Vintage HiFi Audio Forum
Audio Discussion => General Discussion => Topic started by: e_just on November 30, 2009, 07:37:53 PM
-
I am going to recap my KLH 17s in a day or two, it will be my first recap. There is a lot of info on Audio Karma about doing this and it seems as simple as following directions. Any insights or words of wisdom before I begin?
On a side note, I ordered the caps and new binding post from Parts Express. These guys are great and because they are so close, orders from the 412 usually arrive the next day!
-
Good luck in the recaping of the KLH's. OCCD most likely has done something like that. I am sure he will chime in.
-
It is a fairly easy task on most speakers. Just take your time and make sure all the solder joints are solid. :)
-
Yep, have recapped many a set of speakers. Helped AKer Tiga recap his KLH 20s on Saturday.
-
And don't drink BEER!!! ::)
-
And don't drink BEER!!! ::)
I'll save the beer till the job is done. (I have some Sierra Nevada Celebrator in the fridge!)
Good to hear that it should be easy. I ordered a new soldering iron to replace my $10 radio shack one, that should help. I'm also going to replace the binding post. I'll post pics:)
-
Just don't listen to them critically as soon as you are done with the upgrade. Give them time to settle in a bit and smooth out.
-
I'm currently working on it with my SDA-1Cs.
I've done a ton of research on it (different caps, etc) so let me know if you have any questions.
-
Just don't listen to them critically as soon as you are done with the upgrade. Give them time to settle in a bit and smooth out.
How long should they take to settle?
Go Pens!
-
And don't drink BEER!!! ::)
I'll save the beer till the job is done. (I have some Sierra Nevada Celebrator in the fridge!)
Good to hear that it should be easy. I ordered a new soldering iron to replace my $10 radio shack one, that should help. I'm also going to replace the binding post. I'll post pics:)
Celebration is the bomb!
-
Just don't listen to them critically as soon as you are done with the upgrade. Give them time to settle in a bit and smooth out.
How long should they take to settle?
Go Pens!
I've seen a lot of sources that say it takes 100+ hours for the caps to break in fully.
-
Just don't listen to them critically as soon as you are done with the upgrade. Give them time to settle in a bit and smooth out.
How long should they take to settle?
Go Pens!
Controversial issue......but I believe it takes only a few seconds for the new caps to form.
When you replace the binding posts, be sure to insulate them from the aluminum plate they go through. I wrap the posts with electrical tape and use fiber washers bought from PE. Will mail you some if you send me an address.
-
Controversial issue......but I believe it takes only a few seconds for the new caps to form.
Saturation and stability under demanding loads is what makes the time differential. End result to the listener is better sound and performance.
-
Well the recap is done! Everything was pretty easy. Thanks to bmwr75 for sending me washers for the binding post, but unfortunately the post that I bought are a little to big so this upgrade is on hold.
The 17s sound very good after the recap. I don't think the old caps were really bad but now I know they will be good for years to come.
-
When you say they are too big, do you mean in length or diameter? Here's the posts I use from Parts Express:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=091-1245 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=091-1245)
OK, my bad.....just checked those fiber washers I sent you and the ID is too small for the binding posts above. So, my memory must be failing me. Wonder what I bought all those fiber washers for....... :'(
If you go to Home Depot or Lowe's you will probably find an insulative washer in the hardware section that will work to insulate the binding posts from the aluminum plate in the KLH 17s.
-
The other option you have is to install the new binding posts somewhere else on the back of the cabinet by drilling new holes through the wooden back plate. Have done this on another project, see pic below, using KLH 20 cabinets. Drilled the two new holes about 4" below the aluminum plate.
-
Here's a picture of what I described below on mounting the new binding posts. They are really close together because they mount directly into a new crossover I built for these speakers. Suggest you mount your new posts at a width that a dual banana plug will fit.
FYI, the new knob on the aluminum plate is for the L-pad to the new compression driver.
-
When you say they are too big, do you mean in length or diameter? Here's the posts I use from Parts Express:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=091-1245 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=091-1245)
OK, my bad.....just checked those fiber washers I sent you and the ID is too small for the binding posts above. So, my memory must be failing me. Wonder what I bought all those fiber washers for....... :'(
If you go to Home Depot or Lowe's you will probably find an insulative washer in the hardware section that will work to insulate the binding posts from the aluminum plate in the KLH 17s.
