
Build Diary here:
http://billfitzmaurice.info/forum/viewt ... 30&t=13121
First test was at home, and solo. I dialled in my usual tone on the amp (top cut, hi-mids cut, low-mids boosted, about 50% bottom end) and, with some trepidation, fired it up.
Initially my heart sank because immediately, and even at low volume, there was a symphony of buzzes, vibration and rattles which I took to be the cab about to explode in a mushroom cloud of plywood confetti. But on closer investigation, and by a process of elimination, I found the unwanted noises were actually coming from:
1 My collection of 50s and 60s tin robots
2 My amp
3 A filing cabinet
4 My computer
5 An IKEA uplighter
6 A central heating radiator
7 My studio monitors
8 Other things in the house I couldn't identify
Very relieved to discover no noises emanating from the cab at all (except for bass!), which surprised me. I was expecting one or two problems that would need sorting out, but initial impressions were favourable. It go loud! But of course it's pretty much impossible to rate the sound at home under those circumstances.
Next test was at a band rehearsal. Line up: drums, bass, guitar, trumpet, tenor sax, keyboards and percussion. The appearance of the J12 provoked mixed reactions, ranging from admiration to derision.

It sounded truly amazing. It doesn't do 'sub'-type bass, (which sucks up too much bandwidth anyway, IMHO), but you can certainly fire a lot of low end/low mids through it -- there's no farting out, rattling or distortion whatsoever. Yet it's super-clear and you can hear every note, even with the top end and hi-mids cut. A very nice, creamy old-school 'low-mid' sound. Chunky and, dare I say it, 'vintage'.
The word that kept going through my mind was 'solid'.
Yet it's precise, very accurate, and sits very nicely in the mix; but it also has 'presence'; i.e. everyone can hear every note (even the drummer), without the amp needing to be turned up excessively -- which is a very neat trick indeed. This necessitates playing more accurately and being right on it timing-wise, though! Which is a good thing!

The band could hear it well from wherever they were standing in the room, and it seemed to project the same tone everywhere in the room, regardless of distance. I'm very much hoping it will be able to perform this trick on a larger scale, i.e. at a gig. That would be just sweeeet.

I'm using a fraction of the master volume I used with my Warwick WCA Pro 600W 4X10 (4 Ohms) for the same apparent SPL. Yet the J12 is half the size of the 4X10, half the weight, and draws far less power from the amp. It's a huge sound for a small box: 22 X 18 X 18" and 40lb (18kg).
Also, I'm not driving the amp so hard (500W @ 4 Ohms; 300W @ 8 Ohms); the J12 is 8 Ohms, but it all seems so much more effortless somehow, and has a more natural and 'open' sound, less 'choked' -- and there's loads of headroom on tap.
But it doesn't seem to need very many watts through it to get this sound. I'm hoping this means the amp will work less hard, run cooler, and therefore be more reliable -- not that I've had any reliability issues yet, he added quickly.

It's a one-hand lift, and easily fits in the car boot (VW Polo) without the effort of putting the seats down. It's really a very impressive and efficient design indeed, and so far I'm totally delighted with it!

Next: I'll update this review after I've played a gig or two.
