30w setting louder than 50w on my ad50 cs?

[kars0747]

How come the 30 watt setting is noticably louder than my 50 watt setting on my ad50 custom shop? I turn it up about 50% and the 50 watt to about 60-65% on the master and I have to keep the gain a bit lower on the 30 watt setting as well. I am going back and forth between the two and my third option of using yellow jackets which give me about 15-20 watt. With the yellow jackets I turn the bass up a bit and down with the precense a bit. On the other two I turn the bass down a bit and a bit up with the presence. It seems the yellow jackets (el84) play almost as loud as the 50 watt setting. I can set it to about 75% and the 50 watt to 60-65% on the master. For now I like the 50 watt setting the most, which I have hardly used since I bought the amp. Funny how things change

[Jondog]

It's complex, but to start 30 watts isn't theoretically that much louder than 50 watts, barely 3 dB. Also, it's the same tubes, transformers, just the bias method is changed, which changes the current and therefore the power wattage. With the AD50 there is a post phase inverter master volume which will directly affect the ac signal hitting the tube grids depending where it is set. That signal will affect how the power tubes perform differently in each bias method. To do a fair comparison I think the master would have to be at maximum.

[kars0747]

You mean 50 watt is 3db louder. Hmm, You are probably right about full volume on 100%. However, this is not an option. The 30 watt distorts more as well. When I set the two settings at a seemingly equal volume, I have to turn down the 30 watt setting´s gain to make the distortion/gain seem equal as well

[Jondog]

You mean 50 watt is 3db louder. Hmm, You are probably right about full volume on 100%. However, this is not an option. The 30 watt distorts more as well. When I set the two settings at a seemingly equal volume, I have to turn down the 30 watt setting´s gain to make the distortion/gain seem equal as well

Yes, I mean 50 louder. The power tubes will distort easier in cathode bias.

[kars0747]

What is it that makes them distort easier in cathode bias (30watt)? So when it distorts later in fixed bias mode (50w) and in general seem way quieter (less output) than the 30w setting, that means I get more power amp distortion because I can turn up the master more?

[Jondog]

Bias changes constantly in cathode bias when it receives signal, so it gets "hotter" as it receives signal. Fixed bias is pre-determined how hot or cold the signal can be that passes through the tube.