[sdiy] heater voltage: how much is too much?

[anthony]

For the heaters in my 50L6 amp I used a 50C5 in series with the 50L6GT and 
the 12SQ7GT to get a more proper heater voltage of around 112 VAC. However 
my wall voltage is 120 VAC. I was wondering if this difference would be too 
much. My first thought was that it shouldn't be problematic at all and the 
extra 8 volts is distributed over all of the tubes and since the tubes are 
designed for slow turn-on series connections, they should be able to handle. 
Or should I try to squeeze something like a 8Ohm, 10W resistor in series 
with them? I thought using just the heater of the 50C5 was a nifty if 
hackish trick to get the heater voltage right though. Especially since I do 
not forsee wanting to use it for an amp anytime soon since most of the 
accounts that I have read concerning amps made from 50C5's is that they just 
don't make the magic that a 50L6 can. (Although I have read similar things 
about 6AQ5A's, but that when connected in "triode-mode" they sound great...)

aa