These are one of my favourite bookshelf speakers. I've had them for almost a decade and recently I did a small refurb on them, replacing the 22uf electrolytic with new Mundorf electrolytic (Poly caps I had were too big) and new black grill cloth versus the faded brown. Plus a re-oiling of the blond oak veneer. They sounded better than they were before. A lot more livelier on the top end.
Originally, I thought the Audax tweeters were struggling a bit and I wasn't too sure if it was the ferrofluid or the cap. Took a gamble and hoped it was the cap and it paid off.
Story time: When I first auditioned them, wayyyy back in Winnipeg. I had a very interesting A/B comparison with a pair of Rogers LS3/A. I can't remember which version it was nor the power source. But, it did give me an opportunity to listen to a pair of LS3/A. The Rogers and Bozak were very distinct from one another. That the Bozak were a lot flatter in sound signature and the Rogers had a more more mid bass bump (similar to the Celestion Ditton 10) and I thought the top end (tweeter) sounded better on the Bozak. In the end, I was quite pleased with the purchase, and hence why I've kept them for a decade.
While these were Bozak speakers. They were designed by Peter Ledermann who owns and runs Soundsmith. I won't go into the back story. They also sell a more modern version of the MB-80 called the Monarch.
The Bozak MB-80 love power, I run them with SAR Labs MOS-400 power amplifier. They owner's manual actually recommends "more power." From what I can tell, the bass roll off seems to be quite high around 100 Hz for the bass. But, they have an extremely pleasant sound signature. I never found them to be fatiguing at all and they're able to throw quite the wide sound stage where positioning isn't critical.
The mid-bass driver is a 6" aluminum woofer (heavy and where most of the weight comes from) that Peter Ledermann modified from Rudy into an "ultra wide bandwidth performer." Personally, though I am a tad bias, I still think they're fantastic speakers. I do think they're better than the Celestion Ditton 10 in almost every aspect other than bass.
What's interesting about the Bozak is the lamp fuse on the baffle. Not only it helps protect the speakers but, when it gets close to clipping the fuse lamp light up. I haven't been able to do it but, I've seen it in person.
They were in fair shape when I received them and I've maintained their overall condition. One woofer has a crinkle (it seems a lot of them do) but, no issues with performance. The cabinets are in okay shape. Oiling has helped but, one the previous owners has used some wood filler to fill some gaps and the veneer itself is in okay shape (some rough patches). From what I can tell, there were 2 versions, one with the Audax tweeters and one with Vifa tweeters. I am sure the Vifa sounds nice too.
Specifications (from the original owner's manual):
Frequency Response: 80 to 20k Hz, +/- 3dbm 90 dBA, 1M on Axis
Impedance: 8 ohms nominal, minimal 6.5 ohms
Sensitivity: 83dBA @ 2.83 VAC, 1kHz, 1M on axis
Power Handling (Music Signal): 35 Watts RMS min., 250 Watts RMS max
Crossover: Modified 6dB per octave, @ 1600 Hz
Dimensions: 12.5 x 7.875 x 7.125 "
Weight: 16.2 lbs - 7.4 Kgs (Each)