Low Power !?!

[grtamp]

Hi , I finished the amp for my friend ( 100w Hrm with mercury trafo) but the max power I can take is about 86W RMS and I seem low for a 100W amp.

[massygt6]

I guess that you're in the ballpark, assuming that a 100w CONSTANT output power is a value that is so much near to a 100% dissipation.
Judge the sound, not only the "cold" numbers...

[67plexi]

vintage spec. transformers ? The black face fender twin is 85 watts.

[Bob-I]

Hi , I finished the amp for my friend ( 100w Hrm with mercury trafo) but the max power I can take is about 86W RMS and I seem low for a 100W amp.

Sounds about right to me. That extra 14% will give about 1DB so it's not really all that critical.

[ToneMerc]

vintage spec. transformers ? The black face fender twin is 85 watts.

+1

[FUCHSAUDIO]

What's the power line look like while you test ? Oft forgotten. I get major sag on high power amps with the isolation transformer and variac on my bench. Make sure the power supply coming in stays at 120 V.

That being said 85 clean non clipped watts is not off the mark for 4 x 6L6 with average Fender iron.

[grtamp]

Yes , I use a Variac on my test bench , at 225V ( I'm in europe)
The PT in question is a Mercury FBFTP/MT.