Guptech MWAC and Sun Gate Users

berumen77

berumen77

New member
Never posted here before but thought I'd ask for some help. I just got in a brand new Guptech MWAC yesterday afternoon and Im having a ground loop issue and wanted to ask other owners if they've experienced the same or if they can test theirs in 4CM.

Reason I got it was to eliminate the hiss I get while running either my Bogner 101B or Classic while on Red channel. Just hiss no other noise issues with the amps.

Plugged only into the FX loop of the amp, the pedal works. No other noise added or weird artifacts added. But I was hoping to run it in 4CM to see if it would have better response to the dry guitar, especially on clean channel stuff. As soon as I tried it, there was a ground loop hum/buzz with pedal off and when engaged with threshold at lowest settings. When you turn up the threshold it of course disappears but it's only hidden and the actual ground hum is still in the signal. Whats weird is even if it's just guitar to "key" IN and OUT to amp, gate not connected to FX loop, I still get ground hum/buzz. Not sure if it's a power thing but I tried it plugged into a wallwart 9v adapter and by itself with a One Spot with same results.

I tried to lift the ground on the end of a cable and tried that in each of the jacks to break the loop. No go. All 4 jack are non-isolated so they are making ground contact with the pedal enclosure and in turn to themselves. I was going to go for the Phalanx since it had an isolated pair of jacks and a ground lift switch but went this route...

Do those of you that own one of these Guptech noise gates have this issue when using 4CM? Can you test yours?

Thank you in advance, sorry for the long winded essay.
 
berumen77 said:
Never posted here before but thought I'd ask for some help. I just got in a brand new Guptech MWAC yesterday afternoon and Im having a ground loop issue and wanted to ask other owners if they've experienced the same or if they can test theirs in 4CM.

Reason I got it was to eliminate the hiss I get while running either my Bogner 101B or Classic while on Red channel. Just hiss no other noise issues with the amps.

Plugged only into the FX loop of the amp, the pedal works. No other noise added or weird artifacts added. But I was hoping to run it in 4CM to see if it would have better response to the dry guitar, especially on clean channel stuff. As soon as I tried it, there was a ground loop hum/buzz with pedal off and when engaged with threshold at lowest settings. When you turn up the threshold it of course disappears but it's only hidden and the actual ground hum is still in the signal. Whats weird is even if it's just guitar to "key" IN and OUT to amp, gate not connected to FX loop, I still get ground hum/buzz. Not sure if it's a power thing but I tried it plugged into a wallwart 9v adapter and by itself with a One Spot with same results.

I tried to lift the ground on the end of a cable and tried that in each of the jacks to break the loop. No go. All 4 jack are non-isolated so they are making ground contact with the pedal enclosure and in turn to themselves. I was going to go for the Phalanx since it had an isolated pair of jacks and a ground lift switch but went this route...

Do those of you that own one of these Guptech noise gates have this issue when using 4CM? Can you test yours?

Thank you in advance, sorry for the long winded essay.
Click to expand...

My amp does this no matter what noise suppressor I have used in 4CM as well, must be something with the design that just doesn't work. I have tried at least three, though the two that come to mind are Boss NS-2 and Revv G8.
 
I'm wondering if anyone has actually noticed it on their MWAC or Sun Gates. Yeah like I said, if you do the 4CM and have threshold above 10 o'clock you don't hear it but it's still there in the actual signal. Turn the pedal off and it's easily noticable.

If I'm doing something wrong or if there's an easy fix then that would be awesome especially because the pedal itself looks pretty awesome Inside and out. Glow in the dark edition MWAC.
 
berumen77 said:
I'm wondering if anyone has actually noticed it on their MWAC or Sun Gates. Yeah like I said, if you do the 4CM and have threshold above 10 o'clock you don't hear it but it's still there in the actual signal. Turn the pedal off and it's easily noticable.

If I'm doing something wrong or if there's an easy fix then that would be awesome especially because the pedal itself looks pretty awesome Inside and out. Glow in the dark edition MWAC.
Click to expand...
I know you are asking about specific gates, but what I am saying is that it probably doesn't matter which gate you use if your amp is causing the ground loop. I too, was asking about specific gates, and after testing multiple makes and manufacturers and further study, it was my amp. If you have tested 2 pedals with the exact same results, it probably isn't the pedals. If you disconnect one of the cables and the ground loop goes away in 4CM, it is the way the amp is. The only fix in that case would be something like a Lehle. Just trying to save you some efforts. Good luck!
 
Last edited:
I can second the Lehle recommendation. I was having pretty bad ground loop issues running a noise gate in 4cm in conjunction with my amp switcher. I got a P-Split to use as an isolation transformer just before the switcher input and it solved the issue!

