Anyone good at identifying ancient Bozak speakers?

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fishmonster

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Anyone good at identifying ancient Bozak speakers?
« on: 26 Aug 2016, 06:51 pm »
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:







dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #1 on: 28 Aug 2016, 10:09 am »
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).

FullRangeMan

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #2 on: 28 Aug 2016, 10:34 am »
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

FullRangeMan

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« Last Edit: 29 Aug 2016, 11:06 am by FullRangeMan »

ohenry

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #4 on: 28 Aug 2016, 12:15 pm »
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/ and they have some cursory info on the B-300.

Enjoy your speakers and make them pretty.  :D


fishmonster

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #5 on: 28 Aug 2016, 11:01 pm »
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/ 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?

FullRangeMan

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #6 on: 29 Aug 2016, 11:05 am »
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.


S Clark

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #7 on: 29 Aug 2016, 12:58 pm »
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

JakeJ

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #8 on: 29 Aug 2016, 01:03 pm »
SClark beat me to the punch on Acousta-Stuf.  Good on ya, sir!

dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #9 on: 30 Aug 2016, 12:42 am »
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.

glynnw

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #10 on: 30 Aug 2016, 01:10 am »
Out of curiosity I did a Google search on Mr. Bozak - there is a huge amount of data on Wikipedia.

ohenry

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #11 on: 30 Aug 2016, 01:23 am »
... 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.

dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #12 on: 30 Aug 2016, 05:04 am »
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.

dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #13 on: 30 Aug 2016, 05:12 am »
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


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.

fishmonster

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #14 on: 1 Sep 2016, 06:56 pm »
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.

dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #15 on: 2 Sep 2016, 03:58 am »
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!

fishmonster

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #16 on: 2 Sep 2016, 05:15 am »
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. 

FullRangeMan

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #17 on: 2 Sep 2016, 10:47 am »
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.

dB Cooper

Re: Anyone good at identifying ancient Bozak speakers?
« Reply #18 on: 2 Sep 2016, 11:39 am »
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.

fishmonster

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Re: Anyone good at identifying ancient Bozak speakers?
« Reply #19 on: 2 Sep 2016, 10:52 pm »
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.