API A2D Microphone Preamp Review. The API A2D is one of the best preamps around. Fusing classic 312 peamps with state of the art analogue to digital conversion the A2D is a solid American sounding unit that would sit well in any professional recording studio.
It was in the late 60’s that API, formally known as Automated Processes Incorporated, was founded by a group of loyal knowledgeable men with a dream to craft the highest quality amplifiers and other technologies for the developing [record] production industry. Subsequently, only a few years later, they released a groundbreaking analogue console with a brilliant key component; the 2520 operational amplifier. Ever since this moment the 2520 op amp has been the beating heart in everything API and is one of many reasons for why their designs are so highly prized. However, it was in 2006 that API, for the first time ever, took a leap of faith in the developing digital age by marrying two critically acclaimed 312 microphone preamplifiers (featuring the 2510 and the 2520 op amps) with a pair of world class, low latency, low jitter, analogue to digital converters. This created the standalone API A2D unit.
Presented in a standard brown box, API haven’t wasted any time in designing unnecessary fancy packaging, but instead they more than adequately protect the A2D unit with a foam platform and then place in the region specific 1.5m kettle lead, and include the bound manual in a secure location as to not damage the aesthetic details. In terms if dimensions, the unit measures in at 19” x 1.75” x 11.5” and sports affixed rack ears to allow the API A2D to mount within a dedicated studio rack system with one ‘unit’ spare. A brief visual inspection shows that the API A2D is a fanless Class A preamp with an unremarkable solid milled aluminium enclosure and sufficient ventilation grilles that allow the A2D to run comfortably under 29° as a standalone unit or 31°in a rack after two hours of use (tested under ambient temperature of 26°).
If we now return to the faceplate, API have crafted this from an beautiful 2mm brushed aluminium plate with clear black screen printed decals situated beside the various functions. Evidently API have further subdivided the A2D faceplate into three sections known as; ‘Analogue’, ‘Digital’, and ‘Connectivity’ [or parameter settings] for ease of use. On the far right you will find the ‘Connectivity’ subsection which includes an unorthodox triangular push button on/off switch, an ‘external sync’ LED indicator which illuminates yellow when the A2D successfully handshakes and secures a connection with the BNC wordclock input, a very nice aluminium rotary to select the sample rate and following this a series of green LEDs will confirm sample rate. Please note that this unit operates at a maximum of 196kHz 24bit over six predetermined sample rates, which is more than ample for most situations although some studios may demand higher now that portable, albeit expensive to produce and deliver, DSD and DXD capable devices are out in the public domain.
To the far left we can find the ‘Analogue’ subsection which has discreet controls for both microphone preamps. Covering a range of -
In the centre of the faceplate the ‘Digital’ (A2D) section is found which is internally controlled by a pair of Cirrus Logic CS5381KSW analogue to digital IC’s. Both of the ‘Digital’ channels are independent and are monitored via the same 20pt LED VU meters as found within the ‘Analogue’ subsection. However, where this now gets interesting is that you are able to control the output digital signals. Don’t be fooled into thinking that the potentiometers are simply there to attenuate the signal in accordance with best practice input levels for your audio interface, but they are actually a very powerful tool that encourages ‘tone shaping’… especially if you pair this functionality with the 2:1 transformer ratio input and a send and return path from an additional outboard unit. Just by balancing the preamp signal with the A2D signal you can add a whole other dimension to your recordings. An extreme example of this is if you have an input from a guitar cab, then drive the preamps as hard as possible, and turn the A2D circuit low, you to create a messy crunchy tone that is free of any nasty digital distortion; pretty handy in the right situations. Now with this bipolar example you can imagine all of the tones that you can craft between the extremes. Having ultimate control over the entire signal path and conversion appears to be such a simple thing, but can be difficult to implement. API has excelled at handing over complete control over to the engineer and we applaud their efforts.
On the rear of the unit there are tons of inputs and outputs for ultra flexibility. Possibly the only minor grievance is the omission of an ADAT out, although you still do have access to digital AES(3)/EBU (XLR) and S/PDIF (Coaxial) outputs. Other features include an internal 20mHZ to 26mHz ‘Super Clock’, Wordclock input and output, Neutrik branded XLR microphone inputs, Neutrik branded XLR outputs, [balanced] ¼” TRS input to be used in conjunction for a send and return, and finally a 9 Pin D-
Before we begin, for the first part of this discussion, we shall analyse the A2D’s performance on standard settings; ie. No 2:1 transformer routing, preamp at twelve o’clock and A2D at twelve o’clock). Other technology used for the remainder of this review include: Lynx Hilo, Audient iD22, Dynaudio BM6a MK2’s, Beyerdynamic DT250, Shure SM57, sE Electronics SE3, Audio Technica AT4040, various DI instruments, The Chord Company Anthem Tuned Aray, and custom Van Damme cables.
The A2D is a brilliant classic sounding American preamp that works extremely well with almost any microphone or instrument that you can throw at it. Additionally the API 312 preamps that the A2D uses comes to the fore and offers low noise and low distortion, ultimately capturing a dynamic performance with precision and resolution across the whole frequency spectrum. You will also find that you have bags of headroom so you will not necessarily need to push the preamps too hard if you don’t want a more than moderately saturated tone. You will already find that the preamps have a nice warming friendly quality to them without any nasty gritty harmonics, and often they are that good that you will find that you don’t need to apply too much EQ in the box.
When tracking it is evident that the A2D has both beauty and power with an innate ability to capture a three dimensional performance that extends past the instrument and into the atmosphere. This is helped with excellent timing that responds well to tight snappy rhythmic transients and luscious smooth decays, making this one of those ‘universal’ preamps. However, we have found that the A2D performs beautifully with electric and acoustic guitars by amalgamating the various harmonics into a smooth unsegmented tone that cuts through and fits well within the mix. Again the A2D works wonders on central lead male or female vocals, and, in comparison to a neutral preamp, it has this ability to do this because the lower frequencies appear to have a bold smooth substance, the mids are buttery, and the higher frequencies have a touch of shimmer around 2.7kHz -
If we pair the preamps now with the A2D section, this is where it gets interesting. Sure you can use the A2D sections input gain to attenuate the signal sensibly as it goes into your interface, but have you ever wanted to add aggression, real analogue bittyness, or crushing tapered depth to an instrument track? Hell, have you ever wanted to experiment with low-
The API A2D is a beautiful preamp that pairs the old with the new. The 312 preamps are just as incredible as they have always been and the analogue to digital conversion is first class, so much so that this has opened up a whole new world of possibilities. We have been so impressed with the API’s A2D that we can only award it with a full five star rating.