Mercury Recording Equipment Company

Mercury Studio Channel 72 (MSC-72)

M72s Studio Microphone Amplifier with EQ-H1 Studio Program Equalizer

New from the Mercury Custom Shop is Mercury’s twist on a professional studio channel. The Mercury Studio Channel 72 is two independent channels of a Mercury M72s Studio Microphone Amplifier and a Mercury EQ-H1. Each amplifier (the mic amp and EQ’s gain make up amplifier) is fully transformer balanced. The MSC-72 is simply two great Mercury products in 2U chassis, with the option to use them together or independently with separate (balanced) XLR inputs and outputs on the rear of the chassis.

Seeing other choices of "combo boxes," especially ones with compressors along with pre-amps and EQs, choosing to cut corners to either be able to save costs, which usually means less transformers, and or to save space to be able to fit all the components in the products chassis — we wanted to do something much different. Unlike many "channel strips" or "combo boxes" in the marketplace, no corners were cut in the Mercury Studio Channel 72 (or our other studio channel – the Mercury Studio Channel 76).

With the philosophy that each part of your signal chain is important, after selecting a microphone for a specific source, the foundation starts with your microphone amplifier. We designed our Mercury Studio Channels to be a benchmark as the next part of your signal chain by matching up our tube, Mercury Studio Microphone Amplifiers with our tube, Studio Program Equalizers. We did not consider a compressor or limiter to be part of the product from the very beginning, thinking just like a microphone, the compressor is going to vary much more often depending on application or source you are recording concentrated on the heart of the signal chain. This would allow you to use it with any microphone you have in your mic locker and any compressor in your rack, making a Mercury Studio Channel a obvious choice for engineers and producers who are looking for tone, warmth and musicality.

The MSC-72 Mic Amp

The M72s is based on the most sought after vintage "V series" module, the "Telefunken/Siemens V72s," which is most famous for being used in REDD.37 consoles used on the early Beatles recordings by George Martin at Abbey Road Studios in London, England.

The Gain of the Mercury M72s is variable from 28dB to 58dB, in 3dB increments. Also, there is an option of a selectable Input Pad of -16dB or -28dB for even more control. When the -28dB pad is engaged and it is set at the lowest gain setting (28dB) you can run line level signal through the M72s to add warmth and tonality to any tracks, mixes, keyboards, drum machines, samples etc... There are also all the modern features we expect on a new piece of equipment: Phantom Power (on/off) , Phase (Polarity) Reversal, and our amazing sounding FDI (FET Direct Input) Circuit.

After building hundreds of Vintage V72 packages at Marquette Audio Labs it is nice to know we can continue a tradition that we have been providing for over 10 years now. We are very proud of the Mercury M72s Studio Microphone Amplifiers at M.A.L. and I am personally very pleased with this product which has actually exceeded my expectations.

David Marquette, Mercury Recording Equipment/Marquette Audio Labs

The Mercury FDI (FET Direct Input) is a proprietary J-Fet circuit, based on a class-A tube topology. The Mercury FDI is designed to reproduce every nuance of a direct recording, while the circuit lets the tube or solid-state character of the amplifier determine the overall tone. The instrument DI signal is sent through the entire microphone preamp circuitry, including Mercury’s custom, massive input transformers, so that the individual character of each preamp comes through.

The Mercury M72s has the rich lows and punchy mids giving you that 'instant' vocal tone, or assisting with a realistic acoustic guitar tone, punch to bass guitar. The same reaction to instruments or source as the vintage module but with slightly more open high end and openness. The Mercury M72s Studio Microphone Amplifier has that "vintage" tone and break up like the original circuit but it is a bit more musical over all (not cleaner, but more musical—there is a huge difference).

Tubes: The Mercury M72s amplifier in the Mercury Studio Channel 72 uses two EF806s tubes.

