AudioCircle
Audio/Video Gear and Systems => The Vintage Circle => Topic started by: fishmonster on 26 Aug 2016, 06:51 pm
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Many years ago I somehow acquired a set of old Bozak speakers. I was in college at the time, so that's probably related to why I don't remember how I got them. I do remember that the magnets had become dislodged, so I removed them from the cabinets and had the best speaker repair place in town fix them. At the time I was planning on refinishing the cabinets, but never got around to it and the speakers sat in boxes for a couple of decades (in a climate controlled environment). This year I moved, and decided that enough is enough so I reinstalled the speakers and have been listening to them ever since. I love the sound they produce, but don't know what model they are and haven't found any pictures of them doing an image search. I do know they aren't the Concert Grands, so don't be getting excited yet. But here are a couple of pictures for identification:
(http://www.audiocircle.com/image.php?id=149122)
(http://www.audiocircle.com/image.php?id=149123)
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If anyone here has copies of the old 'Vacuum Tube Valley', they did an article on Bozak speakers. I remember seeing this one mentioned but don't recall the model name. Definitely not the Concert Grands (which were HUUUUUUGE).
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Looks 302A to me if it have a mid range driver (?)
Its Alnico hence you liked the sound.
http://www.audioasylumtrader.com/ca/ca.html?ca=28997
(http://i305.photobucket.com/albums/nn220/speakersofthehouse/Marantz-Carver-Nikko-Bozak003.jpg~original)
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My last try is E300 Italian Provincial:
http://www.soundup.ru/index.php?option=com_content&id=2451%3Abozak-speaker-pair-e300-italian-provincial&Itemid=76
(http://www.soundup.ru/images/stories/archive/Classic/Columns/bozak-speaker-pair-e300-italian-provincial/bozak-speaker-pair-2.jpg)
(http://)
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It looks like an early version of the B-300. A quote from Audiokarma I recently saw in a thread:
"The backbone of the Bozak line was the B-302A system, offered in several cabinet styles over a period of years. The 302A systems consisted of one 12" woofer, one midrange driver and one tweeter pair. A 'starter' version, the B-300, was a 2-way system consisting of one 12" woofer and one tweeter pair mounted across the front of the woofer. A single capacitor sufficed as the crossover 'network' for the B-300. The system could be expanded to a 3-way B-302A by adding a midrange and full 3-way Bozak crossover."
It looks like you have an iteration of the B-300 two-way. There seem to be many styles over the years. I'm a member of http://www.radiomuseum.org/ (http://www.radiomuseum.org/) and they have some cursory info on the B-300.
Enjoy your speakers and make them pretty. :D
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It looks like an early version of the B-300. A quote from Audiokarma I recently saw in a thread:
"The backbone of the Bozak line was the B-302A system, offered in several cabinet styles over a period of years. The 302A systems consisted of one 12" woofer, one midrange driver and one tweeter pair. A 'starter' version, the B-300, was a 2-way system consisting of one 12" woofer and one tweeter pair mounted across the front of the woofer. A single capacitor sufficed as the crossover 'network' for the B-300. The system could be expanded to a 3-way B-302A by adding a midrange and full 3-way Bozak crossover."
It looks like you have an iteration of the B-300 two-way. There seem to be many styles over the years. I'm a member of http://www.radiomuseum.org/ (http://www.radiomuseum.org/) and they have some cursory info on the B-300.
Enjoy your speakers and make them pretty. :D
Thanks for the responses, everyone. Based on what you posted, I think you are correct all the way around. They are definitely 2-way speakers, right down to the single capacitor. When I had them open I did a search on the capacitor, but I've forgotten the brand/rating. It is silver, rectangular and about 2.5" x 2" x 1". I'd know it if I saw it. I checked the radio museum site, and they had some similar speakers, but I have to question the 1977 date they provided. The style and material seem more suited to the 1950's/1960's era.
@FullRangeMan, the picture you posted is close, but mine don't have the fluted front face; mine are smooth across the front. Another feature on mine that I haven't seen on many other Bozak speakers it the top. Most that I have seen are smooth across the top, but mine have a piece of trim around the outside that rises above the surface, kind of like an end table might have. But they sound great, and I intend to enjoy them. At some point I might refinish them and look into getting a mid-range Bozak speaker to make them 3-ways, but I'm happy I got them connected and can listen to them now. As old as they are I am also hesitant to crank them up, but we'll see as time goes by...
