Bypassing buffer on EGv2

V

vertigocycles

Member
I’ve read through the manual several times and viewed a number of threads here and still am not 100% certain if the front panel input is routed into the buffer.

If I want to bypass the input buffer, do I need to run a cable from “From Front” to “Input 1-4”?

Currently, I have the instrument input on the front panel and the first pedal is connected to the send1 and return1. I don’t have anything connected to the “from front” either of the buffer jacks or the “input 1-4”. Clearly the instrument input is routed to send1, but I don’t know if the buffer is in the path or not.
 
If you don't have anything connected to From Front, Buffer In, Buffer Out or In 1-4, then the buffer is in the signal path by default. If you want to bypass it, you're correct that connecting From Front to In 1-4 is the way to bypass it.
 
rjmmusic said:
If you don't have anything connected to From Front, Buffer In, Buffer Out or In 1-4, then the buffer is in the signal path by default. If you want to bypass it, you're correct that connecting From Front to In 1-4 is the way to bypass it.
Click to expand...
Thank you for the response, Ron. Next question…should be be noisy when the buffer is bypassed? Sounds like a quiet ground loop with an octave higher square wave on top of it. When the buffer is in the circuit, everything is nice and quiet. Bypassed is pretty ugly
 
When you're not using the buffer, there might not be a ground connection from the EG's chassis to ground. The connection is only made in a few places, in an attempt to prevent ground loops. The first thing to try is switch the ground lift switch on the rear.
 
rjmmusic said:
When you're not using the buffer, there might not be a ground connection from the EG's chassis to ground. The connection is only made in a few places, in an attempt to prevent ground loops. The first thing to try is switch the ground lift switch on the rear.
Click to expand...
Thanks. I tried the ground lift switch yesterday and it didn’t change things. I’ll remove it from the rack today to see if it changes things. I’ve got insulation washers on everything. I know that sometimes bare spots on the rack units where they make contact can cause issues. Everything here is in perfect shape so I doubt that’s the issue, but I’ll try to rule it out anyway.
 
The problem is actually the reverse - without the buffer, you have too few ground connections. If you have an unused loop, connect the buffer input or output to one of the loop's jacks. That will complete the ground connection. Otherwise, what we tend to do is open up one of the cables connecting to a loop, solder an extra wire to the ground, then connect that wire to another 1/4" plug - connecting the ground only - and plug that into the buffer in or out. That will give you a ground connection without actually using the buffer.
 
rjmmusic said:
The problem is actually the reverse - without the buffer, you have too few ground connections. If you have an unused loop, connect the buffer input or output to one of the loop's jacks. That will complete the ground connection. Otherwise, what we tend to do is open up one of the cables connecting to a loop, solder an extra wire to the ground, then connect that wire to another 1/4" plug - connecting the ground only - and plug that into the buffer in or out. That will give you a ground connection without actually using the buffer.
Click to expand...
Thank you so much, Ron! I'll try it right now.

edit: tried the extra loop method and there was no change. I'll make a cable to try the other method later
 
Last edited:
I was out of town for a while and didn’t get to try the other method until today. I connected an 18g wire to a ground in loop 1 to another TS plug that I tried in both of the buffer jacks…no change. I even pulled the unit, removed all the relays that I had previously installed to make them stereo loops (I have everything in the first four slots using TS plugs, not TRS) and not surprisingly, there was no change. Had to try just in case and it was easier than making a bunch more TRS cables.

Is there anything else that I’m overlooking?

I’m just trying to get the buffer away from my fuzz pedal. It seems to really decrease the touch sensitivity. It responds better with the buffer out of the signal chain but the extra noise is unbearable.

Just for fun, I’ll try going “from front” into one of the last four loops with the fuzz pedal, and then into “input 1-4” to see if it makes a difference

edit: Same noise. This pedal might have to go on the floor unless there’s a good suggestion on how to deal with the noise.
 
Last edited:
Not sure what's going on here, but it still seems like a ground issue.

What if you plug your guitar into In 1-4, and connect the buffer to Out 1-4 and In 5-8? That would put the buffer after loop 4.
 
rjmmusic said:
Not sure what's going on here, but it still seems like a ground issue.

What if you plug your guitar into In 1-4, and connect the buffer to Out 1-4 and In 5-8? That would put the buffer after loop 4.
Click to expand...
I'll try it later today, thanks for the suggestion.

side question...how sensitive is the EG to EMI? It's mounted under my Furman
 
It's a steel enclosure, which is pretty good for shielding. But if something is really radiating a lot of EMF or magnetic field, it can definitely get in. But, if using the buffer eliminates the issue, grounding is still the most likely suspect. Lack of proper grounding will make a good shield into a bad one.
 
using loops 5-8 and putting the buffer after seems to have done the trick, though I think there's something to learn here...I just don't know what it is yet. I'm going to want to use 1-4 as I continue to setup this rig over the next few weeks and would love to find a solution to the hum problem.

I used a decibel meter placed about 1/2r to a speaker cone to grab a little data.
With everything on in the room, and no instrument plugged in, the room is about 42dB.

With a guitar plugged directly into the preamp, EG completely out of the path, it's about 50dB

With four devices in loops 1-4, instrument into the front panel, "from front" into "1-4" and 1-4 out directly to the preamp - 63dB*
Using the same setup EXCEPT for runing "1-4 out" to the buffer in, and buffer out to the preamp - 52dB**

Same setup, but instrument directly into "1-4 in" - 53dB**

devices in 5-8, instrument into front panel, "from front" into "in 5-8", "5-8 out" to preamp - 64dB*
same setup but "5-8 out" to buffer in, buffer out to preamp - 53dB**

*the loudest frequency was around 2200Hz, but to my ear, there's also ground loop with a prominent ~120Hz and significant white noise on top of all of it. The graph wasn't very peaky...pretty mellow slope up to the 2200Hz peak.
** the loudest frequency was right around 120Hz with a prominent peak

Having the buffer in the circuit seems to be the big difference and the fuzz is much more responsive to touch and volume controls with the buffer behind it.
 
You must log in or register to reply here.
Back
Top