Truth. Even if you don't have spares, sometimes swapping the positions of the preamp tubes can clear something up (keep them in the same family, pretty sure that's a non-issue with the HRD). If it does so, put some spares of that sort on your shopping list. Hell, I've made problems go away by simply pulling and re-seating a tube, though they exhibited different symptoms than what's under discussion.rfurtkamp wrote:If a problem comes along, swap tubes!
I just pulled a schematic for a HRD and I notice they have a jack switched (normalled) effects loop. It *might* be a bit early for THAT to give you grief, but I have observed it in older amps where those jacks go unused - the switch contacts (which complete the circuit from preamp to power amp sections) can oxidize or collect a film (especially if you smoke or gig in a smoked place), giving intermittent problems that can be tied to vibration and a sense of power loss, etc. Sometimes some contact cleaner & exercise of those jacks is enough to correct that issue, but if the jack is open frame dipping a small strip of paper into isopropyl and pulling that through the closed switch contacts will fix it quick.
Don't mind me, I'm just firing guns into the air.





