Fulltone GT-500 upgrades and mods info

Discussion in 'Effects, Pedals, Strings & Things' started by Angle Loss, Feb 10, 2008.


  1. Angle Loss

    Angle Loss Supporting Member

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    After reading another thread on the GT-500, I found out that Fulltone has made some mods to the GT already. I contacted axe2grind who did some of the mods, and was given the Fulltone pdf by Rod. Thanks to both of you for the information!

    There are four mods:
    #1--lessen compression in distortion (most all GT's already have this).
    #2--smoothen distortion (pre-gain treble reduction I believe)
    #3--"Highs" control mod to reduce treble
    #4--bass reduction for boost

    My GT is #62 and was once sent in to Fulltone for a bad Dist. volume pot. When I checked the mods, I noticed that mine already had the input mod (#1). I haven't done mod #3 (highs control mod), and have no need for the boost mod.

    I spent all my time experimenting with mod #2, which I believe affects the pre-distortion treble (someone in the know correct me if I am wrong). I used some alligator clamps to quickly change different value caps. 330pf (per the mod) was pretty subtle, though it did take away a little harshness. I found that it sounded better, but couldn't really put my finger on it. 470pf made a noticeable difference in the harshness, but didn't really change the way the drive felt too much. It stayed pretty clear. At 1nf, the pedal became very creamy sounding. It was like the distortion channel went from JCM800 to JTM45. I liked it through my '65 Princeton, but felt it might be a shade too dark with my TopHats. In addition, it came a lot closer to some of my other overdrives in tone. I finally settled on the 470pf and hope it will be the perfect compromise as I test it the next few weeks. I am pretty sure it will stay.

    I will probably update this thread myself after some time testing. I hope it will be useful for anyone who is almost really happy with the GT. If anyone can contribute info on the other mods, please post it for the community. Now if could only mod the ugly gray paint job--how boring! ;)
     
  2. 205

    205 Senior Member

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    I did all the mods , except for the first one which was already done.

    Made a huge difference!
     
  3. DeuceII

    DeuceII Supporting Member

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    So what serial number is "V2", with mods already included? Or are these not being done by Fulltone, just DIY'ers? It's on my list, but I don't wanna have to do a bunch of mods (my soldering skills suck).
     
  4. Analog Assassin

    Analog Assassin Senior Member

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    So what's the strategy with all the mods? Keeps people buying new ones? Or is it that he can't design the pedal right the first time?
     
  5. Yutaka

    Yutaka Member

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    It's to attract the haters on TGP, to have them create a 10+ pages long thread of negativity/misinformation about his product, so that Fulltone can eventually sue TGP.

    :BEER Kidding.
     
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  6. Angle Loss

    Angle Loss Supporting Member

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    There really are no V2s. Mod #1 starts at 169, mod #2 at 1743, mod #3 at 1211, mod #4 at 2382. I have labeled them with numbers from what page they appear on the pdf.

    Repeatedly modifying and updating circuits is not anything new. Quite frankly, I laugh at Lovepedal's inconsistency, but others here love it and like collecting the variations as if they were baseball cards--and that is okay. Eventide offers software upgrades for their processors and pedals, and nobody seems to get upset about it! But this thread is not about whether you approve or disapprove of modifications and updates. It is merely to help those that may want to do them. It is only being done by DIY'ers. To my knowledge, Fulltone isn't offering upgrades, and I highly doubt they ever will again after the OCD.

    If anybody has info on mod #3, I would be interested in hearing what it does. Is it pre-gain or post gain EQ'ing? How does it change the sound?
     
  7. DeuceII

    DeuceII Supporting Member

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    Yeah, I figured there weren't really v2's per se, especially after all the talk over the OCD versions. But I'm confused on two things you state above that seem to cancel each other out. You state certain mods begin after certain serial numbers, but then state that only DIY'ers are doing them. I'm gonna assume you mean that the new versions from Fulltone ship with all the mods, and previous ones include the mods relevant to their serial numbers. But any previous one without a given mod (ex. serial #168 and lower have none of the mods) are only modable by DIY as Fulltone isn't doing them via upgrades. I think I've answered my own confusing question, but could you verify that my assumption is accurate?
     
  8. Angle Loss

    Angle Loss Supporting Member

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    Hey Deuce, that is my understanding as well. I've just been spending some time with mine over the last hour through my TopHat T-50 (BassmanJTM45/Plexi cross). The distortion side is going to see a lot more use.
    :BEER
     
  9. scottro123

    scottro123 Member

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    OK, so I received the PDF from Fulltone, but I'm confused on where to source parts from. I've built a BYOC Large Beaver as well as soldered pickups and other minor repairs, so I feel comfortable doing the mods.

    This is my first time sourcing the parts, when I search I either get way too many matches or none at all. Does anyone have the correct part numbers from SmallBear or Mouser?

    Thanks!


    For the search engine: GT500 GT 500
     
  10. scottro123

    scottro123 Member

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    Bump for a little help?
     
