New output transformer

[ampman66]

Hey so I am restoring this old custom amp and the output transformer needs to be replaced. it is a 5 wire ultra linear with the tap. But I can only find one and it is rated at 35 watts. The old is 40. just do i lower plate voltage? how would I do this?

[Zozobra]

What primary impedance and UL tap do you need? May be worth checking out the edcor CXPP stuff if you haven't already as they have a 40% UL tap. All their stuff is built to order so it may be worth shooting them an email if you need something slightly different.

What amp is us btw?

[Racing]

Yep.
UL taps are normally at either 25% or 40%. Agreed.
What most fail to realize though is that the UL principle is mainly one of AC. Ie; signal,in this case. In other words the UL principle works just as much if the UL taps are headed for the OT AFTER the main B+ node.

IOW it might be a good idea to question what amp and what usage.?

[ajaxlepinski]

Ampman66 - Welcome to the fold brother - this is the best guitar/amp forum on the interwebznet!!!

Zozobra and Racing are the most knowledgeable amp people you will ever come across... I do not exaggerate.

Everytime I read one of their threads, I wind up spending an hour googling things so I can understand what they are talking about!
Here's what I learned today; the etymology behind the phrase "B+ Voltage": https://en.wikipedia.org/wiki/Battery_(vacuum_tube)
Surprisingly, I didn't have to look up UL transformers because, my Sunn Solaus has one!

[Zozobra]

I know enough to be dangerous with a soldering iron