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Jim dunlop volume pedal review & volume adjustment fix

July 15th, 2009 · 23 Comments

This article was meant to be a Dunlop volume pedal (GCB-80 is the model) review but as it turns out, it will be a how-to-fix-it manual as well…

Let’s start at the end – this pedal has one “tiny” problem -it does not allow no volume at all, but rather the pedal starts from some volume (still, very audible, especially if distortion effect applied) to full. It’s kinda weird that the pedal does not fully do, the only thing it’s supposed to do – control the volume.

From visiting a few forums I’ve learned that this is a known issue among people who bought it and most people were pretty disappointed . But, thinking about it again, maybe it’s how the manufacturer intended it to be, low volume for rhythm parts and then break into heavy parts with full volume. In this way, you can never mute the guitar , you got minimum and maximum set.

Anyway, this was no good for me , cause I needed a volume pedal for mostly guitar effects, such as whaling sound (Mark Knopfler’s  “brothers in arms” for ex.) and so on. It is more practical to use a pedal then messing with the guitar volume knob, although the pedal does take some time to get used to.

So, I looked here and there, and found out there is a remedy to this, but no explanation whatsoever on how to do it. But, at least now I knew that the potentiometer inside can be adjusted. It’s not a technical or electronic limitation, or malfunction etc.

Before we get into how to fix it, you probably ask, why didn’t I return it?
Well, the pedal itself is very sturdy, built from solid aluminum. It’s heavy too which is great cause you don’t want a light pedal that will flip over if you pull the guitar cable a bit or slightly kick it with your foot (I also have the Dunlop cry baby wah wah™ (GCB-95), so I was familiar with the built quality). So, it’s stable. It looks good. The pedal movement up and down is very smooth and accurate, and the sound is neutral, with no noise what so ever. potentiometer (the electric component that varies the volume) is said to have a million cycle life span. Mine has 999,800 cycles left 😛

FIXING the volume pedal step by step

In simple words, the pedal is just a volume knob actuated by your foot. This volume knob in the pedal, was not set to the minimum it can be set to, but it starts from some volume. What you want to do, is open the pedal, and reset the volume knob (which is a gear) fully clockwise – to volume off.
This is how you do it:


Unscrew the 4 screws at the bottom

This is how it looks inside. we got the white plastic grommet (1) that pushes the arm (2) on to the gear (3)

This is how it looks inside. we got the white plastic grommet (1) that pushes the arm (2) on to the gear (3). The cream colored paste you see is grease, don’t wipe it, leave it as it is.

4_Jim_dunlop_volume_pedal_r open the screw a bit (1) and put aside the grommet. Now you can disengage the arm (2) from the gear (3), push it gently to the right side as shown while you keep the pedal closed (arm 2, has come to the end of it's travel) , like as if it would be when your foot lowers the volume (look at the next photo). When the arm is down, rotate with your hand the gear (3) fully clockwise.

Do this step when the pedal is set to minimum. The arm (2) should be as in the photo, at the end of it’s travel (way down)- you will keep this pedal position throughout all the steps . Open the screw a bit and put aside the grommet (1). Now you can disengage the arm (2) from the gear (3), push it gently to the right side as the arrow shows. When the arm is disengaged, rotate with your hand the gear (3) fully clockwise.


remember to keep holding the pedal in this position. Front pedal side, the one with the HIGH GAIN logo, should be fully opened.


Follow instructions. If you see you can’t set the arm (2) with the gear (3) when the pedal is fully open (like in previous photo) , close it just a tiny bit, as much needed to engage the gear/arm teeth together. When you’re done, turn back the grommet on to the arm, and tighten the retaining screw, don’t over do it, just tight enough to secure the grommet. One important thing – the arm (2) should engage with the gear freely (3), if you see you’re using force to engage them both, skip 1 tooth and it should engage perfectly.

Before you put on the back cover, test your pedal.

