[JCarney]

Hi guys, I thought it might be a good idea to ask first if there is trick to getting off the KEF trim rings before I attempted it myself. Any help is as always, greatly appreciated. I've included a pic of one of the speakers. We have a boxer and as you can see he has been decorating.

Thanks,
JCarney

[Hobbsmeerkat]

Safest way is getting your fingernails under the inner side of the ring and slowly working your way around until you can lift it up.
The surround is flexible enough that if you take it slow you wont damage the driver.

[JCarney]

Ahhh, a little patience and finesse, neither of which I possess. Thanks for the reply Hobbs.

JCarney

[JCarney]

Thanks for the tip Hobbs, the rings were much easier to remove than I anticipated. I'm going to attach a pic of the xover, all three parts, and see what the community has to say. I'm a little hesitant to do anything because I've not seen a xover board that looks like this one. Thank You to anyone who takes the time to answer. The values of the cap and what I think is a coil are: MDL cap: MPT 4.4J 1001v and the coil VDSON 0.9mH.

JCarney

[Hobbsmeerkat]

It looks like its just two 1st-order filters.
A resistor and capacitor on the tweeter then a tiny iron-core indictor on the woofer.

I would just swap out the parts with the same value parts, just better quality.
For example:
4.4uF Sonicap
12W 1.5ohm Mills resistor
0.9mH air core (16 gauge)
Then a pair of tube connectors to replace the binding posts.

It'll maintain the stock sound signature, but boost their clarity and detail from top to bottom.

[JCarney]

Doing some research on first order crossovers, and finding someone else who wanted to upgrade the Q350, I read that the 1.5ohm resistor is padding down the output of the tweeter. If this is correct, how would one point to point wire a new crossover with the same values? I cannot seem to figure it out.

Thanks,
JCarney

[E-Zee]

I could see 2 likely ways that would wired.  If you add closeup photo of the back of that board, we can answer that for you with greater certainty.

[JCarney]

Thanks E-Zee, here is pic I found off of reddit.

JCarney

[Hobbsmeerkat]

If I'm looking at it correctly, it's goes like this:

Tweeter:
+ input > 4.4uF > 1.5 Ohm > Tw- > Tw+ > - input
(polarity is flipped on the tweeter)

Woofer:
+ input > 0.9mH > W+ >W- > - input

[E-Zee]

JCarney,

If you needed any second confirmation, Hobbs is 100% correct in his assessment of the stock crossover.

Here it is drawn for you as point to point for your upgraded version.



Considering, how small that board is, and the significant amount of space in the cabinet, I would not even bother to remove the old crossover.  Build your new board and install it anywhere you want, with new wiring.

  If you go the distance of adding tube connectors or any other pair of new binding post, you can even leave the old network as is, still connected to the original binding posts and the drivers.  Connect the new boards using the tube connectors, and you can easily switch back to compare the old vs new circuits, just be sure to never power both sets of inputs at the same time.

[JCarney]

Hobbs and Ezee, it is help like this, and helpful people like the two of you, that make this a great audio enthusiast site. I really appreciate the advise, the detail in the explanations, and a drawing to boot! Once the parts get here, I should have a pretty easy time of it with the guidance provided by you two.

Thank You Very Much,
JCarney

[JCarney]

Hobbs and Ezee, I wanted to Thank You guys again for the help on the xover for my Q350's. I received the parts today, took a little time to label everything and assembled and mounted the xovers in the bottom of the speakers. I pulled the speaker terminal cup, ensuring I could get if out through the hole, and soldered everything up, including the drivers. Put it all back in, pulled the cup through the hole, attached it, glued xovers to bottom, put in drivers. Everything works! WooHoo!  Both the written and the drawn instructions made it easy. While I was waiting on the parts, I used CANOPUS car sound deadening mats. The knuckle test was impressive afterwards. Much deader than with out. I know No-Rez is the best, but at $15 delivered from amazon, it is a real alternative to No-Rez and Dynomat for the budget minded, or cheap bugger like me. 

Thanks,
JCarney

[AndrewDIY]

This thread has been very helpful for me too. I am looking to do pretty much this exact thing but on the q150’s. They have the same crossover layout just different values. The tweeter cap values on the q150’s are 3.7. I was thinking about upgrading caps to either Sonicaps or Jantzen Superiors and then bypassing with a Miflex. I am not sure what value would be best for the Miflex though (.1 or .047)? I also couldn’t find the exact .8 air core inductor with a gauge that was large enough to match the dcr of the outgoing solid core inductor, but I found a .82 with 15awg which I am hoping will be close enough.