Just out of curiosity, when I got them they had standard fiberglass bat insulation in them, which I removed. I'd rather not put that in, so is there something as good, but less hard on the lungs that is used these days?
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This speaker are vintage worth to keep original condition.
The fiberglass is not dangerous if you dont mess w/it, it do a nice job to damp the woofer and add oomph to the bass performance, it may be a bit difficult find other stuff material w/the same sound characteristics.
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Polyfil pillow stuffing works nearly as well, without the health concerns. You should be able to find it at any fabric store, or maybe the local Walmart.
Here is a version at a higher price... http://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317
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SClark beat me to the punch on Acousta-Stuf. Good on ya, sir!
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I agree with Fullrangeman, changing the fill material could alter the tuning. A pair of dishwashing gloves and a painting respirator (and if you're really paranoid, goggles) should be all you'd need to handle the stuffing safely. If possible, work with it outdoors.
The electrical condition of the capacitors could be suspect. It might be worth the cost of a capacitor checker to make sure they are within spec (are they labeled?) and, better yet, matched.
The defunct Vacuum Tube Valley magazine had a really good, detailed article on Bozak speakers. If I still had it, I'd scan it and send it to you. It would be worth tracking down.
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Out of curiosity I did a Google search on Mr. Bozak - there is a huge amount of data on Wikipedia.
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... I checked the radio museum site, and they had some similar speakers, but I have to question the 1977 date they provided. The style and material seem more suited to the 1950's/1960's era...
I agree; he's about 17 years late on that timing. :D
Some guys question whether the B-300 is inferior to the B-302. I haven't heard either (unfortunately), but I'd do some research before modifying your speakers.
Too bad about the fiberglass. I'd be inclined to replace it with... fiberglass. As mentioned, it's a sealed cabinet and poses no harm. While you have them open again, it probably wouldn't hurt to explore a little with some decent quality caps to see if it helps.
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Yeah, the caps (and thus the crossover parameters) are likely to be out of spec after 50+ years, especially if they are the commonly used nonpolar electrolytics. They dont need to be expensive, but might use a "refresh". Apparently Bozak used gentlle 6dB/oct crossover slopes as a matter of routine, according to the VTV article.
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My last try is E300 Italian Provincial:
http://www.soundup.ru/index.php?option=com_content&id=2451%3Abozak-speaker-pair-e300-italian-provincial&Itemid=76
(http://www.soundup.ru/images/stories/archive/Classic/Columns/bozak-speaker-pair-e300-italian-provincial/bozak-speaker-pair-2.jpg)
(http://)
This may be the 3-way version. Looking closely at the grille, one can see at lest two circular areas with slight discoloration. fishmonster's speakers clearly have only one. Jeez I wish I hadn't tossed that VTV magazine. Maybe someone on here will have it.
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I hadn't considered that the capacitors could change over the years. The speakers sound fine to me, but the next time I crack them open I'll get the specs off the capacitors and see about replacing them. When I searched for them earlier I did notice that they were available on Amazon. If there is no problem with fiberglass insulation I will probably roll up a couple of bats and toss them in while I'm at it. And yes, dB Cooper, I can also see the discoloration in the image--lower left corner for the woofer/horn combination, and a few inches down from the upper right for the mid-range. I admit that I am really split on refinishing them, though. It would be nice if they looked uptight and out of sight, but the warning bells from the Antique Roadshow are ringing loud and clear. They warn about even cleaning vintage items. But there is definitely one thing I should probably do the next time I open them. Some of the screws holding the speakers in are stripped in the plywood to which they are attached. So I'll rotate the speakers a few degrees so that all the screws find new wood and will hold another 50+ years. The rim of the speaker will hide the old holes, so there won't be any cosmetic blemishes, even though we're talking about the inside of the cabinet.
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Hey fishmonster I hit paydirt!!!!