I've got those Guptech noise gates on my radar, what do you think of them and how do the two compare? I've heard the Sun is the more stop-on-a-dime metal gate and the MWAC maybe more all around with better sensitivity for leads?
 
Meeotch said:
I can second the Lehle recommendation. I was having pretty bad ground loop issues running a noise gate in 4cm in conjunction with my amp switcher. I got a P-Split to use as an isolation transformer just before the switcher input and it solved the issue!

I've got those Guptech noise gates on my radar, what do you think of them and how do the two compare? I've heard the Sun is the more stop-on-a-dime metal gate and the MWAC maybe more all around with better sensitivity for leads?
Click to expand...
It's my first noise gate and works great on the hiss while allowing the note to slowly trail out as the gate rolls in at between 9 and 11o'clock.

So the Lehle P-Split just sends one signal to the "key" IN of the gate and it's other signal to the amp input? You don't use the actual Out of the gate to run to the amp input.
 
Last edited:
berumen77 said:
It's my first noise gate and works great on the hiss while allowing the note to slowly trail out as the gate rolls in at between 9 and 11o'clock.

So the Lehle P-Split just sends one signal to the "key" IN of the gate and it's other signal to the amp input? You don't use the actual Out of the gate to run to the amp input.
Click to expand...
I place the isolation transformer in line with my signal, just before the amp input. The P-Split has two outputs for a wider variety of applications but you could also just use the P-Iso. Either way Lehle is top of the line in this dept.
 
My MWAC did the same thing as well with my Ecstasy, which was the only amp I tried to use it in 4CM with. I emailed Guptech, and he was a bit surprised, and wanted me to try a couple things. Realistically I don't use a lot of gain, and I ran out of time to troubleshoot it before a gig, so I threw it up front at the end of my chain to knock down some of the noise when I play live, and haven't thought about it since.

The ambient noise floor of my amps aren't awful so I figured that was good enough for my needs. Even only running in front I prefer it over my old ISP Decimator II.
 
grimmchaos said:
My MWAC did the same thing as well with my Ecstasy, which was the only amp I tried to use it in 4CM with. I emailed Guptech, and he was a bit surprised, and wanted me to try a couple things. Realistically I don't use a lot of gain, and I ran out of time to troubleshoot it before a gig, so I threw it up front at the end of my chain to knock down some of the noise when I play live, and haven't thought about it since.

The ambient noise floor of my amps aren't awful so I figured that was good enough for my needs. Even only running in front I prefer it over my old ISP Decimator II.
Click to expand...
They do have a pdf on noise gates that I found that discuss ground loops while using the 4CM. Solution discussed was lifting a ground or snipping the ground off the cable going into the IN/key of the pedal. I just spent another hour troubleshooting it with a couple cables that had the grounds lifted on one end plugging to the input output and fx loop, no luck.

Using standard cables with Guitar into IN and OUT to amp, as soon as I plug a single cable from FX loop (Send or Return) it buzzes. With both it's even louder. No cables to FX loop and just 9V plugged in it buzzes just as loud.

It does react quicker and more responsive with the 4CM but on longer sustained notes you can hear the ground hum/buzz come up as the note dies off and right before the gate kicks in. To some that might sound like a crackling/fizzy artifact of the gate, but it's from the ground loop not the effect.

I'll see if I can reach out to the builder. I just wanted to see if anyone had this similar issue and had found a way to fix it.
 
Meeotch said:
I place the isolation transformer in line with my signal, just before the amp input. The P-Split has two outputs for a wider variety of applications but you could also just use the P-Iso. Either way Lehle is top of the line in this dept.
Click to expand...
The P-Split is passive correct? Does it have any effect on the tone, loww of highs or low-end?
 
berumen77 said:
The P-Split is passive correct? Does it have any effect on the tone, loww of highs or low-end?
Click to expand...
I can tell you that the P-Split is completely passive. Also, as someone who is intensely focused on pedals/cables/etc changing tone - the Lehle does not seem to change the tone one bit. I primarily use it for reamping and things like that.
 
So have you guys been able to isolate the issue to the Guptech, or is it the nature of the specific amplifier loop? Do other gates act the same? I have a SUN, and love it, but I've never tried it with the 4cm using the loop. I run my OD's on its own loop, and it's my favorite gate so far out of the limited ones I've used. ie. Boss, MXR, Decimator series. That would be a bummer if they don't play well with loops.
 
