Vintage Asylum: Re: bosak B305 what are there value? by AudCon
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In Reply to: Re: bosak B305 what are there value? posted by Nat on December 17, 2003 at 10:11:50:
All the jillions of Bozak tweeters with the bright metal foil center caps that show up on ebay are B-200X, paper cone. (The very originals were B-200, but the X version came out in the early '50s; very few of the B-200s are around.)
The B-200Y was the first aluminum-cone tweeter, appearing in '62. The aluminum cone is covered with a thin, black coating of latex, which suppresses the surface reflections that otherwise occur on a metallic cone. They are easy to spot - the center cap is black. The Y tweets had a long run - from '62 to '76.
In 1977 the B-200Z superseded the Y version. Still aluminum alloy cone with the latex covering. The main visible difference is that the cone shape is "curviliner," not a true conical shape. Easy to spot - the cone radial angle changes from center to rim, nearer conical at the center, nearer flat at the rim. In the very late systems of the early '80s, the Z tweet was used without the latex covering. The differences in the three tweeter models is considerable, but too much to explain in one post.
The original B-209 (no B or C suffix) midrange is also paper cone. Easy to spot even in a photo because in their old age, the cones have faded to a lighter color, often tan. In '60 the B-209A appeared (before the Y version tweeters). The B-209A has the 'new' aluminum curvilinear cone, black latex covered. But the A version requires a separate damping ring mounted just in front of the driver. It is a metal ring supporting a ring of foam which presses against the outer suspension of the driver. So the B-209A is really a two-piece driver, and would be under-damped if the damping ring is missing.
In '63 the B-209B appeared, not requiring the seperate damping ring. The midrange, certainly one of the best ever made, using the same magnet and basic motor (voice coil and magnet assy.) as the woofer, remained unchanged until used without the latex coating in the LS-330A and other systems, in the early '80s. The B-209C is the same as the B-209B except in a squarish frame rather than round, intended to be easier to mount from the front.
The B-199A woofer remained substantially unchanged from the early '50s until the B-199B appeared in '75. The B-199B was re-designed to work better in smaller enclosed air spaces.
Then there is the 8" B-800/B-800B. It originally appeared in 1960 as a midrange for the 'new' B-4000 'Symphony' systems. It was also used in several of the early small systems, but the bass in those systems was limited to around 100 Hz because the suspension was optimized for midrange use, therefore rather stiff and the resonance rather high for a woofer. Some time between '63 and '68, the designation changed to B-800A. In 1970, the midrange in the B-4000 systems was changed to the 'regular' B-209B.
In '74 the B-800B appeared, re-designed with a resonance of 37 Hz, intended for woofer-thru-midrange application. This is a fantastic speaker. When Bozak finally departed from policy and began using vented, later tube-ported cabinets with the B-199B, the results were sensational, altho sacrificing a little of the famous Bozak bass transient response in the active enclosures.
I certainly have no argument with "time alignment" by means of offsetting the drivers with a stepped baffle, as used in the very late LS systems. But reversing the polarity of the midrange, as done from the late '60s until the late '70s, was a tragic mistake, IMHO.
I hope this outline is helpful. This year is my 50th anniversary since I first heard Bozaks in 1953. I have used and studied them every since. Plenty more to tell, if anyone is interested.
Holiday best wishes to all,
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Topic - bosak B305 what are there value? - slxrti 20:40:29 12/15/03 ( 19)
- Re: bosak B305 what are there value? - Nat 10:11:50 12/17/03 ( 11)
- Re: bosak B305 what are there value? - AudCon 12/17/03 14:17:57 12/17/03 ( 10)
- Re: bosak B305 what are there value? - Jareb 15:11:11 12/17/03 ( 3)
- Re: bosak B305 what are there value? - AudCon 14:24:27 12/17/03 ( 2)
Re: bosak B305 what are there value? - Brian Levy 11:28:50 12/16/03 ( 0)
Re: bosak B305 what are there value? - Nat 06:44:34 12/16/03 ( 5)
- Re: bosak B305 what are there value? - Jareb 08:37:28 12/16/03 ( 4)
- Re: bosak B305 what are there value? - AudCon 13:26:25 12/16/03 ( 0)