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KEF 104/2 biamping / bridging question

post #1 of 14
Thread Starter 
I just bought a second pair of KEF 104/2s to use out here in CA. My original ones were not biamp-able, but these are. (At least, they have 4 terminals on the back of each, though I see no indication or labelling that they are Raymond Cooke models. The serial numbers are 5910 A & B.). These are certainly a later version than my originals, as these have the magnetic grille attachments rather than the pegs on my first set.
However, there appears to be no visible / external 'bridge' between the two pairs on the back of each speaker. IIRC, if I want to use these WITHOUT biamping, there should be an external bridge, right?

If that is correct, it may be easier to simply biamp ( which I can do) rather than try to find or jerry-rig bridges.

Sorry if this question reveals my profound ignorance of all matters bi-amp, it's just not something I've ever dealt with before. I searched the forums here and elsewhere, but no luck. TIA for any guidance!
post #2 of 14
Quote:
Originally Posted by miami View Post

I just bought a second pair of KEF 104/2s to use out here in CA. My original ones were not biamp-able, but these are. (At least, they have 4 terminals on the back of each, though I see no indication or labelling that they are Raymond Cooke models. The serial numbers are 5910 A & B.). These are certainly a later version than my originals, as these have the magnetic grille attachments rather than the pegs on my first set.
However, there appears to be no visible / external 'bridge' between the two pairs on the back of each speaker. IIRC, if I want to use these WITHOUT biamping, there should be an external bridge, right?

If that is correct, it may be easier to simply biamp ( which I can do) rather than try to find or jerry-rig bridges.

Sorry if this question reveals my profound ignorance of all matters bi-amp, it's just not something I've ever dealt with before. I searched the forums here and elsewhere, but no luck. TIA for any guidance!

 

I have the same speakers and mine do have the bridge so yours were apparently lost somewhere along the way. Just use a short length of speaker wire and bridge the upper and lower posts. That will work just as well as the factory bridges. I wouldn't bother with bi-amping. You'll get no improvement.

post #3 of 14
Just use some extra speaker wire from one set of terminals to the other. Jumpers are just pretty pieces of metal that do the same thing. Don't waste your time biwiring or biamping. It's BS. Any speaker with a passive crossover will not benefit from biwiring or passive biamping. The only way to truly biamp would be to rip out the current crossovers and get separate amps with DSP. Not worth the time and effort IMO.
post #4 of 14
Thread Starter 
Thanks for the help - Just from my own curiosity, if bi-amping has no benefit, why did KEF set the later models up for it? They were usually not ones for show vs. go. Also, as everyone seems to agree that these always benefit from more power, why wouldn't bi-amping help? (I have 130 wpc, and a bi-amp option on the power.)

Understand, I am definitely NOT challenging the kind answers, just trying to comprehend!
post #5 of 14
Quote:
Originally Posted by miami View Post

Thanks for the help - Just from my own curiosity, if bi-amping has no benefit, why did KEF set the later models up for it? They were usually not ones for show vs. go. Also, as everyone seems to agree that these always benefit from more power, why wouldn't bi-amping help? (I have 130 wpc, and a bi-amp option on the power.)

Understand, I am definitely NOT challenging the kind answers, just trying to comprehend!

 

It helps to sell speakers. If the competition does it you follow along. Sill useful for bi-amping the way flying fool stated. If you bi-amp through the speakers internal crossover you'll get no benefit.

post #6 of 14
In those days it was big to use a tube amp for the mids & tweets and SS for the woofers. Still probably a good thing to do.
post #7 of 14

If you're interested here's a pic of a 104/2 crossover. It'll have to come out if you ever replace the woofer surrounds. It's a PIA compared to other speakers. Those surrounds will need to be replaced sooner or later.

 


Edited by XStanleyX - 7/27/13 at 6:55pm
post #8 of 14
Quote:
Originally Posted by jima4a View Post

In those days it was big to use a tube amp for the mids & tweets and SS for the woofers. Still probably a good thing to do.
No it's not. It won't do anything at all. All you have to do is take a gander at the pic of the crossover. It's all interconnected. How does the power and signal get routed separately if its all interconnected? Also, if you look at the specs of most all receivers in biamp mode, there actually is no more power to be had because a receiver has limited power output. In order to get more power in one place you have to rob it from another.

Test after test has shown there is zero benefit to passive biamping. It's nothing more than a gimmick.
post #9 of 14
Thread Starter 
Thanks for the explanation, much appreciated!

One last question -- I assume that, as I'm using plain 14 gauge to connect, I may as well run the one wire through both terminals (with bare patch for each terminal), rather than have a separate piece as a jumper ... Right?

Logically, it seems like that would be the same, but I have learned that, like taxes, in matters electronic, logic is an uncertain guide.
Edited by miami - 7/28/13 at 3:59pm
post #10 of 14

Like the photo but bare wire at the ends work just as well. This photo is the back side of my bookshelves. They come from the factory using braided speaker wire.

 

post #11 of 14
Thread Starter 
Thanks for the quick reply (it's hooked up but I wanna get the OK here before music happens ... )

I understand it, I just need to know is there any problem or difference between
a) using a separate piece of wire as the jumper vs.
b) just running the speaker wire through both terminals instead.
post #12 of 14
Quote:
Originally Posted by miami View Post

Thanks for the quick reply (it's hooked up but I wanna get the OK here before music happens ... )

I understand it, I just need to know is there any problem or difference between
a) using a separate piece of wire as the jumper vs.
b) just running the speaker wire through both terminals instead.

 

I'd personally use a separate piece of wire although either way will work.

post #13 of 14
Thread Starter 
OK, thanks for the help ...

First song on a new-to-me pair of 20-year-old speakers, after 3 weeks with no music but a clock radio ... Critical listening can wait, I wanna rattle the sashwork.

"Burning Down the House" will do fine ...

Aaaaahhhhhh -- Thanks again!
post #14 of 14

Enjoy, they're some great speakers. smile.gif

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