Query failed: connection to localhost:9312 failed (errno=111, msg=Connection refused). 68 custom deluxe ‘bassman’ tone stack - Amps Discussions on The Fretboard
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UNPLANNED DOWNTIME: 12th Oct 23:45

68 custom deluxe ‘bassman’ tone stack

Alex2678Alex2678 Frets: 909
in Amps
I know it’s not a bassman tone stack. Lyle of Psionic says he converts these to Super Reverb values, looking at the schematics it looks to me like the only difference between the custom channel on the 68 is and the normal channel of the Super is r72, which my amp is missing anyway. Can anyone with good eyes confirm?



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Comments

  • ICBMICBM Frets: 69426
    Yes, and the only function of R72 is to limit the lower end of the bass pot range so that it can't turn off completely. If you never turn the control that low, it makes no difference.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Alex2678Alex2678 Frets: 909
    Nice one @ICBM ;
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  • Alex2678Alex2678 Frets: 909
    Got confused because on his video he said .022 was a Marshall value 
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  • ICBMICBM Frets: 69426
    Alex2678 said:
    Got confused because on his video he said .022 was a Marshall value 
    It is - C3 is .022uF in the standard Marshall tone stack, as still is C4 (and in the 5F6-A Bassman the Marshall was copied from). C2 is 250pF in the Bass/PA/Organ model (and the 5F6-A) and 500pF in the Lead, R6 is 56K in the Bass/PA/Organ/5F6-A and 33K in the Lead. A further difference is that C4 is connected to the wiper of the mid pot rather than it being a simple variable resistor - so as you turn the mids down, the bass increases slightly - this is essentially what R72 is simulating, albeit inaccurately.

    This is the only part of the tone stack that could be described as 'Bassman' really. However, the most important part of both the 5F6-A and the Marshall is that the tone stack is driven by a cathode-follower and comes after a significant part of the distortion - this doesn't happen in the BF/SF circuit at all, so calling this a Bassman tone stack is completely inaccurate really.



    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Alex2678Alex2678 Frets: 909
    Wonder why they’d call it a bassman tone stack and not compare it to a Super - they did seem to be focusing on mid heavy rocky tones in their amp marketing for a while - think that was the entire idea of the bassbreakers 
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  • ICBMICBM Frets: 69426
    Alex2678 said:
    Wonder why they’d call it a bassman tone stack and not compare it to a Super - they did seem to be focusing on mid heavy rocky tones in their amp marketing for a while - think that was the entire idea of the bassbreakers 
    And fitting Celestions to everything whether it suits them or not...

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Alex2678Alex2678 Frets: 909
    edited July 2023
    Mmhm. Diluted from both ends. Kind of in between but neither really doesn’t seem like much of an attractive proposition. 
    I think I’m almost all the way to 65 circuit wise now, which would’ve been my first choice, but I do prefer the silver face look
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  • p90foolp90fool Frets: 29588
    I think the idea of the "Bassman" tone stack in the Custom range is really just to hint that it has a friendlier midrange to drives and fuzzes than the more hi-fi '65 up tonestack.

    It's obviously a bit of marketing fluff which does have a function, though it's not meant to sound like a dimed Bassman. 

    To be honest, switching component values between 65 and 68 Custom spec on a Princeton wasn't nearly as big a difference as speaker choice really. 
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  • Alex2678Alex2678 Frets: 909
    No I’ve whacked a Jensen in and it was the biggest difference, after that probably the nfb 
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