FOCUSRITE OCTOPRE Details

NAMM 2002 saw the unveiling of the latest Focusrite processor, the Platinum OctoPre. Providing eight pristine discrete channels of Focusrite Class A mic pre and compression, OctoPre routes directly to any digital audio workstation via eight standard analogue outputs, or via a choice of two optional 24-bit, 96kHz A/D converters (see below for details). The new OctoPre offers the unique qualities associated with the Focusrite name at an affordable price.

Each channel features a revolutionary compressor/limiter circuit, providing a warm-sounding compressor, which morphs into a brick wall limiter to avoid those critical overs, ensuring total control over all eight channels.

The mic pres featured in OctoPre are the same as those featured elsewhere in the award winning Focusrite Platinum range. They are a transistor-based Class A design utilising the same full-bandwidth philosophy as the legendary Red and ISA mic pres, ensuring detail and clarity without colouration. The first two 'super channels' also feature phase reverse, as well as TRS jack inputs on the front fascia for quick and easy, DI-free instrument plug-in.

Eight line level balanced (+4 dBu) analogue inputs and outputs are provided as standard via 25-pin D-type connectors. These D-type connectors may be routed to 8 XLRs by means of an 8-way 25-pin D-type to 8 XLR breakout cable, available separately. In addition to the analogue outputs, the OctoPre can be fitted with one of the following two digital output options:

24-bit/96 kHz ADAT™ interface card

This card provides digital outputs for all eight OctoPre channels, which operate over the full sample frequency range (44.1, 48, 88.2 and 96 kHz) and can be dithered to 16-, 20-, or 24-bit depths depending upon the destination. External word clock synchronisation is possible using the rear panel BNC connector. The card features two ADAT™-type lightpipe output connectors. For speeds up to 48KHz both connectors transmit all 8 channels simultaneously. However, ADAT™-type connectors are bandwidth limited at sample rates above 48 kHz - each audio channel uses two ADAT™ digital channels to accommodate the increased quantity of data, hence the need for two ADAT™ connectors to allow 8 channels of conversion at high speed.

24-bit/96 kHz AES/SPDIF/ADAT™ interface card

This card contains exactly the same ADAT™-type digital output facilities as described above, with the addition of AES and SPDIF format outputs via a 9-pin D-type connector on the rear panel. As with the ADAT™-type outputs, the full range of sample rates and bit depths are available, and the converter may be synchronised to an external word clock source if required. To access the digital signals from the 9-pin D-type AES/SPDIF output connector the A/D card must be purchased with either an AES or SPDIF D-Type conversion cable, available separately. Either 8 AES or 8 SPDIF outputs can be used simultaneously with 8 ADAT™ outputs and the OctoPre's analogue outputs.

With Class A Focusrite processing and almost all the interface options known to man, the Platinum Octopre is the perfect partner for any Pro Tools system or any other digital audio workstation, making high quality, multi-channel recording easy. Equally it could be utilised as an instant location recording solution, or as an additional set of mic pres for any analogue or digital console, or hard disk recorder.

Please note: The power supply featured in OctoPre is not a switching power supply. Consequently, 120v OctoPres are not suitable for use in 220-240v territories, and vice versa.

 

FOCUSRITE OCTOPRE Specs

Specifications
Inputs

Electronically balanced 20kW

Nominal level +4dBu / -10dBV

Input Connectors

1/4” jack (channels one and two only)

25 pin D-type 8 channel line level analogue connector

8 XLR inputs for Mic

Front Panel Controls

Phantom Power: On/Off: +48V

Gain (mic): 0dB to 60dB

Gain (line): -10dB to +10 dB

Gain (instrument): 0dB to 60dB (Impedance > 1MOhm)

Phase Reverse: On/Off (Channel 1 & 2 only)

High Pass filter: On/Off: -12dB / octave. –6dB at 75Hz

Dynamics: Limiter threshold is fixed at 20dBu. Compressor threshold and ratio is variable

Frequency select: Switchable (44.1, 48, 88.2, 96kHz)

Dither: 24-, 20- or 16-bit

Metering

Signal Present: -20dBFS (green LED)

Overload: +22dBu (red LED)

Compressor mode: Yellow LED intensity increases with compression

Hard Limit mode: Red LED on when limiting (threshold = +20dBu)

Analogue Output

25-pin D-type 8 channel analogue connector

Performance specifications

THD: 0.001% @ 20dBu input, mic and line at 0dB gain

Noise: -96dB at unity gain through the unit

Mic EIN: -128 dBu @ 6dB of gain with 150Ohm termination impedance

Frequency response: -1dB at 10Hz to 200kHz

Dimensions

480mm (w) x 44mm (H) x 265mm (D)

Weight

3.2kg

 

FOCUSRITE OCTOPRE FAQ

FAQs

Q: What are the basic features of the OctoPre?
Eight mic pre's, eight compressor limiters, optional 8-channel A/D conversion (2 formats available.)

