New Caps Did make Real difference

[Hawkeye83]

KEF speakers are inherently voiced to the soft side. If the OEM's were lytics, then KEF will surely recommend new lytics so as not to change the voicing. MKP film types would most surely alter the voicing somewhat.

Thanks! I know many proponents of sticking with the OEM style. I'm not opposed to "hot-rodding" or "improving" or "upgrading"...but they sound so darn good with the electrolytics I was scared to screw up a good thing. One thing that makes me less hesitant is my 107's were re-capped using some poly caps (not by me) and they still sound great too (but quite possibly slightly different than they would with electrolytic caps).

 

[Old Guy8]

The meter would have to have a uF or MFD symbol somewhere on the meter's dial of testing choices. If it doesn't, the meter won't help you measure capacitance. Some of the better meters like Fluke for example have the ability to measure capacitance, but not ESR. That requires a specialized meter like an LCR or dedicated ESR meter.

Thanks for info. That meter has only an on off button. It senses the circuit and guesses what you want. Gives reading on LCD screen is CAT 4 rated. May be aimed at building electricians rather than bench work. I'll read the manual. Thanks

 

[spkrdtr]

Electrolytic caps have gotten a seriously bad rap on forums. Yes, they do have a shorter life than film types due to their chemical make up. However, that's still a very useful 15-20 years, assuming you get new, good, quality lytics from an audio supplier; not just anything from bulk electronics supply houses.

 

[Alobar]

Since the caps were "stuck" quite literally in a can and partially smothered with some sort of goo I decided to build a new crossover for my L200's. In place of the iron core I used air core inductors, poly caps and resistors from Parts Express. I felt the bass improved on mine but no way to measure anything so maybe it's all in my noggin. Still all and all the speakers sound much better, with just a slight tone change and that only detected when one speaker was connected to the new xover and the other still hooked up to the old one. It was a great SQ bump, and one I should have done before now!

 

[mech986]

Spkrdtr,
So I once worked for Greenlee Tool Co. and have one of thier fancy self sensing multimeters. Might this be able to test caps, or is it more envolved? Can they be checked while in a circuit? Is there a sticky thread that might cover this? I've just done three sets so far. But have some ADS may want to recap.

Depends on the type of meter. If a regular digital multimeter (DMM), then no, they only measure resistance, voltage and current, with occasional diode or continuity. You need at least a capacitance checker, and then preferably an ESR (equivalent series resistance) tester which measures a different type of cap resistance. If you're really into it, there are other cap parameters that can be measured but by that point, the old cap should be replaced anyways.

I don't understand how a cap change in this speaker could make a difference in bass response. Did you make any measurements or is this just a gut feeling? I always do one speaker at a time when I make changes and then compare the modified to the unmodified with mono music and test tones. I've never detected a difference in bass response from a cap change, except for when I bypassed the woofer blocking caps Infinity likes to use, and even then, the difference was surprisingly small, except in woofer movement below 30 Hz.

Most woofers use a low pass circuit so they are rolling off the top end nearer the upper mid-bass and lower midrange so the bass and low bass is mostly a function of the woofer TS parameters and the cabinet loading and damping system plus amplifier drive. IMO, with smaller woofers pushed hard for bass excursion or volume, the potential for improvement from better or replaced caps is more likely than with larger woofers because a bass-mid is being asked to do both bass and mids at the same time.

Low bass and subsonic filtering at the speaker crossover is helpful to avoid wasting amp power making excessive cone motion, especially with vented speakers below resonance or large woofer cabinet arrays where the cones all form a rather lossy wall. So bypassing that cap may actually hurt amp power reserve. Since most of those Infinty caps are large value electrolytics, in the hundreds of uF IIRC, getting quality large value current capable non-polar electrolytics or film cap arrays isn't easy or inexpensive.

Most of the time, the critical caps are the electrolytics used in midrange or tweeter filters because they are less than ideal in many parameters, can degrade over time and the effects can be more audible because we are more sensitive to those frequencies and a lot of music and speech information is there. Crossovers that use film caps already have less tendency to have parameter changes because plastic film caps (mostly Mylar, polyester film, or metallized polyester) are much more stable over time. However, many feel that newer materials like polypropylene, Teflon, and polycarbonate have better and more ideal capacitor properties and may sound "better". However, there are vast differences in capacity vs size and volumetric efficiency and costs.

