GE-7 in effects loop for boost - works too well!

doghouseman

Senior Member
Messages
3,046
I have been running a GE-7 in the effects loop (serial) of my Marshall DSL100, and it works too well. By that I mean, I just increase the boost output of the GE-7 a small amount and it seems like I get a huge increase in volume. I mean, I can't actually adjust the boost in a small enough increments to get the boost in volume that I want. So I started using it as just a treble boost, which works a little better, but I am wondering what the problem is.

Is this because I am using it at the end of my chain in a serial effects loop?

If I put it at the beginning of the chain maybe the boost would not be so dramatic?

Or maybe I should put it in front of the amp?
 

teefus

Senior Member
Messages
8,941
I have been running a GE-7 in the effects loop (serial) of my Marshall DSL100, and it works too well. By that I mean, I just increase the boost output of the GE-7 a small amount and it seems like I get a huge increase in volume. I mean, I can't actually adjust the boost in a small enough increments to get the boost in volume that I want. So I started using it as just a treble boost, which works a little better, but I am wondering what the problem is.

Is this because I am using it at the end of my chain in a serial effects loop?

If I put it at the beginning of the chain maybe the boost would not be so dramatic?

Or maybe I should put it in front of the amp?
it might be the level of the loop as set by marshall. i assume this model doesn't have loop in/out controls. you might be able to adjust the freq levels instead of the overall volume on the ge7. i have had better luck with a ge7 in the loop of my rivera knucklehead 55 than in front of the amp. sometimes there isn't enough headroom to boost in front of the amp.
 

doghouseman

Senior Member
Messages
3,046
The loop level for the Marshall is set correctly. The level works well with all my other pedals. The DSL 100 has a button next to the effects loop to set the a low or high level, but there is no knob on the front of the amp. The button allows you to use rack effects with a lower output in the loop. I am adjusting the frequency on the GE-7 but even that requires a very fine adjustment.
 

teefus

Senior Member
Messages
8,941
have you tried a volume pedal in the loop as an alternative. my eb mvp jr has a gain and min. volume adjustment that works well for this purpose.
 

demea26

Member
Messages
1,391
I've been using the GE-7 exactly like you with my DSL50 and numerous other amps successfully. I set everything flat, with a slight rainbow in the mids.
The EQ and volume sliders are VERY sensitive

Works great as a solo boost.
 

NorCal_Val

Member
Messages
13,528
Great trick! I used to do that many years ago with my Randall RG-80;
Boss EQ pedal in the effects loop, and the old DOD Bi-FET boost pedal
in front.
 

Psychotronic

Member
Messages
850
I stopped using my GE-7 as a boost because it was just too difficult to set a usable volume. That slider is sensitive.
 

c diddy 5000

Member
Messages
468
I stopped using my GE-7 as a boost because it was just too difficult to set a usable volume. That slider is sensitive.
I too, have had a similar experience with the GE-7. It works really well for this function, but very touchy to dial in the right amount of vol. I have recently switched to the source audio programmable eq, and that problem is solved. It allows for incremental changes, and is quieter.
 

doghouseman

Senior Member
Messages
3,046
I've been using the GE-7 exactly like you with my DSL50 and numerous other amps successfully. I set everything flat, with a slight rainbow in the mids.
The EQ and volume sliders are VERY sensitive

Works great as a solo boost.
Interesting... I wonder if I would have slightly more control using it as a mid boost. Yes, the EQ and volume sliders are VERY VERY sensitive.
 

doghouseman

Senior Member
Messages
3,046
have you tried a volume pedal in the loop as an alternative. my eb mvp jr has a gain and min. volume adjustment that works well for this purpose.
Yes, I have tried a volume pedal in the loop. My problem is that I have used a Wah pedal for too long and I can't use the volume pedal correctly. So, the first thing I do with the volume pedal is push it all the way to the ground, and I have trouble leaning back on it. I just get all this interference in my head from using the wah for so long... just not enough practice, that's all. I just recently pulled the volume pedal back off my board. The volume knob on my guitar is more intuitive more me to use, and I actually like using a boost pedal, just need to find the right settings.
 

doghouseman

Senior Member
Messages
3,046
Just wondering if anyone has found a solution to this problem so I am bumping this old thread. I would like to find something similar to a GE7 to use in my effects loop as a boost pedal, but with a slider that is not so sensitive. I am also considering a modification to the slider to make it less sensitive.
 

Kyle B

Silver Supporting Member
Messages
5,102
Just wondering if anyone has found a solution to this problem so I am bumping this old thread. I would like to find something similar to a GE7 to use in my effects loop as a boost pedal, but with a slider that is not so sensitive. I am also considering a modification to the slider to make it less sensitive.
I was looking at the same thing you are (Using my GE-7 as a lead boost through the effects loop) and finding the same thing you are (the level control is way too sensitive to be practical). I thought maybe I'd google a bit and see if anybody had a mod for this. Coming upon this thread, I realize said mod probably doesn't exist.

...