Q: Is the compressor just a global compressor across all eight channels?
A: No, each OctoPre channel features a unique, independent compressor/limiter, so you have EIGHT discrete compressors in total. Each can be set independently to act as a brick wall limiter, or to add increasingly heavy amounts of compression to a given channel.

Q: Which applications is the OctoPre suitable for?
A: The OctoPre can be used as a multi-channel front end for Digital Audio Workstations, allowing multi-channel recording to HD. Equally it can be used simply as the perfect interface/ A/D converter for synths/other line level devices. It provides additional channels for anyone who has run out of mic pre's on their analogue console (either live or recording,) and is especially useful as a source of additional mic pre's for digital consoles. Finally, anyone who needs 8 channels of compression/ limiting will find the OctoPre extremely useful.

Q: How many rack spaces does OctoPre take up?
A: The OctoPre is just a 1U device.

Q: Does the OctoPre support phantom power on each channel?
A: Yes it does.

Q: What rear panel connections are featured?
A: The OctoPre has 8 XLR connectors for microphone input, and 8 line level inputs and 8 line level outputs connected via two 25-pin d-sub connectors. This allows the OctoPre to be connected to a patch bay and have every input connected at all times for easy operation. (Note: some competitive products make you physically remove the unit from your rack to switch between +4 and -10 operation, and cannot be permanently wired to a patchbay.)

Q: What other connections are on the back panel of OctoPre?
A: The fully loaded unit features a 9-pin D-type connector allowing digital output in AES/EBU or S/PDIF format, and two Lightpipe ports for 96kHz ADAT (aka S/MUX2.)

Q: Is the OctoPre a Class A device, and why is that important?
A: Yes, the OctoPre is a Class A device. Why? Class A is a type of amplifier design in which you have a standing DC current running through your amplifier circuits all the time. As the signal comes along you vary what you're taking from that, rather than switching between supplying a positive current for one half of the waveform and a negative current for the other half. This results in the ability to represent audio in a linear (distortion free) manner all the way through the circuit. Cheaper processors use IC amplifiers which run close to Class B and don't have the same standing DC current, which means the transistors inside the chips are switching on and off, inevitably resulting in less linear performance.

Q: Should balanced connectors be used with the OctoPre?
A: Yes, where possible. However the line level analogue inputs and outputs (although balanced, operating at +4 dBu,) can operate with unbalanced –10dBV input sources. Alternatively, if using an unbalanced instrument source, you can connect to the unbalanced 1/4" inputs on channels 1 and 2.

Q: Does the OctoPre have the same kind of spectacular bandwidth that has given the Red and ISA range units their reputation for ‘open-ended' sound?
A: Yes. The audio bandwidth of the OctoPre is 10 Hz to 200 kHz!

Q: Is there an optional digital input card?
A: No, because all the processing in the OctoPre is entirely analogue - so even if there were a digital input, the digital signal would have to immediately pass through a D/A converter to allow processing!

Q: Why is the 24-bit 96kHz specification important?
A: An A/D converter works by sampling the audio waveform at regular points in time, and then quantizing those values into a binary number, which relates to the number of bits specified. The quantized signal must then be passed through a D/A converter before it becomes audible. In simple terms, the D/A essentially joins the dots plotted by the A/D converter when the signal was first converted to digital. The number of dots to join, combined with how little those dots have been moved, determines how accurate the final signal will be compared to the original. The greater the sample rate and bit rate, the more accurate the whole digital process is. So 24 bit/96 kHz performance will ensure more accurate digital transfer of your audio information compared to the old 16-bit/44.1kHz standards. This is especially important if further digital signal processing is to be applied to the signal once converted to digital, as any mathematical operations taking place on the data, (for example as a result of a gain change, or dynamic
effect process,) may result in quantization and rounding errors. The higher the
resolution of the digital data, the smaller the audible effect of these errors will be.

Q: What if my system only operates at 16 bit, 44.1kHz?
A: No problem, the OctoPre features dithering and supports most sample rates, (simply select the rate you need from the OctoPre's front panel,) so you can use an OctoPre with a 16, 20 or 24 bit system operating at 44.1, 48, 88.2 or 96kHz.