Found a link to a good quality PDF scan of the complete Vacuum Tube Valley issue set. Here is the direct link to the issue I was thinking of (the article about Bozak starts on page 17) :
https://web.archive.org/web/20131122142023/http://www.jumpjet.info/Pioneering-Wireless/eMagazines/VTV/VTV18.pdf
Hope this helps.
Given the horizontal tweeter array, both for appearance and performance perhaps it might be better to use screw inserts/spacers than to rotate the speakers?
Good luck!
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Hey fishmonster I hit paydirt!!!!
Found a link to a good quality PDF scan of the complete Vacuum Tube Valley issue set. Here is the direct link to the issue I was thinking of (the article about Bozak starts on page 17) :
https://web.archive.org/web/20131122142023/http://www.jumpjet.info/Pioneering-Wireless/eMagazines/VTV/VTV18.pdf
Hope this helps.
Given the horizontal tweeter array, both for appearance and performance perhaps it might be better to use screw inserts/spacers than to rotate the speakers?
Good luck!
Wow! I downloaded the issue and read the article non-stop, and it was absolutely amazing. Thanks for taking the time to find it for me. I checked a place called Tube Depot that was supposed to have issues, but they seem to be gone. I've downloaded a lot of stuff from the Internet Archive, but never thought to look there for this. That was good thinking on your part. Hopefully you have access to several more issues, as well.
When you say screw inserts, are you talking about something like a wall molley, but for wood? I'd never considered something like that. After reading that article I now have a whole new perspective on these speakers. Though they aren't the top of the line, they are definitely something special and I now have to rethink everything I thought about them and planned to do. In one sense I sort of see myself as having a responsibility to preserve a bit history.
I will say this about the clarity of the sound. When I leave my house I frequently leave a stereo on to make any would-be intruders ask themselves if anyone is home. If I leave my modern stereo on, with speakers ranging from 10-20 years old I stand outside and the sound is muffled compared to the Bozaks at the same volume. They are clear as a bell when standing outside the door and being powered by an old Kenwood KR-4400 receiver. Even switching back and forth between the two units with the local classical station tuned in the difference is remarkable. I question if the Bozaks would sound as good with modern music coming from a CD player, but one day I might risk defilement and connect the CD player to them and find out.
Oh, and one other thing. I really want a set of Concert Grands now. Again, thanks for finding and posting the link to that article. It's definitely going into the file cabinet after I print it.
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Wow! I downloaded the issue and read the article non-stop, and it was absolutely amazing. Thanks for taking the time to find it for me. I checked a place called Tube Depot that was supposed to have issues, but they seem to be gone. I've downloaded a lot of stuff from the Internet Archive, but never thought to look there for this. That was good thinking on your part. Hopefully you have access to several more issues, as well.
When you say screw inserts, are you talking about something like a wall molley, but for wood? I'd never considered something like that. After reading that article I now have a whole new perspective on these speakers. Though they aren't the top of the line, they are definitely something special and I now have to rethink everything I thought about them and planned to do. In one sense I sort of see myself as having a responsibility to preserve a bit history.
I will say this about the clarity of the sound. When I leave my house I frequently leave a stereo on to make any would-be intruders ask themselves if anyone is home. If I leave my modern stereo on, with speakers ranging from 10-20 years old I stand outside and the sound is muffled compared to the Bozaks at the same volume. They are clear as a bell when standing outside the door and being powered by an old Kenwood KR-4400 receiver. Even switching back and forth between the two units with the local classical station tuned in the difference is remarkable. I question if the Bozaks would sound as good with modern music coming from a CD player, but one day I might risk defilement and connect the CD player to them and find out.
Oh, and one other thing. I really want a set of Concert Grands now. Again, thanks for finding and posting the link to that article. It's definitely going into the file cabinet after I print it.
The sound of Bozak speakers are not good in a broad sense, just the Bozak loudspeakers which have Alnico woofers have good sound due the Alnico harmonics being pleased to the human brain.
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Wow! I downloaded the issue and read the article non-stop, and it was absolutely amazing. Thanks for taking the time to find it for me. I checked a place called Tube Depot that was supposed to have issues, but they seem to be gone. I've downloaded a lot of stuff from the Internet Archive, but never thought to look there for this. That was good thinking on your part. Hopefully you have access to several more issues, as well.
