Quick Question: Connecting a preamp to an amp head

Discussion in 'Amps and Cabs [BG]' started by JamesNC, Aug 10, 2019.

  1. JamesNC


    Dec 10, 2016
    i was unable to find my old thread where this was explained to me. I simply want to connect my Ashly preamp to my SWR head. It’s my understanding this disables the preamp section of the SWR, using it only to power the Ashly.

    The plug that’s inserted in the fx send is the diode distortion mod for this SC-40 preamp.

    Last edited: Aug 10, 2019
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  2. SteveIII


    Jul 11, 2019
    Oshawa Ontario
    If you have an effects loop on your swr amp you plug the output of the preamp into the return of the swr. You did not specify which swr amp.
    Aqualung60 likes this.
  3. Stumbo

    Stumbo Guest

    Feb 11, 2008
  4. JamesNC


    Dec 10, 2016
    SWR Bass 350 head.

    So which output on the Ashly? Stage Out high or low, or line out on the P.A. side? I’ve included a photo of the back panel in my first post.
  5. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA


    Use the HIGH-level output to directly drive a power

    amplifier (Crown, BGW, Phase Linear, etc.) and use the LOV/-
    level output to drive conventional musical instrument amps.
    If you need more or less level and can't correct the problem
    by adjustment, try the other output.



    Use the mic-level PA output to directly connect the SC-40

    to a studio or PA system mixing console microphone input, or
    use the LINE-level output to drive a line input. The mic.
    connection should be used for long cable runs because it is a
    balanced line which helps to minimize noise. (This mic-level

    output can be used with any console mic input including
    balanced, unbalanced, and phantom powered types.)


    With the multitude of inputs and outputs available on

    the SC-40, there are many possible variations in its use. A
    few are presented here as an illustration. Experimentation viill
    be necessary to exactly meet individual needs.

    1. When not using the PA output as a direct feed, it may be

    used to feed a second stage amplifier, with seperate level

    When taking a line-level feed from another amplifier of

    preamp, connect it into the EFFECT return rather than the

    front panel input thus bypassing the preamp section of

    the SC-40, but still using the equalizer.

    Smooth distortion may be produced by wiring (2) 1N914 diodes
    paralleled in opposite directions between the tip and sleeve

    of a phone plug and inserting it into the EFFECTS send.
    A foot switch can be wired in series with the tip of the

    plug to switch out the distortion
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  6. JamesNC


    Dec 10, 2016
    Ok so Stage Out Low, correct?
    Zooberwerx likes this.
  7. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    You can try one of three and use that which provides the desired response with lowest noise floor: high-level, low-level, or 1/4" PA out. Be sure to start with volume down! It appears the low-level can be run directly into the SWR's front-end...who knows, they may "play nicely together". Not such an absurd idea as we stack preamps all the time.

    Looking forward to the results...or a huge mushroom cloud!

    Last edited: Aug 10, 2019
    The Rage and Stumbo like this.
  8. Stumbo

    Stumbo Guest

    Feb 11, 2008
    JamesNC and /\/\3phist0 like this.
  9. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Effects Send on the Ashley to the Effects Receive on the SWR.
    Mushroo and wave rider like this.
  10. JamesNC


    Dec 10, 2016
    Stumbo likes this.
  11. JamesNC


    Dec 10, 2016
    I have the mod plug in the effects send as the manual says to do.
  12. JamesNC


    Dec 10, 2016
    Yes, I’m trying different things with it as we speak. Man that diode mod plug offers some hellish levels of distortion if desired.

    [​IMG]anthropology jobs salary
    Last edited: Aug 10, 2019
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  13. wraub


    Apr 9, 2004
    ennui, az
    Back in the day I briefly used an old SWR Grand Prix preamp powered through a Behringer BX300 head. It worked great.

    I still have the Grand Prix. ;)
    JamesNC likes this.
  14. somebrains


    Feb 7, 2017
    My Electric Blue has a mix knob for it's fx loop.
    Check your manual whether you have a series or parallel loop & control available to you.
    Stacking voicings isn't all that bad, some people find advantages to layering their output.
  15. Real Soon

    Real Soon

    Aug 15, 2013
    Atlanta, GA
    Using that setup, my guess would be Stage Out High...as I'm figuring with Stage Out Low, the Ashly would want to put out a little less signal assuming it's going thru the amp head's pre stage, which usually adds more signal via input gain or EQ boosts.

    I'm betting the level will be on the low side if you go Stage Out Low to the SWR's Effects Receive.
  16. JamesNC


    Dec 10, 2016
    The SWR has an fx mix knob. I keep that on 10 when running the Ashly into it’s fx receive. That disables the SWR’s preamp, so there’s no stacking.
  17. Jeff Scott

    Jeff Scott Rickenbacker guru..........

    Apr 11, 2006
    Any of those outputs may/will work into the Effects Return of the SWR. Try all of them and see what works best for you. The Blend control on the SWR should be set fully CW for best results when only using Ashly. Given the parallel nature of the bland control you can use both Ashly's and the SWR's preamps at the same time, if desired, for a plethora of options.
  18. JamesNC


    Dec 10, 2016
    Yes, I switched over to Stage Out High. The Ashly is fun to play with, as far as the eq and if you’re wanting to use the diode mod plug for the distortion. Otherwise, I actually prefer the sound of the SWR without the Ashly. Sounds much cleaner just using the SWR and the A.M.P. cab.

    I’m curious how the A.M.P. SL-1 preamp compares to the Ashly SC-40.
  19. i would go with "line out" from the sc-40 to the "receive" on the swr. i've also got an sc-40. it rules.
    Essthreetee, Stumbo and JamesNC like this.
  20. JamesNC


    Dec 10, 2016
    Do you use the diode mod plug?
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