Chameleon Labs: 7603 & 7603-XMod mic pre/EQ

I’ve always been a big fan of Chameleon Labs’ gear. They were one of the first companies to bring classic audio designs into the realm of affordability. I’ve owned a pair of their 7602 [Tape Op #51] mic pre/EQs plus one of their 7720 [#67] bus compressors for close to ten years now and have used them both on quite a few records. The 7602 is based on the classic Neve 1073 circuit while the 7720 is based on the VCA SSL bus compressor. Are these units identical to a vintage Neve 1073 or an actual SSL bus compressor? No. But that hasn’t stopped me from recording quite a few fantastic sounding tracks with these units, and I’ve always been pleased with the results. Of course, these processors were much, much more affordable than their vintage counterparts, so I was a bit sad to see Chameleon Labs disappear from the marketplace a few years back, but this story has a happy ending, so stay tuned. I was also somewhat frustrated that in the past year or two my 7602s gradually became noisy and intermittent with regards to the EQ frequency selection switches – in some positions they barely worked. While a lot of vintage Neve units may have switch problems, if you exercise them they usually come back pretty quickly. Either way, noisy switches don’t seem like something you want to emulate.

So on both fronts, I was really happy to see that Chameleon Labs was brought back from the brink of extinction by Marcelo Vercelli and that they had completely redesigned the 7602 by re-introducing it into the marketplace as the 7603 with an improved build quality. What a difference one digit makes! The 7603 has completely changed with a huge step up from the older 7602. There are two versions: the standard 7603 with proprietary Chameleon Labs-wound transformers, and the XMod (at $400 more) that incorporates Carnhill input and output transformers. Upon picking up the units from my shipping center, I immediately noticed that they were heavy! I thought maybe they made a mistake by sending four processors instead of a pair, or that there was a massive external power supply for the new unit – nope, just two extremely solid and well-built mic pre/EQs in one box. Next, I disassembled the units to have a peek at the build quality and was very impressed. While some of the circuit utilizes surface mount components, it was obvious that a lot of care went into the construction, design, and component choices of the 7603. Beefy transformers, inductors, and capacitors were an obvious clue to the thoughtful, sturdy design of these units. Looking closer, I could see that the front panel components were solidly mounted so that they would not fail from stressing the circuit board after a few years. Additionally, I was very happy to see that the EQ selection appeared to be custom switches. The 7603’s internal build quality extends to the front panel components. The old 7602s sounded excellent but looked a little cheesy with cheap plastic knobs, while the new 7603s have a much nicer aesthetic, incorporating color-coded anodized aluminum knobs – an improved look and feel that inspires confidence. A few other small but welcome features were added as well, including a VU meter with switches for Input, Output, dB Range, and impedance. I reached out to Marcelo at Chameleon to find out more about the switches and got a lot more info back from him than I had asked for! “We spent a couple of years working on the 7603’s so I would say that they are certainly ‘inspired’ by a Neve design but they also deviate substantially in areas where we had our own ideas. When I studied the Neve 1073 years ago, I felt that it was cleverly done in light of the parts and components available at that time. When I contemplated how we would confront a new design based on this architecture, I made a shortlist of things we wanted to work on in terms of developing something unique. We first looked at the fact that nearly all of the classic audio gear we love has no star ground and by definition has a tough time fighting RF- and EMI-based parasitic noises that are now commonplace in any environment we work in. We spent a lot of time focusing on ground plane design to achieve the lowest possible noise floor and maximum protection of delicate microphone signals. We also had to develop a relatively sophisticated switch mode power supply with five voltage rails and ultra-low noise generation, all while keeping high frequency noise away from the mic stage.