They had the entire VTV collection. I strive for paperlessness so I just downloaded them.
I may be using the wrong term since I am handyman challenged. What I am describing is something like this:
http://www.tognar.com/binding-hole-plastic-screw-inserts-sold-each/
The whole idea is to be able to securely "refresh" a stripped-out screw hole. In the link, they actually describe another option-
filling the hole with epoxy/steel wool and then re-drilling it. I have seen plastic plugs. You tap them into the stripped-out hole and then run the screw in. Describe what you are trying to do to your local hardware store guy and they should be able to help. Only saying this because the speakers might look a little weird if the tweeter arrays are crooked due to rotating them.
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The sound of Bozak speakers are not good in a broad sense, just the Bozak loudspeakers which have Alnico woofers have good sound due the Alnico harmonics being pleased to the human brain.
I understand what you are saying; there are advantages to modern components. A good comparison to me is that of a vinyl record vs. a CD. The CD doesn't have the hiss and pop, but when you listen to both side by side the music quality of vinyl records far exceed that of the CD, which sounds very thin and one dimensional in comparison. And don't get me started on the audio quality of MP3's and other compressed formats!
I may be using the wrong term since I am handyman challenged. What I am describing is something like this:
http://www.tognar.com/binding-hole-plastic-screw-inserts-sold-each/
I checked out the page and they do function like wall mollies, with the screw forcing the sides of the insert out so that it grips the wall of the hole. The inserts you referenced seem more geared toward skis, but the function is the same. They say they aren't as strong as other repair methods, but skis get a lot more stresses and forces than these speakers will, so they should do just fine. I might do a hybrid of what they recommend and use a bit of epoxy on the outside of the inserts before tapping them in so they are secure in and of themselves.
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Local hardware barn should have something more oriented towards home hardware use.
Fullrangeman, can you share which Bozak speaker models you have heard? I'm wondering what the basis for your blanket dismissal of them is. Has speaker technology advanced in the last fifty years? Certainly. Are there still well-designed vintage speakers that can provide an enjoyable, if perhaps not state-of-the-art, musical experience? Sure.
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Local hardware barn should have something more oriented towards home hardware use.
Fullrangeman, can you share which Bozak speaker models you have heard? I'm wondering what the basis for your blanket dismissal of them is. Has speaker technology advanced in the last fifty years? Certainly. Are there still well-designed vintage speakers that can provide an enjoyable, if perhaps not state-of-the-art, musical experience? Sure.
I have listen none Bozak, just JBL vintage Alnico woofer.
Iam familiar w/magnets sound's in hi-fi and pro-audio, of course Alnico & Ferrite magnets advanced since today, not to mention Neo.
So the situation we have today concerning magnets SQ are:
Alnico for rich harmonic content,
Ferrite for low price,
Neo Dymium for detail.
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I have listen none Bozak, just JBL vintage Alnico woofer.
Iam familiar w/magnets sound's in hi-fi and pro-audio, of course Alnico & Ferrite magnets advanced since today, not to mention Neo.
So the situation we have today concerning magnets SQ are:
Alnico for rich harmonic content,
Ferrite for low price,
Neo Dymium for detail.
So, with all due respect, I don't see how you can comment that "The sound of Bozak speakers are not good in a broad sense" when you have (by your own admission) never heard any. While speaker design and technology has undoubtedly advanced over the years, the Bozak line was highly regarded in its day, and it seems to me that the best way to meaningfully judge the SQ of a given piece of equipment- modern or vintage- is by actually listening to it.
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Bozaks are pretty good. They hit the mark with other quality speakers of that vintage. They can be helped with some renovation and made better. I have a soft spot for appreciating and enjoying old things. For less money and good times, it's just fun to preserve.
If you love music, Bozaks abide. :D
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So, with all due respect, I don't see how you can comment that "The sound of Bozak speakers are not good in a broad sense" when you have (by your own admission) never heard any. While speaker design and technology has undoubtedly advanced over the years, the Bozak line was highly regarded in its day, and it seems to me that the best way to meaningfully judge the SQ of a given piece of equipment- modern or vintage- is by actually listening to it.
I mean say Bozak w/Alnico magnet has good sound and the Ferrite magnets speaker has the usual sound that these magnet are known.
