Upgrading X-over in my Kef IQ9.

[Pirium]

Hi

As part of reconditioning a pair of IQ9's, i'd like to upgrade the crossover a bit.
After reading THIS THREAD i understand I could just as well make matters worse, instead of actually upgrading the crossover..

So, which components would you recommend upgrading, and to what? I'd like to keep costs low, but get a audible upgrade.

All series-inductors are iron core, all capacitors are electrolytic, all resistors are wire wound. The 1.2 ohm resistor in series with the woofers are not a part of the real crossover, i have no idea why it's included in the drawings..

[AllenB]

You might think of starting with the tweeter caps, after which you might adjust the series resistance to taste. If the two shunt capacitors are not old or damaged then I'd probably leave them. Same with all resistors unless I was going to change the values.

I would leave the shunt inductors but the series inductors might be upgradeable if you want to go to air-cores. In the case of the mid driver, you can remove the resistance which will allow you to use an air-core with a DCR of 1.5 ohms which should be inexpensive.

This brings to light the woofer resistor. It is drawn here before the terminal so it might represent something else, maybe an amplifier output impedance? It does seem to offer opportunity to go for higher DCR air-cores.

The midrange cap might benefit from being replaced. Plenty of moderately priced options such as good electros. A poly cap could be expensive. Using a poly bypass may not do much over a quality electrolytic on its own for a mid.

[sreten]

Hi,

I'd upgrade the treble caps and change the treble inductor to air core.
Possibly use two caps to make up each individual value, old trick.

Upgrading the mids or bass end is going to be very expensive, assuming
currently decent quality components, I'd suggest leaving them as is.

rgds, sreten.

[Pirium]

Thanks!

Upgrading the mid caps will be a bity expensive, at least $55 (Axon) to $75 (dayton). Still i feel this should be done, the crossover freq. is 250hz, so the mid and tweeter covers most of the audible frequencies..?

Where can I get an 0.9mH air core inductor with DCR 1,5 ohm? I've only found those with DCR from .67 and down..

If you know any good alternatives to parts-express or partsconnexion, please let me know! (Must ship to Norway)

[Pirium]

Originally Posted by AllenB

You might think of starting with the tweeter caps, after which you might adjust the series resistance to taste. If the two shunt capacitors are not old or damaged then I'd probably leave them. Same with all resistors unless I was going to change the values.

I would leave the shunt inductors but the series inductors might be upgradeable if you want to go to air-cores. In the case of the mid driver, you can remove the resistance which will allow you to use an air-core with a DCR of 1.5 ohms which should be inexpensive.

This brings to light the woofer resistor. It is drawn here before the terminal so it might represent something else, maybe an amplifier output impedance? It does seem to offer opportunity to go for higher DCR air-cores.

The midrange cap might benefit from being replaced. Plenty of moderately priced options such as good electros. A poly cap could be expensive. Using a poly bypass may not do much over a quality electrolytic on its own for a mid.

How do I know which electros are good, and which aren't?
Do I have to adjust resistance if I upgrade the capacitors too, or just when upgrading inductors?

[Pirium]

Originally Posted by sreten

Hi,

I'd upgrade the treble caps and change the treble inductor to air core.
Possibly use two caps to make up each individual value, old trick.

Upgrading the mids or bass end is going to be very expensive, assuming
currently decent quality components, I'd suggest leaving them as is.

rgds, sreten.

The treble inductor is air core already.
The rest are iron cores.

[AllenB]

You can estimate their condition by their age and the condition of their packaging (that they are not bulging). You may or may not need to increase the series resistance slightly when you move to poly caps.

[sreten]

Originally Posted by Pirium

The treble inductor is air core already.
The rest are iron cores.

Hi, I severely suspected it was, and the diagram indication was wrong, rgds, sreten.

I generally don't replace cored inductors except in the treble, not cost effective.
Given drivers are cored coil devices, quite a lot of nonsense surrounds air cored.

Pragmatically other than the treble caps, midrange caps as well.
You might be lucky if he hasn't sold out :
3mH inductor, 165uF caps