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Thanks for the reply. I currently have AR3a’s hooked up and AR 2ax’s in reserve. Would you consider the Bozaks a good upgrade? At almost two hundred pounds per speaker, I’d have to imagine they are in whole nother league, right?
twiiii
Lunatic Member
When I bought my pair in 2008. I paid $450.00 including a spare mid range and a spare woofer. I changed the grills to match or a least be similar to my Concert Grands. And Like my Grands I added super tweeters. On my Grands they are tri amped, woofer, mid/tweeters, and super tweeters. On the 4005's that are bi=amped, I added the super tweeters passively crossing at 10 KHZ. If the cabinets are in great shape and the speakers have been treated well I would guess some where between 600 and 800 dollars. If they have the more advanced Z tweeters even more. Z tweeters were starting to be used in 76 as I remember. The Z tweeter reaches 18 kHz where the Y tweeter starts rolling off about 12 KHZ. You can use digital mini processor to extend the highs without much effort to 16 KHZ flat with the Y tweeter. And to reach 30 hz with the speakers agains a wall using the eq to smooth out the bass from 70 160 hz which tends to rise using tube amps and placed against the wall. If you pull them 3 ft out from a wall the bass is flat but rolls off like cliff at 40 hz. 
The date code would be the the month number followed by the year. 0876 for instance. Most of the time in the Stereo mode I use about 2 watts with the Grands. In the HT mode the 4005 being the most important speaker is about 2 to 4 watts with 20 watt peaks. But with Techno movies a rare occurrence might require 50 watts total. When I had original 4000 symphony's I used them with a MC 240 for many years very happily.
The date code would be the the month number followed by the year. 0876 for instance. Most of the time in the Stereo mode I use about 2 watts with the Grands. In the HT mode the 4005 being the most important speaker is about 2 to 4 watts with 20 watt peaks. But with Techno movies a rare occurrence might require 50 watts total. When I had original 4000 symphony's I used them with a MC 240 for many years very happily.
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$900 with a little room for negotiation, but I also don’t have any kind of reference point because I can’t find any for sale.
twiiii
Lunatic Member
Thats why the price is going up. There was a time bout 10 to 15 yers ago older folks who bought Bozaks were passing on or had lost their hearing and were selling off their speakers. Well Bozaks have been rediscovered again and are hard to find. Especially Symphonies. They aren't as efficient as a Klipsch but I prefer the natural bass and the more life like midrange with out the honk of a horn. Yes the highs are little compromised with the Y tweeter but that can be fixed. But don't push them to much as distortion rises if you do in the highest highs. 4 db is plenty of an addition at 16 KHZ half octave centered. A filter about an octave and half wide centered at 125 hz will cure the over warm bass is placed against a wall. You should ask to see inside the boxes to make sure all the drivers are original. Take a power screw driver with you. You really want speakers built after 73 as they have the better speaker capacitors. While the older units have the better air coil inductors and will have to have the crossover capacitors replaced. Remember a lot of Symphonies were built as kits and some times things just are not right inside if not direct fully loaded from the factory.
Retrovert
Addicted Member
I have to take issue with that, Twiiii. I know you're trying to maximize the likelihood of running without upgrades, but the reality is that no Bozak should ever be run with original capacitors. Every capacitor should be regarded as degraded and a potential failure point, particularly the wax-paper units.
The units built after the early 1970s are horrendous: cored inductors, often aluminum wiring, with horrendous polyester (tradename Mylar) capacitors which have enormous dielectric absorption. Simply dreadful crossovers which require complete replacement. In addition, the later units had quality control issues for the drivers.
Plus, if one were a purist, the earlier units used alnico magnets. I don't consider this to be an issue as long as the drivers are of the same time.
closetguy
New Member
A year ago looking through craigslist the prices on Bozaks were low. $450 for a pair of concert grands Now they are $2200. It was about 5 years ago that an article appeared in Stereophile and the reviewer was just blown away at how effortly the Grands produced large Orchestral Pieces. When I started my speaker building journey 47 years ago plans were available for all the brands of speakers. All you had to do was buy the drivers from the manufacturer. That's why you see different cabinet designs in the market for the same model speaker. Factory vs Home Made.
I bought 8- 12" Bozak Woofers once with the intent of building my own set. Had to give it up when the wife decided they would definitely not be room friendly. 65 year old caps may need to be replaced. Resistors may need an upgrade to newer carbon comps. Personally I would first play them for a while with the original parts before rebuilding anything. Run a few tests on the parts before and then after using them for a few hours to see if the small current running through them does change spec's. Use your ears to check for distortion.
I bought 8- 12" Bozak Woofers once with the intent of building my own set. Had to give it up when the wife decided they would definitely not be room friendly. 65 year old caps may need to be replaced. Resistors may need an upgrade to newer carbon comps. Personally I would first play them for a while with the original parts before rebuilding anything. Run a few tests on the parts before and then after using them for a few hours to see if the small current running through them does change spec's. Use your ears to check for distortion.
twiiii
Lunatic Member
Remember Alnico magnets loose their strength with use especially if the units are pushed consistently to hard. My Grands are Alnico everything else is ceramic. I bi amp and tri amp so that. gets rid of the majority of caps. There are 5 N-107's in the system and the caps have been replaced. The Grands are tri-amped, with the one cap of the N-107. The symphonies are Bi amped with the one cap of the N-107. Only the 313's have the full N-10102A crossovers. They have been recapped also. When I took out all the caps of the 4005's they all measured with in 2% and their DCR was less than 0.2 ohms. I quit rebuilding Symphonies at. work in 2004, when I retired , adding super tweeters, checking wiring and cap replacing them most of the time. . All were pre 200Z tweeters and they all measured the same after additions and cap replacements with in a db or two. I maybe converted about half of the older units for bi-amping. The N-105's were tossed. I never did Tobin mods back then. Fortunately I never had to deal with the older Bozaks with with paper tweeters and midranges. I kept records at work but the store closed 5 years ago as I remember and all that paper work is gone. I still help friends with ML series speakers and rarely a Bozak owner. They have mostly past on as they were 10 to 40 years older than I was when I started work in the late 60's when Bozaks were so popular. I always wondered what happened to my B4000 Contemporary. 
