OWNER'S MANUAL MANLEY VOXBOX MANLEY LABORATORIES, INC. MANLEY LABORATORIES, INC. 13880 MAGNOLIA AVE. CHINO, CA. 91710 TEL: (909) 627-4256 FAX: (909) 628-2482 email: emanley @ netcom.com http://www.manleylabs.com CONTENTS SECTION INTRODUCTION FRONT PANEL MIC PRE COMPRESSOR EQ & DE-ESSER PAGE 3 4 5 6 7, 8 & 9 BACK PANEL GENERAL DISCUSSION OVERVIEW AND BLOCK DIAGRAM MIC PREAMP COMPRESSOR EQ DE-ESSER SAMPLE SETTINGS TECHNICAL DETAILS MAINS CONNECTIONS TUBE, TRIMMER & JUMPER LOCATIONS CALIBRATION TROUBLESHOOTING SPECIFICATIONS CURVES WARRANTY WARRANTY REGISTRATION APPENDIX 1 - TEMPLATE FOR STORING SETTINGS 10 11 12 13 14 & 15 16 17 18 19 20 & 21 22 23 & 24 25 26 27 INTRODUCTION THANK YOU!... for choosing the Manley VOXBOX. This unit is the result of our customers asking us to make a vocal oriented combination from some favorite Manley designs. We combined the Manley Mic Preamplifier, Electro-Optical Limiter, and Mid Pultec and then went further. Uniquely, we put a compressor before a minimalist mic preamplifier. This can substantially reduce distortion while having no more sonic imprint on the signal than the mic pre by itself because the compressor is just a passive light dependent clamping resistor. For those who want the shortest path to tape, but use compressors, this has to be the ideal solution. We added attack and release controls to the compressor with some "very special" settings such as one that simulates a LA-2A, another "tuned" for drums and a setting that works like a great engineer "riding" a fader. Then we extended the PULTEC MEQ down to 20 Hz and up to 20 kHz so its not just a mid EQ anymore. To this we added a new de-esser circuit and gave it a "Limiter" setting. This final de-esser / limiter is completely independent of the compressor and is post EQ. We wanted the VOXBOX to be "Manley quality" and the first and only "analog combo" (other than consoles) to make a serious entry into the major studios. We provided our style of balanced inputs and outputs and used fewer but better parts. It only required five Manley audio transformers, six multi-tapped inductors, two expensive Multi-Caps, four mil-spec JAN tubes, four Vactol opto-isolators, five regulated power supplies, six Bournes conductive plastic pots & seven Grayhill gold contact rotary switches. A few of these items are likely to cost more than other manufacturer's total parts. With all these serious transformers we even provided ways to go transformerless,the minimalist and purist way to go. We went to great lengths to eliminate typical clicks and pops from switches. The compressor and limiter can be switched in while recording and the change happens smoothly. We added auto-mute circuitry to eliminate the turn-on & turn-off thump and regulated all the power supplies. In fact many of these developments are being incorporated into our next versions of our other pro products. While we were designing the VOXBOX we couldn't help but notice how well it would work on other instruments besides voice. There were some great settings for drums (unusual), bass, guitar and keys. So don't just use it for voice - you can use it everyday and in any situation regardless of how well equipped the studio may be. The name "VOXBOX" represents only the beginning and the most obvious application. Please take a few moments to read through this manual carefully as it contains information essential to proper operation of this unit and we scattered little hints all over. Thank you again, and please enjoy ! GENERAL NOTES LOCATION & VENTILATION The Manley VOXBOX must be installed in a stable location with ample ventilation. It is recommended, if this unit is rack mounted, that you allow enough clearance on the top and bottom of the unit such that a constant flow of air can move through the ventilation holes. WATER & MOISTURE As with any electrical equipment, this equipment should not be used near water or moisture. SERVICING The user should not attempt to service this unit beyond that described in the owner's manual. Refer all servicing to your dealer or Manley Laboratories. 