The main factor in determine sound in a speaker specially woofer and midrange is the magnet type. I follow us, uk and portugal audio scene since the 1970s and Bozak despite being a better product than Bose or HT speakers is not au pair with Infinity IRS, B&W, Magnepan, Quad, Klipsch, Polk, Kef, Monitor Audio, Dynaudio, Apogee etc to stay w/famous brands only of that era. It just happen Bozak had a well made ads in magazines emphasizing its appearance and a efficient made text to convince the audiophile that the product is extraordinary.
But if you believe Bozak are the sweet spot it will be for you.
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Their 12 inch Alnico woofer with hemp/wool cone, and their 6 inch treated aluminum cone, widerange midrange ...B200 and B199 I believe, are extraordinary drivers, to this day. A modern speaker ---> designed around these drivers, especially an OB using the 12, using a high damping factor chip amp, I think, would be fantastic.
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I haven't heard any Bozaks but I'd like to.
That certainly looks like a piece worth preserving.
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I will say this about the clarity of the sound. When I leave my house I frequently leave a stereo on to make any would-be intruders ask themselves if anyone is home. If I leave my modern stereo on, with speakers ranging from 10-20 years old I stand outside and the sound is muffled compared to the Bozaks at the same volume. They are clear as a bell when standing outside the door and being powered by an old Kenwood KR-4400 receiver. Even switching back and forth between the two units with the local classical station tuned in the difference is remarkable. I question if the Bozaks would sound as good with modern music coming from a CD player, but one day I might risk defilement and connect the CD player to them and find out.
This took me back to my childhood. My dad had a Bozak that looks exactly like yours. He changed the door to the bedroom closet and mounted it there. One of the wires from the midrange/tweeter set hung across the room to a cabinet the size of a washing machine that held the woofer part of the system (the capacitor, or whatever is was, suspended in air). Don't know what the acoustic stuff in the woofer cabinet was but our cat usually started her kittens off there. At any rate, re the clarity. Back in the day, my dad would crank up the system (simple tubed amp and preamp + TT) to let's call it realistic levels. He had a test record which was the sound of a train. Apparently one of our neighbors had a bit of a bad day when he was on the toilet and thought a train was coming through his house and decided to leave his house. My dad loved that story and it still makes me laugh. Crazy audiophiles and understanding wives, to say the least. To think that got me started in this weird hobby is amazing. Enjoy your speakers. From (ancient) memory, they sounded lovely - realistic and dynamic.
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I have a pair of Bozak speakers and I think their reproductions of piano music is
more realistic than any of the speakers I have ever owned.
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The ones I heard I think were called 302B, had the 12 but not the weird twin tweeters, the 6 midrange, and another, super serious looking tweeter. that thing looked very much like a rock bit, had it said "Hughes Tool" I wouldnt have been surprised. It was glorious, and was I believe powered by a quality Telefunken PP EL84 twould have been. In a Scottish audiophile doctor's basement. This was great sound, by all means.
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Hey Dan, it's good to see that you're back. 8)
I bought a nice pair of Concert Grands a few days ago in a fit of insanity. The mighty Boz abides and my doctors have job security. :D
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I mean say Bozak w/Alnico magnet has good sound and the Ferrite magnets speaker has the usual sound that these magnet are known.
The main factor in determine sound in a speaker specially woofer and midrange is the magnet type. I follow us, uk and portugal audio scene since the 1970s and Bozak despite being a better product than Bose or HT speakers is not au pair with Infinity IRS, B&W, Magnepan, Quad, Klipsch, Polk, Kef, Monitor Audio, Dynaudio, Apogee etc to stay w/famous brands only of that era. It just happen Bozak had a well made ads in magazines emphasizing its appearance and a efficient made text to convince the audiophile that the product is extraordinary.
But if you believe Bozak are the sweet spot it will be for you.