Q: What is dithering? Why do I need it?
A: When dropping down from e.g. 24-bit to 16-bit, quantizing errors occur because 24-bit sampling involves more samples than 16-bit, so when you reduce the bit depth the extra samples have nowhere to go. At high signal levels these errors are random and not audible, but at lower signal levels the errors correlate more closely to the audio and become audible as distortion. Dithering effectively ‘randomises' the truncation errors at lower levels, causing the 'least significant bit' distortion to disappear.

Q: Can I retrofit a digital board to an analogue OctoPre at a later date?
A: Yes, and you can do it yourself - it can easily be retro-fitted at any time without any soldering etc, just a few screws to undo, and one clip-connector to join to the main PCB.

Q: How can the OctoPre operate with the ADAT lightpipe format at 96kHz? I thought the maximum sample rate for this format was 48kHz?
A: Not any more. The OctoPre supports the new 96kHz ADAT specification, using two discrete optical ports.

Q: So how are the multiple digital outputs configured at 48kHz/96kHz?
A: At 48kHz or lower: the 8 AES or SPDIF (switch-selected from rear panel) outputs can run simultaneously with 8 ADAT outputs, plus 8 ADAT outputs from the second port (hence 24 simultaneous digital outputs in total.) The ADAT outputs in this mode are exact duplicates of each other. All output formats put out the same set of 8 channels in terms of sample rate, dither etc. At 96kHz: outputs are the same as above, except that the two ADAT ports carry
output channels 1-4 and 5-8 respectively (hence 16 simultaneous digital outputs in total). In simple terms, the A/D puts out three separately buffered sets of 8 channels at 48kHz, or two separately buffered sets of 8 channels at 96kHz. The digital outputs can always be fed with any mix of mic, line or instrument inputs.

Q: When the A/D is used, are my analogue outputs available for use?
A: Yes. The line outputs can run simultaneously with both the ADAT and AES or S/PDIF outputs, providing, all at once, 8 line level analogue outputs, 8 Lightpipe ADAT outputs and 8 AES or S/PDIF outputs.

Q: Are the OctoPre 25-pin d-sub connectors (analogue outputs) wired for TASCAM or Mackie wiring spec?
A: The OctoPre sub-connectors are wired to the TASCAM specification.

Q: Do I need to buy an option cable to use the analogue outputs on the OctoPre?
A: Yes. We recommend the following models from Hosa: Line output d-sub connection to 8 x XLR: DTM805 Line input d-sub connection to 8 x XLR: DTF805

Q: Do I need to buy an option cable to use either of the A/D cards?
A: Yes; ADAT optical cables are available from many sources, and Focusrite will offer their own 9-pin to 4 phono (RCA) connectors S/PDIF cable and 9-pin to 4 XLR connectors AES-EBU cable.

Q: Do the OctoPre's A/D options feature WordClock as standard?
A: Yes, Wordclock may be fed in via a BNC connector on each A/D to allow synchronisation to any Wordclock master source.

Q: Why do I need Wordclock anyway?
A: When using multiple pieces of digital equipment it is necessary to make sure that their bit-streams are all in sync. In order to do this all equipment need to be synchronised to a common Wordclock system. Somewhere in this system a Wordclock ‘master' must be dictating the Wordclock for the rest of the equipment, (‘Wordclock slaves') to follow. Failure to sync. all pieces of digital equipment to a common Wordclock source will result in audible clicks and glitches in programme material.

Q: What is the function of the ocean blue LED on the OctoPre's front panel?
A: i.) It indicates when electricity is flowing though the unit. ii.) It looks very cool in low-light conditions.

 

 

FOCUSRITE OCTOPRE Documentation

Product Brochures

• OctoPre_Brochure Size - 256.56 Kb

User Guides

• Octopre 25-pin connector pinout Size - 32.01 Kb

• OctoPre_digiinstall Size - 45.37 Kb

• OctoPre_digioperation Size - 538.39 Kb

• OctoPre_Userguide Size - 447.64 Kb

FOCUSRITE OCTOPRE Review

Quotes
"The equipment offers a very high functional value, using minimal space at an exceedingly attractive price. The OctoPre is small and light with capabilities up to 96kHz. When one can avoid the extreme tax liability of setting up, there is in our opinion, at this time, hardly an alternative in this price range."

"In comparison to the microphone pre-amps of the already installed ADT mixing desk, that we have been using for a long time already, the pre-amps of the OctoPre sounded (on the tested voices) immediately attractive and presentable. The sound image was open and soft..."

