paulemerson Posted March 5, 2021 Share Posted March 5, 2021 hi there ..got my hx effects a few years ago now and have been loving it..its been a big part of my live sound now but there is 2 things i cant find an aswer to.. ive got a fender twin and would like the hx to switch my channels , i can get it to switch the channels but it has a ground loop type sound(thats louder than the guitar) the minute i plug in the lead to the channel select port..its a 3 channel twin and the ive tried a mono guitar lead and i tried a trs lead..the trs dosnt work at all but it still has that noise.the mono lead does switch the channels from crunch to lead channels..the footswitch for the twin has a trs lead and has also a light ,so im guessing there is a current running down that lead,could that be the reason the ground loop noise is there.has anyone managed to get the hx to switch channels on a fender twin? also ive been having problems with the expression pedals i have..they seem to make the volume jump up and down when im not touching the pedal at all..it moves between 70 to 95 untill i really stand on the pedal to the toe pos then i kinda settles but never goes to 100..ever..both expression pedals work flawlessly on my synths anyone have any ideas? thanks in advance paul Quote Link to comment Share on other sites More sharing options...
paulemerson Posted March 5, 2021 Author Share Posted March 5, 2021 just had an idea..would using an insert lead (ie the type of lead you would use to connect a compressor to a mixing desk) work in this situation? Quote Link to comment Share on other sites More sharing options...
kduck Posted March 5, 2021 Share Posted March 5, 2021 Is the amp a Pro Tube "Twin-Amp" with the 4 button footswitch? If so, I'm pretty sure you won't be able to use Helix to switch the channels, etc. because it is not switch-to-ground type footswitch. Quote Link to comment Share on other sites More sharing options...
paulemerson Posted March 5, 2021 Author Share Posted March 5, 2021 thanks for that.yes it is a 4 button footswitch.i can now forget about trying to get this side of things to work much appricated Quote Link to comment Share on other sites More sharing options...
rwinking Posted March 17, 2021 Share Posted March 17, 2021 I wrote about this same issue but with a different amp. Mine is a one button foot switch. The HX will switch channels using a standard cable but there is a ground loop. I get the ground loop tamed by running the cable through a hum eliminator and the hum is gone but it will not switch. I was told to try a TRS to dual mono Y and see if one of the sides of the Y will still switch . I am waiting for the cable to get here and will let you know if that works. Quote Link to comment Share on other sites More sharing options...
kduck Posted March 17, 2021 Share Posted March 17, 2021 @rwinking Without knowing your amp model, I can't comment on your specific issue. The amp referenced by the OP uses an AC voltage source (28 VAC to be exact) for the switching logic, which causes the noise when connected to the HX. It is not actually a ground loop in the OPs case, but sounds similar because it is at 60 hz. The Helix channel switching simply shorts the tip/ring to ground and will not work with AC switching schemes. Also, I don't think a hum eliminator will work at all in the switching circuit because they are essentially isolation transformers and cannot pass DC. Quote Link to comment Share on other sites More sharing options...
rwinking Posted March 17, 2021 Share Posted March 17, 2021 The issue is that the hum eliminator does work. The noise is entirely gone when I use it. However, it will not switch the channels. So it seems that I get one (hum) or the other(channel switching) but not both. BTW, it is a Randall RM50. The channel switching is just a latching switch. Quote Link to comment Share on other sites More sharing options...
kduck Posted March 17, 2021 Share Posted March 17, 2021 I've not worked on a Randall RM50 before, I'll see if I can find a schematic for it. Quote Link to comment Share on other sites More sharing options...
rwinking Posted March 17, 2021 Share Posted March 17, 2021 Thanks so much! you have no idea how much I would appreciate that. This has been frustrating for me! rick Quote Link to comment Share on other sites More sharing options...
kduck Posted March 23, 2021 Share Posted March 23, 2021 @rwinking Found a schematic online. A couple of questions: Do you get the "ground loop" noise if you use the stock footswitch? When you connect the HX (with noise), list all connections between the amp, HX and any other gear When you connect the hum eliminator, where are you putting it in the chain? Assuming you are on 60 Hz power (US): is the noise closer to guitar B (A string, 2nd fret) or an octave lower? Or something else? Quote Link to comment Share on other sites More sharing options...
paulemerson Posted March 24, 2021 Author Share Posted March 24, 2021 the noise i get when i set it up to do the channel switching does not sound like a ground loop,,it sounds like the end of time and not in a pleasant way any one know if a fix for the expression pedal problems....when im watching the volume on hx edit .the numbers are jumping all over the place ,say between 70 and 100 then it settles after a bit of time untill i touch the volume pedal again.. Quote Link to comment Share on other sites More sharing options...
kduck Posted March 24, 2021 Share Posted March 24, 2021 29 minutes ago, paulemerson said: the noise i get when i set it up to do the channel switching does not sound like a ground loop,,it sounds like the end of time and not in a pleasant way Lol, that's what 28 VAC will do. 32 minutes ago, paulemerson said: any one know if a fix for the expression pedal problems ....probably best to create a new post for this. Quote Link to comment Share on other sites More sharing options...
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