Why Recap Speakers and When?
- Thread starter Scorpion8
- Start date
lorne said:
Completely serious. Project for the week-end. Have 4 crossovers to rebuild. They all look about the same.
Putting in Solens caps (8's & 3's), new L-pads, and thinking about adding a .51 OHM resistor for tweeter protection. I see different thoughts on that (adding a resistor) over at audioheritage, but I don't see how it could hurt.
While I'm in there, probably switch out the speaker posts, if I have enough of them.
Last weird thing is the question on the woofer polarity. Supposedly it's opposite of the mid & tweeter for some JBL reason??? I think I'll just put that back as is.
Insulation. Hmmm. I wonder what thick new uniform sized high-tech insull would do. It's all kind of ratted in there now.
Any other ideas would be greatly appreciated. I can't find much in old AK threads re: JBL L-100 Century crossovers.
darko
... and never give up!
Recapping Old Vintage Speakers -> Great !
Have replaced the Caps at Kenwood's KL-660s.
ONE AFTER OTHER, for Compare !
Its a huge Difference in most Frequencies. I mixed different Farad-Values together, to become the exact Value. Soldered all in parallel, of course !
This Weekend, I get some Marantz Speakers.
After One Speaker was Re-capped, I puch the MONO Switch and
have listen all the Night long.
Guys. recap Your old Favorite Speakers and listen the Difference!
Good Work!
Darko
Have replaced the Caps at Kenwood's KL-660s.
ONE AFTER OTHER, for Compare !
Its a huge Difference in most Frequencies. I mixed different Farad-Values together, to become the exact Value. Soldered all in parallel, of course !
This Weekend, I get some Marantz Speakers.
After One Speaker was Re-capped, I puch the MONO Switch and
have listen all the Night long.
Guys. recap Your old Favorite Speakers and listen the Difference!
Good Work!
Darko
Just recapped Large Advents.
Most definately worth the effort. Although the advents have a fairly simple crossover. Used Daytons and like others have said both bass and highs more defined clarity.
As far as other components I tend to follow the school of "if it ain't broke don't fix it". I don't have the technical background to offer an educated opinion. However, most of the people professing engineering backgrounds I have talked to pretty much indicate that in most crossovers the capacitors are subject to greater changes in value overtime. There by justifying replacing them at 20 years of age, certainly at 25.
Peace,
HB
Most definately worth the effort. Although the advents have a fairly simple crossover. Used Daytons and like others have said both bass and highs more defined clarity.
As far as other components I tend to follow the school of "if it ain't broke don't fix it". I don't have the technical background to offer an educated opinion. However, most of the people professing engineering backgrounds I have talked to pretty much indicate that in most crossovers the capacitors are subject to greater changes in value overtime. There by justifying replacing them at 20 years of age, certainly at 25.
Peace,
HB
I've long been an advocate for recapping vintage gear as well as speaker crossovers.
Having just aquired a DMM capable of measuring capacitance, I thought it would be fun to check the values on a pair of crossover caps removed from some Minimus 7 speakers.
The original caps are spec'd at 4.7uf, but they actually measured at 6.06 uf and 6.43 uf respectively. For comparison purposes, a pair of new Dayton 5% caps I have here measure at 4.71 uf.
What is perhaps a bit surprising here (at least to me...) is that there has been considerable drift from the original capacitor values, even though I believe they are likely less than 20 years old! This suggests that recapping even relatively new (i.e. more than 10 years old) speakers may be worthwhile... .especially with the high quality caps available today.
Having just aquired a DMM capable of measuring capacitance, I thought it would be fun to check the values on a pair of crossover caps removed from some Minimus 7 speakers.
The original caps are spec'd at 4.7uf, but they actually measured at 6.06 uf and 6.43 uf respectively. For comparison purposes, a pair of new Dayton 5% caps I have here measure at 4.71 uf.
What is perhaps a bit surprising here (at least to me...) is that there has been considerable drift from the original capacitor values, even though I believe they are likely less than 20 years old! This suggests that recapping even relatively new (i.e. more than 10 years old) speakers may be worthwhile... .especially with the high quality caps available today.
