Dry bleed through effects loop

Stage & Studio Power Station PS-100
1

Hello,

I’m wondering if what I’m experiencing is normal for a PS-100 - basically I’m getting a small “dry” signal coming through my cab, whether the effects loop is engaged or not. Here is my setup for testing this:

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So, as pictured - running a loop pedal to provide a clean guitar signal - and there is a passive volume control in the effects loop. The amp is 100 watts. Everything is set to 16 ohms. I’m using a foot switch to turn the loop on and off.

With the power station’s volume at zero, the power station effects loop off, and the amp’s master volume at a nonzero level, I still get a small signal coming through the cab, and the signal gets louder as I turn up the amp master volume. The same things happens when I turn on the effects loop, and the signal is at the same level, regardless of where I set the volume control that is in the effects loop. This small signal seems to ignore whether the effects loop is on or off; it’s always present. With the power station effects loop on, and the power station’s volume turned up a bit, I get more volume as expected, but again if I turn down the volume control in the effects loop to zero, I still get the small ‘dry’ signal. The same thing happens if I unplug the effects loop volume control and leave the cables plugged in - small dry signal. And, again, if I replace the effects loop volume control with a delay pedal that has no dry signal, I still get this small dry signal before the delay repeats.

So, my theory is that the Power Station’s reactive load is passing some signal to the connected cab, regardless of what the Power Station’s power amp and effects loop are doing. And my question is - is this normal? Is there anything you might recommend I try to keep it from happening? Thanks

2

Hi Telperionflower,

This is an excellent question and the signal path diagram makes it so easy to follow.

I noticed this with my PS-100. I wanted to get it to the most quiet settings above zero. But when I did that, I noticed the same things as you with the FX loop.

What I realised was I had actually put the volume knob at zero. So there was no signal passing from the guitar to the speaker. But what I was hearing was some signal bleed.

The PS-100 is unique; it’s a reactive load and a 100W tube amp is a relatively tiny form factor. It allows you to do things and notice things that you could not do with other attenuators or amps. For example, I bet you can also hear the output transformer of your tube amp for the first time!

The point is: the signal you are hearing coming from the speaker is a tiny bit of bleed. I have measured this – cannot remember the exact signal power now – but I remember it sounding something like I had left a headphone playing somewhere in the room.

The PS-100 is not broken and this is not really an issue because it’s so quiet and goes away when you play at any reasonable volume.

1 Like
3

Thanks Dan! Yeah, not an issue when playing loud certainly. I’m setting up a pretty complex rig with midi control, true bypass switching, mixing effects in parallel, the whole nine yards.. so I’m happy that I figured out what I was hearing, and it wasn’t another issue with the cables I soldered, the switcher, or dry signal coming through an effect when it shouldn’t.