DigiTech GSP2101 Appreciation

Discussion in 'The Rack Space' started by ctreitzell, Sep 2, 2018.

  1. ctreitzell

    ctreitzell Member

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    I seldom use any other tube pre settings on the 2101 other than Distorted Tube...it's just my pref
    and Dieter's unmarked tubes made that circuit sound even better =-D
     
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  2. Priyal de Zoysa

    Priyal de Zoysa Member

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    Incidentally my GSP2101 had Penta valves that says were made in the USA. According to my valve expert he thinks that they look like well known Chinese brand. I will try to post the results (as a blind test) to see what everyone's favourite valve combinations might be.
     
  3. Priyal de Zoysa

    Priyal de Zoysa Member

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    Tried Dieter's valves, I can confirm that they are better than the Penta valves that were in there. I think a bit more bass (for Jazz Lead sound) and also gain for some of the sounds that I use like Warm Sweet Solo. Not sure how much time I have to detailed comparisons. If enough people want to hear the difference then I will try to find a day to make the necessary videos/recordings. The only thing I should mention you should take care when putting the cover back that holds the valves in place -Replacement valves don't fit as snuggly as possibly the original valves do and therefore did not align perfectly with the cover and you need to take care in aligning the valves with the cover. You should get a technical person to do this if you think you might be uncomfortable doing it.
     
  4. ctreitzell

    ctreitzell Member

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    I replaced the original Penta tubes with EHX back in, like, 1999...then I didn't use my 2101 for something like 17 years! it just sat in my attic in a rack...

    The ones from Dieter in 2017 sound remarkably better to my ears vrs the EHX;
    I was under the impression some extra step was suggested best practice when changing the tubes in a 2101..don't remember what, exactly

    I didn't find fitting the latest tubes particularly difficult...nothing like adding the PPC210...which was truly a challenge.

    My 2101 has always had a stripped faceplate screw. I think my unit shipped with the stripped tap. That stripped screw made the unit feel wobbly when racked. Recently I repaired the stripped screw and it now sits really solid when racked.
     
  5. Larry Eh?

    Larry Eh? Member

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    All I can think of is trimpot P9 which is the feedback resistor on op amp U6A which drives the first tube stage. I think Dieter had a procedure for adjusting it to the correct gain.

    Edit: I found it. He calls it R188 but it's P9 on my schematic: Clean Tube Setup
    But I believe it applies no matter what tubes you use.
     
    Last edited: Dec 3, 2019 at 6:56 PM
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  6. ctreitzell

    ctreitzell Member

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    Here we are; from Dieter's Web Shop:
    "Q: Once, you told me that it is necessary to calibrate my Digitech unit after replacing the tubes. Is this really necessary?
    A: Yes, definitely. After replacing the tubes you must calibrate your unit, except you use the selected tubes in this offer.
    The reason why you don't need to calibrate you unit if using the tubes in this offer is that the "gain" or better said the "mutual conductance" is selected to approx. 1500µMHOS."

    He doesn't say how to "Calibrate your unit"; I understand it to mean that if the tubes he sells in that offer are used, the unit doesn't require calibration.
     
    Last edited: Dec 3, 2019 at 7:20 PM
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  7. Larry Eh?

    Larry Eh? Member

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    This brings me back several years ago, but I used to like modding all my gear and optimizing it to my liking. Using my guitar with the hottest pickups, I set Gain1 to 11 and turned everything else down or Off so that the only thing that could trigger the Clip led was the Gain1 adjustment. Then I slammed a few chords and adjusted the trimpot P9 just below clipping. That way I was sure the input op amp wasn't clipping and only the tubes provided the distortion. That allowed me to get the widest adjustment range of distortion. I guess you could increase the trimpot if you only play single coils and such.
     
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