I basically disagree with everything Mcfarland said. Tube amps don't sound more powerful for the same wattage rating as SS amps because tubes sound "warmer." Tube amps sound louder than an equivalent rated SS amp because tubes clip different than SS devices. David Manley postulated that tubes also sound louder due to their high voltage power supplies vice the low voltage power supplies used in SS amps (power tubes typically have somewhere between 300v-500v+ on the plates whereas around 50v is common for the power supply rails feeding output transistors).
Also, I find it interesting that McFarland's output tubes outlast his small signal tubes. As a general rule, high quality small signal tubes can last up to 10,000 hours and it should be common to get at least 5,000 from them. Output tubes usually cry uncle after around 3000 hours. The bottom line here is that your small signal tubes should always outlast your output tubes-not the other way around. Either McFarland has some wierd amp that is eating his small signal tubes or he is replacing them before they really need to be replaced.
Back to your basic question about why you have to turn up the volume higher on the tube amp than the SS amp to achieve the same level-it all has to do with the gain/sensitivity of the two amps. The output section of your tube amp probably requires more voltage from the preamp section to achieve full output than your SS amp which is why you notice you have to turn the volume up higher on the tube amp. It doesn't mean a damn thing unless you think you can never turn up your new tube amp enough to get the volume you want.
Also, I find it interesting that McFarland's output tubes outlast his small signal tubes. As a general rule, high quality small signal tubes can last up to 10,000 hours and it should be common to get at least 5,000 from them. Output tubes usually cry uncle after around 3000 hours. The bottom line here is that your small signal tubes should always outlast your output tubes-not the other way around. Either McFarland has some wierd amp that is eating his small signal tubes or he is replacing them before they really need to be replaced.
Back to your basic question about why you have to turn up the volume higher on the tube amp than the SS amp to achieve the same level-it all has to do with the gain/sensitivity of the two amps. The output section of your tube amp probably requires more voltage from the preamp section to achieve full output than your SS amp which is why you notice you have to turn the volume up higher on the tube amp. It doesn't mean a damn thing unless you think you can never turn up your new tube amp enough to get the volume you want.