User manual SUMMIT MPC-100A

[. . . ] DI Input 1/4" mono jack accepts Hi-Z instruments such as electric guitars and basses; a direct input into the preamp tube, bypassing the input transformer variable resistor for impedance matching of the Hi-Z input (range is 10k to 1M ohms); adjust for desired upper harmonic content in guitar sound 12 position rotary switch controls signal gain in the input preamp only note: for Hi-Z input only top 7 positions have any effect (as shown in blue) left yellow LED indicates preamp vacuum tube saturation; when LED is blinking, the tube is just entering soft clipping 5. OL variable resistor controls compressor vacuum tube gain right yellow LED indicates compressor vacuum tube saturation; when LED is blinking, the tube is just entering soft clipping 10. Threshold variable resistor sets the signal amplitude threshold, above which compression engages *NOTE!!! [. . . ] Turn the output gain up very high, then slowly turn up the preamp gain and compressor gain to the desired recording/ monitoring level. Set the compressor to your desired settings (try threshold 0 dB, slope 5. 5 with fast attack and medium release times). Set the Loading to about . 1M ohm and turn the preamp gain up until the Tube Drive light just starts to flash while the bass is being played (the flashing light indicates soft clipping). Increase the compressor gain until that Tube Drive just starts to flash occasionally, and set the compressor to the desired settings (try ­10 dB threshold, a slope of 5, with fast attack and medium release). Turn the output knob until you achieve the desired recording/ monitoring level. Just take the XLR out of the DI into the Mic input on the MPC-100A, and set the input switch to Mic. De-essing: (Requires external EQ) Plug a TRS insert cable into the side chain jack on the back of the MPC-100A. Plug the send (tip) of the insert cable to the input of the EQ, and the return (ring) of the cable to the EQ output. Ducking: Send the output of the "lead" program material into the side chain input after inserting the MPC-100A on the "background" program material. Example: Send the output of the lead guitar mic into the side chain, with the MPC-100A inserted on the rhythm guitar track. As the lead guitar player plays, the rhythm guitar will decrease in amplitude. This is perfect for broadcast use when the DJ needs to speak over music, live use when the lead singer needs to be heard over the lead guitar, or film sound when an actor's voice has to overcome a noisy background tone. Further Notes. . . . . . Linking: use a 1/4" mono patch cord with tip~signal and sleeve~ground; the MPC100A which is set for more compression will act as the master controller for both units; slope and threshold are the only controls effected [note: an MPC-100A can also be linked to a TLA-100A] Side Chain Insertion: use a 1/4" stereo patch cord with tip~send, ring~return, and sleeve~ground; to execute "ducking" (compression of principle audio signal, triggered by an external audio signal) tie tip and sleeve to ground, and bring the triggering signal in on the ring; to execute "de-essing" (engaging a frequency dependence in the compression of the principle signal) send to the outboard equalizer on the tip, return from the EQ to the compressor on the ring and tie the sleeve to ground - then boost the frequency you want to compress and roll off the frequencies you want uncompressed; this can be particularly useful in removing sibilance from vocal tracks. Sleeve Ring Tip Input Ground Side Chain EQ Output Side Chain connections are unbalanced Unbalanced Connection: to go into the line input XLR jack of the MPC-100A unbalanced, it is necessary to connect the signal to pin 3 and tie pin 2 and pin 1 to ground; unbalanced out has its own dedicated 1/4" mono jack Tonality: because there are two stages of vacuum tube gain in the MPC-100A as well as a discrete, solid state gain stage, the range of tonality in the unit is significantly wide; we recommend that you experiment with moderately overdriving either or both of the tubes and compensating for desired output level using the discrete gain control; be aware that when one of the yellow LED's comes on, it is indicating that the signal is reaching soft clipping "saturation" in the vacuum tube; for the most transparent signal tone set the solid state gain to maximum and adjust the tube gains only as high as your necessary output level requires. A Word About Tubes The tubes that are used in the MPC-100A are selected to give the best possible performance in the position that they are in the circuit. Switching them to different positions might cause performance deterioration of the audio path. Replacing them with "gold" or high end tube types may not be desirable. In cases that we have measured, these tubes have shown higher distortion and noise compared to the tubes we have selected. In some cases, the so called "gold" or high end tubes have made the unit unusable. The reason for this is some of the "gold type" tubes are selected for high distortion in guitar amplifiers. All of these so called "Brand X" types are selected with 6. 3 volts AC on the filaments, whereas Summit Audio uses 5 volts DC on the heaters for longer tube life and lower noise. The reduced gain may raise the noise floor, increase distortion, and reduce headroom. [. . . ] Completely flat frequency measurements are key to giving accurate specifications. Summit Audio devices are the highest quality professional audio gear and the specifications below are made with the flattest possible unweighted measurements, giving the most accurate results. Specifications: · Output: +4 dBu corresponds to 0 VU. The output is balanced or unbalanced using 990 operational amplifiers. [. . . ]