PP Ultralinear VS PP Pentode

After reading the Carver threads , I became interested in what Mr. Carver was doing for a circuit
different from the masses . Unfortunately my expertise does not allow me to quite understand
his explanation for his circuit preference  .
So , I am asking for a description of the difference , in the final sound , of PP pentode as compared to PP ultralinear .
My present amp is PP Ultralinear , so I am familiar with that type of sound signature .

Thank You .
UltraLinear allows the output section to have the linearity of a triode with about 90% of the power of PP pentode. So you wind up making a lower distortion amplifier with UltraLinear.

PP pentode tends to be a bit more aggressive especially if you are pushing it for power.
Ultralinear was invented by Daniel Kerhoes and David Hafler back in the 50's as a way of getting lower distortion compared to PP pentode. Most famously utilized in the Stereo 70 amp (world's best selling tube amp!).
Excellent answers !!! Thank you both very much .