How will a bass damage a guitar amp?

[roffe]

I've played bass (loud!) through an old Marshall head and a 4x12" with G12T75s. Didn't sound bad, but then I do like some grind I also know a guy that used an AC30 as a bass amp for a long time.

 

[IvanMike]

speakers die. See BillFM's post. ..... However, there is a "neat" tone available from some guitar speakers that's difficult to emulate otherwise. I know a few cats who love to play through speakers designed for guitar.

the amp itself will be fine. However, depending upon the tone you want, the preamp voicing (and the transformer if tube) may not be able to deliver the low end.

PA cabs? heck, a good PA cab will handle bass better than a bass guitar speaker. You have to remember, a proper PA is designed to amplify everything. Lots of cats, (self included) enjoy playing bass into a PA speaker, either right out of our amp, or just going direct into the PA.

 

[bdplaid]

Dug Pinnick from King's X uses a Bugera 1960, but plays though bass cabs. Lemmy's sound can hardly be characterized as "bass". And there's a reason guitarists love the Fender bassman - it sounds better. One of my friends recently had to play through a peavey Minx (bass practice amp) as a backup. He liked it a lot, and it didn't sound bad. So bass amps are the way to go for all citizens. We rule the world.

 

[mambo4]

Responses are muddying concepts of AMP and SPEAKER a bit.

I thought the AMP was safe, but the SPEAKERS were specifically in danger from damage due to low frequencies they were not intended to replicate...

Perhaps a more detailed explanation of my concept would help:
I used to use a cheap guitar combo and a bunch o pedals in addition to my bass combo
I would run my bass amp with the highs rolled off, Run the 'tuner out' into the guitar combo ,
and roll off the lows using the guitar amps EQ section. sounded neat, but never got too loud.

Lately my band mates are exposing me to a slew of sweet boutique guitar amps (they have friends who make em.)
Messing around with my bass in these guitar amps has gotten some sounds I really like, especially the touch response,
but I'm aware that too much bass at volume might be bad.
I'd like to try a similar setup again -but I don't want to damage any expensive gear.
So I'm looking for a way to "insulate" the guitar amp from any potentially damaging bass signals.

Is rolling off the bass on the guitar amps EQ enough?

 

[Arthur Strand]

I myself have used a Marshall guitar amp for bass - on a very important job a very long time ago. The speakers are the big problem with bass and can blow more readily. The circuitry for the guitar amp is designed for the frequencies that a guitar uses and likewise for a bass. Some younger musicians may not recall the valve (tube) amps of the 1960s and Selmer marketed a Treble'n'Bass 50 head which was great for either bass or guitar in small to medium sized venues. I also recall 100watt version too.Impact also made a similar model (50 watt).
I would not object to either Selmer or Impact today!!!

 

[seanm]

Responses are muddying concepts of AMP and SPEAKER a bit.

I thought the AMP was safe, but the SPEAKERS were specifically in danger from damage due to low frequencies they were not intended to replicate...

Perhaps a more detailed explanation of my concept would help:
I used to use a cheap guitar combo and a bunch o pedals in addition to my bass combo
I would run my bass amp with the highs rolled off, Run the 'tuner out' into the guitar combo ,
and roll off the lows using the guitar amps EQ section. sounded neat, but never got too loud.

Lately my band mates are exposing me to a slew of sweet boutique guitar amps (they have friends who make em.)
Messing around with my bass in these guitar amps has gotten some sounds I really like, especially the touch response,
but I'm aware that too much bass at volume might be bad.
I'd like to try a similar setup again -but I don't want to damage any expensive gear.
So I'm looking for a way to "insulate" the guitar amp from any potentially damaging bass signals.

Is rolling off the bass on the guitar amps EQ enough?

I would recommend a good High Pass Filter such as Fdeck's.

 

[AwkwardLoudness]

I thought the AMP was safe, but the SPEAKERS were specifically in danger from damage due to low frequencies they were not intended to replicate...

That's correct. Bass frequencies don't harm amps, but in many cases can damage speakers. The risk of damage depends on the speakers themselves, the amp, volume, and EQ.

 

[billfitzmaurice]

I would recommend a good High Pass Filter such as Fdeck's.

If you're going to high pass high enough to use guitar speakers you might as well be playing guitar.

 

[NWB]

A common response to "can I play my bass thru a guitar amp?"
seems to be "yes, but you might harm the speakers"
(after "yes, but it will sound bad" -but I'll ignore asthetics for discussion)

So can someone explain the mechanics of how bass will damage a guitar amp?
If I roll off the lows on teh guitar amp, will this prevent it?

Given the inherent limitations of guitar speakers and enclosures described by BFM, I think the most workable solution is to use a guitar amp into a bass-specific cab.

