Tweet
Im expierencing a fair amount of hiss in my preamp that wasnt there just yesterday it seems. I dont have a schematic, so just try to imagine this. Its basically a Fender clone with an extra stage. Its v1a, coupling cap and volume, v1b, tone controls and master volume, v2a, coupling cap into phase inverter. From my tests, its V1 thats giving me the problem. The hiss was gone when i pulled the PI tube and V2, but it came back when i pulled V1 so it must be somewhere between v1 and v2, right? Tried different tubes, but no luck. Tried a couple grounding schemes and extra filtering, no luck. Tried a different tone stack, no luck. Tried different pots, no luck. The first volume control doesnt increase the hiss when turned up, so the hiss must be after that. The master volume however does affect the hiss a little. Not terribly, but its noticeable. So it must be somewhere after the volume pot and before the master volume, in the area of V1B right? My plate resistors are new from Weber so I wouldnt suspect those, but I should check anyway. I have another post on this site about a quick master volume, and someone responded that I might have too much signal going through. It doesnt seem like such a simple, fairly low gain circuit would cause that much hiss. What in the Lords name is going on here?