Power tube question

[SGFanatic]

I recently purchased (new) an Egnater Vengeance. It's a Marshall-y type overdrive, geared towards metal. It has 4 power tubes with the options of running different power tubes in pairs. It came with 6l6's, but I've been using kt-88 and kt-66. I recently switched out the kt-88 for el-34. I noticed a volume drop (?) I like the sound, but the amp seems quieter. Is there an actual volume difference from the tube wattage being lower, or am I just hearing the low end loss when I removed the kt-88's. I also swapped the pi tube from a 12ax7 to a12at7...wondering if that would affect it.

 

[Edgecrusher]

Re: Power tube question

The PI tube would have more to do with it. Basically the power tubes are seeing less current so it doesnt seem as loud. The only way swapping power tubes from one another would make it sound louder or quieter is if the bias was off but the Egnater is a self biasing design so thats not it in this case. I'm willing to bet if you pop at 12ax7 back in your PI you will get the volume back.

 

[PFDarkside]

Re: Power tube question

KT-88s are the bad boy on the block as far as guitar/bass amps are concerned. However, I agree with Edgecrusher, the lower gain PI is driving the power tubes less hars than the 12ax7.

Sounds like a fun amp to experiment with different tube types.

 

[Edgecrusher]

Re: Power tube question

KT-88s are the bad boy on the block as far as guitar/bass amps are concerned.

Its interesting though... VERY Few amps really use KT88's to their real potential. You can easily get 100 watts out of a pair of them with no sweat. Yet most amps that run them run a quad for 100 watts. The old Marshall Majors used 4 of them to get 200 watts. I wont even get started on how most modern tubes labeled as KT88 are not really KT88's or even meet their specs (many are rebottled 6550's)

 

[SGFanatic]

Re: Power tube question

Kewl...thanks for the response. I'll put that 12ax7 back in and give those el-34's another day in court. I do enjoy the kt-88 low end, but the el-34 has a great crunch to it. The amp is fun! It actually can run 6v6's too. I've never played a 6v6 amp before.