Power load IR causing power tubes to fail and now not working

Hi, I’m having an issue with my power load IR that is less than 4 months old.

For context, I have three amps that I switch between when I play through it - none of them are crazy high power. A deluxe reverb, a 20w Marshall studio plexi, and a 1w Marshall dsl combo.

I connect the amp speaker out to the speaker in on the load box, then connect the IR out to a Scarlette audio interface then into garage band.

I’m using the headphone out on the audio interface and I have the IR level turned up the whole way… this seemed to be the only way to get the IR to sound “real” at a manageable volume through headphones.

Last month after about 4 months of daily use connected to a deluxe reverb the deluxe reverb had a power tube go out. I thought the issue was related to it being a relatively new amp and having a bum power tube from the factory. The deluxe reverb was played almost exclusively through this setup.

Fast forward to last night. I powered everything on and was playing through the 20w plexi. As soon as I started playing it sounded like something was wrong. The sound was thin and weak and not sustaining at all. I thought maybe the audio interface had crapped out on me so I tried playing audio through my computer to test the audio interface headphone amp and it sounded fine so I think I ruled out the audio interface as the issue. I also tried switching channels on the plexi and got virtually no sound through the second channel.

I then switched to a different amp and had the same issue so I think I ruled out both amps - however I do think one of the power tubes on the Marshall might be on the fritz. I then tried switching from the 1/4” out to the XLR out and got even less volume.

All signs are pointing to something being wrong with the power load ir.

For reference the deluxe reverb and the plexi are both very new (owned for less than 6 months) and the 1w Marshall has been around for a while.

The power load Ir was purchased in July of this year brand new.

Any ideas? Is there a warranty on the power load? I hate to point the finger at it but it seems like it’s causing the power tubes on my amps to blow up prematurely and it is now having issues itself with output power.

I’ve been diligent about making sure the impedance is matched to the amp every time I play. I don’t play for more than a couple of hours usually and use it daily…. Probably about 10-12 hours per week total. I do have it plugged into a power strip. I turn that on and off and leave the power supply plugged into the power load ir.

I think that’s about all the details I have.

Anyone else experience anything similar? Is there a warranty available since this is so new? I can’t imagine going through power tubes this frequently is the norm with a load box.

I will try playing both amps through the speaker once my family is awake… that’s the reason I got this; so I could play my tube amps silently.

Thinking that i missed one step in my diagnostics: i added a new pedal to my board yesterday and in the process had to switch from dc connector on my power supply to 9v battery. Seems that pedal with the battery was the issue.

Still I would like to get others perspective on the power load ir and increased wear on power tubes, general thoughts on the IR level knob (do you always have this cranked), and how you are powering on/off the device.

Hi @Mscalamogna and welcome to the forum!

Thanks for coming back to let us know the main culprit was a pedal.

It’s quite a common kind of comment, especially in guitar internet, that loads somehow punish tubes. Electronically, your amp cannot really tell the difference between a speaker and a reactive load. What tends to happen is that because the volume is tamed, as players we play differently; we might max out the master volume and we certainly attack harder with the pick. This can increase wear on the tubes.