Can anything else be placed in the reverb circuit path?

Discussion in 'Amp Tech Center' started by TheGoodTexan, Feb 11, 2020.

  1. TheGoodTexan

    TheGoodTexan Moderator Staff Member Ad Free Member

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    ... such as a chorus or delay pedal? (Time based pedal, as opposed to a boost pedal).

    The reason I ask is that I'd love to use that as sort of a loop for a couple of time based pedals... on an amp that does not have a loop.... but the amp does have a footswitch for turning the reverb on/off.

    Of course there are different connectors... But I'm sure there are differences in impedance and signal level that could cause problems too.

    Am I just being silly here?
     
  2. Jon Snell

    Jon Snell Tele-Meister

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    It is possible but bear in mind the signal path is modified and it may sound tinny.
    There are capacitors to cut bass and reduce treble ... worth a try maybe.
     
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  3. muchxs

    muchxs Doctor of Teleocity

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    Bucket List Alamo Montclair (clone):

    All I want for Christmas is an early all tube Alamo Montclair with a Soldano style buffered FX loop.

    Actually, a Dumble style FX loop is easy.

    The Soldano loop uses two, count 'em, two additional 12AX7 tubes.
     
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  4. The Ballzz

    The Ballzz Tele-Afflicted

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    Do Tell! Please elaborate. Do you have any schematics? Especially of the Dumble or Soldano loop?

    Thank You Sir! :D
    Gene
     
  5. muchxs

    muchxs Doctor of Teleocity

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    The Soldano style loop is pretty trick. It uses a cathode follower to buffer both the send and return. It's great if you have the chassis space for two more 12AX7s.

    Dumble style just breaks the signal path on the it way to the power amp. There is so much inside a Dumble, Uncle Howie elected to go with an external buffer, the Dumble- Ator. A Dumble Ator is an external tube rack mountable FX loop buffer.

    There are bootleg solid state buffers available.


    Without re- visiting The Rack Era, a 25 year old Yamaha digital reverb will get the job done nicely. And I guess we are re- visiting The Rack Era..
     
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  6. muchxs

    muchxs Doctor of Teleocity

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    I retired for the evening without fulfilling my duty... my duty is to say,

    "Don't do it."

    Traditional guitar reverb drives the tank at low impedance, high level. The circuit treats the reverb tank as if it's a speaker. It may be a little different in your Alamo, but in a Fender the drive side is 8 ohms, speaker level.

    Try it some time with your '60s or '70 Fender. Unplug the reverb pan and plug one of your hi-fi speakers into it. Or any old speaker.

    You actually have a one watt "practice" amp built into your Twin Reverb if you're willing to give up the reverb.

    Like feeding speaker level to the guitar input of your amp, I can't imagine feeding a level that hot to the input of your pedal(s) would end well.

    Sure, you could modify the circuit for the correct send level. In effect pardon the pun you would be adding an FX loop.
     
    Last edited: Feb 12, 2020 at 3:14 PM
  7. El Marin

    El Marin Tele-Afflicted

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    I had a Twin Reverb BF RI, I cannot remember where but I remember reading that installing a 47K (or maybe 470K, can't remember) resistor between the live pots at the RCA connector would make reverb lika an Overdrive

    I did built a box and a switch

    Used it sometimes
     
  8. printer2

    printer2 Poster Extraordinaire

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    You would have to have what is effectively a low power amp attenuator on the line going to the reverb. For a cheap and dirty method a power resistor and a trim potentiometer should do the power section. A trim pot for the input to the reverb return. That is without going into the amp. The problem is that Fender rolls off the lows going into the reverb. So if they are missing a capacitor in parallel with the cap to the reverb tube should add some. 8 ohm 5W, two 100k trimers might do it. The bits mounted in a small case, adjust the trimmers to you liking, seal it up.
     
  9. LightningPhil

    LightningPhil Tele-Meister

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    How about a squirrel:
     
  10. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    The reverb out to the pan is actually a speaker out coming from a (12at7 operating as a) power tube and an output transformer, so not great to run into a pedal.
    Circuit could be modded though, and you can also make an overdrive out of it by hitting the return stage with the send but you need a resistor in between.
     
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