FX Loop weird sound

Ross Mc

okay i bought a chorus pedal and i thought i'd try put it into the FX loop in my amp and it was fine until i began adjusting the controls and then their was this really loud whizzing sound.

The way i plugged it in was

Pedal Input > FX Send
Pedal Output > FX Return (Both mono)

Anyone know why this is happening?

rcaz

Loud whizzing sound... Bad power source? Maybe it's like a clock hum bleeding over into the signal? Are you using mains power or a battery?

Ross Mc

Battery

punchdrunk

which amp is it?

if its tube driven it might be a bad valve

Ross Mc

marshall mg, solid state, so no tubes

Alanstrainor

Ross Mc wrote: »

marshall mg, solid state, so no tubes

Is it a mg100? Could it be the fan?

Ross Mc

Alanstrainor wrote: »

Is it a mg100? Could it be the fan?

250 and i doubt it's the fan, i know from computers that a bad fan sounds more like a grinding noise, rather then a whizzing noise.

To Be Honest it's sounds like how with overdrive or distortion if you turn up too much you get feedback, except with this it's an effects pedal

Ross Mc

Oh thought i'd also note, the pedal works fine when plugged straight into the amp input

Taxpayer

Put in a non phase shifting or modulation effect into the effects loops. Something like an overdrive but use the clean channel only when checking. If the whooshy sound is still happening get back to me and I'll point you in the right direction. Are you using an active guitar? Are you using any other phase shifting or modulation pedals at the same time?

Paolo_M

Ross Mc wrote: »

okay i bought a chorus pedal and i thought i'd try put it into the FX loop in my amp and it was fine until i began adjusting the controls and then their was this really loud whizzing sound.

The way i plugged it in was

Pedal Input > FX Send
Pedal Output > FX Return (Both mono)

Anyone know why this is happening?

What controls did you adjust?
Phase shift, as someone has already pointed out, or overdriving the pedal are both possible, and frequent causes, of what you're describing.

Ross Mc

Taxpayer wrote: »

Put in a non phase shifting or modulation effect into the effects loops. Something like an overdrive but use the clean channel only when checking. If the whooshy sound is still happening get back to me and I'll point you in the right direction. Are you using an active guitar? Are you using any other phase shifting or modulation pedals at the same time?

okay cool, i'll use my distortion through it, the pedal works fine plugged through input etc and no it's passive

Ross Mc

hey I tried plugging my Boss Metal Zone into the FX loop but got a sort of feedback type sound.

Taxpayer

Ross Mc wrote: »

hey I tried plugging my Boss Metal Zone into the FX loop but got a sort of feedback type sound.

And you definitely aren't using any other on board effect on the guitar amp at the same time? What is the amp? Is it valve? Is there any FX send volume? If so make sure it's not up completely to 5 O Clock.
Most of the time, that sound you described comes from a modulation fighting modulation- almost out of phase with each other.

There's nothing wrong with your connections by the way, you are quite literally breaking a circuit re connecting the loop.

If you have checked all these problems (try again with another effect something obvious like a delay- just to be sure), it is quite likely there is a short somwhere along the line. Worst case scenario a crack in the PCB.
Let me know where you are based and I'll put you in touch with somebody to get it sorted.

I have to log off now, but I'll check again over the weekend. Best of luck.

Ross Mc

Taxpayer wrote: »

And you definitely aren't using any other on board effect on the guitar amp at the same time? What is the amp? Is it valve? Is there any FX send volume? If so make sure it's not up completely to 5 O Clock.
Most of the time, that sound you described comes from a modulation fighting modulation- almost out of phase with each other.

There's nothing wrong with your connections by the way, you are quite literally breaking a circuit re connecting the loop.

If you have checked all these problems (try again with another effect something obvious like a delay- just to be sure), it is quite likely there is a short somwhere along the line. Worst case scenario a crack in the PCB.
Let me know where you are based and I'll put you in touch with somebody to get it sorted.

I have to log off now, but I'll check again over the weekend. Best of luck.

It's solid state and I know exactly what your talking about cause i'm doing an electronics course, so i could have a look at it myself. I've already had soldering issues before with it, so it could be that again, hopefully.

Taxpayer

Ross Mc wrote: »

It's solid state and I know exactly what your talking about cause i'm doing an electronics course, so i could have a look at it myself. I've already had soldering issues before with it, so it could be that again, hopefully.

Check for dry joints while you're at it. I've read through the rest of the notes- It's an AVT250 right? Pretty much a problem free amp- hopefully you can sort it out yourself but be careful and as I'm sure you know already- don't touch any capacitors if it's been recently turned on.

Gordon

Make sure you get a good recorded sample of the sound, you never know when you'll suddenly think "cr*p, that mad sound would fit well in this track right now, wish I sampled that!".

Ross Mc

Taxpayer wrote: »

Check for dry joints while you're at it. I've read through the rest of the notes- It's an AVT250 right? Pretty much a problem free amp- hopefully you can sort it out yourself but be careful and as I'm sure you know already- don't touch any capacitors if it's been recently turned on.

I wish it was a AVT, you must have read wrong, it's an MG but yeah I know what to look for.

Ross Mc

Gordon wrote: »

Make sure you get a good recorded sample of the sound, you never know when you'll suddenly think "cr*p, that mad sound would fit well in this track right now, wish I sampled that!".

lol, yeah your right, might need a whoosy sound or maybe some random feedback