Speaker crossover mod. Your advice?

Thanks, John, for your advice. I will take a look at the Mundorf thread. I don't know the first thing about caps, so hopefully that will help.

I think the plan at this point is to replace the 2 caps for the tweeter, and possibly the resistor for the tweeter. I am going to leave the inductors alone.

As far as the midrange, I may do that down the line, if I am happy with the tweeter results. But for a first step, I am going to restrict myself to the tweeter. With that in mind, I have a basic, possibly stupid, question as I look around for replacement caps:

The caps for the tweeter are labelled "3.6J" and 6.8J." Does the "J" after the number mean joule? In my preliminary search, all the caps I am seeing are rated in µF. I don't see any caps labelled with "J". Why is that?

Bryon

J indicates value tolerance; I don't know what exactly 'J' means, but I"m sure someone does.
.

Thanks, Jeff. Just discovered this: "J" indicates a 5% tolerance, according to capacitor codes. In light of this...

Is it a safe assumption that the 3.6 and 6.8 caps are 3.6µF and 6.8µF? Are those typical values for caps associated with tweeters?

Also, finding a 3.6µF cap has been a little difficult. The caps I've found so far from various manufacturers are either 3.3µF or 3.9µF. I assume that using a different value will change the frequency of the high pass filter. Is that a bad idea? Or is the difference - .3µF - small enough to be ignored? Should I just keep searching for a 3.6µF cap?

Anyone?

Hi Bryon,

Yes, those are undoubtedly 3.6uF and 6.8uF. FWIW, though, I would not feel comfortable introducing an 8.3% error into the nominal value of the 3.6uF cap, especially in a crossover network that is designed, as this one appears to be, to have sharp slopes.

It might prove helpful to keep in mind that using two caps in parallel, where their individual capacitances sum to 3.6, would be a way of achieving the correct value. I believe 1.8uF is a standard value.

Best regards,
-- Al

Bryon,

I don't have the experience or confidence to change capacitor values, but that is an 8% difference you are considering. The Mundorf M-Cap Supreme line has 2% tolerance. You can read some reviews about caps at humblehomemadehifi, and also Google the Tempo Electric reviews.

I went to the Madisound website and looked at the Solen Fast Caps and didn't see a 3.6micF value. I assume that's what's in your speakers, but maybe Focal had them custom made, and if that's the case, they certainly must have considered that the best value for that tweeter. I wouldn't stray too far.

Here's a couple of options for you:

Option (1): M-Cap Supreme:

- two 1.8micF caps in parallel to give an equivalent 3.6micF value.

- single 6.8micF.

Option (2): Clarity MR w/ Mundorf Silver/Oil bypass caps:

- One Clarity MR 3.3micF with one Mundorf 0.36 S/O cap in parallel to give 3.66micF... (1.7%) but maybe that's okay, I don't know.

- One Clarity MR 6.2micF + 0.68micF S/O = 6.88micF (1.2% off).

I think the M-Cap Supreme would be an upgrade for you and you can maintain your exact values, but if the 1.7% and 1.2% differences are insignificant, some of the members on the other thread I referenced like the MR - S/O combination at lot, but others also report that they get the best results from having a single brand cap in the crossover.

If it were me, I'd do the M-Cap Supreme, it's a safe choice, maintains your exact values, and is a simpler installation.

As for the resistors, on the PartsConnexion website they have a 5.6ohm, 10W Duelund Cast resistor listed. Other than that, I'd go with the Mundorf resistor I guess.

John

P.S.: If you wanted to go all Clarity MR, you could do a 3.3 + 0.36 = 3.66, and then a single 6.8MR.