OPT question

[Andrewbee]

Greetings one and all!

I am building a small PP power amp based on the PP circuit of Nobu Shishido.

My question is, is an OPT sans UL windings better for a triode output stage? IOW lets say I have too OPT's the only difference being one has UL windings, would the one without the UL windings have any advantage over the one without?

Thanks

[hemgjord]

No (provided that it is a competently made opt)


/Olof

[pieter t]

Andrew,

It depends on how the UL connection is made.
Mostly it is merely a tap on the primary winding (two taps for the PP OPT).
In that case you can use the OPT for triodes without loss of quality.
A more sophisticated OPT will have separate UL windings (like McIntosh for instance).
Not using these will have a negative effect (coupling; leakage inductance).

Pieter

[Andrewbee]

Hi all,

the OPT's I have are original Dynaco Z565's so I should be okay then.
I did not know the UL taps were really simply taps. I thought they were derived from another separate winding, something akin to a cathode feedback winding.

Thanks