Join Date: May 2004
Location: Melbourne, Australia
SE UL OT - primary wired in reverse
i want to design a SE amp with different tube types in the output stage.
because i'm a 17 year old high school kid, money's not something i'm going to claim to have a lot of... so custom tranny winds is out of the quesion for me, unless for a really good price... so what i was thinking, was in a SE UL tranny, is it alright to wire the primary in reverse, so the 40% UL tap becomes a 60% tap??? or is there a certain way the tranny is wound and so it is best to use it this way? will this change the reflected impedance (in a multi-tap secondary this is) becuase it changes the magnetic orientation, or something, and therefore will mean say, in a tranny with a 16,8,4 ohm taps, we still get 16 ohm as the value to use on 16 ohm tap for correct reflected imp, but the 8 and 4 ohm taps are now different????
i wanted to know this, because for example, in a tranny with a 5k primary, using the 40% tap will only be a 800ohm primary, which is pretty much unusable... well, ok, it's useable, especially with a number of tubes in parallel, but it's not practical for what i want... and anyway, you don't want to go paralleling a lot of tubes in a SE amp anyway.. it's just false economy.
On the other hand though, if put in reverse, then the 40% tap becaome 60%, and this gives a 1800ohm primary, which is useable.
thanks, any help apreciated.