Bass Amplification by Simulated Emission of Reverberation

June 29, 2009 1:55 PM

What exactly is the difference between a guitar and bass amp? If I were to get the latter, could I plug in the former instrument and still get similar bitchin' sounds out of my rig?

I am interested in learning to play the electric bass and am set to get a beginner model + practice amp. The problem is, I have a (really) shitty guitar from a while back that i can hack out a few tunes on, and would like to amplify it as well. I would much rather not invest in a separate amp for each instrument.

My readings tell me that putting a bass into a guitar amp is not the best idea because it might explode. But how about a guitar plugged into a bass amp? wouldn't that suffice? (research doesn't turn up much) would there even be any difference in sound or anything? If so, what cheap solution can I use to compensate?

Also, past ask threads have been very useful in helping me pick out models, but if any of you have recommendations for certain brands/products, please feel free to shout across the room/

posted by shoebox to media & arts (15 comments total)

I've busted a couple guitar amps in my time by using them to play bass and keyboards. Playing guitar on a bass amp is unlikely to wreck it, but it'll probably sound like junk.

You can pick up a cheap guitar amp (it'll be a lot more passable) for not much -- I sold my old Peavey amp (an Audition 20, I think?) for about $30 the other day. If you're not performing or anything, this is a fine option -- or even one of those cheap belt-clip amps, which sound sort of nice as long as you don't need to turn them up. (I'm going to be flamed for that by amp experts in 3... 2... 1... )
posted by zvs at 1:59 PM on June 29

Once again, from my husband:

a lot of guitar players use tube bass amps, like the old Fender Bassman amps. In fact, guitar amps like the legendary Marshall and a lot of the newer 'boutique' amps use the schematic of the Bassman as their jumping-off point for guitar amp designs.
Having said that, you get a cleaner bass tone through a solid state amp, and SS amps don't really provide much in the way of tone for a guitar. Figure out which you need more and buy to suit your needs.

posted by kellyblah at 2:11 PM on June 29

You can plug a guitar into a bass amp and not do any damage, but...it will sound weird. The design is all different. Voicing, even features. For example, its pretty common for a guitar combo to have a reverb circuit of some kind, and to have a preamp stage thats very easy to overdrive. Bass amps basically never have these features, but they frequently have limiter circuits. Anyway, the voicing of the speakers, cab, gain structure, eq points, and other features will be really different, but you won't do any damage.

If its just so you can hear it, yeah, go nuts. Bass practice amps are nearly useless though, IMHO. You gotta move a lot of air to make a bass guitar work right, a little 15W 10" practice amp is just not going to move much air. Seriously, if you just want to be able to hear it, you'd be safe running it at very low volumes through a guitar amp, and a small guitar amp is totally worth having, unlike a small bass amp. I think you'd even be better off running like a sansamp bass driver through your hifi or something (note: some limiting must be between this and your speakers somewhere). Or get a headphone amp.
posted by jeb at 2:11 PM on June 29 [1 favorite has favorites]

To kellyblah's husband's point, ignore everything I said if you are thinking of getting a Fender Bassman. Totally different story. Although the Bassman isn't really the greatest amp for a bass, oddly.
posted by jeb at 2:13 PM on June 29

Fender makes a whole line of modern bass amps that are called the "Bassman." These are not the amps that kellyblah's husband is talking about.

When people refer to guitar being played through a "Fender Bassman," they are referring to a specific amp made by Fender in the late 1950s and early '60s that was originally designed for bass (and to make the bass sound cut through the mix like a guitar, because it was '50s music and Country/Western). That is the amplifier that was adopted by guitarists due to its fantastic tone when pushed to the limit with a guitar. A current version of that amp is still for sale as a guitar amp by Fender under the name "Fender Vintage Reissue '59 Bassman LTD."

The rest of the amps sold as Fender Bassman are purely bass amps, and will not sound right with a guitar. They won't sound "bad," but they will not sound "right."
posted by The World Famous at 2:33 PM on June 29

i have used bass amp+guitar combinations with varying degrees of success. far and away the best i had found was the Sunn Beta Bass, which had a scad of useful features for someone wanting to use it as a guitar amp (a drive knob, two completely identical channels with their own identical set of tone controls, with a footswitch for a/b/a+b).

i've used some that worked decently well as long as you had some tone affecting pedals. your specific equipment, whatever it is, will sound different to you than to others. your best bet in this situation, as in EVERY "i have an instrument, i need an amp", is to take your instrument with you and try it out.

if YOU like it, you found a good match.

there is no technological reason to avoid running a guitar through a bass amp.