"In conclusion, the OctoPre is exceedingly good value for money, has flexible possibilities and many microphone paths fabricated to good quality. Even if good periphery equipment is used and especially as there is no shortage of DAW front-ends today, market niches still keep cropping up and Focusrite has obviously found one."

Dieter Kahlen, Studio-magazine, Germany

"On spec, this one looks like a knockout bruiser with a list of stats thatwill make competitors train a little harder. It's also got a pedigree - the Focusrite name alone makes this one worth getting a ringside seat."

"Tests on a variety of sources gave great results. I recorded guitars, voices and percussion instruments and the results were more than acceptable. I have an oddball acoustic guitar that is particularly difficult to capture...This is a big-sounding, rich, but not exceptionally bright guitar. I got some of the best results I've ever had recording this instrument with a Rode NT3 mic and the OctoPre. This combination captured the mellowness of this old beauty exceptionally well, with an admirable depth of field. Transparency is an audio quality that is hard to define but easy to hear - I definitely heard it in this test. Voices fared equally well. A nice openness, combined with good detail, were the characteristics of the recordings I made. Percussion instruments sounded rich and full bodied. The amount of gain in the design left me lots of room to capture the transients without distortion."

On the dynamic processing: "Whatever it is, it's quite musical and useful. At its lowest position, limiting only, you've got built-in protection for occasional transient spikes. In the digital world this is a good thing. In compressor mode a little bit goes a long way, but it does sound good. I really liked it on voices and on direct-injected guitars. It's got a nice punch to it and it seems to alter the frequency response in a way that's flattering."

"All in all, it's a far better sounding dynamics processor than those found in other units of this type that I've tried."

"I liked this unit a lot. Enjoyable as it is in the studio, I'd be happy to have it in my live recording rig. I know I would make good use of the dynamics function. In the likely chaos of a live recording, a limiter is a godsend. Eight of them on eight good-sounding Focusrite pre-amps is a miracle. And an affordable one - even with the addition of one of the digital output cards, the OctoPre is incredibly good value for the money."

Bill Stunt, Recording, May 2003

"The mixer's pre amps sound fine, but when I A/B'd it against the OctoPre, it was as if a veil had been lifted (sounds corny but it's true). It brought out the best in all the mics and sources I tested it with. All subtle nuances of the source material were revealed, whether breathy female vocals or the string overtones of an acoustic, with nary a hint of harshness in upper mid range, where many pre amps fall down; highs were open and the bottom end was solid. The entire frequency spectrum was extremely well balanced, and noise not an issue."

"I plugged both bass and guitar straight in, and again the sound was well balanced and superb."

"The dynamics worked better than any single knob has a right to, whether on vocals or guitars, and while it wouldn't do away with a 'character' compressor, it could make other compressor/limiters used for gain control redundant. It was easy to 'dial in' a setting to suit, and the limiter was unnoticeable in virtually all sensible settings."

"When you take into account the exceptional dynamics of this unit, which more than equals many stand alone units, the price per channel comes down to more reasonable levels."

"If you often record more than one channel at a time (in which case a voice channel may be a better option) you really should try the OctoPre out. Chances are that it will be a lot better than the preamps on your board, and you'll end up with noticeably better results."

Chris Martin, Music Mart, March 2003

"The Class A pre-amps on the OctoPre are superb. They are extremely quiet and smooth [...] Taking a guitar feed straight through the front TRS jack inputs on Channels 1 and 2 was equally impressive."

"Focusrite has put a great deal of time and effort into this design and it really does show operationally."

"As you rotate and introduce more compression, the effect smoothes out and you really start to appreciate the amount of control that you actually have."

"Setting up the dynamics to an input source was very simple indeed, with very pleasing results. Both experienced professionals and home studio users will find the OctoPre a real joy to use."

"Even with competition, the OctoPre's versatility and sonic qualities represent quite a reference point for other manufacturers. With the mic pre-amps alone this would be a great addition to any rack."

"With the digital option fitted, the Focusrite OctoPre represents the most cost effective and sonically pleasing stand-alone input stage for digital users, and another good option for both live and studio applications."

Simon Tillbrook, Audio Media

"Once again the English company Focusrite has provided a product that is perfectly suited for all users looking for a unit that provides more than just two efficient class-A mic pre amps for audio productions. Whether as an extension for analogue recording in both studio or live applications, or as an high-class A/D converter for DAW productions, paired up with the optional digital board this unit is certainly impressive, providing easy handling, brilliant technical specs and a great price/performance ratio."

Sound and Vision (Germany)

"OctoPre is a good example of smart design."

"OctoPre offers best mic preamp combined with good compression."

"Great value for money."

