Poor tone when using FX Loop

[nmartin40]

Hey all,

I have a Dual rec three channel solo head, and whenever I use the FX Loop, I can't get a clean sound in channel 1. Seems to be fine when I bypass it. My send is set to 12:00 and my mix is set to 2:30.

Is it something to do with improper settings or a preamp tube. If it's a tube issue, which one should I start with?

Thanks!

 

[nmartin40]

It's also humming noticeably louder than it used to.

 

[JCDenton6]

I think your V4 tube is on the way out, if you take off the cover and lightly tap on it, it should make sounds/squeel.
Try popping a new one in if you have a spare.

Cables are fine correct?

 

[nmartin40]

I don't have one but I'll pick one up. Cables are fine.

Thank you!

 

[nmartin40]

Obviously after I check it ha.

 

[nmartin40]

Just checked and none seem to be crackling or making any odd noises. I just get a volume swell when I switch it on and the hum, cleans through the fx loop are still distorted.

 

[screamingdaisy]

Where are your channel master volumes set at?

 

[nmartin40]

Channel 1 at about 1, channel 2 and three around 11:00.

 

[screamingdaisy]

Try backing them down. Channels 2 and 3 to around 10:00 and bring channel 1 down until the volume balances.

Also, do you currently have any effects plugged into the loop?

 

[deeman]

Hey all,

I have a Dual rec three channel solo head, and whenever I use the FX Loop, I can't get a clean sound in channel 1.
Thanks!

Describe the sound. Is it distorted? When you get the new preamp tube, swap out one at a time and see if you can find if one of the tubes failed.

 

[nmartin40]

Backed the settings down and it's much better now.

The sounded was distorted but punchier/ugly. I have effects going through it. I've tested them and they're all fine.

I think it might have been mostly a setting issue. But it still seems to be humming louder than usual, so i'm still planning on picking up a good preamp tube.

Is the volume swell when switched on from standby normal?

Thanks for the help guys!

 

[screamingdaisy]

If you're using a single power supply to power both the effects in the loop and the effects in front of the preamp you may have created a ground loop. It basically sounds like a moderately loud 60 cycle hum. It can be diagnosed by unplugging the power supply from one set of effects and listening for the hum to stop.

It's usually easiest if you unplug the pedals in front of the preamp and power them via battery for the duration of the test.

 

[markblasco]

Try taking all of the FX out of the loop, and just connecting a cable from the loop out to the loop in. Then, turn the loop on and off. If this causes problems, than you have a loop problem (or something else going wacky with the amp). If this is fine, than the problem is within your FX in the loop (it's possible the level is too hot, causing some of the FX pedals to overload, which can be solved by turning down the channel volumes and raising the master volume).

 

[nmartin40]

I'm actually running my FX with individual 9 volts. The adjustment in volume and FX send/mix seems to have fixed everything but the hum. Probably just a bad tube somewhere.

 

[nmartin40]

Now I'm experiencing a light popping noise pretty often while I play. It does it with FX in the loop and with the loop completely bypassed.

Thanks for the help!