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Recall Sheet 

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Summary of Contents for LA-610 MkII

Page 1: ...Model LA 610 Mk II Universal Audio Inc Customer Service Tech Support 1 877 MY AUDIO Business Sales Marketing 1 866 UAD 1176 www uaudio com ...

Page 2: ...versal Audio Inc Trademarks LA 610 Mk II LA 610 2 610 LA 2A 2 LA 2 1176LN 6176 4110 8110 SOLO 610 SOLO 110 710 Twin Finity DCS Remote Preamp 2192 UAD and the Universal Audio Inc logo are trademarks of Universal Audio Inc Other company and product names mentioned herein are trademarks of their respective companies Thank you for purchasing the Mk II version of the LA 610 Channel Strip The LA 610 is ...

Page 3: ...pression What s more the LA 610 s line level input allows it to be used as a dedicated compressor with or without EQ and tube saturation Most of us at Universal Audio are musicians and or recording engineers We love the recording process and we really get inspired when tracks are beautifully recorded Our design goal for the LA 610 was to build an integrated mic preamp compressor that we would be d...

Page 4: ...em Pay particular attention to cords at plugs convenience receptacles and the point where they exit from the unit Never take hold of the plug or cord if your hand is wet Always grasp the plug body when connecting or disconnecting it 7 Grounding of the Plug This unit is equipped with a 3 wire grounding type plug a plug having a third grounding pin This plug will only fit into a grounding type power...

Page 5: ... History of the 610 LA 610 Overview Compressor Basics Electro Optical Compression Limiting LA 610 Circuit Details About Class A About Negative Feedback Impedance Matching Phantom Power Maintenance Information Meter Calibration Internal Power Fuse Changing Tubes Glossary of Terms Recall Sheet Specifications Additional Resources Product Registration Warranty Service Support Inside back cover i ii 2 ...

Page 6: ...ysically placed and place it there The LA 610 is housed in a standard two rackspace 19 chassis and so we recommend that it be securely mounted in a rack if possible Step 2 Mute your monitors and then using a balanced cable with XLR connectors connect the LA 610 s rear panel line output to the appropriate input on your patch bay mixer or DAW Step 3 Set all three switches on the left side of the fro...

Page 7: ...et the Gain switch to its lowest usable setting with Level set between 7 and 10 If you hear distortion even at the lowest Gain level employ the 15 dB pad to reduce the input level If you are using a connected microphone or Hi Z instrument input experiment also with various impedance settings to achieve optimum tonality for your source signal Step 13 Experiment with the effect of the LA 610 s high ...

Page 8: ...ully level match when doing comparisons because louder tends to sound better Typically a microphone preamplifier should have input impedance roughly equal to about 10 times the microphone output impedance For example if your microphone has an output impedance of approximately 200 ohms the switch should be set to the 2 0K position However making music is not necessarily about adhering to technical ...

Page 9: ... pin 3 is hot positive Polarity reversal may be useful in cases where more than one microphone is utilized in recording a source 5 48 V Most modern condenser microphones require 48 volts of phantom power to operate This toggle switch applies 48 volts to the LA 610 MIC INPUT when the switch is up in the 48V position See page 25 for more information about phantom power 6 Hi Z Input Connect high impe...

Page 10: ...compression while lower settings reduce the amount of compression a setting of 0 with the knob at its fully counterclockwise position results in no compression Note however that all compression performed by the LA 610 is program dependent that is the degree of gain reduction changes as the signal varies see pages 18 22 for more information 13 Gain Once the desired amount of compression or limiting...

Page 11: ... mode BYP With the original even when the LA 610 was set to BYPASS mode incoming signal continued to pass through the compressor section For that reason the compressor Gain control remained active The LA 610 Mk II has true bypass which completely removes the T4 Optical Compressor section including its makeup gain control and GR COMP metering The LA 610 Mk II uses a larger and better lit easier to ...

Page 12: ...or signal processor to this balanced XLR connector Pin 2 is wired positive hot 3 MIC INPUT Connect your microphone to this standard XLR connector Pin 2 is wired positive hot 4 AC Power Connector Connect a standard detachable IEC power cable supplied here The LA 610 can operate from 100V to 240 VAC 50 60 Hz The internal power supply is self sensing and will automatically work throughout this voltag...