The MSC-72 EQ

The Mercury EQ-H1 features a passive EQ circuit with a single ended gain make up amplifier topology, based on the vintage ‘Pultec EQH’ circuit. The Mercury EQ-H1 circuit provides a musically satisfying result unobtainable with active and parametric EQs, since the EQ-H1 does not rely upon negative feedback (and all its associated phase and dynamic distortions) to achieve equalization. The EQ-H1, like all Mercury products, has transformer balanced (XLR) input and outputs. The only additions or changes to the original are a much more powerful and stable power supply and running DC on the heaters, rather than AC.

EQ-H1 vs EQ-P1:

Simply, the key to the tone of these two circuits are its amplifiers, and the Mercury EQ-H1 and EQ-P1 have different amplifiers to make up the gain lost by the passive equalizer circuit, thus they have different tones. The EQ-H1 and EQ-P1 sound different on the same application, and have a different reaction to the same instrumentation or voice.

The EQ-H1 is more punchy and robust and has a slight push in the low end and lower midrange. The EQ-P1 is more open and silky, and equally adds warm to highs, mids and lows of your source. Although both sound amazing on any application and are both multi-purpose tools (equalizers) in the studio, if you had both you could then choose between applications.

The Mercury EQ-H1 is warm and fluid but a bit "thicker" than the EQ-P1, thus shines on thickening (and pushing forward in the mix) your vocals, bass, kick, snare, acoustic guitar, etc... The Mercury EQ-P1 is great for shaping and adding ‘air’ to your vocals, acoustic instruments, guitar, piano etc... and is magical strapped across your two buss to add musicality to your mix.

Tubes: The Mercury EQ-H1 amplifier uses one 12AX7 tube and one 12BH7 tube.


  • Low Frequency Select (CPS; Cycles per second): 20, 30, 60, 100, 200 Hz
  • Low Frequency Boost Control: Shelf Boost, 0dB to +13dB
  • Low Frequency Attenuate Control: Shelf Atten. 0dB to -17dB
  • High Frequency Select (KCS; kilocycles per second ): 3, 4, 5, 8, 10, 12, 16 kHz
  • High Frequency Boost Control: Shelf Boost, 0dB to +16dB
  • High Frequency Attenuate Control: 10k Shelf Attenuate, 0dB to -16dB

The Mercury EQ-H1 and EQ-P1 are based on the original Pultec equalizers which were tools developed to deal with the limitations of recorded music. Limitations that most often manifest themselves in the highest and lowest frequencies of the program material. The family of Pultec EQs were originally designed to bring back the life and musicality lost in the recording. Whether by accident or genius, nothing has been able to do it better. The interaction of the passive boosting and attenuating shelving EQs (not relying on negative feedback), as well as the transformers, tubes and other amplification circuitry all add to the incredibly musical character of the product. Working engineers try other types of equalizers, but always end up coming back to the Pultec style as the equalizer of choice for those final touches while tracking, mixing and even mastering.

Mic Input Impedance:    Approx. 2k
Suggested Source Impedance:    Approx. 200 ohms
Input Impedance with -28dB Pad:    Approx. 4k
DI Input Impedance:    2M ohms
Internal Output Impedance:    30-50 ohms (depends on gain setting)
Suggested Minimum Load:    500 ohms
Max. Mic Signal Input Level (@ 20 Hz):    +34dBu with -28dB Pad engaged / +6dBu with Pad not engaged
Max. Output Level:    +22dBu
Frequency Response:    20 Hz to 20 kHz +/- 0.5dB
Harmonic Distortion:    All musically related low orders of harmonics, with no significant order above 5th. More info
Rack Size:    2U
Weight:    32 lbs.
Shipping Size:    24" x 16" x 8"

The M72 brings the vocal up in your face in a mix. Not only that, when you're singing, you can distinguish every little nuance.

Ricky Skaggs
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Having used the Mercury M72s I now see no need to scour Eastern Europe to search for the last of the original units.

Joe Chiccarelli

The M72s sounds every bit as good as an original V72s, imparting that nice pillowy softness that is so difficult to get...

Pete Weiss, TapeOp Magazine
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Mercury Studio Channel 72 (MSC-72)
LIST PRICE: $6,875
Custom Shop - Special Order