Vox AC30 Normal and Top Boost Uses

Discussion in 'Ampage Area' started by Waxhead, May 1, 2021.

  1. Waxhead

    Waxhead Country Gent

    Aug 30, 2014
    Australia
    That voxshowroom link certainly has some detail.

    And that Hightop pedal certainly sounds Voxy but video doesn't say what speaker it was run thru.

    And as we know .... speakers are the critical issue with ACs.
    Does the ceramic/alnico switch on it actually change the tone ?
    And then what happens if you then run it through a Fender style amp or non alnico speakers
     
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  2. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    The speaker switch does switch tone, but the effect is far too subtle to put under a foot switch.
    The EF86 switch changes the texture(more grit and harmonic content) and to my ears is far more effective as a tone shaper. Maybe I’m doing something wrong LOL.
     
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  3. BarryMClark

    BarryMClark Country Gent

    Age:
    46
    Apr 4, 2011
    Atlanta
    Man... there are days I REALLY miss my Vox AC15HW. That thing, when you wound it out, was just so, so wonderfully THICK. Neighbors hated it... but MAN it was just glorious. lol
     
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  4. loudnlousy

    loudnlousy Gretschified

    Age:
    55
    Oct 18, 2015
    Germany
    I used a a/b switch on mine. Since it was a vintage one, too I had to dial the volume quite a bit up to get a decent rock tone. But it was worth the ringing ears. The dynamics on this amps were incredible.
    I tried to get a Brian May tone but failed bitterly even when including an expensive Brian May custom treble boost and a Brian May sig. guitar. Let`s say that it is all in the fingers...
    My folks are always joking: "Man , you paid a fortune for a different guitar and amp, spent months on dialing this combo in but you still sound like you used to sound before.:confused:
     
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  5. TV the Wired Turtle

    TV the Wired Turtle Gretschified

    Jul 25, 2009
    so cal
    I wish there was no compression in post edit, it ruins the listening experience for me.. no one sounds this velvety live. lovely pedal none the less, excellent company! Gotta find a more raw n real vid of this
     
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  6. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    Turning the amp up is the only real way to get pure top boost over drive.
    The guitar and pickups have a big impact on the different types of top boost over drive. Believe it or not treble boosters and clean boost pedals give a lot of options too.
    Brian May always used a treble booster with his AC 30 setup. Funny because his tone was never overly bright. It was always thick and creamy.
     
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  7. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    Also I wonder if the Hightop pedal runs at high voltage.
    If not then it's not a true top boost circuit.
     
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  8. Waxhead

    Waxhead Country Gent

    Aug 30, 2014
    Australia
    Yes I've found same on the TA-15.
    And using the Fryette Power Station I can easy do it at home with the amp cranked on 25w and still keep it to any desired volume level.

    Have also tried treble boosting with an MXR EQ pedal.
    Get's very much closer to B May tone but I don't have his special or his fingers :)
     
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  9. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    Rockett’s own demos are none more real, but the Prymaxe one was the first one that popped up…:cool:




    Rockett pedals are awesome. Of course any demo with the likes of Shawn Tubbs and Mark Lettieri takes my money.
     
    Last edited: May 5, 2021
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  10. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    Why would it run at high voltage, when there’s no tubes in it? :cool:

    It’s no different in approach than the other hundreds of “amp in a box” style pedals out there, but adds a pretty unique flavour. Like the promo speak alludes to it’s not an OD, but an EQ/booster circuit.
     
    Last edited: May 5, 2021
  11. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    Top boost is Petty and Beatles. Clean with an edge.
    Purple and Queen is Treble booster and slamming the amp’s pre with a good 25-30db of signal boost. A decent pedal EQ is not even halfway at 6-12db.
     