(the reasons i've heard for not running a BASS through a GUITAR amp are about range and whatnot, with the guitar amp speakers not being able to properly handle the low end of the bass. because of the frequency ranges of a guitar, running one through a bass amp causes no such technical problems)
posted by radiosilents at 2:34 PM on June 29 [1 favorite has favorites]

Get a little crappy practice amp from a pawn shop. It will sound better in the end. I haven't heard of anyone blowing the amp meant for a bass but have heard a guitar amp blown when it had a bass played through it. Might have just been one of those days. /shrugs.

KellyBlah's husband is pretty much spot on, but I will add that many bass players prefer the warmth of a tube amp to the clean tone from a SS. I am a tube amp guy as I prefer the dirtier sound

I ran a Warwick thumb 5-string through an Eden Head and placed a SansAmp in the line and never looked back. Shit was golden to me anyways. ;)
posted by Gravitus at 2:50 PM on June 29

You won't blow a guitar amp playing bass through it as long as you don't crank the volume/gain knobs. Just don't try to max out the amp when playing your bass and you'll be fine.

Also, as for guitar through a bass amp, I preferred the deeper sound of a larger speaker, so when I'm not playing through my toneport, I play through my bass amp (of course I fiddle with the knobs so that it doesn't sound weird, but I like the deeper bass and thicker tone).
posted by Chan at 3:55 PM on June 29

I've heard acceptable guitar sounds from a Roland KC-150, which also does bass fairly well at practice volumes. It is technically a keyboard amp, which gives you a decent-enough frequency response to cover both instruments at reasonable volumes. You'll probably want to pick up a guitar pre-amp such as a SansAmp to get that real electric guitar tone, though.
posted by Benjy at 4:02 PM on June 29

What exactly is the difference between a guitar and bass amp?

Guitar amps and bass amps are not merely devices for making the instrument louder. Instead, they are made to actually color the sound of the instrument. Indeed, the electric guitar as an instrument does not simply consist of the guitar itself. The instrument consists of the guitar, the amplifier, and anything else that runs between them (like effects).

A guitar amp is made to color the sound in very specific ways so that it sounds like an electric guitar "should." Amps employ various electronic techniques to color the sound right - typically either vacuum tube circuitry (the preferred method) or digital circuitry that is generally designed to emulate tubes. There are also a lot of non-digital solid state amps that attempt (generally unsuccessfully) to sound like the classic tube guitar sound, as well as a very small number of solid state amps that do not emulate tube amps but are considered to be brilliant instruments in their own right (e.g. the Roland JC-120 Jazz Chorus guitar amp). As a result, when you play guitar through a keyboard amp, a bass amp, a P.A., or whatever else, it might sound "good," but it will not sound "like an electric guitar should." And if you play, say, an acoustic guitar, bass, keyboard, whatever through a "real" electric guitar amp, it will not sound "right." Tube amps add a level of dynamic response that you can literally feel as you play the guitar through them - responding to different playing styles, picking styles, volume, etc. in a way that is completely different from what it would be if you just amplified the sound of the guitar. For example, if you really push a good tube amp hard, you get what's called "sag," where there is sort of a natural compression, smoothing out the notes and adding sustain. Technically speaking, sag is a drooping of the power supply voltage when hit with a big, loud signal (and I'll omit the further geekery that could follow or elaborate on that - suffice it to say that tube amps do it best, and it is awesome).

Sometimes using the "wrong" amp is done to good effect. Examples of this include guitarists' use of the '59 Bassman (see, e.g., Stevie Ray Vaughan) or keyboard players' use of Marshall stacks for electric piano (see, e.g., "And The Cradle Will Rock" by Van Halen, where Eddie runs an electric piano through a distorted guitar amp, and it sounds like a guitar). I have run my electrric guitar through an Ampeg SVT bass amp, and it has a very unique and cool sound - but it sounds "wrong" if what you're looking for is a standard electric guitar sound.