Erock said:
So have you guys been able to isolate the issue to the Guptech, or is it the nature of the specific amplifier loop? Do other gates act the same? I have a SUN, and love it, but I've never tried it with the 4cm using the loop. I run my OD's on its own loop, and it's my favorite gate so far out of the limited ones I've used. ie. Boss, MXR, Decimator series. That would be a bummer if they don't play well with loops.
Click to expand...
Okay, this is gonna be long...

I tried it with my Bogner 101B and Classic, my Mesa Stiletto Ace, and my BluGuitar Mercury. It caused ground hum/buzz with 4CM, FX Loop and In/Out to Amp. I don't think it's the pedal's fault. I actually really like what the pedal does to the tone which is why I'm trying to solve it.

Guptech has a pdf article on noise gates that goes over all the possible wiring schemes as well as ground loops and how to combat them. He did contact me and thought it could be power supply issue but I'm not so sure. I tried several power supplies. Pedal is quiet when just the FX Loop is plugged in but as soon as it gets connected to the Amp Input it has hum/buzz. This is not a Guptech issue. I'm certain that this happens with other gates that use 4CM but we just don't notice or think about the ground hum/buzz since it kinda goes away when the gate is active. A company would have to have a way to buffer/split/iso the Input internally to avoid the issue.

Basically what I'm reading and researching is that the 4 cable method will just lead to ground loop hum/buzz especially if all 4 jacks are all metal nonisolated and grounded to the pedal or multi fx enclosure. Some guys even have issues with the expensive Fractal stuff and need special Humbuster cables and line isolaters. You could even end up having to run one or two line isolators to break the loop at amp input and FX return. So now you're buying more gear in order to use the pedal and possibly having to run one iso into the amp input compromising the the initial signal. So with 4CM, a gate will create more noise than you had initially but when activated and you turn the threshold up it "hides" the noise even though it's still in the signal when actually playing. Sustained notes have the noise on top of them.

Best way it seems is to avoid the 4 cable method altogether and maybe shoot for the 3 cable method, FX Loop Send and Return and a Key Input to trigger. This seems to be Guptech's preference in their pdf article. Leaving only one avenue for a possible ground loop, the Key Input. So then you need a buffered splitter with an isolated out for the Key Input so that it won't cause a ground loop or interfere with the signal to the amp input. I did a rough test with a passive A/B pedal with an out to the Input (Key) and used a patch cable with one of the grounds lifted. No buzz or hum and the gate was triggering at lower level on the threshold knob but the signal was affected a bit.

I ordered a hum eliminator to try and also ordered an Axess Electronics buffer/splitter (EVH) to troubleshoot. Kinda silly thinking about now that all I wanted to get rid of was amp hiss while on the Red Channel of my Bogner Ecstasys.
 
Last edited:
berumen77 said:
Okay, this is gonna be long...

I tried it with my Bogner 101B and Classic, my Mesa Stiletto Ace, and my BluGuitar Mercury. It caused ground hum/buzz with 4CM, FX Loop and In/Out to Amp. I don't think it's the pedal's fault. I actually really like what the pedal does to the tone which is why I'm trying to solve it.

Guptech has a pdf article on noise gates that goes over all the possible wiring schemes as well as ground loops and how to combat them. He did contact me and thought it could be power supply issue but I'm not so sure. I tried several power supplies. Pedal is quiet when just the FX Loop is plugged in but as soon as it gets connected to the Amp Input it has hum/buzz. This is not a Guptech issue. I'm certain that this happens with other gates that use 4CM but we just don't notice or think about the ground hum/buzz since it kinda goes away when the gate is active. A company would have to have a way to buffer/split/iso the Input internally to avoid the issue.

Basically what I'm reading and researching is that the 4 cable method will just lead to ground loop hum/buzz especially if all 4 jacks are all metal nonisolated and grounded to the pedal or multi fx enclosure. Some guys even have issues with the expensive Fractal stuff and need special Humbuster cables and line isolaters. You could even end up having to run one or two line isolators to break the loop at amp input and FX return. So now you're buying more gear in order to use the pedal and possibly having to run one iso into the amp input compromising the the initial signal. So with 4CM, a gate will create more noise than you had initially but when activated and you turn the threshold up it "hides" the noise even though it's still in the signal when actually playing. Sustained notes have the noise on top of them.

Best way it seems is to avoid the 4 cable method altogether and maybe shoot for the 3 cable method, FX Loop Send and Return and a Key Input to trigger. This seems to be Guptech's preference in their pdf article. Leaving only one avenue for a possible ground loop, the Key Input. So then you need a buffered splitter with an isolated out for the Key Input so that it won't cause a ground loop or interfere with the signal to the amp input. I did a rough test with a passive A/B pedal with an out to the Input (Key) and used a patch cable with one of the grounds lifted. No buzz or hum and the gate was triggering at lower level on the threshold knob but the signal was affected a bit.

