PS-2 Cracking, hissing and popping

Stage & Studio Power Station PS-2
1

Hello all,

I’ve got a problem of crackling and popping noise with my PS-2. It makes noticeable noises once it is heated up and once I’ve used it with a tube amp. The problem is repeatable and it seems to occur faster if I’m running my tube amp louder to the PS-2 or playing very low frequencies. If I keep on playing when PS-2 makes this noise, volume levels are varying wildly and the popping gets very loud. The problem only appears when I run the PS-2 with a tube amp and to a guitar cabinet. If I power off the unit for a lenghty amount of time (+1hr) and power it on, the popping is gone for a while, and reappears after a while once the PS-2 has heated up. I have tried two different tube amp heads with this, all possible front panel toggle combinations and pressing the ground lift on the back as well as moving the amp to a different room using a different power outlet - these have no impact on the issue. In these scenarios the unit works flawlessly:

  1. When using a modeler to fx return and PS-2 to guitar cab
  2. When using a tube amp with the PS-2 but using it only as a reactive load and sending the signal to my audio interface (no guitar cab connected)

I have changed all the tubes once and that did not solve the issue. My local tech had a look at the unit but deemed troubleshooting impossible without the schematics.

Here’s a video of the issue:

And here a pic of the internals:

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Could you please advice what is causing the issue?

2

Hi @OlZu

Thanks for the helpful context. Just a few initial things, but the short answer if we can always do an RMA and solve any problem. But my job here is to save you time and money by just poking a bit to see if it is anything silly first.

  1. When you say “all” tubes, did you also change the 12AX7 driver? Preamp tubes can cause this kind of issue too.
  2. unit works flawlessly when:
    A) “modeler to fx return and PS-2 to guitar cab” – this is odd because in this configuration you are using all tubes in the PS-2 and driving a cab. So if it were the tubes, I would expect this to be cracking too. This seems to say it not the tubes. Please confirm you are not talking about BYPASS. The PS-2A is OPERATE and driving the cab or your amp is driving the cab?
    B) " using PS-2 as a reactive load and sending the signal to my audio interface (no guitar cab connected)" – this bypasses the tubes.

Can you try this:

  • Unplug everything from FX loop of your amp and of the PS-2
  • Guitar → Amp → PS-2A → Cab
  • PS-2A in operate — problem appears?
  • PS-2A in bypass — problem goes away?

Then:

  • Your amp off and unplugged.
  • Connect your guitar to Line In (yes signal will be low level but that’s fine for testing)
  • Guitar → PS-2A (Line In) → PS-2A (TO SPKR) → Cab
  • PS-2A in operate — problem appears?
  • PS-2A in bypass — problem goes away?

Let me know!