Kappa 9 Semits wired in series with Emits

MiamiBoy

Active Member
A little over a month ago I purchased a pair of Kappa 9’s and have been doing some upgrades on the capacitors and inspecting all the wires and driver connections on both speakers. One thing I found that was odd is the Semit tweeters on both speakers are not wired directly to the high tweeter crossover connection but instead are wired in series to the front Emit tweeter just below it.

The two wires coming from the crossover that should be connected to the Semit were just left unconnected in the speaker. The Emit tweeter is connected to the correct wires from the crossover but the Semits are just connected to the Emits. The wiring is identical in both speakers.

The speakers don't appear as though they have been modified. The solder connections and wires all look original and both tweeters felt like they had not been previously removed. Is it possible they came from Infinity this way? The person I bought the K9’s from knew the original owner and swore no work had been done except a woofer re-foam.

I do plan on reconnecting the Semits as per the schematic but wanted to know if anyone else has seen this before?
 
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Well, after looking closer at the solder connections I can see that the connections are not identical to the other original driver connections Infinity did. So it does look like someone modified the SEMIT connection after the speaker left Infinity. The question is why? :scratch2:

For the time being I am going to leave the SEMIT's wired as they are because I am upgrading all the capacitors in the Polydome and Polygraph Xover circuits on only one speaker and want the capacitor changes to be the only changes made so I can perform a pure A vs B comparison between the speakers to see how much of an improvement the new capacitors make. I will be disappointed if I don't hear a major improvement in the mid-range. I bit the bullet and dropped some serious change on Mundorf Supreme capacitors based on recommendations in other older posts here. They are friggin HUGE. I had to install the capacitors on separate PCB boards because they were too large to install in the existing Xover board.

Here is what it looks like. The two pcb boards on the right contain the caps for ONLY the Polydome and Polygraph drivers. Each new cap is wired directly to where the old cap used to be on the original board on the left.

20150727_143655.jpg
 
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wire one side the right way and see the difference...

I plan to rewire them both correctly when I finish my comparison listening of the new caps I just installed in the one speaker. The only reasonable explanation I can come up with for the Semit wiring is that there is a problem in one of the Semit xover circuits and instead of finding and correcting the problem they just opted to wire both Semits to the Emits. So when I rewire the Semits I might find a new problem to address.

When I do get around to it I will post a follow up.
 
Another plausible explanation is an attempt to "correct" the impedence drop at 7KHz. Kappa 9's have two impedence drops below 1 ohm across the frequency response. One in the 30-40Hz range and one right around 7KHz; however, there is a switch on the crossover to add a 1 ohm resistor to the woofer circuit to help compensate for the low end dip.

If a previous owner was bi-amping with a "less than capable" amp on the top end, they may have figured wiring the sEMIT in series with the EMIT might help "normalize" that impedence dip.
 
Savatage, I am familiar with the K9 impedance curve and have had a question about those two drops below 1ohm that I will ask now, not as a challenge but because I need to clarify something for my sake.

Couldn't almost any amp drive that little puny Semit even at below 1 ohm? Isn't the low ohm problem really about how much current is needed by a driver at a given ohm not just the ohms? Mechanically, woofers need a lot of current to move them at low ohms but I don't see how it would require a lot of current to "move" those little pieces of foil. And if the Semits and Emits really required enough current to pose a problem at low ohmns then I suspect Infinity likely would have installed a second by-pass switch on the tweeter xover circuits as well.
 
Yes, the woofers are the real current hogs, and the biggest problem. However, it depends on the protection circuit of the amp as to whether the high frequency dip will shut down the amp. Many amps will "see" that dip as a dead short (which it virtually is) and go into protect, even though it is not drawing a tremendous amount of current. That's kind of why I used the "less than capable" caveat.

Think of it this way--if you get one tiny stray strand of speaker wire that arcs across the speaker terminals, it surely shouldn't cause the amp to "melt down", but it probably will put most amps into protection.

And I don't think Infinity really cared or thought the impedence issue out--they kind of assumed that if you were buying those speakers, you were driving them with an equivalent quality amp. Hence the "nominal" 4-6 ohm rating--the impedence issues were "discovered" by consumers, not published by Infinity.
 
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We performed upgrades on other models. You may want to try bypassing the high pass on the standard EMIT and allow the SEMIT to come in at that HZ, or higher.

The Kappa 8 was fine; adding another woofer would have been enough, so I believe?
 
Well I finally got around to digging into both Kappa 9's and what I found is that in both speakers, the small breakers rated .85A 30W on the SEMIT xover circuits are bad. Continuity test failed on both. So I guess the SEMITs were wired in series with the EMITs because someone couldn't figure out what was wrong so they did the easiest thing.

My question now is that I have searched for .85A circuit breakers and can only find .70A or 1A, not .85A and both are rated at higher watts. Is a 1A 50W breaker ok to replace the .85A 30W?
 
My question now is that I have searched for .85A circuit breakers and can only find .70A or 1A, not .85A and both are rated at higher watts. Is a 1A 50W breaker ok to replace the .85A 30W?

The higher power rating (50 watts vs the original 30 watts) is OK but don't replace a 0.85 amp breaker with a 1.0 amp breaker, it won't provide enough protection. Using the 0.7 amp breaker will be OK and provide a little more protection for the tweeter.
 
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