Those are the same as the post that I bought but mine are silver. I'll be stoping by Lowes sometime in the next week so I'll have to see what they have.
-
I'm of the opinion that any speaker, new or old, using electrolytic's will benefit from an upgrade to better caps.
What brand did you use?
It's my experience that burn in time is generally 200 to 300 hours.
-
I went with Dayton caps. So far the 17s are sounding great!
-
Controversial issue......but I believe it takes only a few seconds for the new caps to form.
I don't know how a cap forms, but I do know that it takes time for a cap to saturate. I've seen it too many times.....a cap "tests" good, then under a load? Fails. That same cap, once saturated will perform just fine on the test bench as well as under a load.
Why? I have not one freakin' clue. I just know what I know.
-
I went with Dayton caps. So far the 17s are sounding great!
A good practical choice.
-
Hello all,
Thoght you might like to read this.
Using Capacitors
Hybrids, Parallels--Voltage and Precision ratings for crossover circuits
Capacitors do two things when used with circuits having alternating current (music signals)
1. They filter the signal—Cross-over according to the size (“value”) of the capacitor in micro-farads and the impedance of the circuit (expressed in Ohms).
2. They also stabilize a circuit in terms of the speed of delivery and recovery associated with an impulse (note of music).
In terms of filtering a musical signal to protect drivers from signal overload from too much volume or too much bas, electrolytic type capacitors and film type capacitors work equally well.
In terms of stabilizing a circuit, film capacitors sound much better (see About Capacitors)
Do Not Use Polarized Capacitors in Crossovers!
Electrolytic types must always be special Non-Polar types (sometimes called Bi-Polar). By definition all film types are non-polar types.
Hybrids/Bypassing
NP Electrolytic capacitors, which are less expensive, can be mixed with film types (which are more expensive) to form a hybrid capacitors that delivers a cleaner signal than a simple NPE type. The practice is called bypassing.
The higher the percentage of film in the bypass/hybrid arrangement, the better the impulse characteristics (i.e. the DF—the measurable Dissipation Factor.) One percent of film will not do much to improve a NPE capacitor’s performance, whereas a 50/50 mix can do a lot.
Paralleling
Capacitors can be mixed, without regard to the type (film or NPE) to build a larger cap that is the sum of the two (or more) individual values. This can be very useful to get special values or to use capacitors on hand rather than paying costly shipping and handling charges to buy individual value capacitors.
Voltage Ratings for Crossovers:
Rating should be about 30 percent above the voltage of the amplifier’s power supply.
For automobile installations any capacitor rated for 50volt use or above is abundant
For home speakers, any capacitor rated for 100volt use or above is abundant.
Higher voltage ratings give only marginal improvements at best, compared to better dielectric material (a basic 100 volt Mylar capacitor will sound vastly superior to a 200 volt NP electrolytic)
A voltage rating expressed in VAC is actually about 50 % greater than the same in DC.
How much precision is necessary?
Capacitors can—and do!--vary in precision (even in the same lot) but always within the tolerance specified as +/-on the cap. NPE caps tend to measure on the high side, film on the low side.
Generally one need only be within 10 percent of the crossover value called for in the design (i.e., for practical purposes, a 4.7uf cap and a 5.0 cap are interchangeable in almost all crossovers).
And This
About Capacitors
What you DON’T hear can matter most
For speaker crossovers and automobile sound installations, capacitors break down into only two types: film and electrolytic. Film caps cost much more than electrolytics to manufacture but they deliver a much better pulse, which gives a “cleaner” sound.
The measure of capacitance is microfarads, written on the capacitor as either “uF” or “mfd.” This tells you what is called the value of the capacitor in uF’s, but it does not tell you about the quality.
Capacitors are essentially batteries that charge and discharge extremely quickly. The better the material used, the better they perform. If you could see sound, electrolytic capacitors would deliver a yellower light and film capacitors would deliver a brighter, whiter light. In midbass and woofer crossover circuits, this is generally not a difference one can hear. In midrange crossovers it makes a difference--and for tweeter circuits, where the ear is especially sensitive, the choice of capacitor can makes a big difference. Here not only film but the kind of film capacitor used can make an audible difference. It is worth noting also, that electrolytic types can dry out, leak, or downright fail over time, while film types never go bad and are even self-healing if overloaded.
