuit and the input of the equalizer circuit The Compressor Send jack is located directly after the Compressor Output level control This jack may be used to send an unbalanced signal directly to an input of a recorder mixer or other piece of outboard equipment The EQ Return jack is located directly before the input of the equalizer circuit This jack may be used to connect the output of a piece of equipment to the input of the equalizer circuit in the Tube Channel Since there is no input level control to the equalizer in the Tube Channel the piece of equipment in the insert loop should have level matching capabilities 1 an output level control Loop Connections To use only the preamp of the Tube Channel Plug a mic ins
20. ompressor Threshold Control outer 1 10 Compressor Output Level Control inner 1 10 Clip Indicat en neninn ie 11 EQUALIZER CIRCUIT 11 Low Frequency 1 11 11 Lo Mid Frequency Control 12 Lo Mid Shift x 10 12 Hi Mid Frequency 12 Hi Mid Shift x 10 12 High Frequency Control 12 High eiee 13 Bypass 59 13 Master Output Level Control 13 Phase Switch 13 Output Level VU Meter ideii 14 ks AE NE EERE 14 REAR PANEL CONNECTIONS ccccccscssssssssssssssscsssscssccccceses 15 INPUT AND OUTPUT CONNECTIONS 15 TINPU Ts 15 15 LOOP INSERTS even tee erie Teer ae eee UOT Le 15 Preamp Compressor 16 Compressor AEE AE EEE 16 LOOP Connections ieies e e 16 gt 17 SPECIAL EFFECTS 18 FO TIPS 19 What is the best
21. place at its option defective product or component parts upon prepaid 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 the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs This warranty is void if the serial number is altered defaced or removed AR T reserves the right to make changes in design and make additions or improvements upon this product without any obligation to install the same on products previously manufactured A R T should not be liable for any consequential damages including without limitation damages resulting from the loss of use Some states do not allow limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you This warranty gives you specific rights and you may also have other rights which vary from state to state For products purchased outside the United States service will be provided by an authorized distributor of Applied Research and Technology Inc products Service The following information is provided in the unlikely event that your unit requires service Use this procedure to return units in the United 23 States only For service outside the United States please contact your authorized A R T distributor 1 Be sure the unit is the cause of the problem Check to make
22. preamp and the equalizer follows the compressor although you can change the order of the circuits by utilizing the insert points While the preamp is always active the compressor and equalizer may be individually bypassed The preamplifier s active balanced solid state input provides extremely low noise and excellent CMRR The input has a high impedance which prevents the loading of any device connected to it and makes the Tube Channel perfect for DI or line level applications The preamplifier s second stage 12AX7a tube runs on a regulated DC voltage providing an additional 40dB of gain Our design enables the tube to overload before the input or output stage This allows you to manipulate the tube gain to meet different sonic requirements The compression circuit features a VCA less design and utilizes optical Vactrol electronics for superior musical performance The compressor is soft knee by design Although it is capable of providing a thoroughly squashed signal it was designed to excel in areas where transparent and musical dynamics control is desired The beauty of the optical design is its ability to apply heavy amounts of compression without pumping and breathing like VCA based compressors In many cases you will hear the results of the compression without hearing the compressor The tube based equalizer was designed to help fix the instruments that give us the most headaches when we re recording kick snare b
23. presentation of how it will sound when mixed with other instruments You d be surprised at how bad a killer guitar track can sound when it is isolated from the rest of the mix Remember what makes it killer is how it sounds in relation to the other instruments Always keep the big picture in mind Most people think of EQ as boosting only we ll just add a little EQ Many times a bad sounding instrument 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 one of the mid bands Slowly sweep through the frequency range When the really nasty sound jumps out at you you ll know it when it happens turn the boost back to 0 12 o clock Now put the track back into the mix and cut the 19 frequency have to adjust the level of the instrument depending on how much you cut but you should find that with the problem area pulled out the instrument works better in the mix When recording EQ d instruments you want to make sure you have good representation of frequencies on tape Always monitor off tape when recording This ensures that what you re hearing is what is on tape When recording things like kick drums make sure you have enough low end thud and high end click if applicable before you record Recording guideline You can always boost or c