  11. Angle Loss

    Angle Loss Supporting Member

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    Just caught your post. Small bear has all the right values, but not some of the recommended cap types. You can use different cap types, though the sound may be slightly different. I regularly use Small Bear and a local shop (Orvac), but have not ever used Mouser. Here is some basic info to help you select.

    First, what number is your GT? Having a look at the inside, you will also be able to tell what mods have already been done. Mine is #62, but already had the "Input Mod" which shouldn't have happened until #196. Look to see if you have a cap or a resistor in "C7" on the board. Mod #2 (330pf) will be easy to spot as well--it is either there or not. The other two mods you will need to check the value written on the side of the cap.

    For the capacitors, you need to determine these things:
    -Value (330pf or .01uf, 3nf)
    -Type (Mylar, Ceramic, Film, etc)
    -Voltage--big enough to handle whatever power adaptor anyone might use. 25v would be fine as long is the part is not too big physically.

    If you have an electronics store, you can simply write out what the instructions say and take it to them. They can help you source the part fast.


    Let me/us know if you need more help with the mods or the parts. Check out this page for a quick overview of parts and better explanations than what I give. :p

    http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ#CAPACITORS

    Good luck!
     
  12. 205

    205 Senior Member

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    I live in Australia so can't really help.
    Do you have a local electronics store like Radio Shack where you can go in and get some help?

    Quick google search came up with this:

    DNA Electronic Components Inc., Jacksonville, FL, 904/281-0400

    Don't know if it helps
     
  13. Tubevalvemaniac

    Tubevalvemaniac Member

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    Got recently new GT-500. Great from the very beginning.
    No mods necessary.
     
  14. scottro123

    scottro123 Member

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    Angle Loss, 205 -- Thanks for the replies. The Wiki posted is especially helpful. This should be enough info to get me started.

    I've got a SN in the 400's, so I'll be trying the last 3 mods. I'm particularly interested in the distortion side updates. It's already a great pedal for more modern sounds, though I don't run the treble above 9-o'clock. Hoping these do the trick for making a good pedal even better!

    I'll re-post when the mods are complete.

    Thanks again!
    Scott
     
  15. 89strat

    89strat Member

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    I have number 2370. It's a big improvement over the earlier one I had. Much better, warmer, smoother, etc... Still not 100% sold on it though. My wife pretty much nailed it on the head. She said it reminded her of the OCD in that It has a certain something or frequency, probably in the midrange, that is always present and anoying. After a while of playing at loud volumes, it seems to bother me more than my other pedals which are a Rat and/or a direct drive which I guess have a smoother compression and less of that ear peircing. I play into a deluxe reverb which rarely gets past 3 on the volume. So I'm getting all my drive from the pedals.

    Not getting along fully with this one yet. I do like it, but not as much as others I've been using.
     
  16. Snakum

    Snakum Member

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    Being a TS9/808 mid-hump fan, I will probably like the GT500, which was first on my list for my Annual Spring 'Build Me A Better Bad Monkey' contest. :D
     
  17. DanRoy

    DanRoy Member

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    could someone email the .pdf file to me at fender686 "at" yahoo "dot" com?? it would be much appreciated. or could you just tell me which capacitor (C13?) is the one to tweak for this distortion smoothing effect?

    fulltone didn't respond to my enquiry



    I will agree to the harshness/overbearing frequency observation. to me it's not a tube screamer type thing, the offensive frequency lies more in the upper bass / lower midrange. it's too "fat". yes, bass can be harsh too. the distortion quality is also dry and crusty sounding (ie not liquid and smooth) which adds to the sensation of harshness. I really like the booster side of the pedal, but I'd like to tweak on the dist. side a bit see if I can get it anywhere more generally useful.

    It is good for that super middy Queens of the Stone Age / Them Crooked Vultures / Josh Homme type of no-treble crunch... really good for that, actually. Just dial up the midrange and dial back the treble pretty far on the distortion side. Funny that, Homme uses a lot of Fulltone pedals himself.

    Another trick sound you can get with the right guitar and combo boost/dist settings is that smooth sustainy synth sound you get where the screaming clipping gets subdued somehow into a vowely "ooooh" sine wave type of sound. I think it's distortion before boost, gains cranked up pretty high, lots of bass on the distortion side going into the boost. it's cool to have that sound available in a single pedal
     
  18. drocelot

    drocelot Member

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    Hi I am very interested in the deails of the mods from gray to red. I tried a RED one and loved the distortion side of things. It seems there is a PDF floating around I would aprreciate if someone could send it my way. Thanks.
     
  19. Tweed_Deluxe

    Tweed_Deluxe Member

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    If anyone has a pdf of the mods - I have a grey one that will either be modded or I'm going to trade it in on another pedal ('57 Tweed?)

    Thanks in advance!
     
  20. taildragger

    taildragger Member

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    Anybody willing to share the PDF file for the GT-500 mods?
     
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