Page 13: ... 610 preamp Level control set between 7 and 10 and the compressor Gain control set at approximately 6 unity gain for starting positions Adjustments can then be made to the preamp Gain Impedance and Filter controls as well as the compressor Mode Peak Reduction and Gain controls to achieve the optimum sound for your signal source ...

Page 14: ...quashy compression like a more modern compressor if you want but it can also be very subtle and LA 2A like In these days of DAWs since there s no warmth from tape compression it s critical to have something like the LA 610 Indeed the beauty of the LA 610 is that it rides gain just like an LA 2A and it sounds quite a bit like an LA 2A yet it still delivers its own sonic signature For many years eng...

Page 15: ...s perfect for all applications or for all microphones Fortunately the LA 610 is designed to work with a wide variety of microphones and signal sources and we think you ll find that it acts as the perfect sonic complement for most of them Reviewer Myles Boisen observed in his February 2002 review of the 2 610 for Electronic Musician magazine that the unit can work magic on amplified instruments ele...

Page 16: ...the LA 610 s hi Z input Michael Cooper reported that after setting the unit s preamp gain to 10 for grit cutting the EQ drastically above 4 5 kHz and boosting below 70 Hz and placing the compressor section in Limit mode the results were positively thunderous Myles Boisen stated flatly in his review that The 2 610 has been an absolute smash hit for guitar and electric bass recording at my studio On...

Page 17: ...d that dialing in judicious amounts of peak reduction from the LA 610 compressor section can help get every syllable of a lead vocal intelligible even in a dense backing track and can also help backing vocals to sit correctly Improving the Sound of Your Microphone In some cases the LA 610 can even make an inexpensive microphone sound like an expensive one Boisen found that the 2 610 preamp allowed...

Page 18: ... consoles are commonplace today the 610 was quite a breakthrough at the time While the 610 was designed for practical reasons it was its sound that made it popular with the recording artists who frequented Putnam s studios in the 1960s The unique character of its microphone preamplifier in particular made it a favorite of legendary engineers like Bruce Botnick Bones Howe Lee Hershberg and Bruce Sw...

Page 19: ...nput In addition the preamp section has been voiced with a slight high frequency boost to compensate for the warm nature of the optical compressor it is paired with Compressor section The compressor section of the LA 610 is based upon the LA 2A a vintage tube device still revered by audio professionals everywhere The original design was the brainchild of James F Lawrence Jr who had been a radar op...

Page 20: ...soon became involved in its distribution selling units to numerous broadcast and recording facilities in New York and Nashville In 1962 Lawrence began to reconfigure the LA 2 into the LA 2A at which time the device gained a Limit Compress switch in response to the newfound interest from the recording industry With its 0 to 40 dB of gain limiting a balanced stereo interconnection flat frequency res...

Page 21: ...e ideas Every project taken on by the UA team is driven by its historical roots and a desire to wed classic analog technology with the demands of the modern digital studio LA 610 Overview The LA 610 is a vacuum tube channel strip that combines a microphone instrument line preamplifier with an optical compressor limiter Its creation was based on a simple idea Put a T4 compressor circuit in the outp...

Page 22: ...reamp it yields an enormous bottom end warmth that is unparalleled making it an ideal front end for tracking with modern DAWs Compressor Basics The function of a compressor is to automatically reduce the level of peaks in an audio signal so that the overall dynamic range that is the difference between the loudest sections and the softest ones is reduced or compressed thus making it easier to hear ...

Page 23: ...can add punch and snap to percussion instruments like kick drum and snare drum making them more present without necessarily being louder It can also impart tonal coloration making a signal warmer and fatter Compression can even serve as a musical tool enhancing the sustain of held guitar notes or keyboard pads or providing a snappier attack to horn stabs or string pizzicato Input Signal and Thresh...

Page 24: ... mode that is when the front panel Mode switch is set to COMP the LA 610 uses a compression ratio of approximately 3 1 however as we will see shortly this is program dependent so that the actual ratio changes according to the frequency content of the incoming signal While the terms compression and limiting are often used interchangeably the general definition of compression is gain reduction at ra...