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  12. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    Because they claim that it's the Vox Top Boost circuit in a box. The Vox Top Boost circuit has a tube and runs pretty hot so in that case it's not a true clone of that circuit. Also the pedal has some kind of EF 86 control on it. By the time the Top Boost circuit arrived on the scene Vox had stopped using the EF 86 preamp tube in favor of the 12AX7 because the EF 86 had problems with microphonics.
    Just like all the so called clones out there of the EP3 Echoplex preamp. Most of them run at anemic voltages and are not a true copy of the EP3 circuit. False advertising at best.
     
    Last edited: May 5, 2021
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  13. Waxhead

    Waxhead Country Gent

    Aug 30, 2014
    Australia
    My MXR EQ does up to 18db boost :D
     
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  14. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    I partly agree. It’s actually based on the Matchless DC30 which in turn is based on the Vox AC30/top boost circuit with the addition of the old EF86 channel. An old promo vid even spoke of a DC30 pedal. I suppose the Topboost association works better commercially even though I don’t think it ever sold well.
     
  15. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    Ok, still halfway. :D
     
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  16. Waxhead

    Waxhead Country Gent

    Aug 30, 2014
    Australia
    Is it half full or half empty :p
     
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  17. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    About 9 years ago I built a clone of the EF 86 tone circuit from an early 60s AC 15. There was a Vox AC 15 reissue a while back (early 2000s) that included that circuit with some added controls. I included those as well and installed it into my 1998 Vox AC 15. I put it on an old style metal plate like JMI used to add the Top Boost circuit to non Top Boost AC 30s. It was a factory add on at first until Vox finally made it a standard feature.
    Anyway the EF 86 channel has a very cool sound very different from the top boost channel. Lucky for me the 1998 AC 15 only uses 1/2 of the inverter tube so I was able to tie the EF 86 mod into the unused 1/2 of the inverter tube. Works great. I put the input jack where the 2nd input jack is on the AC 15 so no need to hack up the face plate. If I ever want to return the amp to stock I just unhook a few wires, remove the plate and it's back to stock.
    I'm very proud of that mod so I won't be changing it...:D.
     
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  18. TV the Wired Turtle

    TV the Wired Turtle Gretschified

    Jul 25, 2009
    so cal
    Dont be mad. Liberties taken are going to be solid state and sometimes a processor for emulation. Who is going to run production on a giant box to be a "true clone" when similar reproduction can occur w FETs. Surfy Bear is making a fortune stealing RG KEENs layout for a tubeless surf tank, and it sounds fine.

    [​IMG]

    As well echoplex circuits can sound just fine at 9v because most people arent even playing their tube amps loud enough to experience the total effect of the actual higher powered preamp. I have an echoplex pre at the front end of the echo circuit in my MB and the Space echo pre sitting in front of that. Whether its hit w 9v or 12v it still sounds great and has lovely dynamic response.
    ps. some of us are running 18v internal off a 9v supply anyway, via charge pump.
     
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  19. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    I agree FETs are fine and do a nice job, sound close but there is a difference in head room when you start driving this stuff. I can hear it and feel it. Maybe a young kid isn't to that point in time yet but I think we're doing a dis-service to younger players when we keep telling them "this is just like the real thing" or "This model of an AC 30 sounds exactly like the real Thing" when those of us that have been playing this stuff all our lives know better. When it comes to many of these amp and pedal makers it's all about profit - they couldn't care less if it's not even close to the right parts or circuit design. Since I've been a musician and audio engineer my whole life I feel it's my duty to educate my young customers about all this mis-information about gear out there. I don't want to see them waste tons of money on gear like I did because I believed all the hype and lies when I was their age. They wind up respecting me and seek my opinion and it makes me feel good to see them save money. It's just like today's mixing boards that use micro chips in their preamp sections instead of discreate transistors and use poorly designed switching power supplies. AS soon as you push them a bit they start sounding nasty - trashy treble and spongy bass. No balls or head room at all. They can quickly turn a $2000 Neumann into a $100 mic.
     
    Last edited: May 8, 2021
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