Electrolytics employ alum. oxide on a tiny roll of paper with a dab of electrolyte in a can stoppered against leakage. Film caps use a thin strip of flexible plastic with metal particles vapor deposited on the surface and rolled into a cylinder. Whether they are wrapped in tape (usually yellow) or dipped in epoxy (often brown) makes no difference. Also, radial (two legs pointing down) or axial (leads at either end) makes no difference either. Only the material inside matters.
If you want to see the graphics let me know and I can forward it to you.
Dale
-
That was a good read, Lots of good info. Thank you Dale.
Mike
-
Yeah good job dale. Great little learning experience on recapping.
-
I cannot take credit for this write up. A guy I bought some caps from sent this to me. He reinforced what I have learned very succinctly.
-
Thanks Dale! Great read!
The spekers I re-capped are the KLH 17's I bought from you a while back. They sound great!
-
Glad you are happy!
-
Hybrids/Bypassing
NP Electrolytic capacitors, which are less expensive, can be mixed with film types (which are more expensive) to form a hybrid capacitors that delivers a cleaner signal than a simple NPE type. The practice is called bypassing.
That's not really bypassing. Bypassing is the use of a very small value (like 0.1uF or less) film or silver mica cap in parallel with either an electrolytic or a film cap. The thought is that the small bypass cap will help the bigger cap sound better since the smaller cap is faster and of better quality. This does work (somewhat) when bypassing electrolytic caps. However, it does not work when bypassing film caps as the film caps are good enough already that bypassing them causes time smear issues. At first it seems as though there is an increase in air and detail, but after a short while wise audio folks realize that it creates annoying artifacts that are simply not present in live or recorded music. The use of bypass caps with film caps should be avoided.
Paralleling
Capacitors can be mixed, without regard to the type (film or NPE) to build a larger cap that is the sum of the two (or more) individual values. This can be very useful to get special values or to use capacitors on hand rather than paying costly shipping and handling charges to buy individual value capacitors.
While paralleling in and of itself is not a bad thing and in fact is often required, the mixing of electrolytic and film caps together to obtain a certain value should be avoided for much the same reason I stated above. It's also best when paralleling caps to keep the values as close as possible. That is, use an 8uF and a 7uF to obtain the desired goal of 15uF rather than using a 14uF and a 1uF.
-
Three questions F1nut.
1. With low frequencies won't the energy storage of a cap have less effect, as the caps we will have adequate time to discharge, hence NPEs are ok.
2. If I bypass a large npe with a film cap, as they are in parallel the high frequencies will pass thru the lower value due to less impedeance in that branch, especially if you connect 2 nearly equal values. Seems to me this will allow the film to pass the highs and the npe to pass the lows.
3. If the value of the original is high enough, then based on above reasoning 20-30% might pass the top 1/3 of frequencies.
Love these discussions, but hate typing.
-
1. We're talking about shunt caps, yes? If that's the case then yes, that would be somewhat true, but film caps are still a better choice resulting in improved bass response.
2. Crossovers are generally divided into high, mid and low frequency circuits with specific cap values for each. With that in mind, you cannot have a situation as you describe. What you can have is a film cap bypassing an electrolytic in say the high frequency circuit, which would be the most common use. This film bypass cap will pass a certain frequency range within the specific frequency range faster than the electrolytic.
3. If I'm understanding your comment correctly, it doesn't work that way.
-
Hello again F1nut and all,
I think that perhaps I was unclear in my last post. Yes, I am talking about a shunt cap. And as for 3 in your post, I was thinking of say a Mid Driver working from 6-800 hz to tweeter cutoff. The cap might be a 30- 60 mf (values chosen as an example), and if I put a film cap around it, I thought the film cap would pass the higher frequencies with less smear, and the NPE the lower where the energy stored has more time to be released.
And now that I have read this, maybe the film cap should only be 20-30 % of the total value, keeping the lower frequencies in the NPE.