Hello there Vinh Tho,
Does your au-alpha907L Extra look like the one on the picture below?
(
www.sansui.us picture)
There's a picture of the same amp on Isao's site where you can actually see the serial number. The 3rd number is a 9 so this means it's a 1989 unit.
My AU-X1111 Mos V was made in 1992. It's interesting to see they didn't give these units the same feet.
I'm curious to learn more about the philosophy behind the use of these feet on some of the Sansui amps. I suspect they might provide a better envirenment to help prevent magnetic distortion caused by steel although this is just a raw raw guess, and it would still not explain the 2 variants of feet. (the lighter yellow feet on my amp and the heavier full copper variant on yours)
I remember seeing on Mr. Ichiro Ohshima's website (Sansui's last product manager, who was in charge for the hi-end lines of units, from AU-X111 Mos V till AU-111 G) a photo of the AU-X1111 Mos V fitted with the brass feet. This is when I took notice of the different feet installed on my AU-X1111 and began to wonder which ones were the original ones fitted on the brand new AU-X1111 Mos V's?
(Mr. Ichiro Ohshima's website:
http://www.aqua-audiolab.com/model/custommodel11.html
also note the older transformer used on that unit)
I later discovered another AU-X1111 Mos V and this time on Isao's site, pictured with the full brass feet. This however, could simply be related to the fact that these are photo's of the very same unit.
Engineering philosophies aside, I'm curious if these Sansu full brass are still available as I'm interested to actually find them.
You're correct on the yellow colour of the feet of my AU-X1111 Mos V.
I didn't expect your amp's feet would be more then twice the weight of my amp's feet. This is indeed unbelievable, as the feet on my amp are already of exceptional construction quality.
(and all this talk about feet
)