 

[audiomagnate]

I can't find a schematic for the NLA, but it sure looks like a simple first order design with a coil in series with the woofer and a 12 mf blocking cap on the tweeter. Going to a lower resistance coil might result in audibly tighter, louder bass, but changing a cap in series with the tweeter shouldn't have any effect on bass response.

 

[Old Guy8]

I can't find a schematic for the NLA, but it sure looks like a simrst order design with a coil in series with the woofer and a 12 mf blocking cap on the tweeter. Going to a lower resistance coil might result in audibly tighter, louder bass, but changing a cap in series with the tweeter shouldn't have any effect on bass response.
View attachment 803360

I had found a NLA schematic. Mine has a 13 mf cap. Adds 1.5 ohm resistor for second tweeter position and has 2.5 ohms total resistors for third tweeter position.
The Advent One's that I recaped, and made the post comment on, have 13mf cap with I recall should be 1.5 ohm resistor. In pic I modified with tweeter fuse and new binding posts.
My multimeter can't check the caps. Amp clamp, Vac,Vdc, ohms, continuity only.

 

[Freddymac2]

I wish I had the equipment at my disposal to make the needed measurements, and the training to do it properly. The DQ 10 doesn't have any real bass below 40 hz. After a 8 capacitor replacement the bottom clearly improved in many respects. The upper end always had an edge, that I had blamed on the piezio tweeter was greatly diminished, violins now had a pure sweet tone that wasn't there before. A bow stroke on a bass fiddle, now has a warm texture of vibration that should be there. I really don't care, what you think about my ability to hear, or if it is just in my head I enjoy the music more. All the theories that it can't possibly change the sound, are totally worthless. I am also doing some things that I know will not agree with your level of knowledge, or experience, but it works for me in my system and environment. Or maybe I just can't hear, but can make wonderful music in my head, either way I win.

 

[I LIKE MUSIC]

I can't find a schematic for the NLA, but it sure looks like a simple first order design with a coil in series with the woofer and a 12 mf blocking cap on the tweeter. Going to a lower resistance coil might result in audibly tighter, louder bass, but changing a cap in series with the tweeter shouldn't have any effect on bass response.
View attachment 803360

Here is a little science to think about.

In general a single musical note is not pure single frequency sine wave.

Musical instruments produce various frequencies other than the fundamental frequency of the note being played. It is these other frequencies that produce what is called timbre. Timbre is the characteristic that allows us to differentiate between different instruments playing the same note.

Below is the spectral content of a violin playing a single note.



The fundamental frequency is on the far left and the rest of the frequencies that make up the timber of the violin follow across to the right. It is easy to see that although the fundamental frequency, in this case 294 Hz will be reproduced by the woofer, the tweeter will be reproducing the higher frequencies contained in the spectra that makes up the energy content that results in the timbre of the note being played.

It is easy to see that a change in the performance of a high frequency driver can have an impact on the sound quality (timbre) of the lower frequency notes being reproduced by the woofer.

The change in the spectral energy being reproduced for a note with a fundamental frequency that is being reproduced by the woofer is measurable when there is a change in the performance of the high frequency radiator, for example when its associated crossover capacitor is changed, even in a first order crossover.

Some people are rather sensitive to small changes in timber and some not so much.

Remember that all though the absolute amplitude of a singe frequency, or swept frequency tones reproduced by the woofer may not change, music is made up of musical notes who's fundamental frequency is reproduced by the woofer, but the rest of who's spectral energy is reproduced by the tweeter and this energy reproduced by the tweeter can have an impact on the sound quality of a musical note that we would think of as being reproduced by just the woofer.

This is why is it not unusual for a person that has replaced the one and only capacitor in a speaker with a first order crossover to report that the sound quality of the bass has improved or changed. It is not just about the basic amplitude of the spectra reproduced by the woofer.

Again, some people are more sensitive to this than others and our perception of sound quality is subjective per individual as is the use of the descriptors used when talking about sound quality.

 

[audiomagnate]

...This is why is it not unusual for a person that has replaced the one and only capacitor in a speaker with a first order crossover to report that the sound quality of the bass has improved or changed. It is not just about the basic amplitude of the spectra reproduced by the woofer...

