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Realistic Nova 8b Rebuild & Crossover Re-Design

It wasn't the prettiest soldering but I replaced the caps! The sound improvement is wild! Mids and highs are much louder and more distinguished, and the bass just sounds a little bit tighter.

Thanks for the guidance all! I can see myself rocking these for a while!
 
Taahman said:
It wasn't the prettiest soldering but I replaced the caps! The sound improvement is wild! Mids and highs are much louder and more distinguished, and the bass just sounds a little bit tighter.

Thanks for the guidance all! I can see myself rocking these for a while!
Click to expand...

That is what happened with mine......I have recapped a ton of speakers but the 8Bs had the most improvement. I love my set.
 
DonQuixote99 said:
It is damned likely that you know more about grounds and amplifier output stages than I do. But speakers operate on AC, which is my main point. I always assumed the amp did not change the 60 cycle alternating frequency as supplied, but I don't know everything....
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Speakers are transducers, and for consumer audio purposes function from an amplified alternating source signal. Automobile amplifiers, or many portable audio players for example typically operate off of DC batteries, there would be no 60 Hz AC involved in those cases and the speakers function as normal. The frequency of the power source is incidental to the speaker operationally, but it can certainly add audible distortion if not properly filtered.
 
Schmidlapper said:
Speakers are transducers, and for consumer audio purposes function from an amplified alternating source signal. Automobile amplifiers, or many portable audio players for example typically operate off of DC batteries, there would be no 60 Hz AC involved in those cases and the speakers function as normal. The frequency of the power source is incidental to the speaker operationally, but it can certainly add audible distortion if not properly filtered.
Click to expand...
Am I correct in thinking that the AC frequency determines how many times a second the speaker moves in and out?
 
DonQuixote99 said:
Am I correct in thinking that the AC frequency determines how many times a second the speaker moves in and out?
Click to expand...
The amplified source signal, from say a CD player or turntable for example, is what causes the speaker movements. There will be many frequencies all at once affecting the speaker, all falling somewhere between 20 Hz and 20 KHz typically. An AC or DC power source in theory makes no difference at the speaker, though as I’ve mentioned, AC is more prone to exhibit some distortion if not treated properly.

Edit addition: I suspect based on your previous comments, you might be thinking the 60 Hz AC is used as a carrier signal, it is not in this case. It is only a convenient power source, and quickly converted to DC in the power supply.
 
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I read about many Aha! moments through this whole thread and I have one to share too. I finished my crossover a month ago and was initially happy with them. They felt bright but seemed tighter and I was just happy sound was coming out as an inexperienced solderer. They were fatiguing to listen to, shrill highs sometimes. I wondered if the caps were burning in. Playing with the balance I realized it was just one speaker that was shrill. I swapped the tweeters from left to right and the shrill highs moved with the swap. I had another set of 5bs so I replaced that shrill tweeter and aha!! They really sound good now! I never thought my drivers were bad. They had checked out when I tested the resistance initially. I wonder if some others who weren't happy with the finally result had bad drivers too?

When I took it out the bad driver is different than the other tweeters. It has a sticker on the back and not a stamp like the others I have. The sticker says it is a 0725Ac like the others. Could it be a wrong driver and not a blown driver?

I will need another driver for my other set which I have already recapped and was hoping to do a comparison with the modded set. None available on the auction site right now. I think people have suggested the phenolic ring PE replacement tweets. Anyone have experience with these or others? I see lots of realistic NOS super tweeters on the auction site. How can you know if a tweeter will match this crossover?
 
Started a new thread on this mod, tried to condense pertinent information.

New Look, VideoLady201's Nova 8b crossover

NOTE: This post is extensive, please don’t post remarks/comments until I annotate (THE END). The below mod was designed and tested by Videolady201 (VL) and posted on June 27, 2010 called “Realistic Nova 8b Rebuild & Crossover Re-Design”. That Audiokarma post goes for 98 pages and 1,547 comments...
www.audiokarma.org
 
Has anybody got the T/S parametres for the little Coral 4R mid drivers?
I've just got a set of the 5B at a garage sale and while the bass is pretty good I'd like to have a crack at a better XO for these and maybe reconfiguring as a 4-Way or 3-5
Keeping the original drivers at the top end but perhaps adding in a decent 6" midbass
 
Moondog55Two said:
Has anybody got the T/S parametres for the little Coral 4R mid drivers?
I've just got a set of the 5B at a garage sale and while the bass is pretty good I'd like to have a crack at a better XO for these and maybe reconfiguring as a 4-Way or 3-5
Keeping the original drivers at the top end but perhaps adding in a decent 6" midbass
Click to expand...
Try recapping them first. My set displayed a huge difference with fresh caps, especially in the top end. As this speaker was introduced as a direct competitor to the KLH 5, they have a pretty hot midrange. After fresh caps, I had to back down the mids a bit.
 
If I'm going to invest my time I'd follow the VL crossover first I think.
But these little drivers can be crossed over much lower if the dollars are available.
Just that these drivers have lost the dope from the silk edge membrane
I only paid $40-Aud for the pair so I can afford to spend a little
 
Only thing I can think of is the butyl dope by RoyC (AK user name). It’s intended for woofers but isn’t too terribly thick and can be thinned with xylene or toluene if you can get it. It is also on eBay by seller vintgage-ar. I bought mine directly from Roy here on AK.
 
I've decided that treating the surround makes very little difference, having just managed to score a Coral 5 inch canned midrange I have decided to sell off the small drivers. I'm willing to post Internationally if anybody was really interested but the high cost of shipping makes this an expensive buy
 
Forgive me if this has been discussed already. Can this crossover Re-Design be done to Optimus 5b's? Or is it just for the Nova 8b's? Thanks in advance!
 
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