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Bauhausler
Rational Subjectivist
I'm new to this thread. Today I had to pop the terminal cup off of a Celestion 5 to tighten a loose terminal. I ended up putting big toothed washers on both terminals on both speakers so tha twouldn't happen again. I hate a loose terminal. The tweeter pass cap was a 4.7uf Bennic NP electro. I tossed them and glued in some generic mylar box caps in their place. Soldered 'em in and screwed it back together. Honestly, I don't know if this actually makes a difference, but the speakers are at least 15 years old and no electrolytic ever made equaled a mylar of the same value at high frequencies, especially after a decade and a half. I just toss the electrolytics as a matter of course every chance I get. I left in the NPE parallel cap on the woofer, not having a 6uf NPE handy. That should probably go as well. If it loses capacitance or gains resistance with age, the woofer's passband will rise into the tweeter's and might cause audible effects in the overlap range.
In my considerable experience with vintage speakers, a lot of what we consider the 'mellow' sound of vintage 2-ways is out of spec tweeter pass caps. They're mellow until the crossover is performing the way the designer intended, then they brighten up and sound new again. I say 2-ways because a tweeter with a lower crossover will have a larger cap. A larger cap will be more susceptible to aging effects that would affect the treble, or so goes my thinking. I know it improved my AR3a's, KLH 7's, Large Advents, Small Advents and many others.
Any design that depends on the parasitic resistances of a capacitor for its 'voicing' is a defective design.
Come to think of it though, maybe that's the answer to an old mystery. I had a number of Unity Audio speakers when that company was operating here in MI. One of them, the Signature 3 I think, ran the woofer fullrange and had a simple tweeter crossover consisting of a 6uf cap in series with each tweeter lead, essentially 2 6uf caps in series for 3uf effective capacitance. He called a 'balanced' crossover. Bob Grost is a very smart dude and I suspected he was up to something. The series inductance of 2 6uf caps is probably 4 times that of a single 3 uf cap. That might be useful in damping a HF peak in the tweeter. Only reason I can think of that isn't complete snake oil.
In my considerable experience with vintage speakers, a lot of what we consider the 'mellow' sound of vintage 2-ways is out of spec tweeter pass caps. They're mellow until the crossover is performing the way the designer intended, then they brighten up and sound new again. I say 2-ways because a tweeter with a lower crossover will have a larger cap. A larger cap will be more susceptible to aging effects that would affect the treble, or so goes my thinking. I know it improved my AR3a's, KLH 7's, Large Advents, Small Advents and many others.
Any design that depends on the parasitic resistances of a capacitor for its 'voicing' is a defective design.
Come to think of it though, maybe that's the answer to an old mystery. I had a number of Unity Audio speakers when that company was operating here in MI. One of them, the Signature 3 I think, ran the woofer fullrange and had a simple tweeter crossover consisting of a 6uf cap in series with each tweeter lead, essentially 2 6uf caps in series for 3uf effective capacitance. He called a 'balanced' crossover. Bob Grost is a very smart dude and I suspected he was up to something. The series inductance of 2 6uf caps is probably 4 times that of a single 3 uf cap. That might be useful in damping a HF peak in the tweeter. Only reason I can think of that isn't complete snake oil.
MikeCh
Super Member
hpsenicka said:
Per an early post:
"As the capacitor ages, depending on the quality of the dielectric and application, the dielectric slowly loses its ability to remain polarized. The typical shelf life of good quality caps is measured in several years. If they are used in an application where little or no polarizing voltage is applied, there is nothing to prevent the natural depolarizing."
It's unfortunate that they don't last as long/retain their original value as we'd all like.
Mike
Tapehead47
Addicted Member
I want to recap 2 pair of JBL 4311's. The parts would be about $80 from Parts Express. Has anyone out there have an idea how much it would cost to have it done for me?
After looking at many of the pix on this thread, I'm a little intimidated.
Rick
After looking at many of the pix on this thread, I'm a little intimidated.
Rick
lorne
Sonic Lizard
Hi Tapehead. I don't know the speaker, so I'm not the one to give a possible number. But let's look at some stuff:
* If the original board uses electroytic capacitors, and if you are substituting film capacitors (a good idea IMHO) the new caps may not fit on the cross-over network board. If this is the case, the technician you are paying will have to construct something or add something in order to mount the caps. This will take time and money.
* Some networks are more complicated than others. In my modest experience, the time it takes to exchange network caps varies from one to the other considerabley.
* What is the rate for shop time where you are? $60.00/hr?
