- Intermittent complete loss of audio while playing
- Sudden return of full volume after the dropout
- Occasional electrical pops and crackling
- Behaviour is consistent across different amps and sources
- No distortion or gradual fade — the signal cuts out cleanly
The unit is less than a year old and I love it, so really want it fixed.
I’m tempted to replace the 12AX7 power tube, but worried this may nullify the warranty.
Could someone advise please?
Best regards,
John
Hi @Lord_Clifton and welcome to the forum!
Replacing tubes does not void the warrenty.
Q: Do you still get intermittent sounds in BYPASS or only in OPERATE? – If you get in both bodes then it it likely a cabling issuing. If only in OPERATE then it is likely an PS-2 issue.
Before buy new tubes I recommend following these troubleshooting steps.
- Check input cable.
- Check volume controls.
- Make sure the amplifier volume and/or gain controls are turned up.
- Unplug the FX loop, check for sound.
- Connect a jumper cable from FX send directly to FX return; check for sound.
- Connect a jumper cable from Line Out directly to Line In; check for sound.
- PLEASE NOTE: When you have remove the feet to install a rack mount kit, DO NOT REINSTALL JUST THE FEET FIXING SCREWS. This will damage the unit internally and will require factory service. See Rack Kit instructions for details
- Check speaker cable to see if it is disconnected or shorted.
- Make sure that the impedance selector is fully engaged in its detent.
- Check the standby switch.
- Check for a blown speaker.
- Check the mains fuse, and replace if necessary. If it blows again, refer to qualified service personnel.
Please report back and we take if from there!
Thanks for the swift reply. Appreciate it.
To add more depth to the issue, all seemed well until I got a new Mesa 4x12. I was playing a Tonex into the Line in, and then out to the guitar cab. It’s when I changed cabs that I started getting drop outs.
I immediately thought it must be the cab, but further research suggested that the Mesa is more likely to identify faults further up the chain.
I’ve tried a Victory MKX into the ps-2a tonight, and there were no drop outs. All seemed to work well. The MKX has a steady power section. So the power tubes seem fine.
I’m going to change the phase inverter to see if that makes a difference. Is it a 12ax7?
Do you think I’m going down the right path?
I’m not sure what to make of the new information, to be honest.
I think the important thing is that you toggle between BYPASS and OPERATE on the PS-2. If you have these issues in both modes, then the problem is likely cabling.
Please do go through the above list carefully; the advice sounds obvious, but really it catched a lot of problems.
From what you said, I cannot isolate the PS-2 as the problem yet so it might be too early to start swapping out tubes. But yes PS-2 uses a 12AX7 phase splitter/driver.