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Replacement Tweeter for Realistic Nova 7B

J

JonL64

New Member
Hello:

I'm looking for replacement tweeters for my realistic Nova 7B speakers. These speakers had a weird way to handle midrange/treble, they used two tweeters (Part# 0705Ae).

I need four that will perform well/no buzzing. No originals on ebay. Wondering if there is an aftermarket replacement that will work just as OE?
 
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Are the originals not working, or do you simple want to upgrade?

Unfortunately, most speakers need a complete crossover re-design when you change drivers.
 
When searching eBay also check listings for Optimus 1B tweeters. They are the exact same driver.

Another possible option is substituting mid-tweeters from Optimus 21, part no. 0738. They are the same size, have the same wide frequency range and power rating and look identical to 0705Ae. The difference is they are 4Ω so you merely wire them in series rather than in parallel like the original 16Ω tweeters.
Stuart Pedaso said:
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Thanks for the replies. I'm looking for a direct replacement, so the Optimus 1 or 21 tweeter idea seems to be best - if I can't find the 0705Ae's. If I go with 0738, I'll need to figure out to wire them in series.
 
Or you could just be patient. I've bought Nova 7B tweeters's from the "bay" within the last year, so they will be up again if you have the time to wait for them.
 
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thread resurrection alert...working a pair of 7Bs I got 'working, but the seller who is a friend didnt know...the tweeters in 1 are blown.

they are 50W speakers but the crossover is set up for about 1300hz (I will explain why later) and its a 1sr order....me thinks too much power can get thru in the 2Khz region

The tweeters are really full range drivers, just small, they run down to 350hz and up to 18Khz and are 16 ohms each. both tweeters are hard wired in parallel to give 8 ohms.

the 1 henry inductor is wired in parallel with them, but after the 15uf cap. This will cause the tweeters to experience a 12bdb rolloff/octave.

The woofers run free and the writing says they are good to 5Khz so this gives a pretty good separation lets the lower mids be handled by the larger speaker and the transition to the upper speakers is spread out over a large range.

that all being said, if you want to hear the 'tweeters' at all...change that 15uf cap.

now given that full range speakers of this size that fit and that impedance are rare, I am working on a true 3 way hybrid.

so far I have selected
Dayton Audio PC83-8 3" Full-Range Poly Cone Driver

This can run 'free' after the uf cap and before the selector and inductor and the 2 resistors.

it also has the power handling to survive.

I am looking at a tweeter like this:
RT-6 2" Phenolic Ring Tweeter with Grill 8 Ohm

and change the entry crossover cap to give a crossover at 10K (Fs is 4077) and with the inductor still in the circuit and this tweeter being 5db more sensitive than the 'med' I think the highs will stand out.

Im getting another pair of 7Bs in great shape and will test both - stock and mine - side by side using a switch from my amp

Both these replacements are from parts express at a good price so the coast is about $20 per speaker. and no more blown up tweeters.

now as for the 1300hz, I plugged in the numbers in using the fact that the tweeters are 16ohm (14.7 measured) and came up "around" 1300hz
 
yessir, they are long in a new home. I think there is a thread somewhere as to what all I did
 
quaddriver said:
yessir, they are long in a new home. I think there is a thread somewhere as to what all I did
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Sorry, what I meant to ask is how did your 3 way hybrid compare to the original 7B's in the side by side test. If the project speakers sound as good as factory 7B with new caps then I sure would like to know your crossover design. My reason is that I listen to my 7B's which I did replace the original 15 or 16 ? cap with a Dayton or Audyn Q4 cap of the same uF as the originals. And they sound really good to me on a Pioneer SX-880 receiver and as you know if I blow a tweeter then I will be in dire straights finding a replacement. What entry crossover cap did you choose, did you add a choke or other passives? If you consider what I am asking for proprietary then just say so and I will quit bugging you. I have looked for your thread unsuccessfully. Is it maybe on a different forum? Thanks for any help you can supply.
 
well when i got these, a tweeter set was blown so i never had a side by side, i looked into the drivers and how they were used. i dont remember the values, i have to find what i posted and where to get details...but I paired them with the sta 86? they came with and the same person took the package I never ran them on anything else but my sx890 for a short time to test them. since I normally run carvin studio monitors, its hard to do a taste test as the carvins outshine almost all speakers at low wattage intimate set ups - hence the whole studio monitor use... the buyer however, loves the whole setup

i just found my craigslist ad for them and it seems i replaced the original cap with same, and u used wide range 5b tweeters as midranges at 8 ohm and I used an original 16 ohm tweeter now and stated a person can experiment with 3-10uf, but i chose one that gave a 12db/octave drop for the tweeters. i didnt save any other notes sorry...
 
Not to be sorry. Thanks, your info will give me a starting place if my mid/tweets do blow. But now I have them paired with a Harman/Kardon 730 receiver and I don't worry over it.
Thanks again QD.
 
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