Page 25: ...s through unscathed before compression begins on the rest of the signal The release time is the time it takes for the signal to then return to its initial pre compressed level If the release time is too short pumping and breathing artifacts can occur due to the rapid rise of background noise as the gain is restored If the release time is too long however a loud section of the program may cause gai...

Page 26: ... predominantly gives an electro optical compressor its signature sound Note While the el op circuit design was one of the first of its kind and is still used to this day in other compressor products Universal Audio has its photo cells uniquely manufactured to exacting specs that were originally found on the LA 2A No other manufacturers have access to these cells The genius of the el op circuit lie...

Page 27: ...adual release that can take as much as several seconds This kind of program dependent dual stage quick then gradual release results in a warm and natural sound without the pumping which plagues so many other compressor designs The amount of time it takes for the photo cell to recover after the light is removed depends on how long light had been shining on it and how bright the light was This cause...

Page 28: ... 0K ohms allowing it to accommodate virtually every kind of microphone Switching between these two positions while listening to a connected mic may reveal different tonal qualities and or gain differences be sure to carefully level match when doing comparisons because louder tends to sound better Generally speaking a microphone preamplifier should have an input impedance roughly equal to about ten...

Page 29: ...multaneous contact Even if all is good the application of phantom power can often result in a loud pop transient For these reasons we strongly recommend that the the LA 610 Phantom switch be left in its off down position when connecting and disconnecting microphones Only turn the Phantom switch on if you are certain that the connected microphone requires 48 volts of phantom power If in doubt consu...

Page 30: ...nal Power Fuse The LA 610 can operate from 100V to 240 VAC 50 60 Hz The internal power supply is self sensing and will automatically work throughout this voltage range The AC power fuse is located on the internal power supply circuit board inside the LA 610 MK II However in the event the fuse fails it is symptomatic of a serious problem with the unit and should be serviced by Universal Audio Chang...

Page 31: ...n clipping occurs in a digital recording device the result is an especially unpleasant sound Compression The process of automatically reducing the level of peaks in an audio signal so that the overall dynamic range that is the difference between the loudest sections and the softest ones is reduced or compressed Compression is sometimes described as gain reduction or peak reduction Compression rati...

Page 32: ... lights up quickly when electrical signal is applied the stronger the signal the brighter the light Electro optical compression el op compression A compressor that uses a circuit design whereby a light source and a photoelectric cell are used for gain reduction Both the LA 610 and the LA 2A use electro optical compression EQ Short for Equalization a circuit that allows selected frequency areas in ...

Page 33: ...c preamp The output level of microphones is very low and therefore requires specially designed mic preamplifiers to raise amplify their level to that needed by a mixing console tape recorder or digital audio workstation DAW Millisecond ms A thousandth of a second Negative feedback Negative feedback is a design technique whereby a portion of the preamplifier s output signal is reversed in phase and...

Page 34: ...a small element usually a corrugated strip of metal in a strong magnetic field This ribbon is moved by the motion of air molecules and in doing so it cuts across the magnetic lines of flux causing an electrical signal to be generated Ribbon microphones tend to be delicate and somewhat expensive but often have very flat frequency response Threshold A term used to describe the level at which a compr...

Page 35: ...Recall Sheet __________________________________________________________ 31 ...

Page 36: ...ce 80 Ω Recommended Minimum Load 600 Ω Frequency Response 20 Hz to 20 kHz 0 5 dB Maximum Gain 40 dB Line 77dB Mic Noise Floor 72 dBu 20 Hz 20kHz Line in unity gain Compressor Ratio 3 1 soft knee program dependent Limiter Ratio 1 soft knee program dependent Attack Time 10 ms program dependent Release Time Dual stage 60 ms for 50 release then 1 15 seconds program dependent Tube Complement 3 12AX7 1 ...

Page 37: ...d running again as soon as possible The first thing to do if you re having trouble with your device is to check for any loose or faulty external cables bad patchbay connections grounding trouble from a power strip and all inputs outputs mic line Hi Z etc If your problem persists call tech support at 877 MY UAUDIO or send an email to hardwaresupport uaudio com and we will help you troubleshoot your...

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