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API Audio 512C 500-Series Mic Preamp - Used  From API

The Original 500 series mic pre featuring the classic API sound, all you need is the lunchbox!


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API Audio

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What We Think

I love using API mic pres because I always know what I’m going to get. Top-of-the-line, military grade build quality and a distinct, aggressive sound that, when the situation calls for it, is nothing short of amazing. This is my top choice when miking a drum kit and want a contemporary sound. It delivers a level of punchy, dynamic tones with an incredible overall forwardness that I just can’t seem to get out of another preamp model. 
The API preamp (3124 and 512c) also performs incredibly well on electric guitars, especially within heavier genres. It’s unparalleled responsiveness and bold overall sound does an excellent job in capturing and showcasing the aggressive playing in metal and hard rock in a very clear and powerful way. I’ve found it to perform at its best when pushing harder on the gain to the point of saturating the fully discrete electronics, resulting in more mid-focused saturation that brings out even more information in the guitar. In these scenarios, I’ll often have to engage the pad to control the signal level and prevent clipping my converter’s input, however it’s a small price to pay to get such an incredible result.
For some projects or instruments, fast and punchy may not be ideal. I almost always want to retain high levels of detail, but would prefer additional smoothness and warmth instead of additional punch. In these cases, I reach for the Phoenix DRS-1R for additional analog saturation to push the material back in the mix just a bit. 
In situations where unparalleled punch, detail, and responsiveness are desired regardless of genre, the API preamp delivers stronger than anything else - Period. For hard rock or metal engineers, it’s pretty safe to say your preamp arsenal isn’t complete without at least 4 channels to cover your drums, guitars, and bass.

Manufacturer's Description from API


Discrete Mic / Line Pre


  • Mic Preamp with 65 dB of gain
  • Front and Back Panel Mic Input Access
  • Line/Instrument Preamp with 50 dB of gain
  • Front Panel Line/Instrument Input
  • LED VU meter for monitoring output level
  • 20 dB pad switch, applies to mic/line/instrument
  • 48v Phantom switchable power
  • Traditional API fully discrete circuit design
  • Uses the famous API 2520 Op-Amp

The API 512c is a mic / line / instrument preamp designed to provide a low noise, unusually good sounding front end for all types of audio systems. Sonically, it offers the distinct API sound at an extremely affordable price. Offering low noise (-129 EIN) and 65 dB of gain, the 512c includes phantom power, and switchable polarity, -20 dB pad and Mic/Line or Instrument selector. Front panel XLR and 1/4 inch connectors combined with rear panel mic access allows for additional flexibility when installed into an API lunchbox®, API's 10 position 500V vertical rack, or an API console.

The API 512c remains faithful to the circuit designs of API's founder, Saul Walker. Fully featured and still hand assembled, the 512c carefully preserves the original sound character that made it so much a part of the early days of recording. Offering high headroom and a wide variety of inputs and input access points, it is equally at home in the commercial recording studio as it is in the home project studio.

The 512c Mic/Line Preamp makes use of the 2510 and 2520 op-amps and therefore exhibits the reliability, long life, and uniformity which are characteristic of all API products.

API Audio

About Manufacturer

API (Automated Processes, Inc.) is world famous for its all-discrete audio products: studio and broadcast mixing consoles, and a full line of rack mount mic preamps, equalizers and processors. It all began with a dream. It was 1968. The company: Automated Processes Inc., formed by men with a vision. Best known for their now legendary "2520 amplifier", this unique amp has been and will continue to be the heart of all API discrete products. It continues to provide reliability and sonic purity unmatched by the competition. The resulting console met the needs of the music, commercial and broadcast industry. API became the leading audio broadcast console manufacturer for radio and television networks and high profile stations. In addition, recording studios, large and small, began using API.....and receiving rave reviews from engineers and producers. There are over 700 API consoles across the nation and around the world, including the three major networks. Over thirty years later, many of these consoles are still in daily use in some of the most prestigious recording and broadcast facilities in the world because, to date, there are few, if any consoles of equal sound quality at a cost-effective price.



Rear Connector:

Output on edge connector, MIC Input on edge connector,

can be defeated

Front Connectors:

XLR MIC Input, HI-Z 1/4" Unbal Input

Gain Range:

MIC, 10 dB min, 65 dB max. Unbal HI-Z Input, 14 dB min,

50 dB max

Maximum Input Levels:

MIC, +8 dBu, Unbal HI-Z Input, +36 dBu

Input Impedance:

MIC Input, 1500 Ohms (150 Ohm mic), HI-Z Unbal Input,

20 K Ohms

Output Impedance:

Less than 75 Ohms, Transformer Balanced

Clipping Level:

+30 dBu

Frequency Response:

+0, -.3, 30 to 20 kHz


Equivalent Input Noise: -129, Mic In. -125, Un-Balanced In.

Actual Metered Noise: Mic, -95 dBu, Un-Bal., -90 dBu


Less than .05% @ +4 Out, Less than .1% @ +28 Out

Power Consumption:

±12/18 Volts/DC, @40 ma.


1.5" X 5.25" X 7" Deep

Size (Boxed for Shipping):

4.5" X 6.5" X 10.25"

Actual Weight:

1.41 lbs.

Shipping Weight:

1.94 lbs.