HX FX Ext Amp - Mesa/Boogie RectoVerb 25 - Loud pop when switching channels

[ddivill]

Hi, 

I'm using the HX Effects with my Mesa Boogie Recto-Verb 25. When I use the Ext Amp in a preset/snapshot to switch from the clean-channel to the drive channel there is a loud pop from the amp. 

The amp channel does switch but this loud popping sound makes the HX Effects difficult to work with for gigs. The cable also is a standard TR(Tip/Ring) cable.  

 

When testing this using the standard single-button footswitch that comes with the amp to switch between clean and drive channel,  it exhibits no such behaviour. 

The Mesa Boogie footswitch is nothing more that an input jack and switch, nothing special, so I dont understand why the Ext Amp is sending a voltage down the cable.

 

Is there anything that can be done on the HX Effects side to correct this. 

 

[rd2rk]

This is a problem that's especially prevalent with Mesa amps. There have been many posts, and many helpful suggestions, but I've never seen an actual solution.

I keep suggesting that those with this (and other Mesa related problems) contact Mesa support, but I don't remember anyone actually doing that.

Maybe you could be the first?

[ddivill]

Thanks for the feedback. I’ll see what they say but I’m not too hopeful as the included footswitch doesn’t generate any popping noise like this. I expect them to point back at the HX Effects as the problem .. 

[rd2rk]

1 minute ago, ddivill said:

Thanks for the feedback. I’ll see what they say but I’m not too hopeful as the included footswitch doesn’t generate any popping noise like this. I expect them to point back at the HX Effects as the problem .. 

 

Since this is NOT a problem with most amps, you might point out to them that the ExtAmp switching function on Helix is a simple open/closed circuit switch, and ask them what the difference is in their switching method. Of course, it could be a National Secret/CIA/NEED TO KNOW thing, but the more specific you are when you contact them, the less opportunity they have to "blame the other guy".

[CraigGT]

I seem to recall from somewhere that the Helix Ext Amp is not a relay contact so it's presumably an FET. I just tested mine and it goes between an open circuit and 7 ohms with no DC voltage so it's still pretty much a switch. However my Mesa footswitch has an LED in series with the switch so it's not completely like for like.

 

Try putting an LED in the tip wire of your cable to see if that improves matters, it'll only work one way round but you won't damage anything if you get it the wrong way first time.

 

 

[CraigGT]

Or maybe an easier way to test,

 

Unplug the cable from the Helix and short the tip and sleeve together and see if your amp pops when it switches. If it does then try connecting an LED across the tip and sleeve and see what that does. if it does nothing then try the LED the other way around.

The LED should light when it switches the amp.

 

It's only 5V so it wont bite if you just hold it on there.

 

 

 

[ddivill]

Thanks Craig, some very useful suggestions there. 

I unplugged the cable from the HX Effects and shorted the Tip/Sleeve as you suggested and there was no pop at all. 

I dont have a LED to hand at the moment but it does look to me that the pop is coming from the HX Effects. 

 

I made a quick video showing the issue. First I show the pop when switching channels and then I short the Tip/Sleeve to show there is no massive pop like when switching the channels.

Link for video: https://drive.google.com/file/d/1aTXoZVQkfoY1fogc92lQ83ZW7iYQMNcG/view?usp=sharing

[CraigGT]

I've just had a thought, I don't know the HXFX but the Helix floor has an option for Ext amp, in your case it should be set to 'Tip-to-sleeve' 

I can see how the other settings could upset the HXFX unit.

 

 

[ddivill]

@CraigGT I did look at that already in the Global Setting Menu, under Preferences you can set the Pedal Jack to either Amp or Expression. 

I have it set to Amp and unfortunately that didn't help. 

[CraigGT]

On the floor it's set per preset in Command Center.

[C4TH]

I’ve read on this and other forums that the channel switching between mesa’s and HX effects, seems to be a problem.

Are you running it in 4cm?

Is there a hum or noise when the switching cable is plugged in?

[stef77270]

Hi,
can we have the wiring used please? (HX effect and Mesa) :)

Regards