• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Need help with Bozak 302a Urbans

C

Cubswin100

New Member
Having already purchased an awesome pair of Bozak 301 tempos, I felt a need to grab a matching pair of 302a for $290 on Craigslist. They are stock 1966 so they have the aluminum tweeters. Cabinets are in excellent condition. Drivers work great. One major problem, they don't sound nearly as nice as the smaller tempos. I suspect it is the caps. I have a three part question that I'm hoping someone can answer for me.
1) Should I replace the capacitors or should I opt for the Pat Tobin crossover modification.
2) If the crossover mod is the direction to go, does anyone know if Mr. Tobin still does modifications by rquest?
3) If Pat Tobin no longer works on Bozaks does anyone have a pair of the modified crossovers, or know of a pair for sale.
I've never done a mod before so it would be a big job for me to attempt, but I would love to get these beauties sounding the way they should

Thanks b
 
Register to hide this ad
Do a search here on them as there is lots of info.
Pat Tobin has passed, but there is plenty of info, but it is sketchy and demands some attention. Certain wires need to be moved to execute the crossovers properly. I had a set, did the Tobin mods to better them, liked them less, Econowaved them, liked them no more so I sold them. I didn't pay near $290 for them either.

The crossover mod isn't hard, but you do need to buy the new caps and do some rewiring. Frankly though, if you aren't impressed now, I doubt that the upgrade will sway you more. But we all hear differently, so who knows. I really wanted to love mione, but it just didn't work out.

I'll look for my Bozak thread as it should be helpful.
 
What you want is the 104T crossover mod, it really improves the midrange reproduction. Whats the difference. The mid to woofer frequency is 400 HZ rather than 800 HZ like the 302's biggest brother. .
 
Andyman said:
Do a search here on them as there is lots of info.
Pat Tobin has passed, but there is plenty of info, but it is sketchy and demands some attention. Certain wires need to be moved to execute the crossovers properly. I had a set, did the Tobin mods to better them, liked them less, Econowaved them, liked them no more so I sold them. I didn't pay near $290 for them either.

The crossover mod isn't hard, but you do need to buy the new caps and do some rewiring. Frankly though, if you aren't impressed now, I doubt that the upgrade will sway you more. But we all hear differently, so who knows. I really wanted to love mione, but it just didn't work out.

I'll look for my Bozak thread as it should be helpful.
Click to expand...
I guess I should expand on exactly disappoints me in the sound of them. The bass and midrange sound very good, it's the tweeters that don't sound very nice, kind of muffled and tinty all at the same time if that makes sense. I'm hoping new caps will take care of the problem. Using the high filter on the receiver seems to help somewhat, all in all I'm just a little disappointed that they don't sound as nice as the 301 tempos. If anybody else has had a chance to compare the difference between the 301 and 302, how would you describe it? Thanks for any help
 
I don't have the schematic at hand, but the smart thing to do would to replace the caps in the tweeter signal path with cheap electrolytics to see if that wakes them up since lack of highs is your issues. Old caps become resistive and effectively pad down tweeter output, fresh csps remove the resistance and allow the tweeters to play as designed.
Also you may want to lay on the floor and listen as the tweeters are bridged over the woofers and shooting into your shins. See if that helps at all. It's an odd arrangement and some have moved them on top via a small box with good results.

I'll dig into the schematic and see which caps are directly in the tweeter circuit and let you know which ones to look at.
 
Last edited:
Here's the OEM N-10102 schematic. Try refreshing the 8mf and 4mf caps and see if that helps the highs. Cheap non polar electrolytics will do fine for test purposes as we're hoping to simply reduce resistance from the old caps.

image022.jpg
 
Andyman said:
Here's the OEM N-10102 schematic. Try refreshing the 8mf and 4mf caps and see if that helps the highs. Cheap non polar electrolytics will do fine for test purposes as we're hoping to simply reduce resistance from the old caps.

image022.jpg
Click to expand...
Thank you for the diagram, and everyone for the help
 
I have a spare set of x-overs and the caps but have yet to make the Tobin mods. Wanted to keep the originals and have the Tobins. All it takes is time and I don't seem to have enough.
 
I just did a set of 302 mods two weeks ago, as Omegaman said its not hard, just take your time. Many thanks to Omegamans fine pictures and explainations. I continued going back to his pictures, it took about 4 hours for both. In the parts list you will only need the 50uf Caps. So don't order the 25uf and the 50's, just the 50uf will do it. THANK YOU OMEGAMAN!!!!
 
IMO the Urban's need a super tweeter to help with the upper frequencies. Otherwise they sound dull and lifeless, but the bass and midrange is very good. There is quite a bit on info on this in the Yahoo Bozak forum.
 
My hearing tops out around 16k-17k, and I don't think my Tobinized 302s sound "dull" or "lifeless." The original wax & paper caps used in those crossovers are awful - I didn't like the Bozaks at all until I'd fixed that.
 
HI all -

I am working on a set of Bozak Concert Grands that also use the N-10102 crossover. The taps are set for the N-104 configuration. Can I just bypass the bank of 5uf series capacitors inside the black box and wire the new caps in directly to the (+) leads on the crossover? This seems to be much simpler to have exact values. Also, the crossover points in the manual point to 400Hz and 2500Hz for the Concert Grand. That corresponds to a 50 uF cap on the mid and a 5.6uF cap on the tweeter. These values are vastly different from the original components. What gives? Is the Concert Grand a 16 ohm circuit or an 8 ohm circuit?
 
You must log in or register to reply here.
Back
Top Bottom