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Thread: Screaming Bright Switch Cap??? - 1974 Fender SF Twin Reverb Master Volume Push Pull Switch

  1. #456
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    Quote Originally Posted by Chuck H View Post
    Take 'em out!
    that's all i needed to hear ... LOL

    Quote Originally Posted by Chuck H View Post
    The trem on that amp in the video sounds like @$$. All garbled and distorted. I wouldn't be chasing that video as a tonal standard to aspire to otherwise either. But now I'm just being a wet blanket.
    I'm with you, however I think everything on that video sounds bad and I am thinking is the camera's mic being unable to handle the powerful twin

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    that network DOES introduce a small low pass filter
    Yes, cuts treble above 16kHz.

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    danke! i should not hear a difference if everything happens above 16KHz.

    actually here's an easy side by side comparison on how the circuit looked like during the evolution from the ONLY MASTER VOLUME version (010182 RevC) to the addition of the PULL BOOST (45377 RevE).
    It's clear that that arrangement (12K, .01uF, 1M) is not there in the ONLY MASTER VOLUME version
    however, additionally there is a 1K resistor that is also not there
    the landmarks I used to identify the common components are marked in GREEN and the differences in RED

    I guess that now the complete question is: should i remove: 12K, .01uF, 1M AND the 1K resistor?


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  4. #459
    Bent Member Chuck H's Avatar
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    I don't suspect that area of the amp and it's circuitry in your previous problem. I doubt you'll hear a difference. You can simply lift one end of any of those components to see if it makes any difference for yourself. But to ask us if you "should" isn't something we can answer because the amp is not on any of our benches. I think you should try because the idea seems to please you. If it causes a problem you can put them back.

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    AND the 1K resistor?
    The 1k resistor just adds to the 470k, resulting in 471k +/- 10%.


    should i remove: 12K, .01uF, 1M
    This HF filter may even have a beneficial effect, as it will attenuate residual oscillation blips. So best try both ways as Chuck recommends.





    Is there still a problem with the amp?

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    Last edited by Helmholtz; 01-16-2020 at 08:27 PM.
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    Quote Originally Posted by Helmholtz View Post
    Is there still a problem with the amp?
    I think there's not... but I will only know if I remove these components and find out it sounds better! LOL
    + you're totally right about the 417K

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  7. #462
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    Agree with Helmholtz that the circuit could 'accidentally' help prevent oscillations above 16khz so keep this in mind if anything weird happens with it gone.
    As a side note, since you just worked on the trem; not sure if I mentioned this already but this era Fender sometimes has the shielded cables dressed very close to the trem bug, and it can have quite an impact on the trem 'ticking' problem.

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    yes! I had that problem in the past with the tremolo and fixed it by adding the .022 uF cap tremolo tick fix (which was actually a fix Fender came up with)
    thx!

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    Ok, I mentioned that for the cases where the cap fix doesn't get rid of it all.

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    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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