Review: SSL XLogic Alpha Channel & XLogic Alpha VHD

The great thing about having been around for a while as a top-end audio manufacturer is that you accumulate lots of intellectual property in the form of proprietary circuits and industrial designs. And as any good businessperson will tell you, you need to capitalise on your ‘IP’ in as many different ways as possible. To this end we’ve seen companies like Neve, API, Chandler/EMI – and in this case, SSL – release ‘real’ and ‘virtual’ recreations of old devices in recent years, as well as new products that use the prestige and heritage of the company name to get a leg up in the very competitive pro audio market.

The XLogic Alpha Channel and XLogic Alpha VHD Pre from the Solid State Logic camp are two such products that borrow circuit elements from both the ‘G’ and the newest ‘Duality’ series large format consoles that aim to give ‘prosumers’ a touch of that SSL sheen!

Both these single unit rack-mountable devices are built in Old Blighty utilising a single printed circuit board approach with sealed power supplies. The Alpha Channel is intended as an all-in-one digital audio workstation front-end solution, incorporating a mic preamp with variable harmonic drive (VHD), a low-frequency roll-off section, a cut down G-series EQ section, a limiter, an analogue-to-digital converter and some flexible routing options via a switchable insert/sum point, but more on this later.

ALL FOUR SSL

The VHD Pre consists of four separate mic preamps each with input and output gain controls, rear-mounted XLR connectors, a VHD control, a 48V phantom power switch, a pad switch that doubles as an input level indicator using the ‘traffic light’ metering scheme, a Hi-Z switch and a front panel instrument input. Strangely, there are no phase inversion switches, which is a real oversight in my opinion. The Alpha Channel, which has an identical mic pre section, except for the combo instrument/XLR input connector, has a phase inversion switch! So why not the four-channel preamp? When I enquired as to why this was the case, the response was that users could easily flip the phase using their DAW software later, and that there wasn’t enough real estate on the front panel to accommodate these switches!

This forces you, when using the VHD Pre in a multi-mic tracking situation, to monitor through your software and possibly put up with latency and all its attendant problems. For the few extra dollars it would have cost to include phase inversion switching, SSL has really missed the boat on this because we all know the importance of relative phase in a multi mic setup – right?

SSL-AC

One further gripe is the power supply connector on the VHD Pre. The Alpha Channel uses a standard IEC power lead but in the case of the VHD Pre, the supply is external to the unit and is connected via a plastic thinly-covered five-pin DIN plug. I’m told we will see a lot more of this style of connector in the future, but I think it’s a case of power connector devolution. DIN plugs make very poor power connectors and are currently used as MIDI connectors – could not some newbie try and power their VHD Pre with SySex data?! Probably not – but they are certainly not professional power connectors!

SSSOUND

So what do the preamps sound like? Well, the preamps themselves have plenty of headroom, providing a clean and open sound (with the VHD control set to zero) providing up to 76dB of mic and 82dB of instrument gain. As I mentioned before, these units have their roots in other SSL products and in the case of the mic pres, the VHD circuit can be found on the current Duality series console (which has replaced the ‘K’ series as SSL’s new flagship large format console). It is this feature that can give your sound some subtle SSL character.

The ‘Variable Harmonic Distortion’ control works by increasing second and third order harmonic distortion with increasing input level – the harder you drive the preamp and the more you increase the VHD control the more harmonic distortion you get. Using the VHD control will also increase gain up to an extra 6dB depending on how much of it you use. I liked the sound of the VHD as it added fullness and warmth to lower frequencies and impact and a distinctive edge to percussive sounds. The VHD control is nevertheless something that should be used judiciously (or perhaps even applied later to source material – or a whole mix – as an alternative to dialling it in during the tracking stage). After all, the distortion artefacts the VHD circuit adds to a recording cannot be undone later.

SSL-EEK Q

The ‘cut down G-series EQ’ in the Alpha Channel (as it’s described in SSL literature) is a three-band ‘semi-parametric’ design offering up to 19dB of boost or cut. With a low frequency section ranging from 30–300Hz in shelf mode, changing to 35–500Hz in switchable bell mode, a variable-Q mid section from 300Hz to 5.2kHz and a shelving high frequency section from 1.5kHz to 22kHz. This EQ is very versatile and useful. However, one problem I do have with the EQ, is that apart from the extremities of the controls, there are no frequency markings, which I really dislike and think could be addressed. I particularly liked the sound of the LF section, using it with great effect to beef up an electric bass guitar recording. The whole EQ section can be globally switched in and out of the circuit, and there are also two LF roll-off switches prior to the EQ section at 40 and 80Hz. When both are on, you get a combined roll off at – you guessed it – 120Hz.