I’ve developed an issue with my power station 2a effects loop.
Noticed that delay and reverb pedals started sounding like there was a phase issue, very hollow sounding tone with loss of low end.
Also noticed that when turning the pedals off the volume dropped, very low and sounding like bees in a jar.
I’ve removed the cables from the loop and the volume increases and everything sounds fine. Tested with different cables and get the same issues.
I’ve tried just patching a cable across the loop with no pedals, less volume loss but still a hollow tone with less low end .
Any ideas appreciated.
Any advice on a tech based in U.K. who could look it over?
You did great with the debug process! Could you post an audio clip of the FX loops unused (nothing in send and nothing in receive) and then again just with an audio cable patched between the send and return?
Yes, we have techs we work with in the UK, where are you located (approximately)?
I thought I had worked it out by reseating the valves but that didn’t work.
I’ve made 3 clips,
Power station with nothing in the loop
With a lead (10 feet as usual) bridging the loop, slight loss of volume and becomes more fizzy
With a Collider pedal in the loop, here the volume reduces but when I activate the pedal the volume increases to higher than example 1 and there’s a distorted artifact after the note. This is a pedal I’ve used a lot without issues. When I delay or reverb alone the volume increases, if I activate both there is a sound like they are out of phase.
I would appreciate it if you could list some recommendations for servicing though.
It’s getting to 3 years old and probably in need.
Forgot to mention, I’m in the Cheshire area, Runcorn to be more specific.
In the meantime, make sure you don’t have a ground loop issue.
You’re not describing a squeal issue, but this problem does not always express itself that way. Sometimes it’s distortion, level loss and phase anomalies.
The various expressions of ground loop related issues are dependent on the specific devices, which pedal power supply you are using and which amp you are using.
Here’s video #2.
Guitar lead used to patch across the effects loop.
It doesn’t really pick up but there is a volume drop and the sound gets a bit fizzy.
Here’s video #3.
I think YouTube is compressing the sound but it is lower.
When I turn on the reverb in Collider there is a volume jump to louder than in video #1.
If I use the reverb and delay then the volume drop is even more.
I’ve also replicated this using a Plethora X5 and individual pedals.
Plethora and Collider are instrument level so the PS2 loop is set to low and the pedals are in true bypass as usual.
If I set to high in the PS2 loop and pedals to buffered bypass the volume is higher than with nothing in the loop. There is no raise in volume using the effects ( 1 or 2 effects) but there is distortion as the pedals can’t handle the levels.
I can maybe hear something different in the very top end in clip #2 but I can hardly tell the difference between any of clips. How about we do this with a clean guitar signal? If the FX loops is adding anything the sound then we should be able to hear it there.
The tone is very distorted (it sounds like money for nothing!). When dealing with nonlinearities small volume changes can produce larger change in distortion. Maybe the subtle volume change is causing this? Also, did you say the cable was very long? That would mean the cable is acting as a filter and also presenting itself as a capacitive load. Can you shorten the cable to 30cm?
So..
First off, apologies to everyone who said ‘ groundloop’.
Went right back to the beginning and unplugged everything from the power strip, even unplugged the strip.
Then started from amp, speaker and guitar.
Used a dB meter ( an iPad one so not expecting accuracy but figured it would be consistent).
Clean amp at 78dB as a starting point.
Then added the PS2 and ran in bypass, still getting 78dB.
PS2 in operate mode and matched the volume to 78dB , a bit fiddly but got there.
Adjusting dip switches, presence & depth until bypass and operate matched.
Then a short (30cm patch cable ) in the loop , set to low. Still getting 78dB.
Decided I wouldn’t add anything else to the power strip yet so dug out my old Boss RV 5 and DD6 and some 9V batteries. Ran them in the loop on low.
First the Reverb, tone consistent and getting 78dB on the meter, turned on delay and same 78dB.
Put the pedals on my board ( I’d removed all the connections from my Cioks power supply before) and wired in the pedals, connected to power strip and worked like a charm, consistent tone and 78dB.
I’m also sure the set up is quieter in terms of background noise, maybe my imagination though.
So, no idea what was causing the issues, everything is back and plugged in.
They are in a different order on the power strip , not by design, but could that cause a difference?
What have I learned?
When you are sure it’s not a ground loop, it’s probably a ground loop .
Relearned a lot of things I’d forgotten in setting up the PS2, actually going back to A/B between the bypass and operate sort of resets your ears and memory of how the cab should sound, my tone is better for it.
Remembered how good the Boss pedals are, they are staying for now.
