Our Guide To The Cranborne Audio Camden 500 Preamp And Signal Processor
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Our Guide To The Cranborne Audio Camden 500 Preamp And Signal Processor

First Stop, Preamp

Preamps are often the most overlooked component in the recording workflow. Audio interfaces often cite their conversion, DSP, and software facilities as their key assets with the built-in mic preamps and their performance figures rarely finding their way onto the feature list.

The reality is that the preamp is the last stage in your audio chain before the signal reaches your converters. A poor preamp can influence your recordings even more so than microphone choice and conversion quality. In the modern age of plug-ins and DSP processing, every dB of added noise floor and distortion generated by a preamp will be amplified 10-fold by compression, saturation, and EQ effects during the mix process.

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In the same way that a painter begins their artwork with a blank canvas; capturing the purest and most unadulterated form of your audio signal provides the best possible platform to start with when you begin mixing in-the-box. Unfortunately, blank canvases are expensive! Preamps that offer transparency and sonic accuracy as their key attribute will set you back at least £700 with the best designs costing well over £4000.

UK-based audio company Cranborne Audio have developed a preamp that offers sonic performance and technical specifications that exceed the most elite and sought after preamps on the market. It’s a double award-winning preamp, and it can be yours for £299 RRP Inc Vat... with some additional tricks up its sleeve.

Next Stop, Camden

Audio specifications can’t tell you how something will sound, but they will tell you how much influence the audio circuit will have on signals passing through it. Cranborne Audio claim that Camden 500 is “one of the cleanest and most transparent preamps on the market” - quite a bold claim! On close inspection however, the numbers on the technical specifications certainly speak for themselves.  

When legendary reviewer Hugh Robjohns reviewed Camden 500 for Sound on Sound magazine, he was blown away by its sonic performance quoting that “There are far too many preamps to mention even in the 500 series alone, but few are this well built or designed, few sound this clean and quiet, and very few have this much sonic versatility”.

Hugh stated that Camden 500 has “vanishingly low” distortion. Camden 500’s spec sheet proves that with Total Harmonic Distortion that is inaudible at all frequencies and gain positions with 0.0004% THD+N @ 35dB. That’s more than 10 times lower than some high-end preamps on the market (typically with 0.003% THD+N).

Hugh also said that Camden 500’s noise performance is “near perfect” with an EIN of -129.5dB unweighted with a 150ohm load. Considering that the theoretical limit of a single component is -129.6dB EIN, all of Camden 500’s 350+ components and complex circuitry combined only adds 0.1dB onto the noise floor. That’s as close to perfect as you are ever likely to see.

Camden 500 also has a frequency response that extends far beyond the audible band from below 5Hz, to 200kHz with only ±0.7dB of roll off. As Hugh Robjohns pointed out in his review, “that flat-line response really doesn’t vary at all with different gain settings” and “some lesser designs exhibit a curtailed LF and/or HF response as the gain is increased”. He’s not wrong; some preamps can begin cutting audible frequencies between 20Hz and 20kHz once the gain control is increased! - not the case with Camden 500.

Most impressively, at maximum gain Camden 500 has “genuinely negligible low-end phase shift” with 4° of shift from 20Hz - 20kHz at maximum gain. It’s not uncommon to see phase shift figures of 30°+ on even the most elite preamps on the market. The audio effects of phase shift results in slow transients, muddy recordings, and phase cancellation causing havoc when used in multi-mic situations. Phase shift figures as low as Camden 500’s means that transients are immediate and every subtle dynamic nuance of an acoustic instrument are amplified perfectly with smearing or comb filtering.

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Sound on Sound - Camden 500 Review

You can read more about Hugh’s findings when reviewing Camden 500 by reading the full review: https://www.soundonsound.com/reviews/cranborne-audio-camden-500

By the Numbers

Specifications are baffling. What compounds their complexity even more is that different manufacturers quote different figures under different test environments at different gain positions and at different frequencies! This makes comparisons almost impossible as some preamps look impressive by the numbers but in the real world, that preamp doesn’t live up to what is promised. Cranborne Audio are aiming to demystify the spec sheet by focusing on the 4 key areas of performance (THD+N, EIN, Frequency Response, and Phase Shift) and supplying meaningful measurements and graphs to demonstrate Camden 500’s extraordinary performance across all of its gain and frequency ranges.

For a deeper explanation of Camden 500’s technical performance, Cranborne Audio have produced their own video that explains Camden 500’s performance in numbers vs competitors preamps including some audio examples.

Hands-On Performance

Record-breaking sonic performance aside, Camden 500’s layout is clean, concise, and understated. Under the bonnet, Camden 500 has 68dB of Gain available on a stepped, 12-position rotary switch with a quality feel. Putting gain on a rotary switch like this is tricky, however it means that Camden 500 does not suffer from the irregularities and gain bunching that can occur with a variable control. It also means that any two Camden 500’s on the market are perfectly stereo-matched (a feat in itself).

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All of the other controls live on rugged toggle switches that ignite vintage feelings but perform modern duties and operate modern circuits. The High Pass Filter even has a special design to provide subsonic curtailing without attenuating useful information in the 50-60Hz range.