I have to agree with dB Cooper on this one. If you haven't heard them there is no basis for comparison. Granted, there are two parts to what makes a speaker good/great. There is "X", the science/technology part, and then there is "Y", the beholder part. Ultimately, naming the "best" speaker may be like trying to name the best pipe organ, the best bottle of scotch or the best cigar because the "Y" part of the equation isn't really tangible. I don't know where you live FullRangeMan. I've also never experienced the Concert Grands, but you might try searching in your area for some Concert Grands and ask if you can listen to them. Not to be cliche', but in terms of classical music I think I would test them out with Dvorak's 9th Symphony, Tchaikovsky's 1812 Overture or even Gershwin's Rhapsody In Blue, as that was something Bozak himself probably used. If you have 15 minutes on your hands I'd say that a solid performance of Ravel's Bolero would also be good, with the volume set at finale levels so you can experience the range. For rock I'd say The Who's Quadrophenia, the Grateful Dead's Terrapin Station or something like Pink Floyd's Dark Side of the Moon, or anything that has that wall of sound feel. Short of that, I'd suggest reading this review: http://www.stereophile.com/historical/1005bozak/ (http://www.stereophile.com/historical/1005bozak/). It's a few pages, but it is well written and after listening to my low end Bozaks I think I understand where the writer is coming from. The one word he uses to describe the sound he heard from the Concert Grands is "effortless". It's almost like the sound is just there, and not coming from a speaker at all.
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He had a test record which was the sound of a train. Apparently one of our neighbors had a bit of a bad day when he was on the toilet and thought a train was coming through his house and decided to leave his house. My dad loved that story and it still makes me laugh. Crazy audiophiles and understanding wives, to say the least. To think that got me started in this weird hobby is amazing. Enjoy your speakers. From (ancient) memory, they sounded lovely - realistic and dynamic.
Phil, you might want to check that record because you just might have a piece of history yourself. Check this out from the Wikipedia page:
https://en.wikipedia.org/wiki/Rudy_Bozak (https://en.wikipedia.org/wiki/Rudy_Bozak)
Bozak met Emory Cook in the early 1950s; the two hit it off and began working in a shared warehouse basement facility in Stamford. Cook and Bozak thrilled the audio world in 1951 with Cook's ground-breaking stereo recording of train sounds at night: Rail Dynamics. Together, Bozak and Cook implemented a stereo loudspeaker system that would be able to show Cook's stereo recordings to best effect.
It's probably good that they recorded the train sounds at night because the hobos would have been passed out by then.
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I mean say Bozak w/Alnico magnet has good sound and the Ferrite magnets speaker has the usual sound that these magnet are known.
The main factor in determine sound in a speaker specially woofer and midrange is the magnet type. I follow us, uk and portugal audio scene since the 1970s and Bozak despite being a better product than Bose or HT speakers is not au pair with Infinity IRS, B&W, Magnepan, Quad, Klipsch, Polk, Kef, Monitor Audio, Dynaudio, Apogee etc to stay w/famous brands only of that era. It just happen Bozak had a well made ads in magazines emphasizing its appearance and a efficient made text to convince the audiophile that the product is extraordinary.
But if you believe Bozak are the sweet spot it will be for you.
I don't recall saying any of that, and I'm also not the one making pronouncements about the sound quality of speakers I have never heard. The fact that fishmonster's speakers still work after ~50 years says something about their build quality if nothing else. I'm also skeptical that magnet material is the be-all of speaker SQ, more than driver choice, crossover implementation, cabinet tuning, cone profile, driver layout etc etc etc. I doubt the JBLs you mentioned, the Bozaks, or the Dyna A25s I started out with all sound the same even though they all have alnico magnets. Everybody's entitled to their opinions, but without direct firsthand experience I don't see how you can even have that.
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I'm also skeptical that magnet material is the be-all of speaker SQ, more than driver choice, crossover implementation, cabinet tuning, cone profile, driver layout etc etc etc. I doubt the JBLs you mentioned, the Bozaks, or the Dyna A25s I started out with all sound the same even though they all have alnico magnets.
