JBL L16 Decade - capacitor advice needed

[Pat Bateman]

Hi from Australia everyone - long time reader, first time poster. This forum is an incredible resource.

I have recently acquired some JBL L16 Decade speakers. They seem to be in generally good condition and sound pretty good, but I suspect given their age they would sound better with a capacitor replacement. They've already been professionally refoamed.

I'm ok with basic electronics and a soldering iron but totally unfamiliar with the nuances of hi fi electronics.

My question is this - what capacitors, exactly, do I need to acquire to replace the originals? Happy to spend a little to get something decent, but it must be something available internationally.

I've managed to track down the attached circuit diagram, which may help.

Any advice greatly appreciated!

 

[Natertots]

I haven’t made it to recapping gear yet but I have read up on it a fair bit and this is my understanding:

1) You may or may not need new caps. Some people may say, due to their age, go ahead and replace them with new. However, many would say that if they fall within the original specification (+/- 5-10%) there is no need to change them. I would test them and decide what you want to do from there.

2) If you decide to recap the crossovers, you want to replace the capacitors with those of equal value, uF’s (micro farads). Matching voltage is less important, so long as you do not put in a capacitor with a lower voltage rating than the originals. A higher voltage rating capacitor will work fine but will be more expensive than a capacitor with the same voltage as the stock capacitors.

3) Picking the type/brand of capacitor is a whole different discussion. If you ask 10 people, you will get 10 different opinions. Some people swear by one brand, some people swear there is little difference between brands. Many speakers that cost thousands of dollars use modest capacitors. Asking in the JBL forum what people use to get the most out of L16’s might get more of a consensus but I wouldn’t expect it.

Caps go from a few cents to hundreds of dollars. If you wanted to, you could spend more on exotic caps than your speakers are worth.

So which do you buy?

Many people recap all types of speaker using Dayton polypropylene caps from Parts Express. They are a step up from the inexpensive electrolytics but still very affordable. Many people say that is all you need. I have also read many good things about PulseX capacitors from ERSE. They are polypropylene caps in the same price range as the Daytons. Based on the reading I have done, when/if I get around to recapping something and I want to step up to a slightly more expensive product but still fairly affordable, I will look at Clarity capacitors. (Remember, I have no personal experience so I am going off of many threads I have read on the subject of capacitors).

4) If you happen to find that a resistor is out of spec, Mills resistors are what I have seen recommended most everywhere.

5) If you buy parts, you can look at Madisound, Parts Express, ERSE and Parts Connexion. (There are probably others, but those are the ones I am most familiar with)

6) Best of luck.

 

[Pat Bateman]

Thanks for the great response - sounds like we've been on the same journey of trying to learn about this stuff, although you've gone a fair bit further than me.

As far as I can ascertain, the L16s are from around 1975 and so any capacitors in them are at least 45 years old. For comparison I have a pair of L56s which are about 10 years younger and sound much tighter and smoother (not sure of the terminology) than the L16s, although of course that could be a result of any number of things. But I'm keen to start with a relatively simple job of recapping the L16s to see if it achieves anything.

Matching voltage is less important, so long as you do not put in a capacitor with a lower voltage rating than the originals. A higher voltage rating capacitor will work fine but will be more expensive than a capacitor with the same voltage as the stock capacitors.

Thanks, this answers one of my main questions. The Dayton capacitors that seem to be available here are rated at 250v which is presumably ample, then.

So to work this through, that circuit diagram indicates a single 6.0uF capacitor, if I'm reading it right. Dayton don't seem to offer one that's exactly 6.0uF, but my understanding is that I could use a 2.0uF and 4.0uF or two 3.0uF 250v capacitors in parallel as a replacement? Not sure if 2+4 or 3+3 would make any difference in that scenario?

Hopefully not breaking any rules by linking to another site - I'd be looking at something like this:

http://www.theloudspeakerkit.com/dayton-audio-pmpc-4.0-4.0uf-250v-precision-audio-c

Thanks again for your helpful reply.

 

[Dswankey]

Hi from Australia everyone...I have recently acquired some JBL L16 Decade speakers...
My question is this - what capacitors, exactly, do I need to acquire to replace the originals? Happy to spend a little to get something decent, but it must be something available internationally.

Welcome aboard!

There is a dedicated sub forum here at AK on all things JBL so you might try asking there.

https://www.audiokarma.org/forums/index.php?forums/the-lansing-legacy.212/

As to availability for you in OZ I would do some digging on these two websites that are commonly suggested for parts here at AK

Mouser

https://www.mouser.com/Passive-Components/Capacitors/_/N-5g7r

Digikey

https://www.digikey.com/en/products/category/capacitors/3

There are numerous members here based in OZ hopefully some of them will see this thread and chime in with suggestions more local to your part of the world.

 

[Natertots]

So to work this through, that circuit diagram indicates a single 6.0uF capacitor, if I'm reading it right. Dayton don't seem to offer one that's exactly 6.0uF, but my understanding is that I could use a 2.0uF and 4.0uF or two 3.0uF 250v capacitors in parallel as a replacement? Not sure if 2+4 or 3+3 would make any difference in that scenario?

Yes, the value of capacitors in parallel is additive. If my memory is correct, it does not matter if the capacitors are of different size (in theory). I like things to be even so I would go with 3+3, if possible, but 4+2 should work equally well.

it is not unusual to find capacitor with values that are not readily available. If a value is not available in a Dayton cap, it may be available from a different brand like Clarity or Solen. Also, I have read many posts where people settle for a single capacitor with a value close to the one they are replacing, in your case that might be a 6.2uF cap. This might be because the exact value is not available or the person does not have the exact value on hand and they do not want to order/wait on one. While this is not ideal, it is not terribly uncommon.

like @Dswankey said, it may be worth putting a post in the Lansing Legacy board here or in a place another place where JBL fans congregate. Someone there may be able to suggest a certain brand or approach to recapping, if you decide to go that route. Sometimes there are known improvements that can be done, such as substituting a different value capacitor, and you will be more likely to find that insight in a dedicated forum. This one came up with a Google search:

http://www.audioheritage.org/vbulletin/

Good luck.