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Coolest. Amp. Ever. (but could it be cooler?) --fliptop nerd alert--

Discussion in 'Amp Tech Center' started by telemebanana, Mar 4, 2021.

  1. telemebanana

    telemebanana TDPRI Member

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    I'm talking about the Ampeg B12xt! I've had this amp forever and I've never thought to mod it in any way 'til I saw one for sale on Reverb...

    "Slight mod upgrade combines the channels so you can dial in the dry sound with the modulated channel that just gives you this magnificent tone no pedal can match."

    Hold on, what is this "slight" mod of which you speak? How does it work? (does it work?)

    Also can one remove the V1 tube in an Ampeg the same way one does in a Fender to give it a little more...you know...

    I know there are some Ampeg Nerds like me on this forum, I humbly ask for your expertise. Judging by the price for the one on Reverb (more than five times what I paid for mine back in the day, and mine's in better shape) the last thing I want to do is damage it.

    Thanks in advance!
     
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  2. StrangerNY

    StrangerNY Friend of Leo's Gold Supporter

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    Way back in the day, when dinosaurs walked the earth, I had a small Ampeg combo with reverb. Forget the model, but I used to stow my fuzz tone and wah pedal in the back when going to play.

    At some point, something knocked into one of the reverb leads and knocked it loose. I started to play and went to add a little reverb, and instead I got the most heavenly overdrive I'd ever heard. Far beyond what my measly little Heathkit fuzz could produce. I hadn't noticed that the one lead was loose, and after I got done playing I pushed in the connector and the monster overdrive was gone.

    Try as I might, I could never reproduce it. But it sure was fun while I had it.

    - D
     
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  3. Wally

    Wally Telefied Ad Free Member

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    The Fenders in which pulling wither V1...Normal ch...or V2...Vib ch...increases the gain in the remaining channel act that way because the two channels share a common cathode resistor. When one or the other tube is pulled, that change in resistance rebiased the remaining input preamp tube for a bit more gain. Your Ampeg does not share this trait according to the schematic I looked at. As for combining the channels, have you tried simply running your guitar into the #1 input of one channel and then using another cable to go from the #2 input of that channel to the #1 input of the other channel. In a v8ntage Fender two channel reverb amp, the channels are out of phase. Check your amp out...if the daisy chained output with settings 8n both channels alike...is thinner and weaker, those channels are out of phase, too. I think they may be in phase.....but I don’t know how much the effects in that Ampeg drag the gain down. In a Fender, the reverb and iso-optical trem suck some gain out. Check it out...you can do no harm. If it works, yo7 have a wet/dry option there. Maybe an B12XT owner will chime in.
     
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  4. maxvintage

    maxvintage Poster Extraordinaire

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    modulated channel?
     
  5. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    Fliptops rule. I don't know what that "mod" might be, but unless it is easily and *invisibly* reversible, I wouldn't mod a vintage amp.

    By the same token, I would ask, respectfully: when was the last time you had the e-caps replaced?
     
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  6. telemebanana

    telemebanana TDPRI Member

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    Y'know, the channel with the effects on it.
     
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  7. StrangerNY

    StrangerNY Friend of Leo's Gold Supporter

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    Aren't Ampeg fliptops (or 'Portaflex') bass amps? I'm not familiar with a fliptop guitar amp, but I haven't paid attention to Ampeg since I owned an SVT in the 80s.

    EDIT: Just went and looked. I never knew about that model.

    - D
     
  8. telemebanana

    telemebanana TDPRI Member

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    I had the amp gone through a long time ago ( more than a decade) and aside from new power tubes and a three prong cord, it needed nothing. It has been through three cross-country trips in a moving van and a car accident. It's unstoppable.
     
  9. Mr. Lumbergh

    Mr. Lumbergh Poster Extraordinaire

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    Do those have separate inputs for each channel? If so, it's likely just a single wire connecting the tips from the Channel 1 & 2 jacks. If you like the mod, you can install a switch easily to kick it on or off.
     
  10. burntfrijoles

    burntfrijoles Poster Extraordinaire

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    In 1966 or 67 the kid across the street got an Ampeg Flip Top guitar amp. I don't know the model but it was cool and everyone around was envious. It was damn loud too. The kid was only 14 but he could play. He was a couple of years younger than me but he taught some songs and a little theory.
     
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  11. David Barnett

    David Barnett Doctor of Teleocity

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    How about a y-adapter?
     
  12. Zepfan

    Zepfan Doctor of Teleocity Gold Supporter

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    My old Silvertone has 2 channels (HI/LO) and I simply wired the 2 inputs to a 3-way on/on/on switch and a input jack. I plug into that jack and choose either channel or both. All 3 selections sound great.
     
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  13. telemebanana

    telemebanana TDPRI Member

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    It has two inputs per channel - guitar and chick magnet (aka) accordion. That's four inputs to rewire into one?
    The closest thing I can think of would be the old Sunn Model T that had a fifth input in the middle that combined channels. I've never seen one in the wild.
     
  14. David Barnett

    David Barnett Doctor of Teleocity

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    [​IMG]

    Plug your guitar into the first Guitar input. Plug another guitar cable from the first Accordion input to the second Guitar input. Blend at will.
     
    Last edited: Mar 4, 2021
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  15. powerwagonjohn

    powerwagonjohn Tele-Meister

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    I almost always jumper the channels on my Ampeg Gemini II for more drive and control. Welcome aboard neighbor.
    Thanks John
     
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