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Focusrite Platinum Penta

Preset Stereo Compressor By Paul White
Published August 2001


The new compressor in Focusrite's Platinum Range offers pre‑programmed settings for ease of use, whilst still incorporating extensive manual parameter control. Paul White gets to grips with the Penta.

Setting up a compressor is something that still mystifies a lot of people. Even when you do understand the basics, it can take a lot of experience to select the best settings for a particular audio source. A handful of companies have tried to make life easier by offering compressors that include presets optimised for different musical applications, and now Focusrite have developed their own version of the preset‑based compressor as part of their Platinum range.

The Penta uses a new optical gain control system that has been optimised for musicality, transparency and tracking accuracy — the latter clearly being important for stereo operation. Focusrite have also included tube‑emulation, for those seeking a 'warmer' sound, which uses a new three‑tier FET circuit that progressively introduces second, third and then fifth harmonic distortion, in much the same way that valves do when driven hard.

The Penta has been designed to function both as a mono mic, line, or instrument processor, and as a stereo line‑only processor. The front panel of the 2U box shares the distinctive Platinum styling, and carries sockets for the balanced Mic Input and high‑impedance Instrument Input. Dual balanced line I/O is provided via rear‑panel TRS jacks and a further pair of TRS sockets provide unbalanced side‑chain access. The outputs can work at +4dBu or ‑10dBV reference levels, depending on the position of a switch by the output sockets. Plugging into the mic or instrument inputs, or into the left channel's line input, causes the unit to operate in mono, outputting only on the left channel. On the other hand, feeding signal to both line inputs allows for stereo operation.

Front‑panel switches select whether mic/instrument or line inputs are used, and activate the mic input's phantom power, high‑pass filtering and phase inversion. A single Input Gain control operates on the selected input and a pair of eight‑section LED meters show the input level following this control. The preamp is a discrete Class‑A design with a frequency response only 3dB down at 85kHz, and with extremely good noise performance, even when I tried it with electric guitars and basses. The preamp architecture is similar to that used in the Focusrite Voicemaster, except that FETs are used instead of bipolar transistors. One advantage of this is that the circuit then behaves much more politely under overload conditions, approximating the soft limiting of a valve. Maximum mic gain is 60dB.

Occupying the centre of the front panel is the main compressor section where a horizontal row of LEDs is used to indicate which preset is active. Buttons at either end of the row allow navigation through the presets, which is all easy enough, though I found the preset names difficult to read in typical studio lighting conditions, especially against the glare of the status LED.

Unlike some other preset compressors, the Penta features a full set of parameter controls with which you can tweak the action of any of the presets. There are rotary pots for Compression (threshold), Make‑up Gain, Ratio, Attack, Release and Tube Sound, plus switches for Compressor In, Soft Knee and Tube Sound In. Ingeniously, the Ratio, Attack and Release controls always operate from a detented centre position to provide both positive and negative adjustment — in other words, if these controls are left centred, the preset works exactly as programmed by the designers. The teardrop‑shaped switches have integral status LEDs and an eight‑section LED meter shows any gain reduction being applied.

The Penta's presets make it easy to get instant, usable results, but there is also a full set of controls for further fine‑tuning.The Penta's presets make it easy to get instant, usable results, but there is also a full set of controls for further fine‑tuning.

The 16 presets are optimised for the most common musical applications: Kick, Snare, Ambient, Loop, Bass Guitar, Synth Bass, Percussion, Acoustic Picked, Acoustic Strum, Electric Guitar, Piano, Keyboards, Vocals, Crunch, Mix (Pump) and Limit. Crunch is designed for use before guitar overdrive devices. A table in the back of the manual shows the ratio and hard/soft knee status for each of these presets as well as whether the tube simulation is used or not. However, the threshold, attack and release settings are not divulged.