Bass amps also color the sound of the bass to make it sound like the bassist wants. Bass amps vary in the way that they color the sound just as much as guitar amps do. There are sort of "classic" bass sounds that are typically achieved by using specific types of amps. Solid state bass amps are used generally for very clean, broad tone (think soul music), while tube bass amps are typically thought of as giving a grittier tone (think Pixies or Sonic Youth). If you play a bass through a guitar amp, it might sound "cool," but it won't sound "like a bass should." There is also some concern that the low frequencies of the bass can harm or destroy either the circuits or the speakers of a guitar amp. I don't know whether I believe that or not, but I generally take it to heart and don't run a bass through the better of my guitar amps. (I have recently been running a Fender VI, which is sort of a bass, through a small tube guitar combo, though, and it sounds amazing, so who knows?)

If you are using inexpensive little practice amps, you should expect that the coloration of the amps will be there, but that it will not be the same sort of geeky tone-fest that I'm discussing above. Nevertheless, the guitar amp will be made to be played with a guitar and sound like a guitar, and it will at least probably not have the low end to even really hear the bass well if you plug it in there. I plugged a bass through a little 30-watt solid state Fender thing years ago and it didn't blow anything up, but you just couldn't hear the low notes at all. Running the guitar through a little bass practice amp probably won't sound "bad," but it won't sound "right."
posted by The World Famous at 5:26 PM on June 29 [2 favorites has favorites]

There is also some concern that the low frequencies of the bass can harm or destroy either the circuits or the speakers of a guitar amp. I don't know whether I believe that or not.

It's true. I've done it. It's the speakers. You will blow the voice coils. I'm sure there are some guitar amps that either hipass the signal going to the speaker or brickwall limit it, or are just designed with drivers that can handle the excursion and dissipate the voice coil heat/cab designs that will rein them in, but they are not the norm.
posted by jeb at 6:25 PM on June 29

Strictly speaking any speaker will blow if the signal through it is hot enough. Generally, its hard to blow guitar amp speakers with guitar amps, but if you hotrod them, you certainly can (or if the amp is just poorly designed, speaker is below spec, etc...). Same thing with your home stereo: if you crank it and play a Telarc recording of the 1812 Overture with the real cannon shots, you can blow your speakers if your amps are hot enough. Actually, in this case you might blow the speakers' crossovers first, but there's no sacrificial crossover in a normal guitar amp.
posted by jeb at 6:27 PM on June 29

The World Famous is dead-on: this is really about what the 'right' tone you're looking for is.

I'm currently rebuilding my old Crate bass amp into a guitar amp. I've really loved it as an amplifier for my guitar, but that's mostly because of what it delivers: a jazzy and mid- to low-tone-heavy sound. In essence, the tone is clean, clear, and maybe even a little jangly when I pump the treble; that's what I like, so it works. If I were trying to play classic-rock guitar solos or punk-rock rhythm lines, it would be all wrong, but for what I like, it works great.

So: it depends on what you want to do.
posted by koeselitz at 7:35 PM on June 29

...and distortion? Well, that doesn't work very well, really. So if what you're looking for is 'crunch' or 'thud' or heavy metal thunder... a bass amp may be the wrong choice. But, hell, it's an interesting coloration; why not use it?
posted by koeselitz at 7:38 PM on June 29

Bass through a guitar practice amp generally sounds thin sound and the very real possibility that you'll damage the speaker, unless you're very careful. Having to worry about that will take all the fun out of playing bass.

Guitar through a bass amp can sound okay if you like a clean tone and/or have a distortion/overdrive stomp box of some sort. But it won't sound like a dedicated guitar amp. It can work. It won't be fun or inspiring, but it's workable.

What's your budget? I play bass and guitar. Peavey's Max 158 (the current version of the MicroBass, which is what I have) sounds surprisingly decent, is loud enough for little acoustic jams with friends, and will get you started.

For guitar, the best sounding practice amp (on the cheap) I've found is a Kustom Arrow 16R. I put this one up against all the other ones in it's price range (Roland, Vox, etc.), and it won out for me. The spring reverb makes all the difference. And it sounds as good at low volumes as it does at high--relatively speaking--ones. The distortion is believable, and it's actually quite loud. The Roland was a close second, BTW. Try some out at a store. See what you like.

90% of the time, if I'm just practicing by myself--and even bother to plug in--I just run my bass through a Line6 TonePort UX2 (latest version is called POD Studio UX2) and use my the software that comes with it to dial in a sound and some headphones to monitor it.
posted by wheat at 11:50 AM on June 30