Sheppard Floorstanding speakers
- Thread starter bolly
- Start date
Cropwalker
New Member
Looks like I was, supprised they did not go for more in the end! I was not sure if they were exactly what I was looking for so I was cautious.
Cheers Chris
Cheers Chris
ToTo Man
NEVER ENOUGH TOTO!
mech986 said:Hi,
Here's some information on the Concerto from a KEF appreciation site (formerly Allan's Online):
http://www.hifiloudspeakers.info/Anatomy/SpeakerSystems/Concerto/Concerto.html
Also, Here's the link for the schematic of the Concerto Crossover:
http://www.hifiloudspeakers.info/Anatomy/SpeakerSystems/Concerto/ConcertoCrossover.html
The tweeters should be disconnected from the crossover and checked to see that they still have good output. Connect a low power amplifier with bass and mid controls turned down. Find some interstation hiss on an FM tuner and use that as a signal source. You should be able to get good high frequency output with a nudge of the amplifier volume control. Do not put a lot of HF input into any tweeter directly as you can burn them out. Just test to where they get reasonably loud. If the tweeters pass this test, then they probably are fine.
Then you should go ahead and recap the two 5 uf caps in the 18db/octave high pass filter for the T27. Alternatively, you might conisder purchasing new crossovers built by Falcon Acoustics. They have been providing commercial and DIY crossovers for three decades and have some purpose built for the Concerto.
See http://www.falcon-acoustics.co.uk/pl28p4.htm and Networks 5, 6C, 33C, or no. 53. Network 53 is the best one of the bunch and has the uprated acoustic butterworth section that supposedly makes the T27 sound the best. It is a bit more expensive but you would then get all new inductors and capacitors with a pedigree design (Malcom Jones, M.D. of Falcon, worked for KEF designing the crossovers up through the 104aB series). I don't think these use "audiophile" type capacitors but you might be able to get them to make up some using polypropylene caps.
Hope this helps.
Regards,
Bart
Thanks for that info Bart.
Does the butterworth section make the treble louder or just smoother? I'm tempted to go the full show, but it is quite pricey. Perhaps the 6c would be a more economical choice, but then again perhaps I'd be better to start by recapping the two 5uf myself first and see what improvement that makes.You wouldn't happen to know which polarity the midrange B110 driver is supposed to be wired up in the Concerto, would you? (I bought the speakers dismanteled and there were no instructions how to wire them up!). I've tried it both ways and normal polarity seems to be ever so slightly louder.
Hi K-L,
According to KEF and Falcon, the Acoustic Butterworth section makes the filter and the driver function together to form a smoother rolloff in the crossover region and there is a bit of adjustment there to provide a smoother overall response for the T27. According to Falcon, it is the best section for a T27, supposedly better than the BBC LS3/5a crossover T27 section.
Just saw this:
http://cgi.ebay.com/FALCON-CROSSOVE...ryZ50597QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
which would be helpful for us here or if you were in Canada, might be worth sending back to the UK to you since you wouldn't have VAT to add to your Falcon Purchase. I suspect you could contact Falcon to see how to convert to the 33C (probably just not use the supertweeter section or maybe a supertweeter if you are looking for more treble output.)
The price is certainly right and shipping really wouldn't be much for them as I suspect they're not much more than a couple of kilo's total.
However, you don't know how old these caps are either and they are not audiophile versions. So, your choice.
Regarding the B110 polarity, the schematic I posted shows the B110 wired reverse polarity, common with 12 db/octave filters to make the crossover region with the tweeter work properly. Try it that way for a while and see whether the imaging seems stable and centered. With a recording with a solid center image (like vocal) it should seem very sharp. I suspect with it wired incorrectly, the image will seem very wide and hazy, if that makes sense.
Let us know.
Regards,
Bart
According to KEF and Falcon, the Acoustic Butterworth section makes the filter and the driver function together to form a smoother rolloff in the crossover region and there is a bit of adjustment there to provide a smoother overall response for the T27. According to Falcon, it is the best section for a T27, supposedly better than the BBC LS3/5a crossover T27 section.
Just saw this:
http://cgi.ebay.com/FALCON-CROSSOVE...ryZ50597QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
which would be helpful for us here or if you were in Canada, might be worth sending back to the UK to you since you wouldn't have VAT to add to your Falcon Purchase. I suspect you could contact Falcon to see how to convert to the 33C (probably just not use the supertweeter section or maybe a supertweeter if you are looking for more treble output.)
The price is certainly right and shipping really wouldn't be much for them as I suspect they're not much more than a couple of kilo's total.
However, you don't know how old these caps are either and they are not audiophile versions. So, your choice.
Regarding the B110 polarity, the schematic I posted shows the B110 wired reverse polarity, common with 12 db/octave filters to make the crossover region with the tweeter work properly. Try it that way for a while and see whether the imaging seems stable and centered. With a recording with a solid center image (like vocal) it should seem very sharp. I suspect with it wired incorrectly, the image will seem very wide and hazy, if that makes sense.
Let us know.
Regards,
Bart