Can plugging direct into the effects return damage your amp?

Discussion in 'Amps and Cabs [BG]' started by FEBass, Jun 4, 2019.


  1. I play with Boss GT-10b and use a lot of the amp models. Consequently, I usually plug straight from the main output into the effects return of my amp. But I'm starting to have problems with amps. My MB 800 has a transistor that keeps going bad and I wonder if somehow I'm forcing current through it backwards or something? This weekend, I plugged into the rented amp at a gig, a new YB300, and I went into the effects return. 2 songs in, the whole amp went irretrievably into Protect mode. Is my set-up a potential culprit? The pedal board is never turned up even to half output...
     
  2. Also wondering if some amps automatically blend wet and dry and if not supplying the dry signal causes the amp some kind of problem?
     
  3. BassmanPaul

    BassmanPaul Inactive

    Plugging into your Effects Return should have no negative effect on your amplifier.
     
  4. lz4005

    lz4005

    Oct 22, 2013
    You shouldn't be able to damage an amp by plugging into the effects return, unless you were sending it a far too powerful signal. But it would have to be speaker level to damage the amp.
     
  5. Warpeg

    Warpeg

    Jun 20, 2005
    Ohio
    Using that particular effect/modeler device, I would think connecting it to the return would be optimal. No issues there. When it comes to blowing out transistors and amps going into protection mode....well, you might want to make sure you're not pushing too much current through these amps. In other words, be mindful of the master volume knob and excessively-boosted bass and/or mids on your EQ.
     
  6. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Shouldn't be a problem at all.
     
  7. Do some (or most) amps do an automatic blending of the front input and the effects return input? If they do, what is the effect of not providing a signal to the front of the amp?
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Most amps provide a series loop only, so any blending would need to be done on the effects unit itself. Often, effects that are intended to be run in parallel include a wet/dry mix feature on-board. Very few (bass) amps provide a parallel loop because a series lop is much more useful to the majority of players, not just as a loop but as an insert patch point between the preamp and power amp.
     
  9. Warpeg

    Warpeg

    Jun 20, 2005
    Ohio
    In many cases, the use of the return disconnects the preamp signal from the power amp section.
     
  10. Thanks all! The answers are what I hoped/expected, but I wanted to confirm in light of the random problems I seem to be having. The YBA 300 was a real puzzler. I had almost no setup time because it was a short festival set, so when I plugged into the return and the sound seemed to be breaking up, I wasn't able to troubleshoot. The organizers had allotted a whole 5 minutes between groups for setup. Anyway, my pedal's output was set around 10 o'clock. I thought maybe there was a problem with the cabinet, but as long as I was able to hear what I was playing, I resolved to just suffer with crappy sound. Then, two songs in, the amp just quit, like it had gone into protection mode. That kind of behaviour, to me, sounds like some kind of overload from my signal, but with the pedal turned up less than half, I can't imagine how it could have been. The PA still received a signal from the Direct out, but the amp was MIA. Oh well. Next time, I'll bring along a head I can quickly switch the rented rig over to and go with something that's proven it will work.
     
  11. Might be worth noting the YBA 300 is a tube amp, and I was the first person to turn it on that afternoon for the outdoor gig. Wonder if being forced to play it cold could have contributed to the shutdown?
     
  12. beans-on-toast

    beans-on-toast

    Aug 7, 2008
    As others have said, pugging into effect return should not be a problem.

    If the amp has a power amp in jack, plug into that instead. That input normally disconnects the preamp and nothing can flow back.
     
    BluesOnBass likes this.
  13. beans-on-toast

    beans-on-toast

    Aug 7, 2008
    A tube amp going into protect mode can occur if the line power is low. If it was a power generator intended for the purpose there shouldn’t have been a line power issue. Then again, there are a lot of sub standard generators that don’t deliver a clean 60Hz sine wave output and should be used with musical gear.
     
    mikeswals likes this.
  14. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    To clarify; A bad sine wave could cause an amp to go into protect mode? Thanks
     
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Beans is referring to low AC power, or highly distorted AC power with lots of harmonics. Some amps (tube, and solid state) have protection circuits that shut the amp (or parts of the amp) down when abnormal AC power is encountered.
     
  16. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Thanks, I had a problem at last gig where my Tube amp would go into protect mode only when 1st turned on. A re-boot solved the problem and was good for the whole set.
    Then 2nd and 3rd set the same thing happened. a Restart was needed at beginning of each set but then worked flawlessly for each entire set.
    Start-up sequence was: Power on>wait 30 seconds>flip stand-by switch.
     
    Last edited: Sep 22, 2019
  17. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    It could also be something unrelated to power...
     
    FunkHead likes this.
  18. Wasnex

    Wasnex

    Dec 25, 2011
    The effects loop in my Aguilar DB359 can be switched between series and parallel. In parallel you can vary how wet the signal is by adjusting the effect send or return level.
     
  19. Wasnex

    Wasnex

    Dec 25, 2011
    What about if the pedal is faulty and sending a DC offset?
     
  20. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Most loops are (and should be) protected from this.
     
    lz4005 and Wasnex like this.
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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