An all-tube preamp with an amazing ability to make any mic you put through it sound great.
The Tube-Tech MP 1A dual channel preamp and instrument DI has been one of the secrets that engineers and producers have kept to themselves for bringing the rounder and more pleasing sound of analog gear to digital recording. And where some preamps tend to work well with certain mics but not others, the MP 1A also has the uncanny ability to make any mic your put through it sound great. A truly phenomenal-sounding preamp, the MP 1A excels on electric guitars and vocals. To give you an idea of its versatility, the MP 1A has been part of Julio Iglesias' vocal chain for years and is the preamp that Frank Fillipetti used to record Johnathan Davis' vocals on Korn's Take a Look in the Mirror.
Tube-Tech MP 1A, First Take:
Dual channel all-tube mic preamp and instrument DI
Designed for ultra low-noise operation
Switchable —20dB pad, can be used as a unity gain line amplifier, +70dB mic input gain
DI input with switchable high-pass filter and +60 gain
Dual Channel All-Tube Mic Preamp And Instrument DI
The rackmount Tube-Tech MP 1A microphone preamplifier is a combined two channel microphone and DI preamplifier. Each amplifier consists of a microphone input transformer with a step-up of +10 dB, a dual tube preamplifier with a stepped gain (5dB/step, passive and active), an output amplifier with two dual tubes in push-pull and an output transformer. The high impedance DI inputs are unbalanced and placed in the circuit directly after the input transformer, with a gain ranging from +10dB to +60dB.
Designed For Ultra Low-Noise Operation
The amplifiers are all tube based and the heaters are fed stabilized DC-voltage only. This prevents any variation in the DC energy when combined with the musical signal, which would otherwise cause certain types of distortion or hum. All transformers, with the exception of the mains transformer, are enclosed in MU-metal cans. MU-metal (pronounced mew-metal) is a highly permeable alloy that absorbs and redirects interfering magnetic fields away from the transformers. Input and output transformers come with a static screen between the primary and secondary wirings. These screens shield the secondary from the primary and prevent RF (radio frequency) electromagnetic noise from getting across.
Switchable Pad, +70dB Gain
The microphone inputs are provided with a switchable -20dB attenuation pad in front of the mic transformer and switchable +48V phantom-power. The microphone input is capable of accepting levels of up to +6 dBU (1.55V) at 40 Hz without the pad and +26dBU (15.5V) at 40 Hz with the pad, so the microphone input can be used as a unity gain line amplifier*. The gain switch for the mic inputs has a range from +20dB to +70dB in steps of 5dB, which allows use with ribbon mics. A high pass filter for the microphone and the DI input is switchable between off, 20 Hz (12dB/octave) and 40 Hz (6dB/octave). It is advisable to use this filter in environments with high levels of very low-frequency disturbances. Gain errors between the two channels are less than 0.5dB at any gain setting. The two amplifier circuits are completely separated and the cross talk between channels is below -60dB ranging from 20Hz to 20kHz.
* Most audio products use op-amps running from ±15 V rails. A single op-amp drives an unbalanced line to around ±11V peak (+20 dBu). Using two op-amps to drive the line differentially doubles this to ±22 V peak (one goes positive, while the other goes negative), a value equal to +26 dBu. (From Rane Notes 124)
For over twenty years, Tube Tech has been one of the most prominent names in all-tube signal processing equipment. You'll find their gear in the best recording and mastering studios around the world. The company's founder, John Petersen is an electrical engineer who was factory trained at Solid State Logic, EMT, Studer, Sony, Neumann, and NTP Electonik (digital audio routers). He also designed tape recorder playback/recording amps for Lyrec tape recorders (found in the studios of the legendary Joe Meek and Vangelis). His first design under the name of Tube-Tech was an all-tube equalizer based on the legendary Pultec EQP 1A. Petersen continued to design and manufacture a number of innovative all-tube outboard processors including preamps, multiband compressors and summing amps. Thanks to John's dedication to high-quality analog sound you'll see Tube-Tech gear in the racks of pro audio legends such as multi Grammy Award winner Al Schmitt, (Frank Sinatra, Steely Dan, Toto, Quincy Jones, Natalie Cole, Diana Krall), Grammy winner Joe Chiccarelli, (Elton John, Beck, U2, Tori Amos, Counting Crows, Offspring), engineer Russ Long (Sixpence None The Richer, Wilco, Dolly Parton, Allison Moorer), producer-engineer Tony Shepperd (Elton John, Madonna, Kenny Loggins, Barbra Streisand, Lionel Richie, and Whitney Houston), and many more.