Best caps for crossover rebuild

[StimpyWan]

I fully believe you and emphatically agree with you.

I would posit that most folks who disagree haven't done much experimenting with crossovers. Unfortunately they tend to be uncomfortable with viewpoints that aren't their own, and, presumably due to their own insecurities, feel inclined to insult and belittle those of us that have first hand experience with the phenomenon of burn-in/break-in.

Too true, I've been on the receiving end of some of that...!

 

[StuartB]

I have always used Clarity PX caps. They are not very expensive and to me are a step up over Solen or dayton. One poster said they are a little rolled off for him, but that is something that does not bother me. harsh or shouty on the other hand drives me crazy. I have always purchased from Madisound.

 

[KJ244]

I've found (and others have said the same thing here on AK) that capacitors are really a personal preference I've used a variety of capacitors in twelve different KLH speaker restorations including Dayton, Mundorf, Solen, Jantzen Audio, and AudioCap among others. Trying different caps has helped me better appreciate the differences. My personal favorite is Cornell Dubilier caps available from Mouser and others. Not sure what your budget is, but I think they are reasonably priced for the excellent results. They have a 2uF. I've used parallel combinations as well to get the values I've needed. Good luck.

 

[KJ244]

And you have to let the caps break-in. Some take longer than others.

 

[AudioAvarice]

I tend to use Jantzen where possible, as they have an excellent choice for a range of budgets, and have the bonus of often being physically smaller than other brands.

 

[percivilla]

I tend to use Jantzen where possible, as they have an excellent choice for a range of budgets, and have the bonus of often being physically smaller than other brands.

Excellent point, Jantzen caps tend to be about half the size of others, very handy when space is limited.

 

[shelbygt]

Hmm. The speakers I'm working on have horn tweeters and mids, I'm wondering if polypropylene might brighten them. I don't know that I care to do that. These speakers sound great with tube gear. They're a little bright with solid state. Is there an argument here for just sticking with electrolytic?

 

[percivilla]

Hmm. The speakers I'm working on have horn tweeters and mids, I'm wondering if polypropylene might brighten them. I don't know that I care to do that. These speakers sound great with tube gear. They're a little bright with solid state. Is there an argument here for just sticking with electrolytic?

No. Films won't be inherently brighter, but they will be clearer.

 

[RTally]

Hmm. The speakers I'm working on have horn tweeters and mids, I'm wondering if polypropylene might brighten them. I don't know that I care to do that. These speakers sound great with tube gear. They're a little bright with solid state. Is there an argument here for just sticking with electrolytic?

Poly caps have a lower equivalent series resistance (ESR) than electrolytic caps. Generally, the ESR of a fresh electrolytic cap is around 1/2 ohm, give or take a bit. A poly cap has almost zero ESR. When recapping a crossover, many will add a 1/2 ohm, 10 or 15 watt resistor in series with the new poly cap. The resistor will slightly attenuate the signal to the driver and better simulate the original voicing.

The SP-300 speakers have tweeter and mid control switches. I do not have access to the crossover schematic, but often such controls typically switch in resistors to vary the attenuation of the drivers. In that case, adding another resistor in series with the cap is superfluous because operating the switch will have more impact than adding a 1/2 ohm resistor. Sometimes the control switches in a shaping or contour circuit that varies the frequency response of the driver. Without a schematic, I don't know if the SP-300 has that type of crossover.

In your case, if the driver is still too bright at the lowest setting after recapping, you could always add a series resistor to tune to your taste.

 

[shelbygt]

Poly caps have a lower equivalent series resistance (ESR) than electrolytic caps. Generally, the ESR of a fresh electrolytic cap is around 1/2 ohm, give or take a bit. A poly cap has almost zero ESR. When recapping a crossover, many will add a 1/2 ohm, 10 or 15 watt resistor in series with the new poly cap. The resistor will slightly attenuate the signal to the driver and better simulate the original voicing.

The SP-300 speakers have tweeter and mid control switches. I do not have access to the crossover schematic, but often such controls typically switch in resistors to vary the attenuation of the drivers. In that case, adding another resistor in series with the cap is superfluous because operating the switch will have more impact than adding a 1/2 ohm resistor. Sometimes the control switches in a shaping or contour circuit that varies the frequency response of the driver. Without a schematic, I don't know if the SP-300 has that type of crossover.

In your case, if the driver is still too bright at the lowest setting after recapping, you could always add a series resistor to tune to your taste.

You're a wealth of knowledge! As long as I'm ordering I think I'll get some 1/2 ohm resistors just in case. Is there a preference on resistor types?

 

[twk]

Poly caps have a lower equivalent series resistance (ESR) than electrolytic caps. Generally, the ESR of a fresh electrolytic cap is around 1/2 ohm, give or take a bit. A poly cap has almost zero ESR. When recapping a crossover, many will add a 1/2 ohm, 10 or 15 watt resistor in series with the new poly cap. The resistor will slightly attenuate the signal to the driver and better simulate the original voicing.

The SP-300 speakers have tweeter and mid control switches. I do not have access to the crossover schematic, but often such controls typically switch in resistors to vary the attenuation of the drivers. In that case, adding another resistor in series with the cap is superfluous because operating the switch will have more impact than adding a 1/2 ohm resistor. Sometimes the control switches in a shaping or contour circuit that varies the frequency response of the driver. Without a schematic, I don't know if the SP-300 has that type of crossover.

In your case, if the driver is still too bright at the lowest setting after recapping, you could always add a series resistor to tune to your taste.

What is the typical ESR of a Mylar cap vs a metallized polypropylene cap?

I have recapped some crossovers that originally had Poly Caps and may want to add resistors rather than redo the entire crossovers.

 

[RTally]

What is the typical ESR of a Mylar cap vs a metallized polypropylene cap?

I have recapped some crossovers that originally had Poly Caps and may want to add resistors rather than redo the entire crossovers.

Mylar is a trademark by Dupont for a polyester film made of polyethylene terephthalate (PET). There are some differences between Mylar caps and metallized polypropylene caps, but not much. Mylar caps will degrade slightly faster than metallized poly caps, but nothing compared to the degradation of electrolytic caps.

I do not know the exact ESR differences between the two types, but it is not a significant difference. I would not add an extra resistor when recapping original Mylar caps.

 

[Stuart Pedaso]

The SP-300 speakers have tweeter and mid control switches. I do not have access to the crossover schematic, but often such controls typically switch in resistors to vary the attenuation of the drivers.

Sansui SP series of that era take the other approach you mention. Rather than varying series resistance in the circuit, they use tapped coils to change ratios between series and shunt inductance. Tapped coils are seen at the switches in this SP-300 crossover image:


( image from youtube video by Dat Tran Audio Hanoi )

Haven't traced out the SP-300 schematic yet, though my graphic notes for SP-1500 and SP-2000 show circuits with a similar theme:





Maybe they're tweaking band-pass for high end roll-off at various frequencies to achieve "Clear," "Natural" and "Soft" response differences ...?

 

[Eagle_1]

Sometimes I swear engineer’s over think things.

 

[percivilla]

Sometimes I swear engineer’s over think things.

Fortunately they are paid well to do so

 

[TroutBear]

Listened tonight to a pair of KLH Model 20s just reassembled after cabinet refurbishment that I built new crossovers for - Mundorf Supreme caps and Mills resistors - very pleased with the results from the originals present when I picked these up at an estate sale