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Carina II refurbishment project
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JamesMaidstone
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Joined: 04 Aug 2014
Posts: 11
Location: Maidstone, Kent

PostPosted: Tue Aug 19, 2014 9:47 pm    Post subject: Carina II refurbishment project Reply with quote

Hi everyone,

First time post, long time KEF fan!

Alongside my Cadenzas and Coda III I have recently acquired a pair of Carina II to add to my collection. They arrived with all 4 woofers (SP1093) pretty much shot... well totally shot and one was ripped. I managed to acquire 4 which I had shipped from Oregon USA (Ironically I can walk to Ecclestone Road, Tovil in about 5 minutes from my house!)

I replaced all with the new (and visually appearing immaculate) woofers, wired them as per the ones I removed and hooked them up, expecting a delightful sound. Sadly though there is very little bass and I suspect something else is awry.

I'm wondering if the crossovers (SP2021) need replacing and if that could be the cause of the lack of depth of sound.

My questions for anyone who can help are;

Is it likely that the crossover being faulty would cause the sound to be as it is? If so any ideas on a compatible crossover or where I could get a custom one made?

Could the wiring have been wrong (I can't tell if the old drivers had ever been changed)?

Could it be that as the replacement woofers I bought (which look as good as brand new) need some time to "bed in"?

Any advice anyone could offer would be massively appreciated.

I run my Coda III on the amp I tried the Carinas on(35W RMS per channel into 8ohm and these sound fantastic)

Cheers,

James
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Gary
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Location: Toronto, Canada

PostPosted: Thu Aug 21, 2014 1:07 am    Post subject: Reply with quote

It's not too hard to replace the capacitors in crossovers. Are they leaking or do they look burnt?

You say the speakers were "shot" ....do you think they were played hard?

Definitely play them for a few days. Hook up an old receiver and leave it on low volume for three or four days and see what happens.
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JamesMaidstone
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Joined: 04 Aug 2014
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Location: Maidstone, Kent

PostPosted: Thu Aug 21, 2014 7:03 am    Post subject: Carina II refurbishment project Reply with quote

Hi Gary,

Thanks for the suggestion - I'll give that a try.

One of the cones for the old woofers was torn and the other three basically make a crunching sound with any movement (as well as seeming very loose in terms of movement) so I suspect that they were frequently played hard. Either way I am certain the new ones are infinitely better than the old ones Smile

I haven't gotten as far as removing all the acoustic dampener to visually inspect the crossovers - that will be my next task!

I'll update when I've done so and run them for a couple of days.

Thanks again,

James
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Gary
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PostPosted: Wed Aug 27, 2014 10:21 pm    Post subject: Reply with quote

Sounds like a good plan! Smile

The Carina`s 34 year old crossovers may need some TLC but I think they are worth restoring!

Be careful of the types of capacitors that you use if you need to replace any. I once tried Solen caps which are made in France `for the budget audiophilè` but they emphasized detail over reality (or warmth, some would say). I replaced them, rather quickly I might add, with Auricaps.

Not sure what would be best for KEF speakers. But not Solen caps. Shocked
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-- Charles M. Schulz (as Charlie Brown)
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willem-57
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Joined: 18 Jul 2014
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Location: Netherlands

PostPosted: Thu Aug 28, 2014 7:23 am    Post subject: Reply with quote

For kef the alcap capacitators are mutch used, it's the logical succesor of the elcap that kef did use. Falcon acoustics has mutch experience with this matter, http://www.falconacoustics.co.uk/replacement-capacitor-sets/replacement-capacitor-kit-kef.html?p=1. The Carina is not mentioned, but they can make you an offer, i did the same, result is good. Of course you can try other brands if you like.
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JamesMaidstone
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Location: Maidstone, Kent

PostPosted: Sat Aug 30, 2014 2:20 pm    Post subject: Carina II refurbishment project Reply with quote

Hi Gary, Willem,

Thank you both for your advice - I tried running them low for 24 hours and no change. I've gotten round to removing the acoustic foam to access the crossovers and the capacitors in L1 and C3 positions both seem to have leaked (and in fact some of the foam is stuck to both of these)

I'll order my parts and keep my fingers crossed that I can get these up and running again... They've clearly had a hard life!