Before you put on the bottom cover, test your pedal.

So, to buy it or not? that’s up to you. after this quick fix that took me about 5 minutes (with photography) I got a great volume pedal. If you think you know what to do, and you got the idea, then this pedal is recommended.

Jim dunlop  GCB-80 volume pedal on


Tags: DIY (do it yourself) · Music · Musical Instruments


1 Star2 Stars3 Stars4 Stars5 Stars (3 votes, average: 5.00 out of 5)

  • Wow thanks for the great tip!

  • guitar 666

    nice tutorial, thanks.

  • Genghis

    Thanks for the insight!
    Question: When you use this fix do you sacrifice a little of the “Max” volume setting?

  • Ilan (admin)

    good question, as far as my ears can tell, the answer is NO. To test it, I recorded two short pieces of guitar , and played them one after the other back and forth. I didn’t notice any difference in volume.
    The wave level (graphic) of both looked the same too.

    I assume the explanation to this, is that the potentiometer reaches max levels, before the end of it’s turn.


  • nice work. you saved the day….

  • Ngoo Nam

    Thanks, dude.
    I was going to shelve the GCB-80 for another volume pedal. Your article-fix made it stay on the pedalboard for keeps.

  • drumachine

    Great tutorial thanks! But wouldn’t this void the warranty on a new unit? If it ever dies within the one year warranty period you would likely be out of luck.

  • Ilan (admin)

    well yes, I suppose it can void the warranty. Thanks for the comment.


  • Rob-Roy

    Hey, great tutorial! I am still waiting for this pedal to arrive in the mail, and plan on making this adjustment as soon as I toy around with it for a few minutes. I agree…you totally need a zero volume position. Thanks!

  • Rob-Roy

    Okay, so my pedal came, I performed your little fix, and it works like magic! One thing that I noticed is, before I made the adjustment, the last 1/2 inch or so in the toe-down position didn’t make any audible increase in volume. But now the volume increases all the way to the top (toe-down). Thanks!

  • Awesome tutorial! I just did it. Been wondering about this for a while.

  • Jim

    @Ilan (admin), Rob-Roy:
    Sounds to me like it is a logarithmic pot instead of a linear one if there is not a lot of difference towards the end of the travel.

    Good that you have documented this fix because I might well invest in the pedal knowing that it does full volume sweep with a little adjustment makes it a worth while investment – especially since I can’t build it to the same quality from scratch.

  • Jury

    thanks. that was very useful

  • Jack Hill

    Thank you for the volume pedal tip. I tried it and

    it worked as demonstrated. Thanks again.

  • Thanks for this tip. It worked exactly right. I am so happy!!

  • Nev

    i have this pedal and when i got it it had full volume right down to none,problem is i wanted a pedal that had a minimum volume as well as max (i use my tuner to cut sound completely),have you any idea if doing the opposite of this method would allow me to set a minimum volume?

  • Ilan

    @ Nev

    You can use the same instructions to set the minimum/initial volume as you please. That is done by positioning the “gear” (number 3 in the photo), at fifth OR quarter of the way and so on).

  • I bought this volume pedal from amazon and thought I would need to modify it as shown ,BUT it goes from full volume to zero volume so I am satisfied. It will take some use to get the volume swells sounding like they do when I use the volume knob on my strat. , tele, and ES 335. It is a sturdy reliable volume control pedal which also works well on my keyboard especially for organ volume swells used in concert with the Jim Dunlop Rotovibe.

  • Ilan

    @ taariq hassan

    Thanks for the comment. Maybe Dunlop fixed it 🙂 ?
    Nice music btw, loved “delhi underground”.

  • Carlos

    Thanks a lot from Colombia

  • Alex Kahanga

    excelente… lo modifique y ahora a probarlo…! gracias desde chile

  • Pingback: The Best Volume Pedal (2016) | The Smart Consumer()

  • Thanks for your tutorial, i would like to try this too.

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