How would you describe the difference in sound with your upgrade?

[Hobbsmeerkat]

.1uF will be perfect for the Miflex bypass, no need to go lower.
0.82mH is close enough to not be an issue as it's within typical 5% tolerances.

Personally I would go with a Sonicap with a Miflex bypass, but most anything you use will be better quality than the stock caps, even cheap Audyn caps.

Generally speaking you should notice an improvement in clarity and detail especially if you also directly solder the wire to the drivers and replace any steel on the binding posts.

You should also get a more open, transparent sound, while miflex bypass will give a slightly richer/smoother tone to whatever cap its attached to though it can take up to 400 hours to finally burn them in. Most good polycaps, like Sonicaps/Jantzen need about 200 hrs to sound their best

Putting heavy vinyl tiles or butyl products, like Dynamat, on the wall will help in much the same way as the canopus mats. Then adding a little extra polyfill or fiberglass/ Rockwool insulation will also help.

[JCarney]

Andrew,
Immediately better. The new parts with no break in at all, sounded worlds better than the original parts completely broken in. I ordered a Dayton air core inductor, a Dayton 4.3uF poly cap with Audyn 0.1uF by-pass to get my 4.4uF, and a Jantzen resistor from Parts Express. For just 6 parts, I decided not to bother Hobbs with an order. With shipping I only spent $54 on parts plus the $15 for the dampening material. Had some wire leftover from another build I used just to connect to the binding posts. I left the wire from the xover to the driver intact, cutting at the xover, because of the way they wired the tweeter, then I jut labeled the wires so I knew where they went on the new one. I'm guessing the only difference in your xover is the values, the wiring I bet is the same. Well worth it all the way around. Not much spent, big improvement, and I had fun.

JCarney

[AndrewDIY]

Thank you both for your great responses! Man, you all got me so stoked for this upgrade!

Hobbs, do you stock 3.6 uf sonicaps? .1 Miflex? I figure similar to JCarney, this 3.6 plus the .1 Miflex bypass would get me to the original 3.7 value. I am considering tube connectors as well, but wasn’t sure if my system would be resolving enough for that to make a significant difference. My Kef q150’s are currently connected to a Sony STR-DH190…no one laugh please

JCarney, did you end up leaving in the original crossover? I am considering this because of the awkwardness of taking original out.

[JCarney]

No. I had already yarded out one of them before Ezee suggested leaving them in. It helped me because I did not want to mess with the connections to the drivers. Where the wires terminate to the board were all marked so I could easily label and snip the wires so I did not goof. The originals are so bad, I saw no reason to keep em. They were in the way of sound dampening anyway.

JCarney

[Hobbsmeerkat]

Thank you both for your great responses! Man, you all got me so stoked for this upgrade!

Hobbs, do you stock 3.6 uf sonicaps? .1 Miflex? I figure similar to JCarney, this 3.6 plus the .1 Miflex bypass would get me to the original 3.7 value. I am considering tube connectors as well, but wasn’t sure if my system would be resolving enough for that to make a significant difference. My Kef q150’s are currently connected to a Sony STR-DH190…no one laugh please

JCarney, did you end up leaving in the original crossover? I am considering this because of the awkwardness of taking original out.

We do not. The closest Sonicaps we have is 3.3uF and 4uF

We do have 0.1uF miflex caps though.

Tube conncetors will make a difference. Even on more budget systems, the difference is noticable even with my little Sprout 100 and my original base level X-LS kit. Especially in the treble with things like cymbals and bells etc.

It all adds up the more you improve.
Replacing the original wire and directly soldering the connection will also be a benefit to performance and improve clarity across the board, especially if you're going the sonicap/miflex route

[JCarney]

This is a funny PSA:

I built a little wide band driver with teeny ported cabinet kit, similar looking to the LGK1. It has a notch filter like what I read recently on the new LGK2 with an option of adding a second provided inductor to flatten out a peak. I used the second inductor, and put them in the box without thinking. I had both of them hot glued to the bottom of the little box laying flat. Put in the driver after hook up, and what a flat dead sound. Two days later it dawned on me looking at the other unfinished box, that I had done a no-no in xover assembly. I rectified the situation and got one them standing up perpendicular like it is supposed to be. And of course all that lifelessness went away and low and behold, good sound.

Hope ya chuckled,
JCarney

[Hobbsmeerkat]

This image is a handy one for orienting Inductors:



Laying them down next to one another is unfortunately a pretty common issue, even among commercial manufacturers.