You are right on target with this observation. I think that Bozak's proprietary blend of paper pulp, lamb's wool and secret construction methods for the cones are as important to the Bozak sound as anything else. That lamb's wool in the cones just strikes me as brilliant for strength and flexibility in the resonance that the cones provide. The drivers and crossovers are also just as important. And I don't think we can leave out the finely tuned ears of Rudy Bozak and his years of expertise as an audio engineer, either. Not to sound sexist, but if Rudy Bozak had a son in addition to his daughters, and that son was inclined to follow his dad into the family business we might still be listening to Bozak speakers to this day. Between the article in Vacuum Tube Valley and the Wikipedia article on Rudy Bozak I get the distinct impression that he was disheartened and felt abandoned when he sold the company. They relegated him to a back room in his final years and basically covered any contributions he could have made with a wet blanket. In fact, I think his strength was in seeing a challenge and rising to meet it. His work at two World Fairs and designing the audio for the Pope might have been, in his eyes the greatest moments of his professional career. When speaker technology started changing in the 1970's he may have been somewhat flummoxed in applying his expertise. But if he had a son running the company and who came to him for his expertise in bridging the technological generations the story would have ended far differently than it did. Without a problem to solve he may have felt useless, which for an older man of his generation is the equivalent of a death sentence.
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Hi,
Thank you for providing this information as I found it really informative.
Cheers Rod
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May I add something here ?
It's not because a manufacturer doesn't exist any more
that the products he built are no good today.
I remember when I was working at Cité Électronique in Montréal, Canada in 1967
of RSC (Radio Speaker of Canada) with their models:
Santa Maria, Nina and Pinta, I thought at the time that they sounded very good.
They went out of business, don't know why, but you can still find some use units,
minds you very rare.
So Bozak had at the time a very good reputation,
I don't know why it should be different today,
if they were well built and they were, then they are worth buying with or without
modifications - improvements.
Now, I will get of your hair.
Guy 13
on planet Vietnam.
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I don't recall saying any of that, and I'm also not the one making pronouncements about the sound quality of speakers I have never heard. The fact that fishmonster's speakers still work after ~50 years says something about their build quality if nothing else. I'm also skeptical that magnet material is the be-all of speaker SQ, more than driver choice, crossover implementation, cabinet tuning, cone profile, driver layout etc etc etc. I doubt the JBLs you mentioned, the Bozaks, or the Dyna A25s I started out with all sound the same even though they all have alnico magnets. Everybody's entitled to their opinions, but without direct firsthand experience I don't see how you can even have that.
Unfortunately it is(magnets), its impossible to made a ferrite driver sound like an Alnico, they have totally different sound character and project approach, it would be a bliss if possible.
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Phil, you might want to check that record because you just might have a piece of history yourself. Check this out from the Wikipedia page:
https://en.wikipedia.org/wiki/Rudy_Bozak (https://en.wikipedia.org/wiki/Rudy_Bozak)
It's probably good that they recorded the train sounds at night because the hobos would have been passed out by then.
Thank you for the link to an interesting factoid. Clearly they succeeded in producing a "dynamic" speaker. My dad's system filled the entire (small) house with sound. The system was in the bedroom on the second floor and I could enjoy what we called Church music (classical played on Sundays) downstairs. When I was recently talking with my dad about amplifier power, he was surprised that speakers needed more than 10 watts to get going. "My Boak's didn't need so much power," he commented. Indeed they didn't.
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Fishmonster, I don't mean to rain on your parade, but several items.
1. the paper-coned shiny dust cap B-200X tweeters from the 1950s are terrible in comparison to the B-200Y (60s), or B-200Z (70s). Whether it was they are from the 50s and were only designed to get up to 8kHz or whether 50+ years of oxidation has taken its toll on the cone, I do not know. If you use them only below 7kHz they are tolerable. B-200Ys are plentiful and vastly better.
2. Rudy Bozak never used fiberglass as acoustic damping. In the 50s he used Kimsul a pleated paper affair, that turns, literally, to dust by now. From the 60's onward he us Tufflex a woven cotton mat. If you want to get what the Bozaks are capable of, dump the fiberglass and get some cotton batting and put that on all interior surfaces, except the front, and hang a curtain of it about 4-6" from the back. The woofer is designed to be in an infinite baffle enclosure and the idea is to eliminate the back wave.
