Joel Hamilton and Allen Farmelo each spent extended time working with the AnaMod AM670, a solid-state recreation of the Fairchild 670 Limiter, one of the most revered audio components ever produced. For the review, the two sat down together and discussed their experiences with the unit. Here is an abridged account of their conversation.

Allen Farmelo: AnaMod is the only audio company I know that does analog modeling of analog gear, and if nothing else, it’s a totally unique approach. Dave Amels (Tape Op #31), who was a Bomb Factory guy, and Greg Gualtieri (#38), the mind behind Pendulum Audio, are the two partners in AnaMod. Dave has years of experience mathematically modeling analog circuitry and implementing those models in digital code. The two of them are now taking those same patented techniques and realizing the mathematical models as analog circuitry. I reviewed their ATS-1 tape simulator (#67) earlier; it’s pretty damn impressive. It’s like having up to four enormous tape machines in two rackspaces. This AM670 compressor doesn’t weigh very much, which you found really handy for traveling, as did I.

Joel Hamilton: I did. I have an Anthony DeMaria Labs ADL 670 (Tape Op #35), and in general I kind of hate pitting this against that — one piece against another piece — because every compressor finds its day. Therefore, I didn’t just want to put the AnaMod next to the ADL. I know what the ADL does enough that it wasn’t like I was going to patch back and forth between the two. So I thought, “What can’t I do with the one that I already have?” I brought the AnaMod to Bogota, Colombia. Just in case I was captured, I could trade it for my life, and it traveled incredibly well. The ADL would have been absolutely destroyed. But in practice, I was surprised that what I ended up bringing was a really large compressor for what I thought it actually did for me when I got there. This is during tracking, mind you. I did bring it back and wound up using it during mixing, but not in a back and forth way, because I feel you need to make decisions through the device — to flatter it instead of just pulling the rug from under it to see if it still stands up straight. So I wanted to get a mix happening through this device, and I can see how it’s an incredibly useful piece. I don’t know what it costs.

AF: It sells for $3295 in the US.

JH: Yeah, a tenth of a Fairchild 670, basically. And I have used the Gates 6144 across a mix; I’ve used things like Elysia mpressor (Tape Op #63), tube, non-tube, vintage, modern, whatever; and every single time it forces you into particular decisions in the mix. It moves you gently towards a different upper-mid character if you let that information filter through you, rather than butt up against it the whole time, and I found that this thing has a particular character that I feel like I can also get with other devices that are way above its price point. Is it the best compressor for $3295? I hate that question, but I would have to say that if you need something on the mix bus, it might be one of the best choices if you can’t come up with the money for a 6144 or some vintage, vibey thingamajig.

AF: I ended up using it on the mix bus, too, when it came with me to Philadelphia. I was there to mix Cinematic Orchestra’s 10–20 minute long film scores. We were using

JH: That’s because it’s an AGC [auto gain controller], which is why people kind of confuse the idea with when you use something that just imparts compression and the level actually drops. When you hit the threshold with a 670, you see your 2-mix meters hang out at zero no matter how hard you dig into it. Well, within reason, as you can clearly overcome the ratio, but if you are bouncing up against it, you are holding the level at zero. That was the whole idea of the 670 AGC.

AF: And it worked beautifully for me in that way. And also the sonic character it imparted put a very glassy sheen on these mixes, and it helped them become very articulate and very 3D in a way that the mixes hadn’t been before. I also used it to compress bass on more of a rock track, and I cascaded the channels into each other, just to try it out. This was a different project by the children’s artist K, and I was playing bass, so it really needed a lot of help! So, I cascaded the channels into each other and just kind of got it moving a little bit, and it just sounded huge, like a reggae bass, and I didn’t really have to do much.

JH: That’s interesting that you say that about reggae. I actually wound up using the thing when I was doing some 5.1 stuff for Matisyahu. Now, I don’t have five channels of 670, you know, and forget about the sub. I was okay with the image moving around a bit dynamically, so I wound up with the AnaMod on the rears and the ADL 670 on the fronts, and that was the only time I had them “in the ring” together. I had them at the same settings, by ear, with the release curve and input gain as close as I could get them. And it was really interesting to then bus some of the stuff I was listening to in the front and then turn around and listen to it in the back and think, “Wow — that’s like twenty grand versus three grand, and it’s really, really, just about the same thing happening to the rear.” The only time that I cared about the difference was when I wanted to dig into a bus, so I did throw it on a parallel drum bus just so I could torture it. I figured it would be really neat to have a 670 just for that bus, where I usually have an Elysia mpressor or a Neve 33609 parked as one of the parallel pieces of outboard. But, when I dug into the AnaMod, it didn’t do anything fun.

AF: And this touches on a more global issue that I think Francisco [Botero, Joel’s assistant] actually spelled out really well in another conversation once, which is that when you push analog gear, it starts to shoots off in weird angles due to nonlinearities. It begins to misbehave in really cool ways.

JH: I couldn’t quite get the AnaMod to get exciting in that way that I can with my ADL. The AnaMod felt like a really good compressor, but maybe it’s just a little beige-pants at the edges when you push it.

