MusicRadar

The R24 is every inch the professional quality unit

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• Review

According to API company president Larry Droppa, Arsenal Audio has been set up to create products that do not fit into the signature API design parameters. Currently there are three models in the Arsenal Audio fold: the R24 EQ, the V14 EQ (half an R24 in a 500-series frame) and the R20 dual mic preamp.

All three share a military green paint scheme, with the R24 and R20 featuring a 'dog-tag' style product label on the front panel to complete the MASH look. Although the price tag is around the £1,000 mark the R24 is a more cost conscious unit than the API products, especially as it does not feature the legendary API 2520 discrete op amp.

Solid build

The first thing that strikes you about the R24 is the build quality. The military green front plate is a bullet-proof 5mm thick framed with sturdy handles. Having taken the lid off and snooped around the circuit board, it is obvious this is a simple electronic design, something one hopes translates into a clean quality sound.

The EQ ranges for each of the four bands are set through good quality capacitors, with amplification carried out by standard TL072CN op amps. Although these are not the highest-grade option on the market, with a well-designed circuit, they offer plenty of clean gain and bandwidth.

There are two inclusions on the board that are also essential to the performance of the R24. Firstly, each channel has a relay for 'True Bypass' via a front panel 'In/Out' switch. This means that in bypass mode the input is sent directly to the output and so leaves the audio completely unaffected (the unit can be turned on and off without any audible effect on the signal).

Quality transformers

Secondly, there is a transformer on the output of each channel for signal balancing. We are big fans of (quality) transformers on audio outputs as they can provide a more forgiving harmonic distortion (compared to standard op amps) when driven hard.

The two channels of the R24 each feature eight knobs and the EQ In/Out switch. The small upper row of four knobs controls the frequencies for each of the four bands, while the lower four knobs control the 12dB cut/boost. The horizontal offset between the knobs allows plenty of finger room and the value legends are large and clear, making this an easy unit to operate.

The gain control pots are not centre-dented for setting an absolute zero gain value, but in practise this is not an issue due to the bypass switches and the gentle first few dBs of gain. Zero-ing the gain pots is also listed on the factory checklist that is provided in the box.

Sound

With regard to sound, the industry standard adjectives would have to be smooth, transparent and musical. This is every inch the professional quality unit one would expect from API. The wide Q of each frequency band keeps the sound free from unseemly peaking and phase shift artefacts even when two adjacent bands overlap.