SF Vibrolux - Normal Channel - any mods suggestions?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by RobBozic, Feb 7, 2006.


  1. RobBozic

    RobBozic Member

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    Hi,

    I own a non master volume Vibrolux which has been Blackfaced & fitted with Weber Ceramics.

    I'm happy with the amps Vubrato channel but want to try some mods on the Normal channel. I want some extra gain in there so I use an A/B box to switch between the two.

    I've already changed the tone caps to Orange Drops .022.

    Does anyone have any other suggestions?

    Thanks in advance
    Rob
     
  2. 908SSP

    908SSP Member

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    Run a pedal between the a/b box and the normal channel. Then you can have any kind of distorsion you want.
     
  3. spikeRI

    spikeRI Member

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    or buy something that works.(for you)
    Don't hack up a fine amp like that..........or if you must, make sure they are reversible.
     
  4. slider313

    slider313 Silver Supporting Member

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    Take a .02 ceramic disc cap and put it in place of the 120pf on your bright switch. This gives the normal channel a mid boost when the switch is on. Easy to remove if you don't like it.
     
  5. rockycreeker

    rockycreeker Member

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    I have a 66 BFVR that is my main gigging amp - and I've just started experimenting with feeding a Fulltone OCD to the normal channel and using the reverb channel for my other FX - switching between the two with an AB box. After one gig - I'm pretty sold on the idea - I can vary the volume and EQ on the normal channel specifically for the OCD, which is a pretty bright pedal, and have the reverb channel maximized for my other FX

    The only mod I've had done to the amp is a midrange control wired into the second speaker jack - and that is 100% reversible - but it really helps to dial in a little more midrange.
     
  6. cocobolo

    cocobolo Supporting Member

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    Check out this site:
    http://blueguitar.org/

    There is an easy mod to add reverb to the first channel as well as some other mods.
     
  7. bluesaxe

    bluesaxe Member

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    One thing I've done to a Fender's unused normal channel is to make it a champ flavored boost. This involves bypassing the tonestack to get a serious tweed thing goin' and then connecting this to the PI, paying attention to the phase of the Vibrato channel (+/- verb). All you have is the volume knob. What this will give you is a volume boost and if your running the amp into breakup, some extra gain. Use an A/B/Y switch and play with Normal / Vibrato individually or both at one. You can also jumper them like a 4 input Marshall to get some interesting tones.

    Have fun!

    bluesaxe​
     
  8. TheAmpNerd

    TheAmpNerd Member

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    FYI - The normal channel has one less gain stage then the 'vubrato'
    channel. Wanting more gain outta this then the other, with some
    added flex from reverb too.

    Well, there was that sone who I forgot who sang an wrote it...

    "Look before you leap"
     
  9. hasserl

    hasserl Member

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    Holy ****! Talk about peircing highs. :eek: You're joking, right? :D
     
  10. slider313

    slider313 Silver Supporting Member

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    A 220pf would be a .02, there is a 120pf there as stock. This would let more mids through or even a .047 would be ok. Correct me if I'm wrong,but the higher the value, the more lows and mids,ie.,a .001 lets more highs through than a .02 and a .047 more lows and mids than the .02.
     
  11. hasserl

    hasserl Member

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    220pf = .00022uf

    Increasing the bright cap is not the place you want to do something like this. 120pf is bright enough (maybe too bright), increasing it tends to make it piercing and unusable. Increasing the value of the mid resistor would work better for what you are looking at.

    Using the bright cap switch to lift the ground of the mid resistor is one way to do the tweed thing bluesaxe mentioned. Or use a push/pull volume switch. A better solution might be to use a pot to vary the amount of lift from the mid resistor, a Raw control. You can mount it in place of the ext. speaker jack.
     
  12. slider313

    slider313 Silver Supporting Member

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    How about the mid boost on the Vibroking using it place of the bright switch?An extra midrange cap in series when using the boost?
     
  13. RobBozic

    RobBozic Member

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    Thanks for your replies. I had a look at the "Hot Rod" mod for AB763 on the Blueguitar.com website & did the mod. I also replaced the coupling caps to Sprague Orange Drops for the rest of the amp.
    While I was there I did the "both channels with reverb/vibrato mod".
    The normal channel "Hot Rod" mod sounds great, I did increase the resistor on the bass control from 10K to 15K for extra mids (stock 6.8K).
    With a Les Paul & the amps volume on 4-5, it does early ZZ Top, ACDC no problem. And the vibrato channel sounds even better with the sprague caps.

    Rob
     

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