* If there is a DIY AKer living near you, and if you were to spring for the beer and a pizza, maybe you can get together and make an afternoon of it. You can apprentice to the technique and help the next guy down the road.
* You could also take some good digi pics and let us try and talk you through it. Make a large drawing on a big sheet of paper in order to show us what you are intending to do before you start — a schematic drawing of sorts. Digi-image the drawing and include it in your upload.
Just some suggestions ...
* If the original board uses electroytic capacitors, and if you are substituting film capacitors (a good idea IMHO) the new caps may not fit on the cross-over network board. If this is the case, the technician you are paying will have to construct something or add something in order to mount the caps. This will take time and money.
* Some networks are more complicated than others. In my modest experience, the time it takes to exchange network caps varies from one to the other considerabley.
* What is the rate for shop time where you are? $60.00/hr?
* If there is a DIY AKer living near you, and if you were to spring for the beer and a pizza, maybe you can get together and make an afternoon of it. You can apprentice to the technique and help the next guy down the road.
* You could also take some good digi pics and let us try and talk you through it. Make a large drawing on a big sheet of paper in order to show us what you are intending to do before you start — a schematic drawing of sorts. Digi-image the drawing and include it in your upload.
Just some suggestions ...
Tapehead47
Addicted Member
Good ideas, Lorne
I don't know any AKers near me, but I have a Master Electrician friend who could do it. I don't think he works on speakers, but he wires all kinds of fancy things like dentist equipment, hospital gear, high-end surveylence systems, etc.
He had a great stereo years back, including a lot of Pioneer gear and HPM-100's.
I'll have to give him a call.
Thanks,
Rick
I don't know any AKers near me, but I have a Master Electrician friend who could do it. I don't think he works on speakers, but he wires all kinds of fancy things like dentist equipment, hospital gear, high-end surveylence systems, etc.
He had a great stereo years back, including a lot of Pioneer gear and HPM-100's.
I'll have to give him a call.
Thanks,
Rick
FoolForARadio
Super Member
I don't know what you want to stick caps in. It might be something really nice. But I have found that I can do this type of work, and I am completely not handy with tools! I should say that I am working on speakers I have bought cheap, so far, EPI 100V's and Sansui SP-100's. I bought some caps from Parts Express, a soldering station and tools (including heat sink) at Radio Shack, practiced a little bit, and went for it. It makes an audible difference to the speakers, and it's just not that hard. I take out one cap at a time and replace it, so I don't get confused. You should try it. It's very satisfying and a lot of bang for the buck!
Tapehead47
Addicted Member
Thanks, Fool...Your words are encouraging. I'm recapping 4 JBL 4311's. I repeat: I (that's me) will be doing the work.
Rick
Rick
RobD8870
Member
Hey Whaleman!!!!!!!!!!!!!!!! I was reading this post for this very reason. i just picked up cs-99A and Both speakers work great except my mids are gone on the one. No output at all. I checked inside. All connections look good *for as much as that is worth* but at least one cap was leaking. I will have to recap mine so if you have the list of values and where you got them that would save me a lot of time!!! Also how much? Not even sure if you have picked them up yet I was just so excited to see you had the same speaker with similiar problems......
Tapehead47
Addicted Member
Recap or Upgrade?
I'm putting the recapping of my 4311's on hold until my birthday (July). I'm planning ahead.
Question: would you, as a loyal AKer:
A) Go to Maui for a week?
B) Vacation on Anna Maria Island, (south of Tampa) for a week?
C) Recap 4 4311's?
D) Upgrade your system?
I LOVE Anna Maria. I LOVE my speakers. I LOVE Hawaii. I'd LOVE to have an upgraded (not necessarily new) system.
So many possibilites, and plenty of time to choose.
Rick in Lutz, Fl.
I'm putting the recapping of my 4311's on hold until my birthday (July). I'm planning ahead.
Question: would you, as a loyal AKer:
A) Go to Maui for a week?
B) Vacation on Anna Maria Island, (south of Tampa) for a week?
C) Recap 4 4311's?
D) Upgrade your system?
I LOVE Anna Maria. I LOVE my speakers. I LOVE Hawaii. I'd LOVE to have an upgraded (not necessarily new) system.
So many possibilites, and plenty of time to choose.
Rick in Lutz, Fl.
:tresbon: :thmbsp: 
