I recently purchased the Phil Jones Briefcase bass combo amp via theperfectbass.com, and as a former owner of a GKMB150E (which I sold to pay off the Briefcase debt!) I thought I'd compare the two, and throw my 2 cents in.
The buying experience was excellent, I am in SE Michigan, and Perfect Bass is in Baton Rouge, La, and I was able to track the shipment within 4 hours after the transaction up to my door, 3 days later. They got right on it for sure. None of this "We ship on Tuesdays and Thursdays" crap I've seen elsewhere.
The box arrived in fairly good shape. There was a couple of 2 inch circular dents in the box, that looked like they could be trouble, but when I opened it, I needn't worry, the combo is almost totally enclosed in very firm spongy foam blocks that are laminated together, anywhere from 2 to 4 inches thick, depending on the dimension you're looking at.
The combo was of course wrapped in plastic, and the cord was in a small box under the amp, and a heavy duty ziplock bag with the manual, warranty registration card, and an envelope from PerfectBass explaining their 5 day return policy (5 days? Oh well) was tucked under there as well as the cigar lighter to DC jack charging cable.
The combo was quite a sight to behold, with the chrome corners, black tolex, and chrome oval grills with the PJB logo on the sides for cooling, and the sturdy black and chrome handle. Very nice very high quality look to everything, nothing was loose or haphazard, very well assembled. And oh the smell of a new piece of gear! I wish they made cologne like that, or at least a car air freshener. But I digress.
The weird things for me I guess: The 12 and a half foot long power cord. I prefer a shorter cord (actually, I've never seen more than a 6 footer/2 meter cord) for stuffing into my bag, but whatever, it'll give you quite a reach anyway. And the fact that to turn the amp on, the power switch goes down. Perhaps that's a European thing. Also, when I weighed it on a fairly accurate scale (we use this scale at work to compare competetive parts) it came in at 31 lbs, 4 oz. That's 3 lbs more than the 28 cited on their website. Are English pounds lighter than US pounds?
Finally, the comparison part. I flattened the controls, and plugged my homemade fretless in, with the input switch set to the passive position. The tonal difference between the two combo's is immediately apparent. I heard a low level hiss coming out of the amp, and was able to tune it out with the highest EQ slider. As I was routing the signal through my pedals, I turned the combo off, and went straight into it instead, and bingo, no more hiss. The hiss from my pedals I had never heard before from my MB150. This is an indication of the fidelity of the Briefcase. It amplifies everything.
The Briefcase uses a 5 band graphic EQ, and the MB150E uses a Treble, Low Mid, High Mid, and Bass tone control (in that order, left to right…). The Briefcase seemed to offer a bit more extreme control compared to the BM150E controls, which is nice. After playing at fairly low levels to get used to the different EQ settings' sound, I flattened the EQ again, and turned it up. I got to about 12 o'clock with the volume control, before things started to get slightly funky. The speakers were reacting and were beginning to flap a bit if I pushed it beyond that with my open E string. 12 o'clock fine, 1 o'clock I started feeling like I should turn it down. Now, I had the briefcase and the MB150E in the same basement room, 7 foot ceiling, 500 square feet, nothing to absorb sound like furniture or the like. Kind of like an empty coffee house gig. Don't ask.
The MB150E with its 12 inch speaker produced a mellower sound when it was cranked up to just below flap level than the Briefcase. However, to get the same clarity as the Briefcase, I would have to deviate from flat on the MB150E and add some upper mids and treble. And I don't think that the MB150E was as clear and clean as the Briefcase even then, as far as the upper register goes anyway. I play my fretless with the treble full up all of the time, so I am used to getting the snarl part of the mmmrrrowww. The briefcase did this better than the MB150E for me.
The midrange tones out of the Briefcase were more articulate too, they didn't come across as honky as the MB150E midrange tones did, which is something that has always irritated me about the flat EQ sound of the MB150E. The Briefcase is clean and even from the lower mids to the upper mids. No particular tendency to favor a certain band of midrange frequencies over another. I noticed that a lot of the power of the Briefcase seemed to be concentrated in the midrange, more so than the MB150E.
The lower frequency response of the Briefcase was less than the MB150E, not surprisingly, due to the area of the speakers I'm sure. The MB150E has a very mellow full bodied lower range for its size (and weight!) and this quality of it is probably why it is so popular. But, you can get there with the Briefcase by tweaking the lowest EQ setting. It won't be as warm, but it will be dang close, and the lower response is, on the flip side, a little tighter. I like both tones actually, and while I will miss my MB150E for its natural warmth in the lower frequencies, I will enjoy the Briefcase for its clarity.
Now on the volume thing. The MB150E is an amazing combo for its volume capability. I mean, it weighs 27 pounds, and can put out the bass! I once hooked it up to an SWR GoliathIII, and with a hand held SPL meter, measured 123db weighted at 6 feet with it. That's pretty loud. The Briefcase is quieter, but not by much in my opinion. Of course, and on this I take issue with some of the other revues of the Briefcase, (and the MB150E, for that matter) this is a small portable amp, and as such it is not to be expected that it is going to blow the glass out of the windows of anything! It's teeny! And for it's size it makes a darn big noise, but it's not an SVT6 on top of an 8 by 10 cabinet!!!
Put it this way, you can keep your whole house awake all night, but you won't disturb your neighbors. Unless you live in an apartment or condo, then, you will disturb your neighbors.
I now use the Briefcase as my upstairs amp, and to jam with friends. I have been asked to turn it down, jamming with a drum machine and a buddy with a small Marshall combo…not bad! I haven't tried it with a drummer, most of whom I know are too loud (why don't more drummers use volume control in their performance, the pro's do for gosh sake!) and perhaps a mellow jazz set would fit well with the Briefcase.
But that's not why I bought it, I bought it for the size and the tone and the price. For the money, I don't think you can get higher fidelity, and I love high fidelity!