kef IQ3 mod

[hcbonfim]

Hi dear,

I want to mod my kef iq3 speakers (capacitor´s, wires... )
anyone has the schematic of KEF IQ3 speakers ?
I will apreciate,

best regards

[gabrielbecheanu]

Today I modify my pair of IQ3 witch I bought last week.
I change all the capacitors with Bennic and Visaton the resistor with Mundorf, and DIY coil.
Also the cable was changed with Real Cable.
Bass C 16uF/250v Bennic, R 6.8ohm, L 1.1mH
Tweeter C1 15uF/250v Visaton. C2 5.6uF/250v Bennic, R 1.2ohm L 0.125mH
The sound for this speaker after the modification in unbelievable, sound is more accurate more clean.

[alan-1-b]

gabriel and hcbonfim, and anyone else ...

how did you get the crossover circuit board out of the cabinet ?

In my iQ3 the board is very tightly held by plastic, or nylon, studs and will not come off over them.
I do not want to break the circuit board.
Perhaps I will have to cut the tops off the retaining studs,
or break the corners off the circuit board.

Any suggestions from anyone who has done this please ?

[AndrewT]

Hi,
do the plastic studs have a "core" in the middle.
This pushes out to release the tangs on the other side to allow dismantling.

Can the sides of the protruding stud be squeezed in to release the PCB?

I have some Ci 130QS.
Are these the same drivers as in the IQ3?

[alan-1-b]

Hi Andrew,

I tried squeezing the sides of the studs, but they do not push in.

I think I tried pressing the tops, and I didn't notice a push-in function in the tops.

It looked like the board is simply pushed on over non-retractable retaining studs - the cheapest possible type.
My guess is that KEF do not intend these to be removed for Servicing even,
unless their technicians have a special tool to remove the boards from the studs ...
Its all silly, because the capacitors are all electrolytics, thus limited service life as well as slightly fuzzy sound,
BUT the drivers seem to be very good and worth a better quality components' crossover !

The drivers are co-axial - a metal dome tweeter mounted in the centre of a metal coated, plastic cone mid-bass driver.

The iQ3 and the new iQ30 have 165mm -{6 1/2"}- diameter drivers.
iQ1 and iQ10 have 130mm -{5 1/4"}- diameter co-axial drivers.

I have not seen Ci 130QS, nor any in the Ci series.

The basic C series drivers are not co-axials, but are separately placed tweeter and mid-bass drivers.

[AndrewT]

It looks like the Ci 130Q is an equivalent to the iQ1 & iQ10

The Ci160Q seems like the equivalent to iQ3.

I would expect the q & Vas of the bass/mid to be quite different, but the mid range and treble should be very similar.

[gabrielbecheanu]

Hi Alan
If you want to remove the crossover you must remove also the speakers terminal in the rear, with a lantern you will se the crossover and the all four plastic supports.
You will figure how to take it out. If not you can cut them. Use screw to fix the new crossover.
Forget about the Kef crossover, after a lot of A/B tests with a few speakers like Triangle Genese Trio and Jamo D830 I decide to replace the stock crossover with an older design from a Grundig Super HI-FI box 450 This has a crossover frequency at 1.5 kHz. I will try to put later the schematic diagram of the crossover. If any body wants to see the differences between the original crossover and the Grundig can build one and make some test. I use these speakers with an Onkyo A 8870.

[alan-1-b]

Hi Andrew,

I found I do have a small brochure about the Ci series.
The pictures are small and the Dimensions are stated for the drivers in their mountings only, thus I am not sure what the actual drivers' diameters are.

On the back of my 6.5" driver's chassis is a KEF sticker with the Part Number :- SP1535 .
SP**** for part numbers has been used by KEF for many, many years.

The drivers in the iQ10 and iQ30 look to have the same cones and domes as their predecessors in iQ1 and iQ3, but there is now also what KEF call a Tangerine Waveguide - metal pieces protruding from the tweeter's flange - in the 10, 30, and all the new iQ*0 series.
This disperses the upper treble frequencies around the forward response area more widely than occurred with the previous iQ* series, BUT, and I have listened to both iQ3 and iQ30, the actual spectral content is different from different listening axis, and for some musical instruments I like the upper treble sounds untidy - so I am staying with my iQ3, but some listeners may prefer the new series - it spreads the sounds of cymbals well, but for pitch-specific harmonics, such as from violins, the Timbre changes too much for my liking when I move my head sideways even a little when listening.

iQ*0 series have apparently better capacitors in their crossovers AND the cross point has been moved down in frequency a little, thus I want to try that because a small amount of the inevitable cone breakup is audible, and crossing lower will reduce that audibility.
It is NOT highly intrusive breakup - unlike the large amount of midrange resonances that come out via the port !
With the port blocked sounds much better to me, and the bass is better pitch defined then also.

Q and Vas, etc will depend on whether same magnet size and type is used for the Ci series drivers as for iQ series, and perhaps they are.
Hopefully you can find out via the Part Number I noted above, as the 130mm drivers will have specific SP**** numbers.
iQ30 driver will have a different SP**** to iQ3's because the tangerine waveguide is part of the driver.
iQ3 driver does NOT look like the driver pictured in the new Ci160.2QS,
BUT, it does look like the driver in new Ci130.2QS, and that does not have the tangerine waveguide !

[alan-1-b]

Hi Gabriel,

Thankyou for you comments about how to access the in-cabinet crossover.

I am very interested to see a schematic for a better sounding crossover, if you are able to Post it or describe where it can be found.
See my new Post, above, for more of my thinking about the iQ3 driver and crossover hopes.

[gabrielbecheanu]

Hi Alan
I will draw the schematic. I will tell you also the value for coils and capacitors.
For the woofer a 22uF and a resistor 2.7ohmi the value for coil is 1.45mH and for tweeter a capacitor 8.2uf and a 0.43mH coil.
The crossover is second order.
first diagram is the woofer