24. rs We recommend using only high quality cables equipped with the appropriate connectors Installation The Tube Channel may be employed in a number of setups including Between a microphone and a mixer digital multi track recorder DAT machine hard disk recorder or analog recorder In a mixer s channel insert points Between a microphone and signal processors Between electronic musical instruments synthesizers guitars basses samplers acoustic instruments with pickups and other gear Safety Precautions Warning To avoid the risk of shock or fire do not expose this unit to moisture Do not remove metal panels or chassis parts Removing any chassis parts exposes dangerous high voltages There are no user serviceable parts inside Refer all servicing to qualified personnel Note If your power cord becomes damaged and must be replaced always replace it with the proper 3 prong type Powering Up When the power switch is turned on the VU meter will illuminate It is important to remember to turn the Tube Channel on before any monitoring levels or power amps are turned on The Tube Channel has the ability to add over 60dB of gain to its input signal This can cause the Tube Channel to produce a thump on power up and power down Note Like all tube based equipment the Tube Channel needs to warm up before being used Allow one to two minutes for the tubes to reach proper operating temperature before using If the T
25. sure the unit has power supplied all cables are connected correctly and the cables themselves are in working condition 2 If you find the unit to be at fault write down a description of the problem including how and when the problem occurs 3 Call the factory for a Return Authorization 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 RA number clearly under the address 5 Include with your unit a return shipping address we cannot ship to a P O Box a copy of your purchase receipt a daytime phone number and the description of the problem 6 Ship the unit to Applied Research and Technology Inc 215 Tremont Street Rochester NY 14608 Attn Repair Department R A 7 Contact our Customer Service department at 716 436 2720 for your Return Authorization number or questions regarding your repair Customer Service hours are Monday through Friday 9 00AM to 5 00PM Eastern time 1998 Applied Research and Technology Inc 24
26. t control to set the level out of the preamp circuit much like using the master volume control on a guitar amplifier Use the Preamp Output control to add more gain when you have the Gain control set low for a clean sound Likewise you can use the Preamp Output control to decrease the level out of the preamp circuit when you re cranking the Gain control up for maximum tube warmth Optical Compressor Circuit Slope Switch The Slope Switch selects the compression ratio for the compressor circuit In its out position the compression ratio is an active 2 3 1 This means that for every 2 3dB over the threshold the input signal rises the compressor s output will change by 1dB This is a very mild and musical compression ratio which is ideal for smoothing all types of signals In its in position the compression ratio is greater than 6 1 This is typically called soft limiting as it allows only a 1dB change in signal level for any signal reaching over 6dB of the set threshold This setting is ideal for applications where exceeding a set level is not desirable 1 mixing popping bass digital recording etc Speed Switch The position of the Speed switch selects the release characteristics of the compressor circuit The out fast position allows the compressor to recover quickly once the signal falls below the threshold The in auto position allows the compressor to adjust itself depen
27. thing connected to XLR input However it is still preferable to disconnect any unused cables to avoid pick up of extraneous noise hum or RF interference Output Both balanced and unbalanced output connections may be used simultaneously This is particularly useful when using the Tube Channel as a direct box for instruments or line level signals Note If you experience a hum when using both output connectors simultaneously one to the console and one to an instrument amp a ground loop may be the problem To remedy this problem disconnect the ground wire pin 1 from the XLR cable plugged into the Tube Channel s output or use a ground lifted audio cable This interrupts the ground path and therefore breaks the loop Loop Inserts Two signal loops are provided to connect external equipment to the Tube Channel to use only specific individual circuits or to take direct 15 signal paths from specific sections The connections are unbalanced 14 Tip Hot Sleeve Ground Both of the send jacks may be used without interrupting signal flow through the Tube Channel The return jacks break the signal flow when a jack 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 provided between the output of the preamp circuit and the input of the compressor c
