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68.19.16.108
If you string two capacitors together in series you add the capacitance to find you total, correct? When bypassing a capacitor, are you still adding capacitance or is it volage? Since I was really only thinking about bypassing the lower frequency cap (a 68 uf cap that is too expensive to use anything but a Solen) I have read that is the least important of the three, should I bother?
Sorry if my explanation below wsn't clear. I asumed you knew the rules for how resistors combined.
Now it all is a function of how many dB the crossover is but for a second order (12dB) there would be a series cap to a tweter and a shunt inductor across it. For the woofer the inductor would be in series and the cap in shunt (shunt means across the driver terminals). In general put your money into the series parts and save on the shunt parts.
Also be advised that a film cap is going to tend to sound brighter so that might not be a good thing on a klipsch tweeter or mid range as they can sould a tad aggressive already. Real point being, to make one change at a time and keep the old parts. Listen for a week or two and then put the old part back in to be certain you like the change. Don't be afriad to scroung old motor run caps, from discarded air conditioning units and the like, as a cheap source for large film caps. Plus they have somewhat more delicate sound sometimes.
Russ
It is for the Klipsch, and I do understand the part about adding resistors so I was surprised by the capacitor answer. One of those things that I just couldn't wrap my mind around.
Thanks for the suggestions. I think I might build the crossover in a seperate box to be able to do the changes bit by bit without always having to get into the speaker. Apparently some of the coils are too close together and need to be seperated anyway.
About the worst possible place for crossover parts is inside a speaker cabinet! Not only will it be easier to work on but I bet it will sound better not having to deal with all the sound pressure waves and vibration.
You have done your homework I see and made a wise choice. The Cornwall is about the only other one I'd rather see you have....besides the two other (unamed) ones that are way too big and costly:)
Pay attention to the DCR of the inductors (coils) as they are often part of the crossover design. I know in some of the Klipsch speakers they used oil caps in big metal cans. If you have those I'd keep them. IIRC some had transformers with taps and for sure you want to hold on to them too. And keep in mind what Tom said about Remora's:) You might want to start with damping the horns themselves.
Now you need a top notch turntable.....or reel to reel....LOL...It is a sickness you know!
Russ
The more I get into it. Got the amps, got the speakers (though I have my eye on a pair of Fostex that I might add to the collection though they will be the last Fostex I audition if I don't like them), next is the turntable. Probably a VPI or that direct drive that all the DJ's use which name escapes me for some reason.
The Klipsch guys say to upgrade the caps and resistors but not to touch the inductors on the Chorus II. And thanks for the compliment, I read a great deal and the Chorus II seemed to have the quality, and importantly, the size considerations I needed.
I am not familiar with DCR.
DCR is the series resistance component of the complex impedance of the inductor. This is really a non-linear system due to more than just the hysteresis of the iron core, but it is satisfactory to model it as a series combination of resistance (DCR) and inductance (Le).
Jeff Robinson
It is just something that has to be taken into account in the crossover design. Sometimes it is overlooked when guys want to upgrade with something better.
Russ
P.S. You will be happy with Mills resistors:) I don't know what size caps you need so until then...
hey paully-
i think, whether in series or parallel, you're just adding capacitance by chaining caps.
if you're using a first order-- i would think if you're using in order of 68uF, you're not going to see too much benefit of using a 'bypass'-- but you might actually benefit from using an electrolytic. this is not of my own trying-- but advice from others which has helped me a bunch.
why are you thinking of bypassing that low anyhow? different sonic effects?
yrs
d.
For the mid and HF I will go ahead and use Kimber Kaps or some such, though I am starting to wonder if I should use Solen throughout. Since I was thinking I would use a nicer cap on the higher frequencies I might want to bypass the LF to give it some of the same sonic signature. Maybe I am just better off using the same capacitor throughout, I don't know. Solens will be a heck of a lot better than what is in there now (1990 vintage speaker that didn't use good caps even then).
Put your money in the HF cap...a little less in the MF cap....and not much into the bass cap. If money is an issue then maybe an electrolytic bass cap and put whatever extra to buy that nice HF cap. I think that Solens is a little grainy for HF..of course, it is probably better than what came OEM.
When you put two caps in series (same value caps) the voltage rating doubles but the capacitance falls by 50%.
If you "bypassed" a cap with another one then the values add.
Kinda like resistors only backwards:)
Russ
Time to go read up, I don't see how capacitance can fall (not saying you are wrong, saying I don't understand).
But what I do gather is that two caps in parallel adds capacitance. Got that, thanks!
Any recommendations on what to caps to use? Would you use a 68uf Solen and bypass it then use better caps on higher frequencies (or not bypass it all), maybe just use Solen throughout, or do you have any caps that are good for speaker crossovers that don't cost an arm and a leg? I mention Kimber Kap above and I think Dayton is reasonable.
Hornlover's explanation is correct. Oddly enough, a good way to remember it is to consider non-polarized electrolytic caps. The reason why non-polarized caps are so expensive is because each cap is two polarized caps wired in series. Consequently, each of their values is cut in half. So, your 68uF cap is actually two 136uF polarized caps wired in series with their positive terminal pointed out. So, if you wanted to bypass your 68uF non-polarized cap and maintain the same capacitance, you could wire two 100uF polarized caps in series, with their positive terminals facing outward , and bypass the whole with a 10uf and an 8uf film caps in parallel.
Capacitors work the opposite of resistors. With resistors, when wired in series, the values add. When wired in parallel, the value reduces. With caps, when wired in series, the value reduces, and when wired in parallel, the values add. The formula for series caps (and parallel resistors) is:
V total= 1/(1/v1 + 1/v2 + 1/v3 etc.)
where v=value.
In series, capacitor voltage increases. For instance, two 68uF 50V caps in series becomes 34uF @ 100V.
Caps in parallel, add the values together, but voltage stays the same.
To add capacitance to a circuit, all caps need to see the same voltage. So, they need to be connected to the same source voltage. So, they need to be connected in parallel. :)
.
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