Crossover caps?

[Gregory]

It is always best to measure new caps. I think your meter is off in this case though. 5% out I can believe but if they all read high. What did the old caps measure? As these old caps wear they tend to read high so they should be higher than the new ones on your meter.

I'll bring in a few an measure them on the Fluke, then compare to the readings at home. Meanwhile I've ordered some 47uF NPs. Since the crossovers easily come out of the cabinet.... well let's not go there right now.

Will be posting some photos of the rebuilt crossovers this weekend.


-Gregory

 

[Gregory]

It is always best to measure new caps. I think your meter is off in this case though. 5% out I can believe but if they all read high. What did the old caps measure? As these old caps wear they tend to read high so they should be higher than the new ones on your meter.

Ron.. I haven't yet removed the old caps from the network (crossover) boards. That will happen this weekend, possibly even tonight. Have measured several other newly purchased caps.

The ACCURACY of the DVM in Capacitance mode for various ranges is:

4.0nF ... not specified
40nF ... +/-3%
400nF ... +/-3%
4.0uF ... +/-3%
40uF ... not specified
100uF ... not specified

So it's questionable above 4uF.


-Gregory

 

[Gregory]

The Caps and resistors have been removed from the crossover boards.

I've also been able to measure, factor out errors and select matched PAIRS of caps from a batch. Here are examples.. two pair for each batch, one pair low and one pair a high.

Question

Since the 22uF caps above are 3uF lower than the schematic value of 25uF, what's the best way to INCREASE by 3uF? Add a 3uF NP in parallel? Add a 3uF Poly cap in parallel? In that case, should there still be a 0.1uF bypass cap?


-Gregory

 

[4343]

I'm not sure what your budget for caps is, but if you need a pair of 25 uf and a pair of 50uf, you'd probably be looking at a bit over 30.00 shipped at PE for quality caps.

I found these sound nice:
https://www.partsconnexion.com/capacitor_film_axon.html
And they are half price.
Since it's a one time deal, the values are not all there, they do have 24 and 50, but the 1.0 you would need to make a 24 into a 25 is out of stock already. I had to buy lots of 50's to make 100's for my biased networks when they ran out of 100's... (I used 4 50's in Series/Parallel to make one 50!) Waiting for the first one to break in now, I found they need a day or so to sound right...