Bozak 302a Tobin Mods 2015
- Thread starter Omegaman
- Start date
Retrovert
Addicted Member
You might conclude that but your sample size is too small. Bozak's model change decisions are rarely defined by a single demarcation point.
The midrange polarity reversal first occurred circa 1961 with the introduction of the aluminum-cone B-200Y tweeter which replaced the paper-cone B-200X. The modification attempted to create a more forward presentation for the aluminum-cone B-209 to better match the now louder tweeter without attenuating the tweeter, which would effectively reduce the dispersion in a large room. (Tobin added a fixed attenuator to adjust the SPL, but Bozak never used such a solution.) The midrange's polarity reversal initially was a factory/dealer option, then an optional customer retrofit by the dealer, and by 1970 was the standard product.
Many speakers were changing to reversed-polarity midranges starting in the 1960s. Roy Allison convinced Vilchur to change the AR-3 in 1959 and this remained common until the speakers after the AR-3a.
I've elsewhere quoted Betts' discussion as to why Bozak made that decision.
Oddly enough, the only piece of equipment I’ve ever truly missed were a pair of custom 302a’s that I made right, my first Bozaks. Retrovert spent a tireless 2 weeks helping me through the crossover updating. They were the most perfect sounding speakers. I ended up trading them for a pair of EMF TLS 80s. I sold those soon after. It took a few years of patient waiting, and impatient pestering for the new owner to sell them back to me. A 4 hour round trip and they’re back home. Everything else? Meh.
Biggles
@drbiggles I just got my first 302's. Retrovert is helping me muddle thru the upgrades. I love the sound as-is. Can't wait to hear them after all the upgrades. Glad to hear you liked them so much. Gives me motivation to do them right!
@Retrovert Agreed, my sample of one does not make it so for all. Just thought I'd share in case someone else is in the same boat. Your comment here finallly made clear to me why Bozak introduced the polarity shift to begin with. To compensate for the louder tweeter model. ...it's all slowly coming into focus!
My office system at one time
I had urbans and centurys
Those were the days my friend
https://audiokarma.org/forums/index.php?threads/added-taper-legs-to-my-bozaks.585705/
Retrovert
Addicted Member
The polarity reversal is a faux compensation, as the midrange is not actually increased in volume (SPL measured in dB), it is merely perceived as being more prominent or noticeable.
The balance and precision between as is and properly updated is quite remarkable. It’s not for the feint of heart though, it’s an advanced project.
Biggles
Retrovert
Addicted Member
I consider working with you on those Bozaks as the single best investment of time I ever made in providing Bozak assistance!
Thank you. Valid because in turn I went and helped so many others. In paid off quite well.
Biggles
Retrovert
Addicted Member
I sometimes think our work sparked the second wave of interest on AK.
Rule 3 of Bozak Cult: Rebuild failure is never an option; no Bozak left behind.
Retrovert
Addicted Member
Best. Job. Ever.
Now that we're all under quarantine, no excuse.
I need to order parts while the the UPS and the USPS are still delivering.
Iam at work in the lab, no rest for me. All I care about is access to food. The only thing the profiteers left were canned garbanzos.
Biggles
brian welch
New Member
Nicely done Omegaman...I am about to embark on the same journey.
Curious, can anyone advise to a downside for using female terminal connectors as opposed to directly solldering each connection?
Assuming all connectors are properly/completely soldered to the conductors/wires. I tried some practice joints, and crimped, then soldered the F connectors. So far all have tested as good...
Thanks in advance