Hagstrom 620 power supply quandry

[phydauex]

Hey All,

Going through an older Hagstrom 620 amp and noticed something kind of odd, namely the screen supply is taken from the first filter node and the OT centertap on the2nd one. Is there any reason not to switch them around? The amp has solid state rectifiers and no standby, so when turned on, the screens are hit with voltage first then the plates. Voltages are moderate in this circuit (about 268v on the screens and 240v on the plates). I'm trying to clean it up and get it back to stock form, but don't like the idea of the screen coming first in the supply chain. Any thoughts or reasons why I should leave it be. BTW, I've got it wired up to the 130 volt PT tap, so voltages are a little lower, I'll only hook up the 110 tap if I get the owner to use a voltage dropper on it or the 240 tap with a 240 v step up. It has a weird voltage selector that's broken, so it has to be hard wired to one of the taps.

[Enzo]

One reason to leave it might be that it has worked this way for decades. We may not know what design thinking went into that decision, but we might allow it to remain without good reason other than "seems wrong".

If it works on 130v, why wire it to 110 and expect someone to do something to accommodate that? Why not leave it on 130?

[phydauex]

Well, 130v seems to be the best compromise for here in the states. I was planning on leaving it there for safety. Your right Enzo about the original designers intent, I would like to know how that decision was arrived at. I just haven't seen that configuration before and wasn't sure if it would make sense to change it for longevity. But again your right about running for many years that way. Stocks of old EL86's seems plentiful and inexpensive so..... I'll quit over thinking stuff.