Bass guitar through guitar amp for effects?


  1. Espis

    Espis Well-Known Member

    OK, so this one is for the guitarists/bassists out there:

    I have recently bought myself an electric bass guitar, and an amp. As I am a die-hard Muse fan, I REALLY want to get some distortion on my bass guitar. But I don't have a pedal. Yet.

    However, I do already have a Fender Mustang I guitar amplifier, with several effects built in.
    I know that I can't play my bass directly through my guitar amp, but can I safely plug my bass guitar into the guitar amp and then run a cable from the headphone output, into my bass amp? Or will it blow up my guitar amp?

    In my head this will work perfectly fine, but I'm not an experienced musician like some of you are. :)

    Thanks for your help.

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  2. Mayhem

    Mayhem Well-Known Member Contributor

    I would think that the bass tones are too deep and would fry something. You could always try it on low volume before cranking it up.

    You might consider Craigslisting the guitar amp and getting a pedal instead. You might even find someone willing to trade.
    Espis likes this.
  3. Espis

    Espis Well-Known Member

    OK, I'll try it on a very low volume first. I'll let you know if it works well or not :)
  4. pbf98

    pbf98 Well-Known Member Contributor

    The main thing you have to be careful for is the speaker. The speaker in a guitar amp is designed for the Highs and mids, and too much of the low can blow the speaker. But since you'll be using headphones the speaker will be spared haha

    As far as tone that you'll get from it, it won't be the best because the amp it self is also designed for delivering the high and mid range sound, even with adjusting the High Mid and Low settings that are on the amp you might not find the "right" tone.

    And when you're looking for a pedal, be sure to check to see it works with bass guitars as some do not. My pedal only works with guitars, and I thought that at least the tuner would work for a bass but I was wrong.

    Hope I am able to help. If you ever need advice in this area, feel free to ask. I have 15 years experience playing guitar and lugging around the equipment haha
    Espis likes this.
  5. Espis

    Espis Well-Known Member

    Ok, so I tried it now, and it worked!

    Well, there was a lot of noise and not exactly perfect sound quality like you said, but it will work fair enough in emergencies. I never play gigs anyway :p

    I'll write that on a piece of paper and glue it to the computer, thanks!

    Thanks again for all your help!
  6. Speed Daemon

    Speed Daemon Disabled

    I don't see why you can't plug your electric bass into a guitar amp. Unless it has an integrated preamp in the body, it's pretty much the same high-Z TS plug that most electric guitars use. If anything, I'd think that the output from an electric bass (with its more massive strings) would be greater than that of an electric guitar, which will help you overload the front end for distortion.

    You need to remember that guitar amps aren't like loudspeaker amps. They're designed to be driven into distortion. While slapping bass strings at high output volume settings may damage the little 8" driver in the Mustang, the amp itself shouldn't be damaged by driving it into distortion. If you have the model with built-in DSP effects, you can just use one of those to give you a distortion pedal effect without overdriving the amp.
  7. Espis

    Espis Well-Known Member

    That's true, because both my guitar and bass guitar use 1/4" jacks, but my main concern was whether the speaker itself on the guitar amp would vibrate itself apart because of the low frequencies of the bass guitar. I've seen vids on youtube of guitar amplifier speakers that destroy themselves when they are played through with a bass guitar.
  8. Speed Daemon

    Speed Daemon Disabled

    That's a legitimate concern, especially with the tiny 8" driver that the Mustang combo amp uses. As Mayhem said, start with the volume set low, and ease it up gradually.

    Traditional guitar amps, especially the vacuum tube (thermionic valve) types don't have very good bass response to begin with, and the drivers in guitar combo amps, which are often open back designs, use low compliance drivers to prevent over-excursion of the driver voice coil. Nevertheless you can overextend the driver if you try hard enough. If you do, you'll know; it makes a surprisingly loud "crack" when the voice coil bottoms out. As soon as you hear a crack sound, turn the volume down!

    You said that you want to get some distortion out of the amp. You can do this by keeping the "Volume" and "Master" knobs set low (keep the "Bass" knob right in the middle) and use the "Gain" knob to overdrive the front end.

    Because the signal coming out of the average electric guitar or bass is made solely by the vibration of the strings, guitar (and bass) amps have two gain stages: one to bring the voltage up to line level, and another to drive the speakers. When you have an amp with separate controls for each gain stage, you can crank up the first stage to produce distortion without overloading the power stage or the speaker driver(s).

    Some guitar players prefer to overdrive the high power stage, which is fine as long as the drivers can handle it. The most popular "4x12" guitar cabinets have four 12" Celestion drivers in a closed-back cabinet, and can handle the full output of a "100W" guitar amp at full tilt. Since you're using a bass with a guitar amp combo, you will not want to get your distortion by overdriving the power section and/or the speaker cone!

    I don't know precisely how the headphone output on your Mustang amp, but if it's enough to drive headphones, it will totally overload your bass amp's instrument input stage. This may or may not give you the sound that you desire. If you want to use the effects on the Mustang amp without overloading the bass amp's front end, you'll need an attenuator of some sort to lower the signal level down from line level down to the instrument level that the bass amp expects. You might be able to do this by keeping your "Volume" and/or "Master" knobs set low. An external box like the Electro-Harmonix Signal Pad (~$50US) might be a good idea. And of course you'll need an adapter cable to connect the tiny TRS male headphone jack to the 1/4" TS male input on your bass amp.
  9. zuben el genub

    zuben el genub Well-Known Member

    I have an old Lafayette tube guitar amp that has had bass played through it.
    Both the Vulcan and daughter play bass. Amp still works.
  10. Espis

    Espis Well-Known Member

    Ok, thanks for the info.
    I have looked at the Electro Harmonix Bass Big Muff Pi. I think I'm going to get it in the near future. That will get me the sound i want :)
  11. Speed Daemon

    Speed Daemon Disabled

    Before you buy, you should look at this. Some Big Muffs are more equal than others.

    My Big Muff Pi was the 1976 op-amp version, and the distortion was always harsh and difficult to tame. Great if you want a heavily clipped sound, like the guitar in Neil Young's "Rust Never Sleeps". If you're looking for the creamy distortion that's associated with an overdriven Marshall (or Hiwatt etc.) amp., you might want to audition different models.

    According to the link that I provided, the Bass model seems to be a good overall choice. Still, if you have a local guitar shop where you can audition other distortion pedals, why not? ;)

    BTW if you're not familiar with Pete Cornish, you should check out his website. Pete is a genuine rock and roll legend, and he still answers the phone himself! Owning a Pete Cornish pedal won't make you a better musician, but it's a great investment, for one day he will be gone.
  12. Espis

    Espis Well-Known Member

    The next time I'm around a music store, I'll drop by and listen to some pedals. Then I'll surely find one that suits my needs. :)

    As for the Pete Cornish pedals, I could hear my wallet laugh cruelly when I browsed their site. I'm sure they are awesome pedals, but they are light years out of my wallet's reach...
  13. Speed Daemon

    Speed Daemon Disabled

    That's a good choice. To be honest with you, I wouldn't take advice from me... ;)

    Well, some of the cables are reasonable. :D
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