Modular Audio Products M-27 500 Series Mic Preamp

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Modular Audio Products M-27 500 Series Mic Preamp

$499.00 $599.00

Harmonic sheen in spades!

The M-27 500 Series Mic Preamp is a compact, single channel recreation of the Melcor®/Modular Audio Products™ class A AM-27 preamp module from the 1970s.

Now adapted to the popular API 500 series format, and constructed with the same NOS 70s transistors and carbon comp resistors as the original unit, the M-27 is like a NOS AM-27 assembled fifty years later - and it’s compatible with your Lunchbox®!

Please allow approximately 3-4 weeks for production lead time

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A Melcor-Inspired 1731-Based 500 SERIES Mic Preamp

Inspired by the original MAP™ AM-27 preamp module from the 1970’s, inherited from MAP’s predecessor Melcor®, the new M-27 utilizes the same core circuit as our 19” rackmount D.AM-27 Dual Channel Mic Preamp. We’ve received a number of requests to adapt that unit to 500 series format - especially since launching its compressor cousin, the FET-based CL-20 - so it was only a matter of time!

Class A 1731 Discrete Opamp-Based Mic Preamp

Based around the 1731 Class A discrete opamp, originally designed by Melcor® Industries in the 1960s, the M-27 features our own meticulously engineered and reconstructed opamps. Built using the same NOS transistors and carbon composition resistors as the originals, these are effectively 1:1 drop-in replacements for the OG opamps - just manufactured 50 years later!

Vintage Voicing With Modern Functionality

As with the D.AM-27, we've added a few modern features to make this classic vintage-sounding circuit even more usable in today's studios. These include +48V phantom power, switchable 120hz high-pass filter (HPF), in addition to a +4 dBm line-level input and hi-Z DI input. The M-27 also features a 10-segment LED meter for easy level monitoring.

Mid-Century Aesthetics & Vibe

Outfitted with the same custom, hand-painted triangle knobs found on our D.AM-27 and CL-20 FET compressor, the M-27 is a stylish addition to any 500 series rack, true to the mid-century aesthetics of its predecessors.

Rich Harmonics & Present Midrange

Sonically, the M-27 imbues sources with the thick, present midrange and harmonic sheen that 1731® aficionados would expect. Slower and more laid back than the classic and better known Farmingdale discrete op amp that would follow, the 1731® still lends a punchy, thick, undeniably 70s vibe and character to anything recorded or mixed through it.

Now returned to its original “modular” form, true to the Modular Audio Products™ brand, the M-27 brings the killer punch, depth, and mid-forward presence of the AM-27 to 500 series racks everywhere!

*All trademarks are the property of their respective owners.

About Our MAP Recreations
The MAP 1731® op amp utilizes all thru-hole old-school components; this is like a vintage op amp coming off the production line in 2024. It is based on the 1731 op amp that originated with Melcor® in the late 1960’s, though MAP utilized this op amp design (and others) in its projects after Melcor’s® demise. We are including some photos of MAP’s 1731® above for historical reference. Having dissected many of these over the years, we found that the earliest versions of the 1731® were constructed with carbon composition resistors and film caps, later versions moved to carbon film resistors. We have opted to use carbon composition resistors in this run (yum!) and styroflex caps across the input. The same, original, 2n3707 transistors are utilized throughout. One modern deviation, for reliability and tone, is the integration of silver-can output transistors. These vintage style transistors can handle the heat dissipation better and, quite frankly, we found them sonically superior in our listening tests. With this minor but necessary change, these op amps are now made to last a lifetime.

Why Modular Audio Products?

The idea of bringing this back is to pay homage in the most respectful way possible to Modular Audio Products, while tapping into the spirit of what they set out to achieve. The original MAP products, while rare, were highly ambitious designs for their time and would still be on the must-have list for many studios. Chris has been personally collecting and admiring these original pieces for many years. This is just the beginning, stay tuned!

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FEATURES & SPECS:

Handcrafted End to End in the USA
In-house MAP 1731® class A discrete op amp with original parts
Original spec carbon composition resistors and precision Dale resistors throughout
Original spec Melcor®-Era USA made Transformers
10 Led Bar graph for precision Gain metering
MAP’s new Triangular knob design (a knob that means business!)
Output Attenuator to drive gain and get as much coloration as desired
Switchable 120hz high-pass filter (HPF)
-20 dB Pad
+48V Phantom Power
Input Phase reverse
+4 dBm Line input
1/4” Front Panel DI Input
+69dB of Max Gain per Channel (+/- 1db), Fully Variable
Alpha potentiometers
**specifications, parts & pricing subject to change