KEF Subwoofer AV1 and KEF Activator. Need specifications

It's self amplified. Feed it a subwoofer Line Level.

Just for clarity, I need to explain what the four inputs are on the KEF subwoofer. There is a left and right RCA input which is the input signal to the subwoofer and there is a left and right RCA output which is the High Pass output from the subwoofer.

On the back of the Yamaha receiver, you said you have a subwoofer output. This output is most likely the mono subwoofer part of the home theater system and can be used if you like. The left right signal input into the KEF is summed into mono so if you only connect one channel you will basically reduce the signal level by 1/2 (-3dB) but it will work fine.

Alternatively, if your Yamaha receiver has monitor out and monitor in, you can run the monitor output signals to the subwoofer and you can then run the high pass outputs from the subwoofer back to the monitor in. This will give you the subwoofer and provide a smoother signal matching with your audio system.

It is not always easy to connect the subwoofer up to an integrated receiver/home cinema system using the high pass channels of the subwoofer as you don't always have access to the analog output and input of the front channels. In this case, just use the Subwoofer output or just the monitor out only.

I hope this solution is helpful.

Manual posted at the following link:
http://lug.demon.co.uk/kef/psw2150_user_manual.pdf

You have a bad set of Audio output IC's for the sub. There is two of them. TDA7293 REPLACE BOTH!!!
There is 4 on one side of board,and 2 on other "also 1 small one" The the two are for the sub,the other 4 are for the main speakers/surround. They sell on Ebay for $6-10 each or a kit of all 6 for $25.

You might have a bunch of bees living inside the sub?
You have a bad set of Audio output IC's for the sub. There is two of them. TDA7293 REPLACE BOTH!!!
There is 4 on one side of board,and 2 on other "also 1 small one" The the two are for the sub,the other 4 are for the main speakers/surround. They sell on Ebay for $6-10 each or a kit of all 6 for $25.

You have a bad set of Audio output IC's for the sub. There is two of them. TDA7293 REPLACE BOTH!!!
There is 4 on one side of board,and 2 on other "also 1 small one" The the two are for the sub,the other 4 are for the main speakers/surround. They sell on Ebay for $6-10 each or a kit of all 6 for $25.

You have a bad set of Audio output IC's for the sub. There is two of them. TDA7293 REPLACE BOTH!!!
There is 4 on one side of board,and 2 on other "also 1 small one" The the two are for the sub,the other 4 are for the main speakers/surround. They sell on Ebay for $6-10 each or a kit of all 6 for $25.

I have a spare KIT 100 subwoofer unit. contact [email protected] (SW London)

You have a bad set of Audio output IC's for the sub. There is two of them. TDA7293 REPLACE BOTH!!!
There is 4 on one side of board,and 2 on other "also 1 small one" The the two are for the sub,the other 4 are for the main speakers/surround. They sell on Ebay for $6-10 each or a kit of all 6 for $25.

I see your email address, will do, Axel