Capacitor

One of mine needed to be 125uF. That is pretty big and real expensive. So to save money I used 122uF Jantzen Premium ELKO with a 3.3uF Alumen Z as a bypass cap.   

I view this as similar to the way I used Duelund JDM Silver .01uF bypass caps with the Alumen Z.  

Looking at doing the wire, but with 17 drivers per speaker that is a big project for a Moab! Might still do it but really need to do some planning first.

Indeed. One substantial difference, if the drivers are upgraded they will almost certainly be different response and therefore require at least some crossover changes. If the upgraded driver is a known commodity, like adding a Be tweeter to Moab for example, something the manufacturer actually does and knows how to do, that is one thing. But to just pick a superior driver that fits, well that is almost certainly going to call for a lot of crossover tweaking.

As opposed to not really changing anything in the design at all, but merely implementing it with superior quality parts. That is what I did.

Also keep in mind, not only the caps, resistors and inductors. Also the inductors are now oriented better, their axes all at 90 degrees to each other. Also they are mounted on Omega eMat. They are no longer mounted on a wafer thin bit of fiber board, they are now on massive dense carbon fiber BDR Shelf. They are no longer hot-glued to a brace, but isolated on Townshend Pods.

Each and every one of these changes would be a pretty decent improvement on their own. All of them combined is why this upgrade elevates these speakers to such a high level. The beauty of this approach is that by being so careful to use all the same electrical values this means all Eric’s original work is retained and nothing needs to be trimmed or adjusted or experimented with.

As Rick knows, that JDM Silver was one that went into my Moab crossover upgrade. Along with Jantzen Alumen Z, Jantzen Premium ELKO, Path Audio resistors and Goertz Alpha Core inductors. Mounted on eMat and BDR Shelf, on Townshend Pods, and treated with TDF, fO.q tape and Herbie’s Grunge Buster, all mechanically crimped direct and soldered component to component with Cardas Quad Eutetic.

Original crossover values were maintained, as determined by measuring all the stock crossover individual component parts. The result is easily my greatest mod type upgrade and exceeded all expectations. Compared to the Talon X crossovers professionally built by Michael Farnsworth and that cost almost as much but provided a barely noticeable improvement, this crossover upgrade transformed the Moabs to a whole new level, night and day.

The question of what is ’best’ is as far as I’m concerned a chimera. A phantom. A ghost. The only way to even begin would be to try all the different parts. Inductors alone on this cost $300. For one set. There were at least three possible contenders. One of them, Deulund, would have cost much more than the $2k total cost of what I have. The capacitor review sheet that was used to select mine had some hundred caps on it. Resistors, at least three, probably six contenders. Then there are the combinations, permutations.

What I did, weigh all the listener comments, and selected what I thought would get me darn close to cost no object for a fraction of the COTA price. I will never know how close I got. But, guess what? Don’t care! 😂🤣
Full crossover details can be found here: https://systems.audiogon.com/systems/8367

The only identified issue with film caps is a potential for mechanical resonance specific to a frequency but audiophiles make up all kinds of things like posts in this thread. Caps can be in high or low pass filter networks. They are critical in both.

So which is it then? Because if they are so critical then it would seem we would want the best ones, and you already admitted there are problems like mechanical resonance. Which is indeed a factor. So how can you be sure we are just "making up all kinds of things" about which is best? Help me understand your, uh, reasoning.

What value is important the uf or the vdc

The critical value is uF, micro-Farads, the unit of capacitance. VDC is voltage, which matters only in that you do not want to use a low voltage cap with high voltage as it can destroy the cap. Crossovers are in the single digits to tens of volts, not hundreds, so this number 630VDC is irrelevant. You just don't want one that is too low. 

Capacitors in crossovers are sometimes called filter caps because that is what they do, filter lower frequencies. The greater the capacitance the more energy the cap stores. Because of this, if you change the value from say 100uF to 150uF this will shift the frequency and this will cause the speaker to sound different.

All caps and resistors have a tolerance, typically of a few percent, often printed on the part along with the value. So if your cap is 100uF +/- 5% it can be 95 to 105uF. If the manufacturer specs this cap that alone should be enough to tell you one or two uF one way or the other is not critical. If you really want to know you can buy a LCR meter and measure actual capacitance and inductance yourself.

The idea someone had that the only thing that matters is the measured value and gives as his "reason" because, physics, is patently false. The better caps do indeed sound better even though they measure the same. And you want to know why? PHYSICS!

What is actually happening inside a cap is electron charges are constantly shifting one way and another, in and out, according to the music signal. When we measure all we get is a static, fixed state number. There is nothing in it having anything to do with how fast and smooth these charges shift back and forth. Which with music is EVERYTHING! That is why some of these expensive caps use such an elaborate manufacturing process, to ensure extreme consistency and sensitivity down to the electron level.

It ain’t cheap. It ain’t easy. And it can’t be measured by no meter. Thus the link to the cap comparison page above.

I recently upgraded my entire crossover with huge, huge improvement! https://forum.audiogon.com/discussions/millercarbon-s-mega-moab-mod-meander
The two smaller value caps I was able to do with the very highly regarded Jantzen Alumen Zcaps, with a Duelund JDM Silver .01uF bypass cap. There was one cap of 125uF which would have been very expensive to do that way. So instead I used one 100uF and one 22uF Jantzen Premium Elko, with a 3.2uF Alumen Z bypass cap. (Voltage btw is not a factor, that is for use in a tube amp or other applications not in a crossover that will never see even 100V.)   

Pictures of actual parts used are on my system page here https://systems.audiogon.com/systems/8367


Alumen Z are not cheap, but compared to Duelund they are! And they are very highly rated. http://www.humblehomemadehifi.com/Cap.html

Thank you very much, Rick!

If you go this way please be sure to pay attention to your space and the dimensions of the upgrade parts as the physical size of quality parts is huge compared to lesser quality parts!

Also everyone focuses for some reason on caps, but do not underestimate the contribution of inductors and resistors. Read my thread, I did all of that and more, and it is not just a huge improvement it is like better than I ever heard before.