JBL Mylar cap replacements and other thoughts

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04-10-2012, 09:35 AM
jfine

JBL Mylar cap replacements and other thoughts

This concerns L150's, L150A's that I own, (and other models that I don't own anymore), but probably applies to most 70's JBL's with stock Mylar caps on mid and high pass circuits.

I know the general consensus is that metalized polypropylene caps like Solen, Dayton and the higher up films Mundorf, Clarity, all provide "better" (or different) sound when trying to upgrade, or replace, capacitors. I've tried those, tried Audio Cap theta film, they're OK, haven't tried teflon yet.

I have found after a lot of messing about, that I like the stock yellow Mylar polyester caps JBL used.

Between all these different caps out there, it's possible the ESR, or other measurements, are different, not just the TYPE of cap, so the ESR could also contribute to the sound, by maybe altering crossover points, impedance, etc., just guessing here. I do know that when I tried some of the new caps mentioned, the left to right balance evened out a bit more.

I just think the stock mylars have more tone, smoother--3 way system doesn't sound so much like 3 different speakers, rather the blend is much better. Sure they don't have the detail of some other caps, nor the extra "air" that seems to be added by some caps. But something about the tonality of Mylar sounds right to me. Seems like most all my LP collection sound better as opposed to maybe half sounding OK with "other" caps.

I'm concerned though, that over time, they can drift, not as drastic as an electrolytic, but still over time there might be some ESR drift? Or maybe even altered by previous owners cranking the crap out of 'em with low powered amps.

My question is, even if I had a tool to measure ESR, I don't know what they measured originally. So I have nothing to use as a guide. Yes I know I've heard the lower the better, but I'm not so sure that applies in every configuration. Not to say one should purposely buy a higher ESR cap, but rather should try to replace with the correct replacement cap as close as possible. I have heard some Mylar caps arrive from the factory with a bit higher ESR already.

I have found some new Carli caps, and some new Erse caps, both Mylar with the values I need.

Has anyone had experience with these for direct JBL replacements? Kinda getting tired of pulling the boards, and also would like to hear other experiences.

thanks
04-10-2012, 10:49 AM
Mannermusic

Basic engineering

Quote:

Originally Posted by jfine

This concerns L150's, L150A's that I own, (and other models that I don't own anymore), but probably applies to most 70's JBL's with stock Mylar caps on mid and high pass circuits.

I know the general consensus is that metalized polypropylene caps like Solen, Dayton and the higher up films Mundorf, Clarity, all provide "better" (or different) sound when trying to upgrade, or replace, capacitors. I've tried those, tried Audio Cap theta film, they're OK, haven't tried teflon yet.

I have found after a lot of messing about, that I like the stock yellow Mylar polyester caps JBL used.

Between all these different caps out there, it's possible the ESR, or other measurements, are different, not just the TYPE of cap, so the ESR could also contribute to the sound, by maybe altering crossover points, impedance, etc., just guessing here. I do know that when I tried some of the new caps mentioned, the left to right balance evened out a bit more.

I just think the stock mylars have more tone, smoother--3 way system doesn't sound so much like 3 different speakers, rather the blend is much better. Sure they don't have the detail of some other caps, nor the extra "air" that seems to be added by some caps. But something about the tonality of Mylar sounds right to me. Seems like most all my LP collection sound better as opposed to maybe half sounding OK with "other" caps.

I'm concerned though, that over time, they can drift, not as drastic as an electrolytic, but still over time there might be some ESR drift? Or maybe even altered by previous owners cranking the crap out of 'em with low powered amps.

My question is, even if I had a tool to measure ESR, I don't know what they measured originally. So I have nothing to use as a guide. Yes I know I've heard the lower the better, but I'm not so sure that applies in every configuration. Not to say one should purposely buy a higher ESR cap, but rather should try to replace with the correct replacement cap as close as possible. I have heard some Mylar caps arrive from the factory with a bit higher ESR already.

I have found some new Carli caps, and some new Erse caps, both Mylar with the values I need.

Has anyone had experience with these for direct JBL replacements? Kinda getting tired of pulling the boards, and also would like to hear other experiences.

thanks

Welcome to the world of engineering product development. All the stuff in those systems is in there for a reason; a product of endless hours of testing and re-testing. All products whether automotive, audio or you name it go through a similar process. When you decide to change any link in the system, you change the whole system. THERE IS NO CORRECT OR INCORRECT ANSWER. You become the chief development engineer. So, it becomes your responsibility, no one can tell you what you think is best.
04-10-2012, 11:13 AM
jfine

JBL direct replacements

Quote:

Originally Posted by Mannermusic

Welcome to the world of engineering product development. All the stuff in those systems is in there for a reason; a product of endless hours of testing and re-testing. All products whether automotive, audio or you name it go through a similar process. When you decide to change any link in the system, you change the whole system. THERE IS NO CORRECT OR INCORRECT ANSWER. You become the chief development engineer. So, it becomes your responsibility, no one can tell you what you think is best.

Agreed. Now I'm just looking for similar experiences/thoughts using Carli or Erse Mylar caps for direct JBL replacements.

thanks.