Vintage Capacitors

[famousmockingbird]

Hello gang I have a pair of 1982 Klipsch La Scala's (Type AA crossover) and I was possibly looking into replacing the original can oil caps. They sound really good to me but I had some questions before I do anything. The original capacitors were made by Aerovox.


My questions are:

What is the original ESR of these types of capacitors? I am asking this for two reasons; First, I won't replace them if I pull them out and they test how they should in regard to capacitance and ESR. Second, If I do replace them I want to match the ESR so I don't mess with the intended crossover design.

Should I be worried about these old caps having increased leakage current? How can I test them for this without special equipment?

Thanks,

-bird

 

[Ron E]

I highly doubt the original design considered the ESR of the caps...
Decent caps don't have hardly any.

Now if these are electrolytic and not paper-oil, actually best to replace them.
Take a picture of the crossover.

 

[freddi]

I used Obbligato poly/oil motor run caps on an AA network - probably preferred the old Aerovox. My klipsch Heresy Is have NOS KBG caps and I like their sound. (their ESR probably measures higher than some other caps)

here's an impedance comparison of one of the 2uF Aerovox vs an Obbligato poly/oil vs a 2,2 uF Chinese "Audiophiler"

maybe Ron E. would care to comment on their values and on the significance of ESR in a crossover cap

 

[freddi]

here's some values of 2uF caps

Klipsch 2uF 100v Aerovox (I think from 1978 "7825") 2075nF Vloss 0.3% ESR 0.29 ohm
KBG 2uF 200v (1986 "8606") 2049nF ESR = 0.47 ohm
Obbligato 2uF poly/oil motor run "recent" 2045nF Vloss 0.1%, ESR 0.03 ohm

fwiw I think I preferred the old Aerovox to the Obbligato in a K-horn whose xover I "updated" -(my K-horns never sound good - partly the room's weak/resonant walls)

it would be interesting to hear if ~0.47 ohm were added to the Obbligato, whether it would then sound like the KBG (?)