RG100ES Noisy Effects Loop

[Deancfh]

Hello,
I recently got an MXR Flanger Doubler and threw it right into the effects loop of my Ranall RG100es which was known to having issues prior. When the effect is on, there is a ton of white noise which requires a significant amount of noise gate to eliminate the noise, however the effect begins to fight the noise gate and it sounds terrible. I threw the MXR F/D into other effect loops and it sounded perfectly fine. The RG100es will also pop and or give off static noises with no guitar signal present if the effects loop is open. With a patch cable, the amp sounds fine. I have also had issues with the reverb in my amp that was fixed by replacing the 4558 within the circuit, however effects in the RG100es effects loop are awfully noisy. Any suggestions?

[The Dude]

If I'm not mistaken, the Randall RG's have an instrument level loop. That means there is probably not enough signal there to properly drive your MXR F/D, which is -10 or +4 line level depending on which jacks you use. This would give you a horrible signal to noise ratio, translation- lots of hiss. Does the Randall loop work properly with a regular guitar pedal designed for instrument level I/O?

[Deancfh]

I have yet to try different instrument level effects. The only other effect I could throw into the loop would be an Aphex 104c Aural Exciter with Big Bottom. The F/D has been used by many in the loop of many RG100's considering it was Dimebag Darrell's tone and I had some friends show me their F/D in the loop and there was no issues. I did have an MXR 175 digital time delay, but its been non-functional for quite some time. May I ask what you mean by "Which jacks you use?"

[The Dude]

Doesn't the MXR have High and Low jacks? Maybe I'm wrong, but that's what I remember.

Edit: So, I just looked at some pics of the unit. I think the rear I/O is +4 and the front is -10. Try different I/O's and see if there is any improvement.

[Deancfh]

So I just used the front I/O and it was quieter, ever so slightly, but still significantly as for white noise. Before trying the I/O's, the effects loop was popping really loud prior to plugging anything in. Can I link videos to this forum?

[Deancfh]

https://youtube.com/shorts/xcOqdY38ov0?feature=share

[DrGonz78]

Does the noise change when you pound on top of the amp with your fist? I mean you will feel better too but just make sure it’s not a bad mechanical connection. Something loose!

[Deancfh]

Just tried it and got interesting results, let me link a video.

[Deancfh]

Here is a video of me smacking the RG100es with the reverb all the way up. https://youtube.com/shorts/xE2_u-n8dHU?feature=share

There is also a significant amount of noise when the reverb is turned up and the amp is extremely quiet when it is turned down all the way.

[DrGonz78]

I hear a crackling in the reverb as it decays. Or I hear the crackling that is just already there still. Of course cranking the reverb and bumping the amp will rattle the springs. What we would be assessing is a quick bump test to see if it affects the crackling noise. The reverb should be off so we can isolate the noise better.

[Deancfh]

Unfortunately, it is too late to risk turning a half stack on at night when everyone is asleep, so I will do this first thing tomorrow morning.

[Deancfh]

So, after smacking to see if something is loose, I present to you a new issue that has never occurred before.

https://youtube.com/shorts/qkWRFLDZyPw?feature=share

The gain in the red channel absolutely went to trash. The popping noise from me hitting the reverb was non existent when the reverb was turned all the way down, however there is crackling in the gain for the red channel.

[The Dude]

If the symptom started after smacking the amp, it's very likely some sort of connection or cold solder problem. You're going to have to get into the amp and track down the intermittent/bad connection.

[Deancfh]

The gain was always funky when I turned it past 7, but it never did this. Should I turn the amp upside down and poke it with a chopstick to see what’s loose?

[The Dude]

Yes, chopstick technique will help find the bad connection. Also, if your pot always acted "funky", you could have a dirty/bad pot or the solder connections to the pot might be cold. Check connections and try Deoxit or similar on the pot.