removing two power valves

[mkstylee]

Hi all and happy Christmas.
I seem to remember someone mentioning this a while ago but could be wrong,If i remove two power tubes does this alter the OHM's as well.I have been told that if i remove two tubes while it is in 8ohm mode i will now have to run in 4ohms.I there any truth in this please?

[sikter]

I don't think it would be so simple.
I would never even try to do something like that.

[surfnorthwest]

What are you trying to achieve by pulling two of the tubes? I would suggest that if it is volume there are better and safer way to achieve that then pulling tubes. A 100 watt amp going down to 50 watts really only is going to be about a 3-5 dB drop in volume.

To your question though, when 2 tubes are pulled from a 4 tube amp the output tranny is looking for twice the original impedance. The "8 Ohm" indicated switch position actually becomes 16 ohms. The "16 Ohm" indicated switch position becomes 32 ohms

[mkstylee]

Thank you surf.I was thinking about volume and struggle to use attenuators as i don't like what happens to my tone when using one,so after I read your views I ended buying some Tube amp doctor 'ToneBones' and It worked a treat.
Cheers