Caps comparison

[Guest David H]

Michael, I have a suggestion, if you can invest a few $$ in a capacitor tester, you can verify these findings for yourself, as many speakers and crossovers as you have and worked with, I think this tool would be valuable for you. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-735

I am not suggesting this as a tool for upgrading, but for returning the crossover to original specs.

A leaking 2uf capacitor that measure 2.2uf is obviously an issue, but a perfectly sealed new looking 2uf capacitor that measures 3.4uf or 1.1uf is far more crutial to the sound and longevity of the drivers than the minor oil leak is to the box.

[Guest David H]

Here is a link to the Solen cap index at parts express http://www.parts-express.com/solen-metallized-polypropylene-capacitors.cfm

These are low cost suitable replacement for the o/e crossover caps I have used many times.

[Guest " "]

"what on Earth is a 'slow' cap and what would running a comp/limiter have to do with them?"

Capacitors vary in their charge times...metal film caps charge faster than poly caps...paper and oil caps charge slower than poly caps.

Caps with slower slew rates (sluggishness of the cap) can be though of as rounding off dynamics

In cases which compressor limiters are used (also rounds off dynamics) theirs no point in using fast caps (caps with low slew rates).

EC PRODUCT	E/M (J/g)	E/v (J/cm3)	Response time (s)	Mass FOM (W/g)	Volume FOM (W/cm3 )
A	Powerstor	1.3	1.9	0.63	2.1	3.0
B	Maxwell PC0323	6.2	6.9	6.3	1.0	1.1
C	Maxwell PC7223	9.7	12.8	20	0.5	0.64
D	Maxwell PC0223	4.5	9.9	9.1	0.5	1.1
E	CAP-XX card	0.047	0.062	0.037	1.3	1.7
F	CAP-XX 120 F	7.4	7.0	10	0.74	0.7
G	CAP-XX 30 F	1.3	1.3	0.48	2.7	2.7
H	CAP-XX 10 F	0.54	0.61	0.15	3.6	4.1
I	CAP-XX 250 F	2.2	1.6	1.0	2.2	1.6
J	ELNA	4.4	5.0	12	0.36	0.4
K	Panasonic	6.7	7.2	20	0.34	0.37
L	ELIT 9.4 F	0.093	0.31	0.097	0.95	3.2
M	ESMA	2.2	4.3	10	0.22	0.43
N	Powercell	7.3	10	110	0.07	0.09
O	ELIT 20 kJ	1.2	2.7	5.9	0.2	0.46
P	ECOND 8/16/0.8	0.68	2.1	7.7	0.09	0.27
Q	ECOND 8/16/10	0.51	1.7	1.2	0.43	1.4

[colterphoto1]

'where comp/limiters are used'...

you mean ALL modern recordings?

[Don Richard]

Capacitors vary in their charge times...metal film caps charge faster than poly caps...paper and oil caps charge slower than poly caps.

Not sure what these data mean. The "fastest" one listed "charges" in 1/16th second. Thus it would be effective to only 16 Hz, seemingly making it and all the rest unsuitable for audio useage.

If these data are defining DC charge times, then the data is irrelevent to this discussion since there better not be DC in a crossover. Could you please explain these numbers and possibly the test setup used to derive them?

Thanks

[Guest David H]

Deleted this post, seems that there is no good coming from this thread.

[Don Richard]

Deleted this post, seems that there is no good coming from this thread.

No good answers, for sure[]

[djk]

"Capacitors vary in their charge times...metal film caps charge faster than poly caps...paper and oil caps charge slower than poly caps."

Not true, it is largely a function of the resistance and capacitance.

The most important measurement for sound quality is dielectric absorption, and then the leads and the method of attachment.

JBL has gone to battery bias of very inexpensive caps to achive very high performance. In my first post, Fig.7, 8, 9 show the improvements in linearity that can be achived using battery bias.

[fini]

"But they are all bad and someday all will leak all over your nice speaker cabinet."

Bob, I feel that this is a gross generalization.

Any kind of gooey oil leak is gross.

[colterphoto1]

sorry if I've been a bit snippy here fellas. Between the stock market, oral surgery, and depression kicking my butt, I've been 'grumpy Michael' this week.

I'll work on it.

M

[colterphoto1]

bump for newer member with cap questions