I was just responding to the "more bass" comment from the OP. I haven't experienced that, nor does it make any sense to me, but my stereo always seems to sound better when my dog's in the room, so who am I to argue?

 

[mech986]

I can't find a schematic for the NLA, but it sure looks like a simple first order design with a coil in series with the woofer and a 12 mf blocking cap on the tweeter. Going to a lower resistance coil might result in audibly tighter, louder bass, but changing a cap in series with the tweeter shouldn't have any effect on bass response.
View attachment 803360

Well, that's true because in this instance the woofer has a simple 6db/octave first order crossover in the form of the inductor. Couple that with the natural roll off of the woofer for the acoustic response. So a low DCR iron or air core inductor may allow more signal and if larger cored, more headroom without inductor saturation leading to distortion.

But here the tweeter is also being asked to cover some midrange too so the tweeter cap, again as a 6db/octave first order high pass circuit, plays a big part at the crossover point. Both drivers interact and overlap over a full octave to 2 octaves and both contribute to what you hear in the critical crossover region.

IMO, since you're only dealing with 2 caps total on the NLA, might be fun to get a few different types of film caps to try out, the value is not huge so cost isn't bad.

Or you could go whole hog and try out a Charge coupled capacitor setup with only double the value and double the number of caps, two 1M ohm resistors, and a couple of 9V batteries and holders.

 

[Old Guy8]

I have been enjoying both this discussion and my recapped Advents. They do sound crisper to me.

 

[NAD80]

Recapped my Mission 737R's with Dayton's. Now have a high end. Both speakers had caps from different sources.

 

[Arthur Smith]

I too was very skeptical about recapping my vintage KLH Model 6's. To my ears, they sounded great. After recapping, they have crisp highs and mids, and true soundstaging and stereo imaging. I think people go a bit crazy recapping things, but with vintage speakers, I think a simple recap really can make a big difference. Like everything in this hobby, mileage may vary.

 

[fastguy1955]

Recapped my Mission 737R's with Dayton's. Now have a high end. Both speakers had caps from different sources.

Hi,
Just got a set 737R Renaissance speakers, like to recap and possibly change the resistors and inductors. I have the 19mm vifa tweeter version, Can you share what the caps , resistors and inductor values were?

Thanks!

 

[Lavane]

Ive recapped several speakers sets leaving one stock to A/B them. Replaceing the 35 to 45 year old electrolytics with film caps did make a difference. I have a pair of beveled original large advents I just picked up with fresh surrounds. Im hoping the caps were replaced when the surrounds were replaced. I'll be popping out a woofer to see when I refinish them.

 

[NAD80]

Hello fastguy1955. Welcome to AK. All I did was changing the old E caps to equivalent film caps. Dayton audio caps from Parts Express. Didn't touch the rest of the crossover. Want to one day to move the crossover from the speaker terminals to a different position in the speaker. The original caps had higher ESR and almost shut down the tweeters.

 

[fastguy1955]

Hello fastguy1955. Welcome to AK. All I did was changing the old E caps to equivalent film caps. Dayton audio caps from Parts Express. Didn't touch the rest of the crossover. Want to one day to move the crossover from the speaker terminals to a different position in the speaker. The original caps had higher ESR and almost shut down the tweeters.

Thanks for the response NAD80! Which version do you have?

 

[NAD80]

The caps were the Dayton precision 1% caps, only because they were just a little more than the 5% caps. Didn't have much room with where the cap was mounted. Cut the old one out and solder the new one in it's place. Found them at SA.http://www.audiokarma.org/forums/index.php?threads/mission-737r.632997/ . Here is a thread to check on opening the speakers.

 

[StimpyWan]

I've been recapping my AR90s recently. Just a little at a time, as I get the chance. I actually just finished one crossover, and did a quick A / B test against the stock speaker. Mainly, I wanted to make sure I didn't screw up anything. So, I found a sacrificial woofer, and tested the 4 output connections. All seemed correct. Encouraged, I got out the dome upper mid driver, and connected it. I played some of the new Jon Anderson / Roine Stolt CD, since I like Anderson as a singer, and his vocals are distinctive. Well, heck yea! The dome by itself was sounding really good. In fact, I was getting a better upper range sound from the single mid, than both the mid and tweeter together, in the stock speaker. The stock crossover now sounded muted and dark. Compressed. I guess those old caps were blocking more than I realized. Time to get to work on that second crossover!