One of the clever things about the 1073 was the way the input gain buffer uses a pair of stages that can be run in series to achieve 70 dB of gain. Most of these circuits use a single-sided 24V power rail. Early on we had clear thoughts on the topology and parts we would use in the signal buffer stages and output stage. We felt we could achieve superior performance by using a +/-16V set of rails that delivered 32V peak to peak.More importantly, we spent a lot of time developing a forgiving, low noise analog architecture using parts that are so much better than the ones available in the early ‘70s. We also focused on controlling noise floor and quiescent noise issues by developing a variable gain output stage that helps keep the unit very quiet. The 1073 was based on the Fairchild BC184C, an expensive and worthy component in its day, but simply outclassed by the transistors available today.

When we purchased Chameleon in 2014, I was really in love with the idea the brand represented; classic analog gear at an affordable price. I felt that if we could focus on developing a core group of important passive components, we could build substantially improved products but continue to be true to our brand’s value commitment. We, therefore, invested in making our own input transformers, output transformers, inductors, switches, and power supplies. We have even begun bobbin winding operations as well as the final test and assembly of all of our products in Woodinville, Washington.

We spent lots of time on the topology of the 7603 so that the circuits themselves are really low noise and sound amazing without driving an output transformer. We felt that if we could get that right, we could really squeeze the harmonics and ‘character’ we wanted from the output transformer. We spent quite a bit of time winding transformers, trying different ratios and techniques, and found that the core and winding structure of the output transformer is where it all really happens in terms of mojo and color. Between that and figuring out how to set up the DC currents flowing to the core correctly, we achieved the character we were looking for. The final embodiment of the product is a function of our desire to make signal flows clean, PCB board, and parts layout tidy, and making sure that the product is reliable and straight forward to manufacture.”

We have a vintage Neve 1073 at Panoramic Studio that’s in pristine condition and was recently overhauled by Steve Veilleux of SVT Audio. He put in all new switches and replaced any worn capacitors and it’s been sounding phenomenal. I met up with engineer Robert Cheek and tracked some guitar and snare drum through both the Neve 1073 and the two Chameleon Labs 7603s. We were pleasantly surprised at how closely the standard 7603 came sonically to the vintage 1073, especially on electric guitar tracks – it was really hard to tell them apart. On the snare drum, however, the vintage 1073 had a nice subtle bump on the low end that the 7603 lacked, and we both felt the Neve sounded a bit better on the snare due to that but also agreed that it was nothing a tiny bit of EQ couldn’t have matched. We also tracked some acoustic guitars through the 7603s with a pair of Soyuz 013 SDC mics [Tape Op #139] and felt like the 7603s more than held their own next to our vintage 1073.

When we moved over to the 7603-XMod, I was surprised at how close it sounded to the standard Chameleon Audio transformer. Sure, there were some minor differences, but nothing very significant. The XMod seemed to have a slight bit more clarity in the bottom end while the top end sounded just a tiny bit smoother, but again nothing hugely significant in my opinion. This speaks well to the engineering efforts Chameleon Labs has put into their own transformer design. While using the 7603s for several weeks on a project, I thought the EQ sounded excellent, was easy to dial in, and delivered exactly what you’d expect from a Neve 1073-based inductor EQ design. Scott McChane recently wrote about the Chameleon Labs 560 EQ [#136], so I’ll refer you there for an in-depth review of the EQ.

If you’re in the market for a solid state mic pre based on the Neve 1073 family, I’d highly encourage you to check out and listen to the Chameleon Labs 7603. They sound fabulous, are affordably priced, sensibly updated (as opposed to boringly recreated), and built to a much higher standard than some of the offerings I’ve seen from other introductory priced gear manufacturers. When you factor in the added VU meter and impedance switch, I think the 7603 is the best value in 1073 clones on the market right now.

If you’ve got the money to spend, it’s nice to have the XMod version so you can claim you own the same transformers as a vintage Neve, but if you don’t want to spend the extra money, you’ll be just fine with the more affordable standard 7603. To be honest, based on the sonics I’m not sure I’d spend the extra money on the XMOD version, as the standard one sounds great. Plus, with the money saved that would allow me to buy one of the 500 series Chameleon EQs, gaining an extra hardware EQ for my studio.