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kEF Concerto - new member - crossover upgrade advice

 
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Jeffn
Introductory Contributor


Joined: 11 Jan 2016
Posts: 2
Location: Newcastle, Australia.

PostPosted: Wed Jan 13, 2016 11:01 am    Post subject: kEF Concerto - new member - crossover upgrade advice Reply with quote

I've been advised to update my concerto crossovers to something falcon acoustics manufacture. I found their website a little confusing actually and am still not sure exactly what crossover I should buy.
I've attached a photo ....taken for other reasons....yes, my Bowie collection....but the crossovers have SP-1004 written on them.

What crossover should I buy and what difference in sound can expect.

... Couldn't work out how to attach the image. [/img]
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Wiesiek Lipowski
Intermediate Contributor 25+


Joined: 10 Dec 2006
Posts: 39
Location: Poland

PostPosted: Wed Jan 13, 2016 2:39 pm    Post subject: Reply with quote

The concerto x-over looks like this:

http://www.hifiloudspeakers.info/Anatomy/SpeakerSystems/Concerto/ConcertoCrossoverSchematic.jpg
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Wiesiek
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Jeffn
Introductory Contributor


Joined: 11 Jan 2016
Posts: 2
Location: Newcastle, Australia.

PostPosted: Wed Jan 13, 2016 10:09 pm    Post subject: Reply with quote

The website says

UPGRADING THE KEF CONCERTO NETWORK

The No.5 network only will fit in the existing network cut-out. All other types are too deep and in the case of the modified ones too wide. The network edge connector is poor and relies on two tin plated surfaces making good contact. It is best to put the network inside the cabinet on the bottom at the back or on the back at the bottom and rewire with a decent cable. We recommend 76/0.2 mm.

If you want to keep an authentic look keep the original SP1004 network and wires as they are, but not connected inside. Just leave the existing bits as they are, but disconnect all the wires inside the cabinet (to units and input) and rewire the new network with good wire to the input and units. Unless you want rear panel authenticity, fit a new input panel or terminals. It will sound better without the connector and with thicker wire.

The No.6 network was originally designed (in a slightly different version) for a prototype Ferrograph system. The network was subsequently offered to Cambridge Audio where Bert Webb was designing the R50 transmission system. Bert made a few simplifications and added a super tweeter.

The No.33 and 33C networks are a higher power handling version. The design never went into KEF production as the Concerto was coming to the end of production. The sound was flatter and smoother than the DN12 SP1004. Note there are 2 versions of the DN12 SP1004. The first had a 60 μF and a 2mH inductor in the MF low frequency roll-off, whilst the later had a 30 μF and a 4mH. This gave a higher impedance at the LF/MF crossover. This became important when transistor amplifiers standardised on 8 Ohm output.
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iso
Senior Contributor 200+


Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Thu Feb 04, 2016 1:34 pm    Post subject: Reply with quote

As far as I remember Colin recommended to use 33 aB version for Concerto. You do non need supertweeter section of crossover.

I suppose guyis in the Fallcon can give better advice for this issue that is after all a bit personal opinion too.

Kimmo
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