A luxury feature of Camden 500 and something that is hard to find on a preamp is its dedicated 3-way input selector switch. This switch radically changes the input impedance, input source, and gain range of the preamp to create the best possible environment for Mic, Line, and Hi-Z sources. The Hi-Z input option of Camden 500 features a unique bipolar junction transistor circuit design that gives a muscular tonality whilst also feeling more forgiving to the musician compared to other Hi-Z input designs. The input impedance of the input is 1.5MΩ, which is high enough to bring out a natural and extended high-frequency response that sounds natural even on Piezo pickups which can easily sound very muted.

The pot on the top of Camden 500 is also a special control. Not because it’s a unique variable control with a true-bypass switch in it’s minimum position, but also because it has the power to transform Camden 500 from a clean, pristine, and natural sounding preamp into the most ‘analogue’, vintage, and coloured preamp in your arsenal...

A True Jekyll & Hyde Preamp

Capturing audio with Camden 500’s extreme sonic transparency results in 3D sonic realism that needs to be heard to be believed, however the guys at Cranborne Audio know that vintage preamps and transformer colouration is equally as desirable in the modern ‘in-the-box’ studio. But rather than turning to transformers and living with their inherent drawbacks, Cranborne Audio developed Mojo; two discrete analogue saturation styles that dial-in authentic transformer-style effects that can be subtle, exaggerated, and crucially bypassed when complete transparency is required.

Mojo started-out as a research project by Cranborne Audio to measure the influence that transformers, valves, and other vintage equipment have on audio signals. Once the data was gathered, Cranborne Audio set to work at emulating those effects using filters and discrete second/third order harmonic generators. The result was two independent Mojo styles; Thump & Cream, that transform Camden 500 into a thick, gooey, and vintage-sounding preamp that stands shoulder to shoulder with the most legendary transformer-based designs on the market.

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is a saturation style that closely matches the legendary VTB1148 transformer that has been found in countless legendary british-console mic preamp designs. Thump increases harmonic saturation and distortion at targeted low-end frequencies between 20Hz to 160Hz for increased low-end weight and thickness. Thump also features a gentle HF harmonic lift that reacts dynamically with the input signal.

Cream closely emulates valve and tape-style saturation by introducing vintage smoothness and drastically increasing THD to smooth-out the low-mid range frequency areas whilst increasing presence. Cream varies entirely on the harmonic signature and level of the incoming source for a dynamic, responsive, and reactive saturation that accentuates the source’s key frequency content to help it sit deep into the mix whilst remaining audible.

Mojo can be used to perfectly dial-in the ideal saturation levels of vintage equipment but it can also be dialed-in to beyond the point that destructive clipping would occur with transformer-based designs for an even wider palette of saturation effects. But unlike transformer-based designs, Mojo’s effects live on a variable control that can be dialed to taste on some sources, and crucially bypassed for others when transparency is desired.

Mojo on a Drum Machine

In this example, Mojo is applied to an electronic drum machine. As Thump is increased, the low-end content increases in sustain whilst remaining tight and responsive with a slight softening of the transients - just like a transformer.

Mojo on a Bass Synth

In this example, Cream is applied to a bass synth. As Cream is increased, the THD rises to up to 50% and that has the effect of softening the HF content and adding extra presence. Cream also dynamically smooths the mid-range area to help the sound sit deep within the mix whilst still remaining audible.

Mojo on an Acoustic Guitar

For this example, Mojo is being used in a slightly different way. This acoustic guitar was mic’d with 2 AKG C451’s; one pointing at the 12 fret, the other pointing at the soundboard. Cream was applied to the fretboard mic, whilst Thump was applied to the soundboard. The resulting effect is additional depth and forwardness to the guitar whilst also widening the stereo image due to Mojo’s dynamic processing.

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Tape Op Magazine - Camden 500 Review

For another perspective on Camden 500’s performance and how it can fit into a professional recording setup, you can read the Tape Op Magazine review: https://tapeop.com/reviews/gear/130/camden-500-preamp/

A Modern Approach To Vintage Sound

Camden 500 is the first product to leave Cranborne Audio’s UK manufacturing facility. It’s a preamp designed around the ever-popular and ever-expanding 500 series format and it sits perfectly inside any 500 series chassis or ‘lunchbox’ on the market.

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The 500 series format is the most cost-effective way to build up a collection of analogue hardware in the smallest possible formfactor. Over 500 different 500 series modules are available from over 200 different manufacturers (not including DIY kits) and the metal racks or ‘lunchboxes’ they are inserted into are equally as popular. Camden 500 is different to other preamps out there as it employs a brand new and groundbreaking preamp topology that is optimised specifically for the 16v current-limitations of the 500 series rather than being a 19” unit, shoehorned into a 5” tall 500 series module with poorer specs than it’s 19” cousin - like alot of the other preamps on the market.

Camden 500 is designed, engineered, and manufactured in the UK with every product sent out of the factory tested by a human with a strict regime of audio tests and visual inspections. A preamp of Camden 500’s extraordinary performance could easily command an extraordinary price tag, however Cranborne Audio’s mission statement is ‘A Modern Approach To Vintage Sound’; that means using the most modern component selection and production techniques to offer that sound we all want to hear with unsurpassable performance and all for a price that all musicians and engineers can afford.

Camden 500 encapsulates that statement perfectly.

Find out more about Cranborne Audio 

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