I'll keep you posted.

Cheers,

James
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JamesMaidstone
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PostPosted: Sat Aug 30, 2014 2:58 pm    Post subject: Carina II refurbishment project Reply with quote

And the L2 position as well!
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JamesMaidstone
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PostPosted: Fri Sep 05, 2014 1:31 pm    Post subject: Carina II Refurb project Reply with quote

I've got the crossovers on their way to Falcon Acoustics to be checked and have the components that need replacing replaced. Starting to think I'd have been better off just buying another pair I saw for £50! But I've started so I'll finish Laughing

Just got to get the cabinets looking tip-top while they're empty...
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willem-57
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PostPosted: Fri Sep 05, 2014 6:11 pm    Post subject: Reply with quote

Good job, youre better off with falcon because you get new components, if you buy another old set, you have maybe the same problems.
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JamesMaidstone
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Location: Maidstone, Kent

PostPosted: Fri Sep 19, 2014 1:14 pm    Post subject: Carina II Refurb project Reply with quote

I've finally received my replacement capacitors, inductors and resistors from Falcon Acoustics and I'm planning to apply these all to the crossover PCB at the weekend... fingers crossed...

The inductors that are coming off were wrapped in a waxy type tape. The new ones are bare wire (and a slightly larger size though I can work with that) Any recommendations as to whether a) I should bother wrapping the inductors in insulator and b) if so will regular electrical insulating tape suffice?

Cheers,

James
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Fri Sep 19, 2014 3:56 pm    Post subject: Re: Carina II Refurb project Reply with quote

I find that most tapes go sticky after a while and either creep and or start unravelling.
Whether good or bad I dunk mine in polyurethane varnish and let it set hard before using.
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iso
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Joined: 29 Aug 2011
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Location: Finland

PostPosted: Sat Sep 20, 2014 12:17 pm    Post subject: Re: Carina II Refurb project Reply with quote

proffski wrote:
Whether good or bad I dunk mine in polyurethane varnish and let it set hard before using.

This is good and easy way to prevent coils to vibrate and short between turns. Coil winding is not rocket science... but it is odd to note, how often old air cored coils have not been dipped in the varnish although old power transformers seems to be varnished quite regularly.

Varnishing in vacuum would be even better, but it is out of reach of most amateurs.

Best Regards

Kimmo
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proffski
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PostPosted: Sun Sep 21, 2014 12:05 pm    Post subject: Re: Carina II Refurb project Reply with quote

I have access to a vacuum pump. but mainly use the method for encapsulating and potting high voltage coils and transformers.
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iso
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Joined: 29 Aug 2011
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Location: Finland

PostPosted: Sun Sep 21, 2014 3:46 pm    Post subject: Reply with quote

I have sometimes wondered if immersing coils in boiling paraffin would be good idea. Air will first expand and then compress when paraffin cools. This should help paraffin to enter between layers of coil.

Paraffin and beeswax was used in old days when output transformers were potted. One old timer told me some 30-40 years ago that properties of beeswax were better than paraffin, when potting output transformers. He thought that beeswax did not increase capacitance as much as paraffin. This should not be too big problem with low impedance coils.

Best Regards

Kimmo
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JamesMaidstone
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Joined: 04 Aug 2014
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Location: Maidstone, Kent

PostPosted: Thu Sep 25, 2014 11:17 pm    Post subject: Carina II refurbishment project Reply with quote

Thanks Proffski and Iso,

As it happens Falcon provided them already set so they've gone onto the PCB as they are...

The results are in and finally completed them this evening - they sound pretty darn good (Finally!) on first test. I do need to hook them up to an amp with a bit more punch than the 35W Teac currently in play but I'm very happy with the results!

I'm now considering replacing the internal wires with new cables to see if that adds to the overall effect... I'll be sure to report back when that's done Smile

Cheers all!

James
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