This is a legacy thread, but should anyone else find themselves pondering a PJB Briefcase...
I bought a Briefcase for one specific purpose: guerilla busking and drive-by 2-song assault maneuvers. Those tactical operations require: 1). Portability; 2). Battery operability; 3). Sufficient volume capability to make an upright audible in a public space (in a group with acoustic guitar, vocals, and light percussion); and 4). Decent sound. My goal was to be able to schlep-in an upright bass and amp, on foot, in a crowded public place with no AC electricity, and be set-up and ready to play in less than 60 seconds from the instant that the amp touches the ground or floor. In practice, I’ve found that I can arrive at a suitable location and hit the downbeat within 45 seconds. It might be possible to shave as much as 10 seconds off that figure but then I’d just be waiting for the other guys.
Based on the above criteria, the Briefcase gets the job done. It’s forte is not FORTE, but portability—it is the smallest combo that I know of capable of providing significant loudness and decent sound, and on those counts it acquits itself rather well. For the purposes of this bassist-on-the-street report, I won’t get into certain design aspects that I feel are shortcomings and instead focus on real-world usability.
Yes, it’s louder than one might expect from such a small rig but it will not-repeat-not compete with a drum kit. While others have described it as “hi-fi” I would call it anything BUT hi-fi. It has a pronounced mid-to-upper-midrange hump that is reflected both in the perceived tonal balance and the supplied response chart. This should not be read as a complaint, however, just an observation. As one should expect, low frequency extension drops off precipitously below about 60Hz giving a diminishing sense of fundamental below A1 (open A string) and virtually ZERO fundamental below E1. Of course, many much larger speaker systems exhibit similar response curves and the Briefcase compares remarkably well. Can it handle the low B? That depends upon what you mean by “handle.” You can tug on the B-string and sound comes out and the unit doesn’t explode in a fusillade of farts, but there’s no fundamental at all (nor should one expect there to be). What the Briefcase produces is a practical, albeit necessarily volume-limited, musical output that adequately covers the range of a 4-string bass, with a generally pleasing tonal palette and an upper mid push that that helps the amp sound a bit louder than it is in a combo setting, such as piano-bass-guitar. Upright players should be aware, however, that the upper midrange response can exacerbate the nasal, fingernails-on-chalkboard character exhibited by many piezo pickups under the bow.
The amp benefits from useful features such as a graphic EQ and a compressor that are optimized for the purpose. The EQ has reasonable frequency points and can be used effectively for tone-shaping or to flatten the frequency response of the rig somewhat if desired (or help tame an edgy piezo). The compressor seems intended solely to keep loud transients from exceeding the limits of the unit. The pre-eq DI-out is relatively quiet and well behaved, at least in the one instance I’ve used it. There is an active/passive selector switch for the instrument input that seems rather poorly implemented based on my own experience—I’ve simply left it in the passive position with upright bass, and passive and active bass guitars, with satisfactory results. The amplifier module can be removed from the Briefcase and used as a stand-alone head, and it is able to power my 4-Ohm Acme B1 (a challenging speaker) to reasonably loud levels while managing to sound very good until the onset of clipping.
Battery life is, as has been pointed-out, about 1-hour using the recommended battery. While the owner’s manual warns against doing so (and therefore I caution you NOT to try this at home), I couldn’t resist the temptation to borrow a friend’s lithium motorcycle battery, a Shorai LFX14 if I recall, which easily lasted an hour and a half and only weighs about 1 and ½ lbs. Note that the Shorai is smaller than the battery compartment so I made foam shims to fill the empty space, along with a couple of pigtail leads with spade lugs for the amp’s cable connectors.
The aesthetic appearance of the Briefcase is rather formal, sort of black-tie-and-tails formal, with cosmetic touches that seem more like high-end audio gear. The quality of construction, fit, and finish is excellent.
In short, the Briefcase provides maximum portability in a bass amp while still being capable of producing a useful volume of sound across the range of a 4-string bass, and doing so without sacrificing any of the tonal characteristics that most bassists find pleasing. If you maintain reasonable expectations and can live with, or workaround, its particular quirks (we’ll call them “quirks” rather than shortcomings) then you will be satisfied with the Briefcase.