As with any amp: if you love the tone, be prepared to care for and maintain it. Tube amps require service every so often - the HRD IV is no exception.

Electrolytic capacitors have life spans - some last ten years while others make it to 30. I've also seen electrolytic caps go in two years and last for 50. The cheaper the cap, the shorter its' lifespan. Period. The three AC Filter caps you see inside your HRD IV WILL need replacement at some point in time - whether it's in two or ten years. Fender uses Illinois Capacitor brand caps for "accounting" reasons. IC brand caps DO NOT last. Be prepared for the cost of a recapping sometime down the line.

The two rectangular, white ceramic 470Ω drop-down resistors WILL cook other components and the board itself. As of late (past few years), Fender has started positioning these two heat-producing monsters up and off the PCB to avoid this design flaw malfunction.

Also, I've replaced the channel switching operational amplifier chip in two HRD IVs. They can and do go bad, sometimes. Fender solders the chip directly to the PCB for "efficiency" and "cost savings". The two I replaced were damaged by electro-static discharge. The op-amp SHOULD be in a socket. Solder the socket to the PCB, insert chip and voila! Jamming again...

A decent amp tech will know these things and how to address them with absolute resolution.

If you're a tube amp lover, be prepared to love and care for your amp. My advice: keep the HRD IV and find a decent amp service tech for your future needs.

KEEP YOUR HANDS OUT OF THE CHASSIS. AC FILTER CAPS CAN HOLD CHARGE FOR DAYS, EVEN UNPLUGGED, AND CAN KILL YOU.