OK for US and Canadian owners of the Lightspeed Attenuator, I just did a search for definate linear wall warts that are all suitable.
First three are regulated, last two are unregulated, it does not really matter, so long as they are linear 9-12v with a 2.1mm plug that is center positive which they all are.
Or you can get the Teradac http://www.ab-system.hk/index.php?route=product/product&path=73&product_id=64 Cheers George
110-115v linear wall warts from Jameco, payment by COD, Paypal or Credit Card
All are suitable.
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_220898_-1
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_1953639_-1
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_162996_-1
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_2192712_-1
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_2197484_-1