To the right of the front panel lies the Output control section, sporting an Image Width control, with it's own bypass button. This manipulates the stereo width of the audio by feeding some phase‑inverted left‑channel signal to the right channel, and vice versa. The advantages of this system are that the results are always mono‑compatible — any added information is cancelled when the channels are summed. Stereo metering of the output level is via two eight‑segment bar–graph meters, and a further LED shows whether the optional digital card is being clocked internally or externally.

Five Live

While it is perfectly possible to create presets for most compressor parameters, the suitability of these will nearly always rely on the input level to the compressor and the setting of the Compression control. Fortunately, because a lot of work has gone into getting the presets right, in most cases there is little else to do beyond tweaking the Make‑up gain control for a sensible output level. Depending on the preset used, the compressor can gently and unobtrusively control the dynamic range or it can display a smooth but obvious attitude that is reminiscent of some of the classic tube compressors. Certainly it's very hard to get a bad sound out of this unit, as even excessive compression still manages to sound musical. I did find that it was well worth trying some of the presets on sources for which they were not primarily intended — for example, the acoustic and bass guitar settings also work well on clean electric guitar.

Mix compression is also handled sympathetically, but again with the capacity to pump up the energy in a more obvious way if needed. Reducing the ratio facilitates more transparent compression, though the presets are fine just as they come for the vast majority of applications. The limiter preset does it's job well enough as a routine limiter, but it's also very nice on vocals for that big, limited rock vocal sound. You can get it so that just about everything from a whisper to a shout sits at the same level, and the inevitable gain reduction artifacts just seem to add to the vitality.

Finally, the tube emulation works particularly well and is great for fattening up vocal or bass sounds without losing the top end or making them seem too muddy. It adds a depth and lower mid‑range warmth that EQ rarely manages to replicate, but although it works by adding controlled distortion, it never goes so far as to let you feel that the sound is being processed excessively.

Having a stereo width control on the output is useful when processing stereo masters, though you need to use it sensibly and not try to make things too wide, otherwise sounds in the middle of the mix may get a bit lost. It is a simple and well‑established method of stereo width enhancement and can produce the illusion that the sound is coming from a wider stage than the loudspeakers normally encompass.

Five Heads Better Than One?

I've tried all the Platinum units so far and have yet to be disappointed. However, the Penta is just a little bit special in the compression department, with surprisingly authentic‑sounding tube emulation. I particularly like the way in which the front panel controls interact with the preset parameters on the rare occasions you do need to make changes.

Overall, the well‑designed presets make the Penta very easy to use, and the availability of mic, line and instrument inputs makes it a good choice as a recording channel. It is very quiet and transparent, even on the instrument input, something that is not always easy to achieve, and the wide audio bandwidth is important, as cascading several systems that have merely adequate frequency response can cause cumulative top‑end loss. On top of that, the stereo line facility means you can use it for mix or stereo subgroup processing, so those with computer‑based systems might find it ideal as both a front end preamp while tracking and as a buss processor when mixing to an external recorder. But, best of all, it costs under £300 in the UK, which is rather less than you might expect for a product of this calibre with the Focusrite name on it. Although it faces competition in the UK from other low‑cost, preset units such as TL Audio's Fatman and the Presonus Bluemax, I can imagine many recording musicians adding the Penta to their wish lists in the near future.

Digital Output Option

Focusrite Platinum Penta

A blanking plate on the rear panel covers an expansion bay which accepts an optional digital output module, though this wasn't available in time for the review. This will offer 128x oversampling A‑D conversion at sample rates of 44.1kHz, 48kHz, 88.2kHz and 96kHz, and at resolutions of up to 24‑bit. Digital output is on coaxial S/PDIF, with a BNC word‑clock input provided for clocking the unit externally.


  • Easy to set up.
  • Extremely good sound quality.
  • Compressor sounds musically satisfying as well as clean.
  • Surprisingly affordable.
  • Useful and effective tube emulation


  • Preset names not always easy to read in typical studio lighting conditions.


Focusrite have not only managed to create a preset compressor that really will meet the needs of the majority of users, but also incorporated plenty of flexibility for the more experienced user.