Another Optimus 5b mod, still all Realistic

[RickeyM]

Using the VL mod for the Nova 8b/Optimus 5b, I wondered what a dome tweeter would sound like in place of the original cone tweet. Don't get me wrong, they sound a lot better with the crossover mod, but IMO, a cone tweeter has it's limits. Listening to a pair of Optimus Pro77's (Minimus 77 with a vent), I liked how the tweeters sounded with a poly cap in place of the stock NPE. I read on this board how someone else put the Minimus tweeter into a Realistic speaker. I don't recall what model speaker that was but, it had to have a smaller tweeter cut out 'cause the original dome faceplate doesn't cover the hole. Please excuse the rough prototype "faceplate", but it works.
What about the sound you say? Very nice I say . Adds a nice bit of sparkle that the original cone tweeter can't match. I had to alter the crossover a bit, I may change it eventually or just leave it alone.

 

[tiga]

Very interesting. What mod did you do to the crossover? I used to have a set of Optimus 5's with a blown tweeter. I recapped them and put a Vifa dome tweeter in and they actually sounded pretty darn nice.

 

[RickeyM]

For the VL crossover, I had a 1.5uF & .22uF cap in parallel, a .33 inductor shunt and a 10-ohm resistor. I just took out the .22uF cap and the resistor. These values are close to a L-R alignment @ 7000hz because I made do with what I had. I'd like to try a Butterworth alignment (2uF/26mH) when I get a chance. Also in the VL mod, the mids & tweeter are both out of phase with the woofer. With this, only the mids are out of phase.
Good dome tweeters really take these speakers up a notch.

 

[willhowl]

Ah,Yes....

Howdy, RickeyM....That was MY thread, concerning Realistic Optimus 25 / Minimus 77 Tweeter Transplantation......

Full thread name .....Tweeter Transplantation....Realistic or Fantasy......

OK... I was in a "Creative" mood that night........


I still like the move, and I think this is a good way to go.......plenty of Realistic material around to play with.....and I do like domes, better than cones, for tweeter topology.......

Thinking hard about my crossovers...:scratch2:.....willhowl

 

[RickeyM]

Back atcha'

Hi willhowl. Yeah, you're the culprit who planted the Realistic dome idea. Looking at the pics in your post, your old tweeter is 8-ohms as well so I see no mismatch there. Consider that poly caps vs electroylitic's is more about clarity than brightness. Not knowing the specs on the Optimus 25 crossover, It's still a safe move to upgrade the caps with poly's of the same value.

 

[Teradacto58]

Realistic "Fried Egg".........