New crossover for NX-Otica MTM

mlundy57 · « **on:** 17 Jul 2020, 09:16 pm »

It's time to upgrade the crossover for my NX-Otica MTMs. The current crossovers are no slouches, Sonicaps with Sonicap Platinum by-pass caps, Mills resistors, and Erse XQ- air core inductors.

The new crossovers are going all out, Copper Caps with Miflex KPCU by-pass caps, Sonicap with Miflex KPCU by-pass cap in the notch filter, Mills resistors, and foil inductors. Here are the new parts

Mike

Hobbsmeerkat · « **Reply #1 on:** 17 Jul 2020, 09:29 pm »

Those are some gorgeous parts! I cant wait to see the results & hear what you think about the upgrade!

Tyson · « **Reply #2 on:** 17 Jul 2020, 11:29 pm »

Very nice!!

mlundy57 · « **Reply #3 on:** 18 Jul 2020, 12:52 am »

I recall in the Super 7 thread some folks swapped the Mills resistors for Path resistors. Was there any upside to this?

Hobbsmeerkat · « **Reply #4 on:** 18 Jul 2020, 01:06 am »

Have you considered trying the mod for the Neo3 that was made in this topic? https://www.audiocircle.com/index.php?topic=151771.0

mlundy57 · « **Reply #5 on:** 18 Jul 2020, 01:21 am »

Quote from: Hobbsmeerkat on 18 Jul 2020, 01:06 am

Have you considered trying the mod for the Neo3 that was made in this topic? https://www.audiocircle.com/index.php?topic=151771.0

No, I haven’t.

Early B. · « **Reply #6 on:** 18 Jul 2020, 03:17 am »

You're gonna be shocked at how much better your speakers will sound with the upgraded crossover.

EHill · « **Reply #7 on:** 18 Jul 2020, 08:29 pm »

If you don’t mind me asking how much is the MTM kit from Danny?

Also where did you purchase the upgraded crossover parts and how much is that upgrade?

Many thanks...

mikeeastman · « **Reply #8 on:** 18 Jul 2020, 09:11 pm »

Go to Dannys web page it has all the prices.

Hobbsmeerkat · « **Reply #9 on:** 18 Jul 2020, 09:39 pm »

It doesn't. The new site will have all the prices, but the current site only has the NX-Otica & NX-treme

TexE4D · « **Reply #10 on:** 19 Jul 2020, 03:09 am »

What is the purpose of the by-pass capacitors?
I only see one resistor on the original XO.

Hobbsmeerkat · « **Reply #11 on:** 19 Jul 2020, 03:30 am »

Quote from: TexE4D on 19 Jul 2020, 03:09 am

What is the purpose of the by-pass capacitors?
I only see one resistor on the original XO.

Im not 100% certain on this, but i believe its because you need to get certain values to achieve the needed value, but don't have availability of the exact value, but can achieve it by using small bypass caps in parallel with the main caps.

Like say you need 9.1mH value capacitor, but none are available in the brand you want. So you run a 9mH & 0.1mH in parallel to get the same effect. (Im no expert, but that's the kind of sense it makes to me conceptually)

TexE4D · « **Reply #12 on:** 19 Jul 2020, 03:48 am »

Thanks for the explanation.

TexE4D · « **Reply #13 on:** 19 Jul 2020, 03:52 am »

I ordered some of these copper caps to upgrades my XOs. I had to order 12uF, 12uF, 9uR to sum 33uF.

mlundy57 · « **Reply #14 on:** 19 Jul 2020, 03:53 am »

As I understand it, the by-pass cap allows the primary cap to discharge faster and the faster the discharge, the cleaner and more detailed the signal will be.

mlundy57 · « **Reply #15 on:** 19 Jul 2020, 03:57 am »

Quote from: TexE4D on 19 Jul 2020, 03:52 am

I ordered some of these copper caps to upgrades my XOs. I had to order 12uF, 12uF, 9uR to sum 33uF.

You can add a by-pass cap to the bundle. I’ve done that with a bundle of Sonicaps in an NX-Otica crossover.

diyman · « **Reply #16 on:** 19 Jul 2020, 04:42 am »

Quote from: Hobbsmeerkat on 19 Jul 2020, 03:30 am

Im not 100% certain on this, but i believe its because you need to get certain values to achieve the needed value, but don't have availability of the exact value, but can achieve it by using small bypass caps in parallel with the main caps.

Like say you need 9.1mH value capacitor, but none are available in the brand you want. So you run a 9mH & 0.1mH in parallel to get the same effect. (Im no expert, but that's the kind of sense it makes to me conceptually)

Capacitor values are measured in microfarads, uf. It's coils (inductors) that are measured in millihenries, mH.

The reason for the small bypass capacitor in parallel with a large one is to shunt high frequency noise around the main capacitor so that it doesn't affect the signal.

Adding a 0.1uf across a 9uf filter capacitor will effectively change the total to 9.1uf, but that is not important. It represents a tuning difference of only 1%, which is inconsequential, and well within the tolerance band of most filter capacitors. It is the ability of the small cap to pass high frequencies around the large one that is important. Ergo the name, bypass capacitor.

Hobbsmeerkat · « **Reply #17 on:** 19 Jul 2020, 05:10 am »

Thanks! Im by no means an electrical engineer, so im more than likely to get things mixed up.

At least I had the basic concept somewhat right-ish, but the wrong terminology.

diyman · « **Reply #18 on:** 19 Jul 2020, 08:24 am »

Quote from: Hobbsmeerkat on 19 Jul 2020, 05:10 am

Thanks! Im by no means an electrical engineer, so im more than likely to get things mixed up.

At least I had the basic concept somewhat right-ish, but the wrong terminology.

Well, just to be clear, the concept is not to try to make a 9.1uf capacitor out of a 9.0uf. That difference is inconsequential to the performance of the filter. And the 9.0 is probably not really what it says on the outside label anyhow. There are fairly wide tolerances with most large capacitors.

So the reason for the small capacitor in parallel is to bypass the high frequencies across the larger one. Not to change to total value of capacitance in the circuit.

Hobbsmeerkat · « **Reply #19 on:** 19 Jul 2020, 02:08 pm »

Quote from: diyman on 19 Jul 2020, 08:24 am

Well, just to be clear, the concept is not to try to make a 9.1uf capacitor out of a 9.0uf. That difference is inconsequential to the performance of the filter. And the 9.0 is probably not really what it says on the outside label anyhow. There are fairly wide tolerances with most large capacitors.

So the reason for the small capacitor in parallel is to bypass the high frequencies across the larger one. Not to change to total value of capacitance in the circuit.

Good point.