Interface, October 2002

"Another multichannel preamp with a thing about the number eight? Possibly, but this unassuming unit represents something of a rethink on traditional functionality and the interpretation of 'wow'."

"Focusrite has obviously put a lot of thought into this product. The result is ideally suited to a whole host of applications and there is a lot more to it than initially meets the eye."

"The front panel of the OctoPre is clear and reasonably uncluttered when you consider exactly how much is going on in the space."

"They [the mic pre-amps] proved to be very quiet, and sound open and natural at all levels of gain. There is little obvious colouration of the sound... they perform very admirably indeed. So well in fact, that Focusrite could be forgiven for leaving things there. But it is with the addition of the OctoPre's two other functions - dynamics processing and digital connectivity - that the application for this unit becomes more obvious."

"Focusrite allows the compressor and limiter to act on fast transients by only severely affecting the high frequency part of the waveform. This leads to less intermodulation distortion and therefore a more musical response."

"As eight channels of decent mic pre-amp alone it may well find a home in many studio outboard racks. With the digital options fitted and the stripped down, yet effective, approach to dynamic processing the OctoPre is also ideally suited as an analogue front end to a DAW, or incorporated into a live recording rig in conjunction with a digital multitrack. In the live recording or project studio DAW scenario, I can see the OctoPre becoming a real alternative to, and taking sales from, the more traditional small format stereo mixer."

"...when you consider the capability, compactness and price it becomes a compelling all-round package with a 'wow' factor all of its own."

Jon Thornton, Resolution, October 2002

"Given that there are eight mic pres crammed into a 1U box you might expect the facilities to be quite basic, but actually Focusrite have been quite smart with what they've included."

"The OctoPre is designed to be as simple to use as possible, and once you've sorted out your chosen interconnections this is certainly true. From the simple fact that each channel only gets one gain knob (there's no output trim as such) and that compression is controlled by another single knob, there really is little margin for error. This is great if you're in the process of recording a live session, leaving you more time to sort out mix positions."

"It's worth noting that in practice the OctoPre's digital output board interfaces seamlessly using the ADAT and S/PDIF connections, and having the bit rate and sample frequency clearly indicated on the front panel is also a welcome feature."

"With so many soundcards supporting the ADAT interface you can't deny the attraction of the OctoPre as a front-end A/D converter for your computer as well as the perfect recording solution for recording multiple sources."

"You'd be hard-pushed to find eight quality mic pres anywhere else at such a competitive price."

"Verdict: 10/10 sounds & results."

"If recording multiple live instruments is part of your music-making process the OctoPre is without a doubt the unit to go for."

Jon Musgrave, Future Music, October 2002

"All knobs and switches are clearly arranged and in spite of it being 1U, are very easy to use"

"It's with the optional AD converter board that the OctoPre gets really interesting"

"Conclusion: Respect! With the OctoPre Focusrite now have a unit in the Platinum range which is suitable for all who are looking for more than two well sounding class-A microphonepreamps. As an extension for analogue live desks or studio operations or with the optional digital board as a high-class AD converter for HD productions, this unit is a good choice in all cases. The OctoPre saves space, is easy to use and futhermore it sounds great."

Soundcheck (Germany), October 2002

"In use, the mic amps sounded excellent at both low and high gain settings, and DI'ing an electric guitar via one of the Super Channels also gave very good results"

"I can see OctoPre owners making a good deal of use of its dynamics... the OctoPre's compressors are more versatile than their single control would suggest. At low settings they are relatively transparent and would be useful for ironing out uneven playing on, say, acoustic guitar; more extreme settings are flattering on vocals and add a healthy 'chunk' to clean electric guitars."

"With the OctoPre, Focusrite have taken advantage of a gap in the market, and the unit has surprisingly little competition."

"At £149 and £249 respectively, both of the OctoPre's digital options offer good value for money."

"I know of no other product that offers the same balance of features at the OctoPre's price, and it must be considered excellent value for money. As a front end for a digital recording system, it's much cheaper than comparable rackmounting alternatives. Meanwhile, compared with the option of using a budget analogue mixer for this purpose, it offers substantial advantages in terms of size, expandability, and (in many cases) sound quality, as well as offering built-in dynamics and A-D conversion. I expect Focusrite to sell bucketloads of them."

"Summary: The current gap in the market for affordable multi-channel mic preamps has given Focusrite an opportunity and they've grasped it with both hands. The OctoPre makes an excellent companion to almost any digital recording system."

Sound on Sound, September 2002

Other views of FOCUSRITE OCTOPRE (Click to enlarge):