I ordered a hum eliminator to try and also ordered an Axess Electronics buffer/splitter (EVH) to troubleshoot. Kinda silly thinking about now that all I wanted to get rid of was amp hiss while on the Red Channel of my Bogner Ecstasys.
Click to expand...
This was my exact experience when I went through the same issue(s). It's funny how difficult some things can be if you care a lot about the guitar tone.
 
berumen77 said:
Okay, this is gonna be long...

I tried it with my Bogner 101B and Classic, my Mesa Stiletto Ace, and my BluGuitar Mercury. It caused ground hum/buzz with 4CM, FX Loop and In/Out to Amp. I don't think it's the pedal's fault. I actually really like what the pedal does to the tone which is why I'm trying to solve it.

Guptech has a pdf article on noise gates that goes over all the possible wiring schemes as well as ground loops and how to combat them. He did contact me and thought it could be power supply issue but I'm not so sure. I tried several power supplies. Pedal is quiet when just the FX Loop is plugged in but as soon as it gets connected to the Amp Input it has hum/buzz. This is not a Guptech issue. I'm certain that this happens with other gates that use 4CM but we just don't notice or think about the ground hum/buzz since it kinda goes away when the gate is active. A company would have to have a way to buffer/split/iso the Input internally to avoid the issue.

Basically what I'm reading and researching is that the 4 cable method will just lead to ground loop hum/buzz especially if all 4 jacks are all metal nonisolated and grounded to the pedal or multi fx enclosure. Some guys even have issues with the expensive Fractal stuff and need special Humbuster cables and line isolaters. You could even end up having to run one or two line isolators to break the loop at amp input and FX return. So now you're buying more gear in order to use the pedal and possibly having to run one iso into the amp input compromising the the initial signal. So with 4CM, a gate will create more noise than you had initially but when activated and you turn the threshold up it "hides" the noise even though it's still in the signal when actually playing. Sustained notes have the noise on top of them.

Best way it seems is to avoid the 4 cable method altogether and maybe shoot for the 3 cable method, FX Loop Send and Return and a Key Input to trigger. This seems to be Guptech's preference in their pdf article. Leaving only one avenue for a possible ground loop, the Key Input. So then you need a buffered splitter with an isolated out for the Key Input so that it won't cause a ground loop or interfere with the signal to the amp input. I did a rough test with a passive A/B pedal with an out to the Input (Key) and used a patch cable with one of the grounds lifted. No buzz or hum and the gate was triggering at lower level on the threshold knob but the signal was affected a bit.

I ordered a hum eliminator to try and also ordered an Axess Electronics buffer/splitter (EVH) to troubleshoot. Kinda silly thinking about now that all I wanted to get rid of was amp hiss while on the Red Channel of my Bogner Ecstasys.
Click to expand...
Thanks for the findings. I wonder if something like the zuul+ would help since it has a ground lift switch.
https://fortinamps.com/products/zuul-plus-blackout
 
GuitarGuy08 said:
This was my exact experience when I went through the same issue(s). It's funny how difficult some things can be if you care a lot about the guitar tone.
Click to expand...
Most of the time I just want to plug straight into the amp and just have a delay in the loop. Pretty simple...and I just want to get rid of the hiss from the preamp gain.

If I want the extra noise I can always just plug into one of my Echoplex EP-3 units.
 
Last edited:
Erock said:
Thanks for the findings. I wonder if something like the zuul+ would help since it has a ground lift switch.
https://fortinamps.com/products/zuul-plus-blackout
Click to expand...
Fortin makes the Roach splitter for the Zuul as well. Do you know if the 3 outs on it are isolated? Looked promising.

Axess Electronics also has a really nice mini COMPATT/X ISO PLUS that has an iso out, ground lift and phase reverse that I think would work for a noise gate Key Input signal.

https://axesselectronics.com/products/compatt-x-isoplus
 
berumen77 said:
Fortin makes the Roach splitter for the Zuul as well. Do you know if the 3 outs on it are isolated? Looked promising.

Axess Electronics also has a really nice mini COMPATT/X ISO PLUS that has an iso out, ground lift and phase reverse that I think would work for a noise gate Key Input signal.

https://axesselectronics.com/products/compatt-x-isoplus
Click to expand...
Sorry, I don't. I just remembered seeing the ground lift switch. Would be interested to hear how it works out.
 
You must log in or register to reply here.
Back
Top