3 FRONT PANEL A BCD ON DE-ESS E H J K N W X 9 KHz 12 KHz Y THRESHOLD Z POWER OFF ON READY PHANTOM 48 VOLTS BYPASS 120 80 FLAT PHASE / IN 0° INST LINE 180° MANLEY VOXBOX GAIN ATTACK PRE O/P LINE IN GR EQ OUT DS THRESHOLD COMPRESS 3:1 EQ IN LOW PEAK MID DIP HIGH PEAK BYPASS BYPASS 0 +10 0 -10 0 +10 INPUT 50 48 45 42 40 RELEASE FAST MED FAST MEDIUM MED SLOW SLOW EQ INPUT INSERT PRE O/P LINE IN 150 100 70 50 35 20 200 300 500 700 1K 1K 700 500 300 200 1K5 2K 3K 4K 5K 7K 5K 4K 3K 2K 1K5 6K4 8K 10K 13K 16K 20K F A G I L M O P QRSTUV INSTRUMENT INPUT: 100K ohm input impedance. The PHASE switch should be in the middle position to use this input so that the mic input transformer is disconnected. Inserting a phone jack here will interupt the back panel LINE INPUT. Compression will lower this impedance and can cause some HF loss on guitars but a few dB of compression is OK. Two ways around this are use a preamp or effects pedal between this input and the guitar or use the limiter part of the de-esser. PHANTOM POWER SWITCH: This is a "locking switch" for safety - Pull out to toggle. Turn down the monitors before toggling. Use the 48 volt phantom power with FET CONDENSOR MICS but not with dynamic or tube mics. See page11 for more on phantom power. PHANTOM LED: Lit when phantom power is on. LOW FILTER: This is a minimum phase shift "high pass" filter that is available for the mic, line and instrument input. The slope is a gentle 6 dB per octave. FLAT = BYPASS PHASE SWITCH: A more correct term is polarity. This function is only available for the mic input. The "0" position is normal (non-inverting). The "180" position reverses the phase of the mic signal. The middle position marked "LINE" disconnects the mic transformer and optimizes the LINE and INSTRUMENT inputs. One might also use that line position to act as a "mute" if no line input is used (or better, the 1/4" jack is shorted). One uses the 180 position, for example, on the bottom of a snare or with vocalists if the headphones or mic is out of phase. INPUT: This is the main level control for all inputs to the preamplifier. It is before the compressor and preamplifier. It allows hot signals to be attenuated before any significant distortion can happen. GAIN SWITCH: This is not a "pad". It sets the amount of negative feedback which has an effect on gain, transient accuracy, noise, clipping characteristics, etc. It is normally used as a tone control and/or to optimise noise. See page 11 for more on this control. VU METER: This is a true standard VU. It is not supposed to "agree" with peak meters. The VU is preferred for recording to analog tape and is intended to show a reasonable representation of how "loud" the signal will be heard. Use your tape machine's meters to safely set an output level. METER SELECT SWITCH: The VU meter shows 3 isolated audio inputs and 2 positions that are used to indicate the amount of gain reduction from the compressor and de-esser / limiter. Because the VU meter is a little slow it may not show some fast peak reduction that is actually occurring but will tend to show the "audibility" of gain changes by the amount and rate of needle swing. B C D E F G H I 4 COMPRESSOR SECTION J COMPRESSOR BYPASS: With this switch up the compressor is engaged. This switch is uniquely designed to be used during music. No clicks, no pops and the change of level occurs smoothly. The compressor is uniquely before the preamp so that transients are "tamed" before the signal enters the tube circuit. This makes it possible to have exceptionally clean, smooth tracks. It also allows the normal "mic preamp into outboard compressor into tape" to be essentially "purist mic pre direct to tape" with compression invisibly taking place. We use a passive opto-isolator for the gain control element which adds no measurable distortion or noise and only 0.1 dB of insertion loss. COMPRESSOR THRESHOLD: Turning this control clockwise increases compression. This control is after the INPUT control. There is no "make-up gain" control so some degree of balancing between INPUT and THRESHOLD is expected. Adding the makeup gain or output level would have compromised the sonic integrity for the sake of conventionality. The compressor "ratio" is program dependent and non-linear but is generally similar to 3:1 ratios on VCA based compressors. ATTACK: This controls how the compressor reacts to transients such as explosive consonants or drums. Slower settings tend to "ignore" transients and let them through untouched. Faster settings tend to