AF: So who do we recommend this for? My recommendation is for somebody who wants to have a really awesome sounding 2-bus compressor, because I think that’s where it excelled the most. And maybe somebody who doesn’t rely on pushing gear into that weird, almost distorted place to get a certain thing to happen, but prefers to have a cleaner, more predictable kind of behavior out of a piece of gear.

JH: I agree. I also think that it could be useful as a general compressor, especially if you’re working primarily in the box. I can totally see tracking vocals with it, for example. Have it on the room mics on the way in, and then the acoustic guitar, and then everything, because overall, what it imparts is really desirable especially on the input stage, actually. And then I could see throwing all of that back through it on the entire mix, just with 2 dB of reduction, not digging in too much. Like when you do multiple layers of paint to get a particular effect, you can’t just goop it all on at once, and this box is the thing you can’t goop on all at once. A couple layers deep, though, I think it could really glue a production together. It’s such a cliché to say “glue”, but I think it’s true in this case.

AF: The other thing I would say is that it’s hard to screw up with this box, so it’s a really nice tracking compressor, especially for vocals, where someone’s got a wicked-high dynamic range, and you’re in your twelfth hour and maybe not riding gain as responsibly as you should.

JH: It’s a good point. It’s why I have a 33609 limiter on a vocal on the way in because I can get away with a quick trip over to 20 dB of reduction if somebody rips into it. And the AM670 can do that.

AF: So it falls into that more forgiving family of compressors. I think that’s an important thing to know. It’s not in the crusher family of compressors. It’s more the smooth, transparent, “wow, I barely noticed it was on, and yet, everything sounds better” kind of compressor. And another really important point: this thing won’t break. It doesn’t have tubes, and it’s not going to require the maintenance of a real tube compressor. None of that nonsense — just plug and play. We should also note that you can use it with tape, without the computer.

JH: And there’s no latency.

AF: Right, no latency. So AnaMod is onto something kind of interesting. And I actually did use it on a tape-only session. And it didn’t even occur to me then, but as I think about it now, I realize that, wow, I was using modeled technology with the computer off. I’m curious to see how this company develops, because they’re doing something totally unique.

JH: Me too.

($3295 direct;


Editor's Update:


I wanted to add some thoughts to Allen and Joel's conversation about the AM670, as it was actually my unit that they held onto for many months while reviewing the device. I don't claim to understand 100 percent how "the AnaMod process" works, but I do grasp the basic principles involved. Dave and Greg (AnaMod's founders) are two of the flat-out smartest guys working in professional audio gear design today. I've had long conversations with both, and what they know about electronics, sound and recording is deep. So when they started AnaMod I took notice and expected great things - I haven't been disappointed. 

Now let me set something straight: First, I've never owned a Fairchild 670 limiter. These classic units are hard to find and sell for $30,000 or more. I don't have that kind of money, and even if I did I'd never spend it on one piece of gear outside of a console. Secondly, I've never used a Fairchild 670. No studio I have worked in owns one. I have heard legendary tales of how great these limiters are, and I've listened to tracks I was mixing that have been recorded through one. I've heard the amazing limiting that happens, and I've heard them blown out with extreme settings (listen again to much of Elliott Smith's From a Basement on the Hill). What my studio arsenal needed was something that performed this function, and dropping $20,000 on a tube-built clone of this device was still too much for me to bear. 

My first use of the AM670 was as a second compressor, in series following a vocal that was being cut through the Pendulum Quartet (also designed by Greg). I was getting vocal level jumps from the singers this day that the smooth Vintage setting on the Quartet's built in compressor section wasn't catching, so I thought I'd pull out the classic two compressor trick. It worked like a charm and the vocals held up in the mix like a dream. It was a serious "Oh wow" moment. 

Since that first impression I've been using the AM670 on an album I'm engineering and co-producing for Christine Havrilla - her Gypsy Fuzz project. Christine can really sing, and knows how to work a mic and room as well, which is always a treat. But she can belt it out one minute and pull up to the mic and sing soft another. For most of her vocals on this record we used a Soundelux Elux 251 (Tape Op #27) tube condenser mic into a Hamptone Silverbox IV tube preamp (Tape Op #55) and into the AM670. In the mixing process more than a few lead vocal takes required no further compression or EQ. This has never happened to me before. When I would apply the AM670 to vocals tracked through a different chain, it would reign them in and hold them clearly in the dense rock mixes. I only encountered one spot where the compression exhibited an artifact that I did not like, tugging at one word in a line, and I will place the blame for that entirely on myself for setting the limiter too hard. 

I later tried the AM670 on bass guitar tracks, and found that once again it held the sound in the mix quite steadily. It was different than my usual 1176 choice, and I could see picking one or the other on occasion or possibly using both at once. 

The important piece of information to take note of here is that the AM670 is a limiter, not "just" a compressor. I've found myself thinking of this tool as something I pull out when I just can't keep something in focus during a mix, or while tracking. I now understand why the original 660/670 units are so well regarded - they fulfill a certain role and function in the studio and do it well. I own a lot of compressors, but I had nothing before the AM670 that could do what this limiter does. AnaMod did something right, and they saved me $26,000 and a few years of missed house payments. For adding this something to my studio that I never thought I would have, I salute them. - Larry Crane


Tape Op is a bi-monthly magazine devoted to the art of record making.

Or Learn More