First Impressions
Like other Chameleon Labs units that I have used and owned, the 7720 is a sturdy one-rack space unit with a thick aluminum faceplate. The pots and switches feel sturdy and operate smoothly and the retro-style analog VU meter is a nice touch as well. A departure from the original Chameleon units is the addition of a 24VAC outboard AC transformer power supply. This is not a traditional wall-wart. DC filtering and regulation is accomplished inside the 7720 itself. The older 7602 channel strips of Chameleon Labs signal processors required the purchase of the CPS-1, a ½ space rack mountable power supply. The 7720 is still compatible with the CPS-1 but the included supply drops the “price of admission” of the 7720 by a substantial amount. Incidentally, this is the same method as how the new 7602mkII channel strip is powered.

The 7720 features stereo only operation (one set of controls for both channels) which indicates that it’s primary design is use as a stereo bus compressor. Two of the handiest features that you will notice when viewing the faceplate is the ability to select the VU’s metering between left or right channel input and output, or it may select to monitor the overall gain reduction. The other feature is the high pass filter in the path of the gain reduction detection circuit – this allows you to compress above a certain knee frequency, allowing the low frequency content of your mix (or stereo subgroup) to retain all it’s power in the mix without also triggering the compression circuit to engage when perhaps you would not want for it to.

In Use
Since the 7720 was designed as a bus compressor that is where I used it during most of my evaluation of the unit. I used the Compressor mainly as an insert on the stereo master fader of my Pro tools HD rig.

My best results were attained by using a compression ratio of 1.5 or 2 and using the HPF side-chain engaged. By dialing the low frequency information out of the gain reduction detection I was able to minimize the unwanted mushy coloration caused by the gain reduction being triggered by the pulsating low end. I found that the 7720’s main strength was at a gain reduction level of about 3-5db. It offered a nice musical glue for the main mix and was easily tweaked by adjusting the unit’s ratio and output controls to balance the gain reduction and make up gain. I did use a plug in limiter after the 7720 for final brick wall limiting and the tweaking of the 7720s output level was crucial to dive the plug in limiter to get the desired final hot level desired in most final masters. As far as the attack and release parameter are concerned I seemed to mainly use a medium attack time and the faster of the release settings. As you would expect though experimenting with different attack and release settings while mixing or mastering is a good idea until you get the feel of the units performance characteristics.

While evaluating the unit I did try it on several sources other than the mix bus. The 7720 did a great job of taming the transients while tracking stereo keyboards but my favorite use of the unit was on clean guitars. This compressor could easily be the best clean guitar tracking dynamics control that I have yet heard. I was able to make to clean guitars much more lively and energetic especially at higher gain reduction levels. They seemed to really jump up front in the mix when being compressed with the HPF set to 220. If you work with country, Americana or indie rock this could be a real magic bullet for your guitar tracking.

While I didn’t get a chance to try it I’ll bet it would sound great tracking direct bass though one side and mic’ed bass though the other. I’ve had great luck using stereo compressors for that in the past.

PROS
Well built, attractive price point, great for tracking as well as mix bus compression, HPF works very well when tracking

CONS
Mainly set up as a stereo unit. Compression mode sounds better than Limiting mode.

Conclusion
While this isn’t the best bus compressor that money can buy, it may very well be the best at it’s price point. It seems that quality stereo hardware compressors usually cost well in excess of 1000.00 and the 7720 is well below that. With it’s price being about ½ of that of competing units the 7720 will surely find a home where budget and the search for serious quality audio meet. I own quite a few Chameleon pieces and they have always been useful workhorse additions to my working collection of high end gear. I find that Chameleon Labs has great customer service for such affordable gear. So, I often recommend CL’s wares to friends and students of my audio classes. The 7720 is no exception.

Buy the Chameleon Labs 7720 Stereo Compressor at Front End Audio