Following the Genlyte Thomas Group's acquisition of Entertainment Technology (ET) in August 2001, ET has made an impact on our industry, introducing a number of innovative products that provide unique solutions to challenging applications. Since the successful application of Insulated Gate Bipolar Transistor (IGBT) dimming technology in its Intelligent Raceway product, ET is certainly creating a comprehensive line of IGBT dimming products with the ultra-compact Bak Pak™ individual dimmer. The Bak Pak was introduced in December 2003 and won an EDDY Award as Lighting Product of the Year in 2004. A single IGBT dimmer, in either 750W or 1200W versions, in a compact, sleek enclosure, with several mounting options, and silent, low heat dimming, the Bak Pak presents a winning package for what it is. Add DMX512 control with in and out 5-pin connectors, a built-in effects generator with network functionality, and a list price of $250, and suddenly, the Bak Pak is a real value leader.
Looking at the footprint of the Bak Pak, one is able to quickly discern the key feature of this dimmer. At 4.53" wide, 6.82" high, and 2.93" deep for the 750W version, and a slightly thicker 3.18" for the 1200W, the Bak Pak is more compact than other single dimmer solutions. The 1200W is only slightly larger due to the increased heat sink required to deal with the heat generated by its potentially higher loading capacity. Weight is kept to a minimum at 2.1lbs. The construction feels solid and road-worthy, yet I think that dropping the Bak Pak would break some internal solid-state dimmer component loose. Anyone who has felt the warmth of even a small wall box dimmer in a residential situation knows that dimming generates heat. It is therefore impressive that the Bak Pak can handle 750W or 1200W loads and not get too hot to touch barehanded after hours of use.
The Bak Pak comes fitted with 36" in and 18" out leads, eliminating the commitment to any one connector. Have the need for an Edison supply and stage-pin out today and a stage-pin in twist-loc out tomorrow? No problem. Simply swap the connectors on the leads; there are no separate ordering codes for a connector version. The same universal philosophy extends to the mounting hardware, which is easily swapped. Hanging clamp, fixture yoke, or wall mountings are all available accessories from ET. I like the way all of the mounting fittings have been designed with a sensitivity to elegance, making the look of the installed Bak Pak that much more acceptable. No unsightly boxes are dangling over the balcony rail from chrome safety cables here! In fact, using a typical C-clamp would only take away from this stylishness, as the clamp itself would be nearly the size of the dimmer.
In addition to the size difference, the model variants are identified by a white laminate plate at the bottom of each, with either a “7” for the 750W or a “12” for the 1200W. The backplate of the dimmer has a silver reflective label with the rating and safety notices. Also located at the bottom label is a test/reset button, which is great for quick focusing or resetting an overload.
The only user-accessible components are a series of dip switches and rotary dials located behind a thumb screw-secured, swivel-away flap. The thumb screw and flap work well. The access they provide and the settings within are not quite as welcoming. This is where the personality of the Bak Pak is defined, DMX addressing is set, and effects are controlled. The wheels require a small “tweaker” to set, provide very little feedback, and are somewhat difficult to read. The dip switches are easier to set and are clearly flipped in one direction or the other. As to the label indicating which direction is on or off, see the aforementioned complaint regarding the ease of setting the wheels. The manual provides diagrams showing which switch does what in relation to the unit's exterior shape. I would say that someone setting up a few of these would want to do as much as possible on the bench rather than after the dimmer is deployed overhead.
A great deal of software functionality is accessed through the switches and wheels. Using the dip switches, one can set up the Bak Pak to behave in either dim or non-dim modes, at 115V or 120V, with a 450 or 800 microsecond rise time, and in either forward or reverse phase control. I get the feeling, however, that these would rarely be altered from factory defaults. The rotary dials set the DMX address while doubling as the adjustment parameters for the built-in effects. Set the first wheel to 8, and the subsequent two wheels dictate a fixed level in percentage, and that sort of control is explained in the manual. The same goes for the flicker effects and so forth, with the wheel's actions shifting with each mode. It works. Some of the effects may be more useful than others. The effects become increasingly powerful when one uses the networked effects feature. This novel communication between units makes for some pretty smart effects in stand-alone applications. It seems as though someone would truly need to study how these effects work and have a very specific application to make it useful.
While we are on the subject of software, I would like to address the functionality of the previously mentioned test/reset button, which is more like a Motorola cellular phone's smart key with function. Momentary contact flashes the dimmer for focusing, while holding will fade the dimmer up and hold the level. Multi-function beauty abounds in the Bak Pak.
The dimming performance of both models was good, with both providing similar results with comparable loads. The Bak Pak is exceptionally responsive and awfully quiet. This is particularly amazing when looking at the small form factor. Although, it seems to me that there is an inherent fast-bottom behavior in the dimmer's curve. In 30-second fades from full to zero, there was a clearly accelerated fall-off from 20% downward. The same was true in the reverse, with the light “turning on” to somewhere above 10% then smoothly fading from there. With the curve being completely software driven, I would like to see a “slow-bottom” curve added to the options settings, principally for smaller loads. I am consistently looking for dimmer responses that start smoothly and slowly and ramp up with intensity, often finding myself applying a slow bottom profile to an entire cue in the console. This is not to say that an inherently slow bottom is right all the time. I see a place for both types of curve, but it seems where the Bak Pak will find itself is the sort of application where this ramping up effect would be most pleasing. Otherwise, dimming response is every bit like that of other SCR type dimmers, if not outwardly faster.
Overall, the Bak Pak is a fine dimmer. I rate it highly for its form factor — dimensions, size, mounting, and connector options, and the like are all spot on. Also favorable is the performance of the IGBT dimming technology and software feature set. Where the Bak Pak comes up short is in dimming curve performance, where I find the fast-bottom curve to be problematic. Again, this can be solved by ET's software engineers, and perhaps they will do some “fixing.”
As for application, I can see many uses for this compact dimmer, particularly in installations where a centrally located dimming solution may be impractical or impossible. Bak Pak's installation is much simpler than that of a conventional rack-based system for the inexperienced contractor, as all one needs to do is run a 20-Amp circuit leaving the DMX and such to others. I do have a couple of concerns with mass installation of distributed dimming. What happens when one dimmer goes on the fritz and seizes DMX transmission to other dimmers downstream? Or when a unit ceases to function in an inaccessible area? The entire lighting system could fall victim to one component's failure. The benefit analysis of distributed dimming is an interesting issue that can only be answered by weighing all considerations for a particular application.
What ET has done with Bak Pak is create a solid, individual, off-the-shelf dimming product at a fantastic price that is certainly worthy of consideration by both basic and advanced users.