Oram Octasonic Plus Eight-Channel Mic Preamp

John Oram's Octasonic Plus eight-channel microphone preamplifier is the latest release in the Oram Octa-series of products. Also in the series is the OctaEQ eight-channel four-band EQ, OctaMix eight-channel stereo summing mixer and OctaFade eight-channel stereo summing mixer with 100mm faders.
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(click thumbnail)John Oram's Octasonic Plus eight-channel microphone preamplifier is the latest release in the Oram Octa-series of products. Also in the series is the OctaEQ eight-channel four-band EQ, OctaMix eight-channel stereo summing mixer and OctaFade eight-channel stereo summing mixer with 100mm faders.
Fast FactsApplications: Studio

Key Features: Eight-channel; 48 volt phantom power switch and LED per channel; phase reverse switch per channel; outboard power supply; balanced outputs (1/4-inch TRS)

Price: $2,880

Contact: Oram at 44-1474-815-300, www.oram.co.uk.
Features

The Octasonic Plus is a single-rackspace, eight-channel mic preamp housed in a sturdy aluminum chassis and done up in Oram's traditional light blue stylings. Power is delivered to the preamps via a locking multipin cable attached to a heavy-duty external power supply unit.

Each channel features a 41-step input gain knob, a phase reverse switch and a recessed 48V phantom power switch plus corresponding LED indicator. A per-channel peak LED indicates when signals reach 6 dB below clipping. The only other front panel feature is a mains power LED indicator, hidden within the "O" in the Oram logo.

The rear panel rivals the front in the simplicity department, featuring a XLR mic input and a 1/4-inch TRS line output per channel. At the far end is the industrial power supply cable connector; the unit's power on/off switch and a corresponding LED are found on the external power supply box.

Preamp input gain ranges from 0 dB to +70 dB, easily accommodating line level signals in addition to most microphones (to a +22 dBu maximum). Oram specifications indicate T.H.D. of less than .005% (20 Hz – 20 kHz), an EIN of –127.8 dBu (200 ohms at max gain), a maximum output level of +28 dBu and an audio bandwidth of 18 Hz – 73 kHz (no ± dB tolerance given).

In Use

There is a cliché about the simpler things in life, and the same can often be said about pro audio gear. Having recently used and/or reviewed a number of feature-laden preamps and channel strips (including the excellent but complex single-channel Buzz Audio ARC-1.1 with its 42 knobs and switches!), I often found myself reaffirming my preference for the simplest of recording paths – especially in simultaneous multitrack recording situations. Single or dual-input recording channel strips, complete with EQ and compression, can be ideal for stereo tracking and overdubs, but for high-input simultaneous recording, I like nothing better than a few racks of simple API preamps straight to tape (or converters, as is the usual case these days). A clean preamp with gain control, phantom power, phase reverse and rudimentary metering – just what the doctor ordered.

In this respect, the Oram Octasonic Plus fits the bill perfectly. The preamps, adapted from Oram's BEQ-series consoles, are straightforward and highly adaptable to a wide range of gain need. From a sonic standpoint, the preamps are impressively quiet and clean, with a hint of personality that seems to become more pronounced with higher-level input sources.

On 96 kHz and 192 kHz live/live-in-studio solo instrument and small ensemble recordings, I ended up using fairly conservative preamp gain settings since I was running straight into calibrated-input converters and had no post-preamp gain control. The resulting recordings were full range, dynamic and plenty clean – even approaching a pristine quality.

For band work, I found a pleasantly colored and slightly aggressive sound could be easily had from the Octasonic Plus by driving the preamps into their peak indicator threshold range and compensating with a post-preamp gain stage prior to the conversion. In many cases, this secondary stage may be a necessity because a preamp input setting approaching the clip-indicator range (-6 dB before actual clipping) pushes the preamp output level well into clipping on +4 dBu-calibrated inputs.

Although clearly an intended feature, I am personally not too keen on the recessed phantom power switches that require the use of a pen (or finger nails filed to a point) to engage/disengage. The theory, of course, is to prevent accidental switching during operation; why, then, is there no protection for the phase switch? My only other minor niggle is the difference in torque from one gain knob to the next – some turn freely with an audible click across the steps, and others are tight and sluggish and produce no click. Minor, I know, but it would be nice to have these narrowed to a more consistent range.

[John Oram responds that the 'torque' differential problem will ameliorate over time as the knob shafts, bushings and heavy lubricating grease used break in – Ed.]

Summary

The Oram Octasonic Plus is a fine example of a simple multi-preamp unit done well: high-quality preamp design; versatile gain range; individual phantom power switches with LEDs; stepped gain controls; quick to setup and easy to use. The Octasonic Plus' preamps are impressively quiet and clean, but a modest amount of color can be introduced by pushing them towards their limit. This unit is highly suited for use as a high-quality analog front end for digital audio workstation-based studios and live recording duties, or combine with Oram's OctaEQ and OctaMix to create a full analog recording/mixing solution.