• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Noob Power transformer question

Why do you assume the OP even needs “30 to 35W”?

Speaking from my own POV, I haven’t built and amp larger that about 10W ever and that range of power is more than sufficient for my needs. Admittedly all of my candidate speakers to listen to are 8ohms and north of 96dB@1W@1m, so I don’t need much in terms of power. I have some HY69s that I should be able to squeeze close to 16W or so out of in PP (mostly class A1) but that is an aspirational project and I don’t really need that much grunt in any case.

My 2 cents, ymmv etc
 
1/2 of a class A cookie gets me 95dB at my listening position. Admittedly only 20dB of headroom over an (average) 75dB SPL. 8 class A cookies gets me 107dB, 32dB of headroom over 75dB average SPL. Which is currently where I’m at with my daily driver and a couple of other amps. I have no need for 30/32 cookies.

But that’s just me.

My 2 cents, ymmv etc