reduce transients which has an audible effect of reducing, for example, the strike of a drum or the "P"s as in "puppy". Vocals will usually be best with medium settings. Engineers most familiar with compressors will notice the unusual way the "attack" rides above the reduction set by the release. Attack changes are most noticable on slower releases on this unit. RELEASE: This controls how fast or slow the compressor returns to full volume. Because various RC networworks are switched in this control also has some effect on attack rates. The final release as reduction approaches 0 dB is a "bonus" function of the Opto. Each setting is actually a separate complex set of "tuned" time constants. The FAST setting mimics the Manley Electro-Optical Limiter and works best in the range of 3 to 8 dB of compression. The MED FAST setting is much like old LA-2A's but is also tuned for drums and bass and works well with dynamic broadcast audio. This setting is designed to pump a bit with the Attack at Slow. MED and MED SLOW are the usual choices for vocals. SLOW is a very slow release and is for the most inaudible compression. RELEASE SLOW + ATTACK SLOW uniquely mimics a good engineer "riding" a fader. Good for great singers, questionable for dynamic material. LA-2A = FAST ATTACK & MEDIUM FAST RELEASE or FAST RELEASE (or LIMITER) LA-3A = SLOW or MEDIUM ATTACK & MEDIUM SLOW RELEASE K L M N LINK: Switching up connects or links a second VOXBOX for stereo applications. It ensures that when either compressor channel reduces gain that both units will reduce the same number of dBs. This is so that a center image does not drift when a peak is on one side. Both sets of controls should normally be set to the same positions. It links both the compressor and the de-esser to the second VOXBOX if RCA LINK interconnects are between both units. The RCA male to male interconnect can be any typical stereo hi-fi type. 5 EQ and DE-ESSER SECTION O EQ BYPASS: Switching this up engages the EQ section. This is a passive PULTEC MEQ style EQ with only one capacitor, one inductor (coil or choke) a conductive plastic pot and a gold contact switch in the audio path for each band of EQ. There are no tubes in the EQ and certainly no ICs or transistors. The tube circuit is only used for flat, fixed make-up gain and is always in circuit. The EQ is before the de-esser / limiter and before the tubes. EQ INPUT: Three inputs are available to feed the EQ / De-esser / Line amp. The LINE IN is a split from the same LINE IN that can feed the mic preamp section. The PRE O/P is the output of the mic preamp / compressor section and is not through the output transformer. When using a line input into the compressor, these two positions allow you to compare compression to no compression without the drop of gain you get just using the compressor BYPASS switch. The INSERT setting allows yet another line input to feed this section. It allows you to insert (or bypass) an external device such as a noise gate between the preamp output and the EQ section. It also allows you to use the VOXBOX for two different tracks. These 3 inputs are switched with high quality sealed relays near the back panel & transformers for the shortest signal path. LOW PEAK FREQUENCY: This simply selects the center frequency to be boosted with the LOW PEAK control. The "Q" or bandwidth is fixed and consistant with the original PULTEC MEQ. There are now 11 positions between 20 Hz and 1 kHz. The settings below 200 are new and were not on PULTEC MEQs. See page 14 for a few tips if you want. LOW PEAK: Adjusts between 0 or flat and typically up to 10 dB of maximum boost. MID DIP FREQUENCY. 11 frequency bands between 200 Hz and 7 kHz (7,000 Hz). 1K5 is "British" for 1,500 hz or 1.5 kilohertz or kilocycles. MID DIP: Adjusts between 0 (flat) and up to (minus) 10 dB of maximum cut. Many top engineers suggest that by using cut EQ (mostly from 200 to 1K5) rather than boost reduces phase shift problems and improves the general clarity and punch. Cutting a bit at 5 or 7 kHz can reduce the resonance of some vocal mics. (It helps to boost 16 or 20 kHz on the High Peak to compensate for lost brightness.) HIGH PEAK FREQUENCY: Again 11 positions but from 1,500 Hz (1K5) to 20 kHz. The settings above 5 kHz are new. Some frequencies may cause s ...