I’ve attached a video exemplifying the issue.
When the unit is initially turned on it works with what seems to be minimal/nominal white noise but as it heats up there’s an exponential increase in hum/buzz/background noise. The video is with the guitar plugged in directly going to the DAW via the IR with an XLR cable. Ground switch position makes no difference, only when I physically touch it does the noise go away…?
@Eoghan07 welcome to the forum!
OK, thanks for posting this. I wonder if there is a grounding issue somewhere. What are the connections to the unit? If you use XLR out does it still happen?
No connections apart from power, IR’s XLR out to DAW, and guitar going in direct.
Usually a ground loop noise would be present all the time. Not just after warmup. That might be a tube or supply issue.
Where are you located? Curious to know what your wall voltage is.
Dave
I’m in South Dakota - metering at about 121VAC from the wall this morning.
I’ve swapped all tubes with alternative healthy tubes but the noise persists.
Bueller, Bueller?
Mongo only pawn in game of life…
Hi @Eoghan07
It’s the kind of thing that might be best investigated at the shop. You have a very simple setup and the video demos. the issue well. If they plug it in at the shop and don’t see this, the risk is the the cost of a wasted repair. So if you are sure it’s not something local and external to the unit we could consider an RMA? Please see here for the next steps How can I send my product to Fryette for a repair (RMA Request)?
I’ve swapped every tube and that’s the extent of what I know to test presently - the IR seems to have a generally high noise floor where a white noise/hiss is omnipresent but increases significantly as the unit heats up. Is there a known issue with some of the IR modules?
Yes, I think you have done all you can do there. No known issues with 1000s of units sold. But defects can happen when producing at scale. The only way forward is the RMA I think.
To whom it may concern reading this in the future, should it help save time and headache -
I did several other tests to isolate the issue including cable swaps, tube swaps, power supply swaps, etc. and after those tests specific to the unit itself I ran the GPDI/IR’s Speaker Out to a Power Load IR Amp In then ran the PLIR’s Balanced IR Out to the DAW instead of using the GPDI’s IR…same issue.
I then ran an original, non-IR model GPDI’s Speaker Out the PLIR’s Amp In to the DAW and curiously enough…same issue. Huh? But here’s where it clarified: the GPDI/IR was still on but not hooked up to anything at all aside from its power cable, yet it was adding noise to the audio purely by being connected to shared power - once I turned the GPDI/IR off the issue went away from the system.
So, by process of elimination, unless there’s something further I’m missing, it would appear the problem is indeed an internal issue of some sort with the GPDI/IR.
Will update further after the unit is inspected by Fryette.