Multi-watt FX loop tone problem

xMax_X · May 25, 2015

Hi all, I recently started to use the FX loop with a Delay/looper ( line6 DL4) when I was practicing with my band on my dual rectifier multiwatt. I've noticed that when the FX loop is engaged, the tone of the amp changes. The highs/topend are dropped and a more pronounced low/midrange tone comes out. It's actually pretty muddy.

Tried switching cables, but it does that even even nothing is plugged in the loop and just engaging it/disengaging it with the footswitch.
The Fx loop is set to the middle value on the back of the amp( not louder or quieter)

Is this normal, anything I can try so the tone stays the same ?

screamingdaisy · May 25, 2015

Try lowering the channel volume, then turn the master output back up to compensate.

I usually run the channel master on the loudest channel around 10:00 and adjust the other channels based off that.

xMax_X · May 25, 2015

Thanks for the reply, master volume is at about that, output is at about 11 o'clock, I'll try lowering it anyway but could you please elaborate on what it has to do with the change in sound that occurs when engaging the fx loop ?

screamingdaisy · May 25, 2015

What I've noticed over the years is that when the send levels are high is that it rounds off the top end and can fatten up the bottom. I suspect it's because the effects loop itself is being overdriven but I have no way of confirming it.

Beyond that, I've periodically alternated between loop bypass and loop active using the switch on the back and in general the most transparent results happen with moderately low channel send levels, which I've noted tend to be where most of the manual's sample settings seem to sit.

xMax_X · May 25, 2015

I see, thanks alot for the heads up man!
I'll try that next band practice...I also read that maybe changing the V4 tube could do some good, is that right ?
-Max

screamingdaisy · May 25, 2015

xMax_X said:
I see, thanks alot for the heads up man!
I'll try that next band practice...I also read that maybe changing the V4 tube could do some good, is that right ?
-Max

It could. It's the FX loop buffer. Just make sure you use a Chinese or JJ tube (stock Mesa are JJ). Russian tubes don't function well as cathode followers and may burn out.