JCM 800 Bright Cap

Discussion in 'The Workbench' started by JM5010, Aug 23, 2019.

  1. JM5010

    JM5010 Member

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    What is a good value for the bright cap that won't make the amp sound too ice picky or too dark sounding?
     
  2. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Umm, what are your amplifier settings and which JCM800 are your talking about?
     
  3. anitoli

    anitoli Well-Known Member

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    Just leave it in, attenuate the shit out of it, and the extra high end will be much appreciated.
     
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  4. Nik Henville

    Nik Henville Well-Known Member

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    Tone
    Controls
    On Guitars
    May well do the job.

    Never 'take away' options permanently if you can avoid it.

    :hippie::pirate::uk:
     
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  5. anitoli

    anitoli Well-Known Member

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    This bright cap thingy kicks me in the balls. I have a 2203x with that setup and i don't find this amp too bright, or rather it's nothing that can't be dialed out either on the amp or guitar. I really don't know what the deal is about the bright cap, internet legend?
     
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  6. Nik Henville

    Nik Henville Well-Known Member

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    It's "any excuse to tinker" rather than just play guitar...

    :hippie::pirate::uk:
     
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  7. anitoli

    anitoli Well-Known Member

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    Honestly i am beginning to understand the "bright cap". It lets you cut through the rest of the band. The audience can hear you. Bright cap is a good thing. :D
     
  8. AlvisX

    AlvisX Well-Known Member

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    Lotta people like ice picky....or settle for it because that's just the way it is .I have a very hard time with it

    I'll tell y'all, in my time in the trenches ,I have found the issue to not be the "bright cap" so much , but the two 470pf treble peak / hi pass cap ....whatever ya wanna call them , in the chain .The one on the input and the one before V2

    Generally ,what happens on my amps,is I end up lifting a leg on the one on the input , and pulling the one on the board , replacing the .001uf brite cap with it

    That's my story, tone don't lie
     
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  9. JM5010

    JM5010 Member

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    Single channel 800's, and i play with all the settings at noon, with the MV at 2
     
    Last edited: Aug 23, 2019
  10. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Try anywhere between 100 pF and 180 pF. I have the 2204 1x12 combo and I find 100 pF is not good. Looses cut but I have settled on 120 or 130 pF I think and love it. But thats based on my setup speakers and tubes. Buy a few and try them shipping will cost more than the caps. Its easy to change and keep the original just in case never cut it out or toss it.

    I do know what you mean though...cut is one thing but stabbing your ear drums is another thing and I dont like running my gear with the treble/tone knobs on 0-1...this gives you some adjustment.
     
  11. Kostas

    Kostas Member

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    Use alligator clips to try a few different caps with different values, put the one that sounds good for you. I did that with my 1959HW, the stock cap was unbearable, IMO.
     
  12. thunderstruck507

    thunderstruck507 Well-Known Member

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    I think I put a 100 or 110 in mine. With the stock one the amp was ear piercing if the gain was below 7 to the point you had to roll off the treble to 3.

    After the mod I can run the treble more towards the middle of it's sweep and the tone still seems a little smoother overall when playing with less gain.
     
    Last edited: Aug 23, 2019
  13. Chris-in-LA

    Chris-in-LA Well-Known Member

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    All the settings at noon will be very bright. Turn treble to 0, use the midrange to dial in how bright you want it, usually between 2 and 4. Turn the gain up to 10 and the amp will sound very dark.
     
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  14. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Those 1000pF and 5000pF are a bit much.

    Everyone seems to like the nice low Fender values. :)

    However, there goes some of that Marshall roar at lower volumes. :hmm:
     
  15. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    True, they are all bypassing mid/high frequencies. As mentioned, that is the Marshall way.
    Also Marshall slapped a 470pF in the TREBLE control circuit for just a bit more.
     
  16. blues

    blues Active Member

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    Yes I did this and I put a 250pF in place of the stock brite cap. Just like you mentioned. Great
    for P-90s and other single coil guitars. Did some tube swaps too. :agreed:


    I do not hear this with my 4010. When I want more roar I just have to turn the gain up. Those mods that Alvis talks about make the gain work better. I can run it around 6-7 on the dial when I don't want lots of gain. With my Strat to boot.

    No loss of mids or bass with this amp either even when I run the volume at 2 on the dial.






    For me it's to get the most out of the amp for my need or liking. I play about 12 hours a month. About 3/4 of that time is with a Strat. But you might be hard pressed to even know anything was done to the amp.


    If I want to tinker I will mess around with pedals in the low input. That's tinkering for me. Or maybe a boost pedal on the high input.
     
  17. johan.b

    johan.b Well-Known Member

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    Marshall brightness was never an issue before people started "love the vintage 30"... just saying..
    J
     
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  18. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Its all what one likes and I for one dont like a thin sounding amp nor do I like having my treble and presences at 0 and my guitar tone knob at 3...simply stupid and no need. Its like having a vette and having a throttle limiter on it at 10%...and to each there own as they say! Marshall isn't perfect either I love them but some amps need a little tweak.
     
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  19. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Something more questionable is Marshall sticking a .0022uF in the coupler after V1 and then placing the .005uF bypass capacitors across the BRIGHT VOLUME. Its almost like not having a volume there afterwards which is another reason everyone bitches "my amplifier is so loud at 1 on the dial" about these amplifiers. It made no sense for that design.

    :scratch: :noplease:
     
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  20. RickyLee

    RickyLee Well-Known Member VIP Member

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    I am still intrigued with the tossing back and forth of the bright caps across the gain pots. I think many people still misunderstand how they actually work in the frequencies that are passed/attenuated. A lot of that is to blame from the interwebz. I still find my own brain wanting to think about them backwards sometimes (along with the treble peak/attenuator pairing circuits). Many of the frequencies are not even heard by our ears from even the smallest 100pF caps that are used. So then that is why it must seem like they are the tamest values compared to a 470pF on up.

    Basically, going to a bigger bright cap lets more mids and lows in the mix. But it is always perceived as the opposite. And then of course, it always depends on the resistance value/gain pot settings.
     
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