PS-2A Power amp has no sound

So my PS-2A line outs function direct to Logic work fine. It has been used primarily with no speaker hooked up, as a load only and running it to my interface into Logic with IR’s.

Hooked a speaker up to it for the first time in quite awhile and at first it worked fine. With the volume control all the way down there was still some signal, which I thought was strange. Unit was in operate mode. Now there is no output at the speaker at all. Unit is on and in operate, amp speaker out to amp in, speaker cab hooked up to Speaker Out jack. Tubes are lit up, no sound out of the speaker.
Any thoughts?
Thanks, George

Hi @Greazygeo :tada: and welcome to the community,

Thanks for describing the setup so well, it really helps.

Firstly, the signal that you hear when the volume is on zero is not coming from the speaker, it the coming from the transformers.

If the volume knob has not been turned for a long time it should be build up of oxidation. One way to fix this is to turn the post all the way to the left and right many times.

Otherwise, your power station might need a service. Hopefully someone from Fryette or the community can also give their opinion.

Thanks for the response Dan. The zero-ed volume amp sound was definately coming from the speakers. I know what you are referring to as the “buzzy” loadbox resistor sounds. Using it primarily as the loadbox direct ir method, pretty used to that.

Hmm. So there is no signal to the speaker at all! If you have checked all the stupid things like cables etc. which I am sure you have already done. I cannot think of anything else but getting it serviced.

What do you think @DavidPhelge @Paul @JohnTheConqueroo?

Hi George,

If you’re getting sound in Bypass mode and no sound in Operate mode, look for a blown DC fuse inside the unit.

Here’s a tutorial with all of the info on that subject including links below the video with fuse specs and recommended replacement tubes.

Yep, tried amp to cab directly with same cable and that works fine. Also tried the line input and no sound. Unit on bypass, there is sound from cab.
When using the line outs and no speaker attached the unit has always been powered up, so the fan is running. Can’t remember if I checked to see it the fan was running….hmm.

Thanks David. I will check the video/ fuse when I get home later.

The fuse was blown, replaced it and all was well. Later that week using it, sound changed and bass went away. Checking it out, one power tube was glowing cherry red. Popped in a new set and working fine.

With the volume all the way down, should the speaker still have sound? It is loud enough I can record with it.

Hi @Greazygeo glad you resolved this.

I’ve noticed the sound from my PS-2 when the volume is all the way down, it was mainly coming from the transformer. This is not something I have encountered before. Is anything connected to the FX loop? What happens if you disconnect that? Otherwise it could be a fault or aging pot, you could try and clean it? Do a few full turns left and then right too and see if that makes a difference.

It is definitely coming from the speaker. It is the normal distored guitar sound. My cab is in another room and mic’d.
There is the normal transformer/ load resistor buzzing while playing in the control room.
It isn’t a big deal or anything, just thought the PS-2 volume control should kill the sound from the speaker.

Ok thanks for confirming.

Do you think the signal you are hearing could be coming from the FX in the loop or a line in? Just to eliminate all possibilities.

If not then, yes, sounds like the pot might be faulty.

  • do some full turn of the pot, the might help clear any debris
  • Clean with pot cleaner if you have?

After that the options are to get a replacement pot or send it in for repair.

Unless I have missed something? Maybe someone else can chime in if so.

Sorry I forgot to mention, nothing is hooked to the fx loop. Just amp to amp in…speaker out to cab. XLR out to interface. I have removed the xlr cable to eliminate that.

I can try rotating the pot and or cleaning it.

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Tried cleaning the volume potentiometer, still not shutting all the way off on zero. Now it is intermittently jumping up and down in volume. Removed the PS2 from the signal path, just using the amplifier / cab and no issues.

Hi @Greazygeo

Thanks for coming back with the info. The only other cleaning I would recommend would be tube sockets and jack sockets using solvent cleaner like IPA (isopropyl alcohol). If that does not help then I think you could try replacing the pot?

Regards,

Dan