3. Most Bozaks out there sound muffled and indistinct because they have the original capacitors. If they have your oil caps (the N-4) they are so old even though oil caps self heal, they only do that for so long and then die. The new partners in the 60s made Bozak go from oil caps to conventional. Unfortunately they choose a model of cap from Chicago Condensor Corporation that aged really fast and really badly. The so-called dirty yellow crayon. I never would have bought my Concert Grands based on what they sounded like 14 years ago with their 31 year old caps. But I knew what they sounded like back when I sold them (we also sold Klipsch, B&O, Magneplanar, Magnepan, ADS/Bruan, Audionics, Canton) so I knew that 2 new caps per box (6db/oct crossovers) and they would sound like they should sound. Also the new partners decided to wire the midrange out of polarity (remember this is a 6db/oct crossover) which gave it more midrange "punch" (I.E., peakiness) which ruined the imaging IMHO. In the 70s a different brand/model of cap was used, that didn't age much better. Shiny yellow crayon.
I think your model with the top ridge was either a custom order or a home-brew and there is nothing the matter with home-brew if the walls are strong and rigid.
Let me know if you want to work on these yourself to get these in better shape. The optimum would be to add a B-209B or B-209C midrange with a small back chamber. The B-209A was a built for 3 years oxidizing disaster that was made before plastic antioxidants were understood, and the old paper-coned B-209 midrange is too old and does not have any of the definition of the spun aluminum coned B-209B/C.
Best way to contact me is on Facebook or a message here on AudioCircle.
Best Wishes,
Ken Seger
P.S. Hint. Rotate the woofer 180 degrees every fifty years to prevent spider/surround sag, so that gravity starts pulling from the opposite direction.
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I got a 2-way Bozak B300 at auction cheap. Listened to it for a month or so mono. Enjoyed it so much I bought a B302A crossover and aluminum mid from eBay to convert the 300 to a 302. This is the normal upgrade path Bozak expected. They designed their loudspeakers to facilitate such customer upgrades. Liked it even better as a 3-way. So I bought a second B302a from eBay missing some trim which I have replaced. The price was reasonable.
The 2 speakers sounded great but their imaging was a little off. It turns out the one I bought complete had the newer style woofer with no cap on the magnet. The 300 I upgraded has the original woofer with the cap and labels. Looked the same otherwise in terms of paper, basket, and so on. But the sound was just a hair off so the imaging was way off. Anyway, as it happens I had another original woofer/tweeter set.
So I just got done replacing the newer style woofer with an original. In the process I did quite a bit of research which is where I found out that the insulation was not fiberglass, but a kind of layered crepe paper and asbestos. That's right, asbestos. So be careful ripping into these speakers because the insulation falls apart and floats up into the air like crazy! It has an interesting history. Look it up: "Kimberly Clarke Kimsul" forms the crepe paper sound baffle and hanging internal blanket. Very fragile and, to stress it again, contains asbestos with its attendant cancer risks.
https://inspectapedia.com/insulation/Crepe-Kraft-Kimsul-Insulation.php
Now, there seems to be some contention about whether the asbestos was a direct ingredient to add bulk or fire-resistance in the paper or may have been accidentally introduced through manufacturing cross-contamination.
https://forums.jlconline.com/forums/forum/jlc-online-expert-forums/building-science/1136-kimsul-insulation
Speaking of exotic materials, the woofer cones in both the original and newer versions both look, feel, and sound like wool felt. No joke. I know Master Bozak was famous for paper-making. But we are not talking a bit of wool here. My haberdashery friend said I'd better watch out for moths after feeling of them.
I really like the Bozak B302a loudspeakers. I suppose the only I like better now are my 1970 Klipsch Cornwalls. But the Bozak have a very solid, confident sound with precise almost sculptural details now that the imaging is better with matching drivers.
I spent some listening time comparing them to period ARs, KLHs, Polks and Mirages from a little later, Bose 901 VI, and Design Acoustics D-12s. All in all, the Cornwalls and B302s are just more satisfying, larger sounding, confident, with more stable, solid imaging, and they both provide music in actual scale. Not just loud, but effortlessly non-fatiguing, and musically convincing.
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Nice thread.
I have B201 Sonoras that I recapped. Quite a nice sound.
Also B313 "bookshelves" that I'm in the process of redoing. at 65lbs ea, they're staying on the bookshelf if I ever get them up there.
Finally, I have a pair of the B4000s in good condition, with a full extra set of drivers. I'll go through those once the B313s are complete.