So I developed one myself :)

...

Basically, the goal would be to limit the max & min gain due to the level slider. Looking at the schematic, I realized R26 and R27 would be the resistors to target.

I first mapped out what the pedal did. I fed in a 1kHz test sinewave, and measured AC output. For full geek-factor, I also include dB values.

For the 'stock' circuit, I found:

EFFECT OFF: 0.050VAC
LEVEL MIN: 0.007VAC (-17dB)
LEVEL MID: 0.040VAC (0dB) (Ideally this would have been 0.050VAC .. but my 0dB point is a tiny bit quieter than 'effect off')
LEVEL MAX: 0.258VAC (+14dB)

Pedal specs are +-15dB gain, so it was good to see my measurements agree fairly well.

I then moved the slider to points I thought were "far enough plus a little". "Far enough", as you know, isn't very far at all from the MID position.

TARGETS:
LEVEL MIN: 0.012VAC (-12dB)
LEVEL MAX: 0.100VAC (+6dB)

Some experimentation and I arrived at
* feedback resistor R26 change from 10k to 5.1k
* other resistor R27 change from 10k to 3.0k

Doing this I arrived at:
LEVEL MIN: 0.012VAC (-12dB)
LEVEL MID: 0.024VAC
LEVEL MAX: 0.101VAC (+6dB)

Note that changing R26 will (roughly) change just the MIN output, while changing R27 will (roughly) change just the MAX output. I'm probably gonna tweak it a bit, raise the MIN level up. I'm thinking -3dB is probably a better MIN value than -12dB.

BTW, my pedal has a different layout than the one I'm finding in GOOGLE searches for the GE-7 service manual (such as the one found here), so I won't tell you exactly where these resistors are physically located.

Even though the PCB layout shown in that link doesn't match mine, the schematic seems to be same (in the area of interest at least)

I'm pretty sure a similar mod to R24/R25 will provide a similar effect to the issue of the EQ sliders also being too sensitive. I'm probably gonna try that too, now that I got the fundamentals worked out :)

http://www.hobby-hour.com/electronics/s/schematics/boss-ge7-equalizer-schematic.png

 

doghouseman

Senior Member
Messages
3,046
I was looking at the same thing you are (Using my GE-7 as a lead boost through the effects loop) and finding the same thing you are (the level control is way too sensitive to be practical). I thought maybe I'd google a bit and see if anybody had a mod for this. Coming upon this thread, I realize said mod probably doesn't exist.

...

So I developed one myself :)

...

Basically, the goal would be to limit the max & min gain due to the level slider. Looking at the schematic, I realized R26 and R27 would be the resistors to target.

I first mapped out what the pedal did. I fed in a 1kHz test sinewave, and measured AC output. For full geek-factor, I also include dB values.

For the 'stock' circuit, I found:

EFFECT OFF: 0.050VAC
LEVEL MIN: 0.007VAC (-17dB)
LEVEL MID: 0.040VAC (0dB) (Ideally this would have been 0.050VAC .. but my 0dB point is a tiny bit quieter than 'effect off')
LEVEL MAX: 0.258VAC (+14dB)

Pedal specs are +-15dB gain, so it was good to see my measurements agree fairly well.

I then moved the slider to points I thought were "far enough plus a little". "Far enough", as you know, isn't very far at all from the MID position.

TARGETS:
LEVEL MIN: 0.012VAC (-12dB)
LEVEL MAX: 0.100VAC (+6dB)

Some experimentation and I arrived at
* feedback resistor R26 change from 10k to 5.1k
* other resistor R27 change from 10k to 3.0k

Doing this I arrived at:
LEVEL MIN: 0.012VAC (-12dB)
LEVEL MID: 0.024VAC
LEVEL MAX: 0.101VAC (+6dB)

Note that changing R26 will (roughly) change just the MIN output, while changing R27 will (roughly) change just the MAX output. I'm probably gonna tweak it a bit, raise the MIN level up. I'm thinking -3dB is probably a better MIN value than -12dB.

BTW, my pedal has a different layout than the one I'm finding in GOOGLE searches for the GE-7 service manual (such as the one found here), so I won't tell you exactly where these resistors are physically located.

Even though the PCB layout shown in that link doesn't match mine, the schematic seems to be same (in the area of interest at least)

I'm pretty sure a similar mod to R24/R25 will provide a similar effect to the issue of the EQ sliders also being too sensitive. I'm probably gonna try that too, now that I got the fundamentals worked out :)

http://www.hobby-hour.com/electronics/s/schematics/boss-ge7-equalizer-schematic.png


Cool, thanks. I might give this to my guitar tech to try out.
 

DaveKS

Member
Messages
16,704
I stopped using my GE-7 as a boost because it was just too difficult to set a usable volume. That slider is sensitive.
^^^^ This, sliders are to touchy. It also colors your tone and makes it seem fatter even if set flat. There's a reason so many folks do mods to these pedals.

Get a EQD Tone Job or VFE Rocket, you'll be much happier.
 






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