PDA

View Full Version : Can replacement capacitors be "too fine" for vintage JBL-drivers?



M1k@el
09-02-2012, 07:42 AM
Now that I've started to tear my beloved JBL:s apart in order to improve their sound I've started to wonder whether there is any risk with swapping in high-grade replacement caps in place if the old ones, for example Jantzen Silvers, Superiors or Audyn Caps.

My concern is that such fine capacitors simply let "too much" information pass into the drivers and that this can have a negative effect on the sound. :confused:

I have had some experiences with this thing happening:

Just recently, I replaced a pair of old caps in a crossover to my 077 with very fine Audyn caps. The sound surely opened up with added detail but it came at a cost of extremely annoying and over-emphasized S-noises.

Some years ago I restored a pair of Intinity Column II:s by swapping out the capacitors, the exact same thing happened with those speakers!

Furthermore, I came across a posting here at Lansing Heritage where one member wrote (as an answer to a question on how to improve the sound in old JBL:s): "Replace the old capacitors with fine new ones .. not too fine though".

Can someone confirm whether this is indeed something that has to be taken into consideration when picking new caps?

Or can I just blame the problems I had on bad luck?

I kind of hesitate to buy new caps for my crossovers since I'm afraid that I'll encounter the same problems once again. And since my JBL:s are keepers (at least for an indefinite period of time) I don't want to screw these up!

Best - Mike

LRBacon
09-02-2012, 10:26 AM
Mike, several years ago I replaced the original capacitors in a pair of L110s with Jantzen Z-Standard caps. I've had absolutely no audio problems with them since I did the replacement.

Larry

Ruediger
09-02-2012, 10:34 AM
... is one which only has a capacitance and does not have any resistance or inductance.

A real capacitor has some unwanted properties such as parasitic resistance and parasitic inductance.

You can throw away money by buing too good a capacitor for a purpose whre a medium quality capacitor would have done.

Publish a sketch of Your network so that people can give recommendations where to use what kind of capacitor.

Ruediger

M1k@el
09-02-2012, 10:43 AM
Mike, several years ago I replaced the original capacitors in a pair of L110s with Jantzen Z-Standard caps. I've had absolutely no audio problems with them since I did the replacement.

Larry

It's quite interesting that you used those since the Jantzen Standards are the exact ones I've considered as replacements in my crossovers.

.. but then again, they are the cheaper ones and not as "fine" as the much more expensive Jantzens, say the Superior och the Silver Z-cap :)




You can throw away money by buing too good a capacitor for a purpose whre a medium quality capacitor would have done.

Publish a sketch of Your network so that people can give recommendations where to use what kind of capacitor.

Ruediger

Sure :)

I run the LX13 for my 2235 and 2410 (and a DIY N8000 for the 077). But it's the LX13 caps I want to upgrade, since I've already done the N8000, with standard Z-caps i might add.

http://www.jblproservice.com/pdf/Network Schematics/LX13.pdf

Thanks for quick response guys :)

Mr. Widget
09-02-2012, 04:56 PM
My concern is that such fine capacitors simply let "too much" information pass into the drivers and that this can have a negative effect on the sound. :confused:
More expensive caps are not necessarily better... that said, vintage JBL drivers in perfect working condition when properly used will benefit from top quality parts and designs.

If you feel you are going backwards, I would look elsewhere. The design of the networks is key. The original LX5, N8000 etc, are not fabulous designs... much better network designs are available... to really nail it, your drivers, horns, and physical layout will be factors that need to be considered for the correct network design. Beyond the network, are you sure your drivers are all up to original spec.? Most are not. Before you spend hundreds of dollars on parts, I'd be putting that money towards new diaphragms...also which drivers and horns do you have? You may have some excellent parts, but they might not be best suited to work together.


Widget

Ruediger
09-03-2012, 12:33 PM
I suggest You go for Metal-Polyester capacitors, Metal-Polypropylen are more expensive. They should be for 100 Volt AC, 160 V DC.

Ruediger

M1k@el
09-03-2012, 01:34 PM
I thought of swapping out the two 3uF and 6uF in parallell to the midrange. Since I already have some very fine Aydun caps laying around I figure I might as well give it a try :)

Eventually, I guess entirely new crossovers will be a consideration. That or upgrading to a pair of 434X.

But since I'm learning lots and lots about crossover design day by day (a lot thanks to you guys) I feel that I want to play around with what I have before I start making any major modifications involving new crossovers.

yggdrasil
09-04-2012, 01:11 AM
If you want to play around, and sort of get the feel for what each upgrade does the upgrade path is:
bypass capacitors
swap capacitors
new crossover design
Each of these upgrades has its own merits.

Enjoy.

Johnny

M1k@el
09-05-2012, 06:36 AM
If you want to play around, and sort of get the feel for what each upgrade does the upgrade path is:
bypass capacitors
swap capacitors
new crossover design
Each of these upgrades has its own merits.

Enjoy.

Johnny

That's more or less exactly the way I want to do it, except I've skipped the bypassing part :D


I suggest You go for Metal-Polyester capacitors, Metal-Polypropylen are more expensive. They should be for 100 Volt AC, 160 V DC.

Ruediger

I was thinking of using Audyn Cap Plus polypropylene caps since they are not that expensive here at my local shop in Sweden :)