Suhr PT15IR with HX Effects - 4CM question - ground hum?

[ledvedder]

Hi guys, when using my HX Effects with the PT15IR in 4 cable method, will I need some sort of gadget to help with any ground loop issue? I had this problem with a Friedman amp, but don't have it with my Marshall or EVH amps. My HX Effects is currently at my rehearsal space, so I'm not able to try it until next week. But, if I need something, I figure I can order it now.

 

[rollyfoster]

Hi guys, when using my HX Effects with the PT15IR in 4 cable method, will I need some sort of gadget to help with any ground loop issue? I had this problem with a Friedman amp, but don't have it with my Marshall or EVH amps. My HX Effects is currently at my rehearsal space, so I'm not able to try it until next week. But, if I need something, I figure I can order it now.

No issues with that amp and an HX stomp for me but had to use this thing with a Mobius. Doesn’t hurt to have one lying around.

Samson MLI1-Mono Passive Isolation Box (MLI1)

 

[ledvedder]

No issues with that amp and an HX stomp for me but had to use this thing with a Mobius. Doesn’t hurt to have one lying around.

Samson MLI1-Mono Passive Isolation Box (MLI1)

Would I need one of these for every cable run?

 

[rollyfoster]

Would I need one of these for every cable run?

no, only one from the pedal to the amp FX loop return if you end up having issues

 

[mlkIII]

no, only one from the pedal to the amp FX loop return if you end up having issues

I never really noticed the hum from 4CM with my HX Effects but it is definitely there now that I read this. Just ordered the Samson you linked @rollyfoster. Thanks a ton!!

 

[sinasl1]

You will need the isolation transformer for the run from the HX fx send to the amp input. That’s the only one that you need to do. I used this set up for all my clinics in 2019.

 

[ledvedder]

I've been using mine without any isolation transformer. It's just powered by a Trutone isolated power supply. I haven't been getting nearly the amount of unwanted noise like I was getting when I had my Friedman Runt. But I still ordered the Samson isolation box.

 

[Ciro Scotto]

I use the Lehle P-iso, which is a really good isolation transformer:

LEHLE

Passive signal isolator with high-impedance LEHLE TRANSFORMER HZ

lehle.com

I also use the Mesa Clearlink Receive, but it is significantly more expensive.

I also have the HXFX used in the 4Cm with my JP-2C, and I get a ground loop. Either the Lehle or Mesa fixed It. As Pete Thorn suggested, I use it between the HXFX send and amp input.

 

[gtrnstuff]

You will need the isolation transformer for the run from the HX fx send to the amp input. That’s the only one that you need to do. I used this set up for all my clinics in 2019.

Same experience here.
I don't need to iso with every head, but with the ones that I do, only one, from the Helix to the amp input.
I use a Suhr Iso Boost or Suhr buffer, iso out, but there are several good options.

 

[Husky]

transformer specs showing loss of bass are when the transformers are loaded hard. For these purposes it isn’t so critical since you are usually running in to a high impedance. You could use our buffer or a passive transformer even built in to the cable.

Which one do you use, Pete? I'm reading different things about the importance of the quality of the transformer, the transformer ratio, and any gain changes (+ or -). The Samson MLI1 transformer referenced in this thread shows a gain spec of +0.2dB. Another popular one, the Radial SB-6, indicates a gain spec of -2dB which seems like it would be no bueno. Both units are passive.

 

[Ciro Scotto]

I'm trying to understand if there will be any sonic difference between a $120 "higher end" ISO transformer like a Lehle P-ISO vs something like the $40 Samson MLI1 referenced earlier in the thread.

One reason I like the P-iso and the Clearlink (and I am sure it will be the same for the Suhr) is they are designed to go before the input of the amp. Before so many choices for iso transformers existed, I used the Ebtech Hum Eliminator. I never liked it because I felt it changed the transient attack of the guitar, which was especially noticeable when palm muting. I have nothing but anecdotal evidence for this, but with both the P-iso and Clearlink, I notice absolutely no change in feel, tone, or any other aspect of the sound when it is placed before the amp input.

 

[gtrnstuff]

One reason I like the P-iso and the Clearlink (and I am sure it will be the same for the Suhr) is they are designed to go before the input of the amp. Before so many choices for iso transformers existed, I used the Ebtech Hum Eliminator. I never liked it because I felt it changed the transient attack of the guitar, which was especially noticeable when palm muting. I have nothing but anecdotal evidence for this, but with both the P-iso and Clearlink, I notice absolutely no change in feel, tone, or any other aspect of the sound when it is placed before the amp input.

The big thing about using the EbTech before guitar-level amp input is you really need a buffer before it. Even a BOSS pedal in "bypass" does the job.
I've used those to solve ground loops in several rigs.
Now, with some of the newer solutions that have built in buffers it's a bit easier, and more transparent.

 

[Ciro Scotto]

The big thing about using the EbTech before guitar-level amp input is you really need a buffer before it. Even a BOSS pedal in "bypass" does the job.
I've used those to solve ground loops in several rigs.
Now, with some of the newer solutions that have built in buffers it's a bit easier, and more transparent.

That makes sense since I run a buffer before the P-iso and the Clearlink, which is how the Clearlink is intended to operate according to the manual (it is usually paired with the Clearlink Send). I have a couple of old Ebtech Hum Eliminator (I even have an older Art version), so just for kicks I will try it with a buffer. I have had such good luck with the other iso transformers that I am reluctant to use anything else. Plus, their size factor works really well with my cramped rigs.

 

[magnus]

transformer specs showing loss of bass are when the transformers are loaded hard. For these purposes it isn’t so critical since you are usually running in to a high impedance. You could use our buffer or a passive transformer even built in to the cable.

Out of curiosity: couldn't a problem like this simply be solved by cutting a ground in some of the signal cables to break the ground loop? Is a transformer really needed?

 

[gtrnstuff]

Out of curiosity: couldn't a problem like this simply be solved by cutting a ground in some of the signal cables to break the ground loop? Is a transformer really needed?

In some cases that does work. I've simply lifted the shield on one end of a TS cable from an amp's load box going to a line mixer in my rack rig. No more ground loop. I'll do that instead of the much less safe 3-to-2 prong AC plug adaptors.
I don't recall it working from a device to an amp's guitar input, but it might.
Most signal switchers I've encountered with multiple amp outputs have iso transformers on the sends to the amp inputs, so I figured guys like Bob Bradshaw knew the best way to make work.

 

[tvegas99]

…

 

[Husky]

Out of curiosity: couldn't a problem like this simply be solved by cutting a ground in some of the signal cables to break the ground loop? Is a transformer really needed?

Often times absolutely and is my first choice. If it works and no noise you can stop there