Amps that pair well with the Vertex Ultraphonix HRM

fills a frequency gapFills in a frequency range the other side doesn't cover, instead of piling more onto what's already there. (bright → smooth)

Revv Generator 100R MkIII 3-Channel Head leans smooth right where the bright tone needs it

Comes later in the signal chain

gain stackingStacks two gain stages for more saturation than either produces alone. (mid-forward → high gain)

Friedman Dirty Shirley layers high gain onto an already mid-forward signal

Comes later in the signal chain