28. those of you who have one of those 250 000 consoles The use of external processing equalizers preamps and compressors has sonic and practical benefits when you consider that most recording is done one or two channels at a time For those of us on a budget it just doesn t make sense to spend a ton of money on a Cadillac console when a budget mixer and a few pieces of external gear is more cost effective Even those engineers who regularly work on big consoles use external EQs compressors and preamps The goal of any recording is to get the sounds right before you commit them to tape The Tube Channel exists to help you get it right so you don t have to fix it in the mix Design Notes The Tube Channel is a multi purpose tool for audio engineering and recording Enclosed in a one rack space 1U chassis are three independent circuits featuring a tube based analog preamplifier a VCA less optical compressor and a semi parametric four band tube based equalizer Used as a direct recording channel a mic line preamp or a DI direct box the Tube Channel is designed to work seamlessly with any recording sound reinforcement or electronic instrument setup A R T s Tube Channel circuitry is a hybrid design utilizing the latest most advanced solid state and tube technology With a transformerless design the Tube Channel maintains exceptional signal integrity and extremely low noise The compressor circuit follows the
29. trument or line level signal into either of the Input Jacks You can use either of 16 the following for an output Plug the output from the Preamp Send jack into the input of the next piece of equipment or bypass the compressor and equalizer circuits and connect either of the Output Jacks to the input of the next piece of equipment To use only the compressor circuit of the Tube Channel Plug a line level signal or a send from a mixer into the Compressor Return Jack Connect the output from the Compressor Send jack into the input of the next piece of equipment or the return of a mixer To use only the equalizer circuit of the Tube Channel Plug a line level signal or a send from a mixer into the EQ Return Jack Connect either output from the Tube Channel into the input of the next piece of equipment or the return of a mixer To place the equalizer circuit before the compressor circuit Connect the Preamp Send to the EQ Return Connect the unbalanced Output to the Compressor Return Use the Compressor Send as the main output to the input of the next piece of equipment Applications The main application of the Tube Channel is as a processing channel for a microphone instrument or line level source To use the Tube Channel as a mic or line preamplifier only simply press the Bypass switches to bypass the compression and equalizer circuitry Plug a microphone directly into either input and set the input and output
30. ube Channel fails to power up when the power switch is turned on check to see that its power cord is plugged into an active outlet If the unit still fails to operate properly turn it off and unplug it Then consult your dealer or A RT s Customer Service department Front Panel Controls amp Indicators Preamp Circuit Gain Control The Gain control sets the amount of input gain of the Tube Channel Turn the control clockwise to increase gain and counterclockwise to decrease gain Selection of the gain range is made with the 20dB gain switch You may control two ranges of gain with this control 9 to 50dB and 11 to 30dB When setting the Gain control refer to the 4 segment Tube Drive Array for a visual reference to the Tube Channel s internal signal levels applied gain Hint the sweet spot for the Tube Channel is when the second warm Light Emitting Diode LED in the Tube Drive array is lit Gain Switch Use the Gain switch to set the range of the Gain control When the switch is in the out Odb position the gain range is 11 to 30dB Depressing the switch adds 20dB of gain With the switch in the gain range is 9 to 50dB Note With most microphone applications you ll find using the Tube Channel with the 20dB gain switch in is needed Use the setting that best fits your application Phantom Power Switch The Tube Channel can power any microphone needing 48 volts DC phantom power Consult your microp
31. ut frequencies after they ve been recorded but you can t add frequencies that weren t recorded Always be prepared for the drummer who says he loves the John Bonham kick drum sound lots of low end power and ambiance you got when recording but during the mix decides he wants to sound like Metallica more click than punch If you get the sounds right when you record the tracks you shouldn t be spending a lot of time re EQing during the mix During mixing you should be concentrating on the blending of tracks and the dynamics of the song If you find yourself EQing everything take a break and come back to it later Start mixing with a group of instruments the whole drum kit or guitars and bass instead of listening to individual tracks Mixing is the time for tweaking not applying a sonic re design Once again if it sounds good print it Trust your ears nevermind where the knobs are pointing Tube Replacement The Tubes in your Tube Channel should last for many years They are hand sorted for performance In the event that you need to replace them A R T suggests that you do so with tubes available from A R T These are matched to the Tube Channel and will yield consistent sonic results You can replace the tubes with other brands however A R T has no responsibility for the resulting sound quality They may sound better they may sound worse The choice is yours Please realize that unauthorized alterations to the Tube C
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