AnaMod AM670

Stereo Limiter

AnaMod AM670 Stereo Limiter

Review by George Shilling

So, here we go again with yet another Fairchild 670 recreation. Only, hold on, this one really doesn’t feel quite right. Yes, they’ve made a good stab at the front panel, but this thing is almost as light as a feather. And that, Fairchild fans, is because this is something a bit different from all those other valve-filled retro clones. If you remember the AnaMod ATS-1 review from Resolution Jan/Feb 2009, or have read about the company elsewhere, you’ll have guessed what’s happened here. For the uninitiated, here’s a brief recap…

AnaMod was founded by Dave Amels, formerly of Bombfactory, and Greg Gualtieri of Pendulum Audio. Together they have created a whole new category of pro-audio gear, with analogue equipment that models analogue equipment. Yes, you read that correctly. They use analogue “building block” circuits which re-create the characteristics of classic gear. So the approach is the same as if creating a digital plugin, but modelling is achieved with circuitry. This unique method was astoundingly successful in the case of the ATS-1 analogue tape simulator, a truly remarkable processor.

For some time there has been available a 500-series AnaMod AM660 module which models the Fairchild 660, and now AnaMod have apparently brought together a pair of these circuits, along with stereo linking options and an integral power supply in the gorgeous looking AM670.

The 3U front panel features kidney-shaped meters, Pultec-style knobs, chunky selector switches and a big metal power toggle. But it’s only 7.5 inches deep, and probably the lightest 3U unit I’ve ever encountered. Under the lid is an almost empty box, with just the power supply mounted against the right side, and the main circuit board hiding against the rear of the front panel, populated mainly with surface-mount chips. However, the AM670 still manages to retain much of the retro-chic of an original Fairchild by virtue of the switchgear, and the white-painted etched-in legending, (although perhaps they should have used the rather smarter AnaMod logo that’s painted on the back, rather than cheesy italic capitals!) Whilst admiring the rearmost logo, one also notes that proper latching Neutrik XLR connectors are employed for top quality signal connections.

There is also a standard IEC socket for mains, and this was a strictly 230V version – in fact some early models were wrongly voltage labelled, so as a precaution, the first example I had was seized back from me before I powered it up! Confidently flicking the toggle on the second one, an orange indicator lit and also just one of the two meters, with a warm vintage yellowy glow. I initially feared a fault, but no, the meter lights individually indicate (hard-wire relay) audio bypass by dimming - a nice idea. Discreetly camouflaged black pushbuttons labelled IN enable the compression circuit. Next to the meters are trimpots to Zero the needles in gain reduction display mode, and the large switches allow you to independently change the metering also to Input or Output level. Knobs for Input Gain and Threshold are continuous and just slightly damped, unlike the light clicking you get on a real Fairchild (for the input at least). This allows for smaller tweaks but makes matching the channels slightly harder, as the scale markings are fairly vague; input level ranges from -15 to +15dB.

The original six Time Constants are present, along with two extra settings. Position 1 is fast, and usually works well for squashing drums and particularly drum ambiance for super-crunchy room sounds. And, Wow! This is very, very close to the original… All that airy distortion and chomping is present in a most authentic way here when you crank up the knobs. It sounds huge, and brings an instant smile to your face. Position 2 is slightly less over-the-top, retaining a bit more drum punch at the expense of pumping when pushed hard. But it all sounds stunningly rich and crunchy. AnaMod have additionally provided 2a and 2b, suggested as vocal-friendly alternatives to position 2. They retain the fairly fast attack of 2, but provide slightly longer release settings – 2b matching the release time of Position 3. I quite liked 2a’s subtlety on a drum subgroup, and 2b retained just the right amount of punch on a McCartney-style Hofner bass part, lending a hint of warm valve breakup to enhance the richness of the sound. However, on vocals, I generally gravitated towards position 3 or even 4, which, even when pushed hard retained a smoothness that I couldn’t quite achieve with any of the ‘2’ settings, those seeming often to add a very slight pop at the start of notes. Despite those new vocal settings, I found position 3 absolutely sublime on a close breathy folk-country female vocal.

On the mix buss I like the Auto release setting of position 5 using the UAD Fairchild plugin if I’m in-the-box. The AnaMod seemed a little faster, quicker than I recall on real Fairchilds I’ve encountered, but of course they can vary. Position 6 has a faster attack and the release for this was variable internally on original 670s. Here, it is wonderfully sedate. One thing I’d forgotten was how hard the knee can seem (in all modes), and how tricky it can be balancing the Input and Threshold knobs – this must be fiddly on the diminutive AM660. Here, it’s still a fiddle but one has the luxury of enormous, smooth knobs!

At the far right is a mode selector for dual Left/Right operation, Lat/Vert (M-S) mode, and a Stereo Link mode (not found on original Fairchilds). I’m delighted that the Lat-Vert mode was retained from the original – playing with M-S signals to vary apparent width or create extra punch in the important mid signals can be great fun. Setting up the Stereo mode is perhaps not quite as straightforward as on some other stereo compressors, as one must carefully match left and right settings on each channel to be certain of accurate balance. The image remains stable, but with the sensitive nature of the knee it is easy to send the whole thing slightly lopsided. I have happily used 670s across the mix buss on occasion – and no doubt many stereo discs were cut in the 60s through ‘dual-mono’ 670s without disastrous consequences, but Stereo mode is a wonderful bonus.

Any fears that somehow the modelling process might not match the magic of valves are unfounded. Despite my gushing praise for the ATS-1 a year ago, I was still unprepared for how breathtaking the AM670 sounded. Absolutely love it!

Pros: Stunningly and magically authentic Fairchild sound; No latency; Compact

Cons: Fairly expensive (but cheaper than a Fairchild!)

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