I see very few advantages to using a guitar driver with bass and a lot of disadvantages.

 

[Munjibunga]

Not even. A good bass driver has about 5mm xmax, the average guitar driver 1mm or less.

OK, 1/5 of an inch. I want speakers with 12mm xmax so I can create a hurricane of bass.

 

[JTE]

Actually there are some classic examples of bass being played through a guitar amp/speaker rig and sounding great. Carol Kaye and Joe Osborn both used a Fender Concert amp (two 6L6's, four 10" speakers in an open back cabinet- essentially a Super Reverb without reverb) for a LOT of their early recordings. And Tommy Cogbill used a Twin Reverb with one of the 12's blown and disconnected to record "Dusty In Memphis", including "Son Of A Preacher Man".

However, like they say- you won't hurt the amp at all, but the speakers may or may not survive the onslaught. For the stuff you specifically mention, cutting the lows going to the guitar FX/combo it might work great. Tom Peterson of Cheap Trick used to do exactly that, using Deluxe Reverbs (two 6V6 power tubes and a single 12" speaker) for part of his rig, and maybe still does.

John

 

[Raymeous]

I have nothing scientific to back this up with so take it for what its worth.

Unlike the early days there are some pretty substantial differences between guitar amp and bass amp design, and as others have said I think you would run into more issues with the speakers than the amp itself. The only amp thing I can see happening is that some basses have some pretty hot signals coming off of their built in preamps, and I'm not sure how many guitar amps are designed to take that amount of extra db coming in. My LB76 with dual MM style humbuckers is loud with the +/- 12db (or 18 I forget which) 3 band EQ. You could potentially fry the front end but I'm not sure just how valid this is. Just a guess.

Guitar speakers are still essentially based off the old design model and they tend to break up/distort a bit, whereas modern bass speakers have more in common with PA speakers, and can handle higher wattages, which means that they do not break up and distort as quickly. Guitar speakers can handle around 100w while bass/PA speakers generally can handle at least double that amount. So could you pop a guitar speaker? Oh yeah, depending on the amp, but I think more often then not your more immediate thing would be just a farty distorted tone verses clean and defined.

I have a Carvin BX1500 amp going into a BRX10.4 cabinet and the sound I get is very clean and articulate. However, when I want a more "growly" rock tone I can run my P-bass Special through my X100B guitar halfstack with pretty good results. My Mesa 4x12 handles my 6 string basses better than the Carvin 4x12 and I think it's due to the Mesa's larger cabinet as much as the speakers. Depending on how I EQ the amp and the basses EQ I can get a pretty respectable "bass" sound, however the B string doesn't sound quite as good as it does through my bass cabinet.

I think it really just comes down to the frequency range the amp and cabinet are design to reproduce, speaker breakup, and just what kind of sound you're looking for.

 

[stiles72]

Go for it. The worst that will happen is you don't like the way it sounds. On the other hand it might just work out for you. I don't like 10's for bass, but I have a Fender 4x12 guitar cabinet that sounds very warm and rich for bass, especially with a V4BH. Not trebley or middy at all. Has a nice bottom with lots of vintage character.

 

[amos]

I use an old Peavey Bandit 12 guitar combo for solid state distortion---just set the bass knob to 0. The distortion cuts like crazy, so I don't have to turn it up very loud. Not saying this isn't risky , but I've done gigs with this setup and have not had any problems so far.

 

[rekesbass]

Not to get off topic but, I believe that's why Rickenbacker put the .0047 cap on the treble(bridge) pup on the 4001..sort of an old school "on board" hi-pass filter,so when the Ric-o-sound feature was used one can send the "treble" pup to a guitar amp and the "bass"(neck)pup to a bass amp and have a "quasi-bi-amp" rig...

 

[kski94]

I Played Through My Dad's Combo For The First Two Years Of My Playing. No Harm Was Ever Done. It Didn't Sound Great, But Oh Well. Didn't Blow The Speaker Until I Used It With My First Band, And That Was Because We Had Two Instruments Plugged Into It. Childhood Stupidity

 

[Robby Hoinsky]

Not to get off topic but, I believe that's why Rickenbacker put the .0047 cap on the treble(bridge) pup on the 4001..sort of an old school "on board" hi-pass filter,so when the Ric-o-sound feature was used one can send the "treble" pup to a guitar amp and the "bass"(neck)pup to a bass amp and have a "quasi-bi-amp" rig...

It has two outputs?

 

[billfitzmaurice]

Actually there are some classic examples of bass being played through a guitar amp/speaker rig and sounding great.

Until the early 70s most 'bass' speakers were that in name only, actually using guitar drivers. That includes the original SVT, and that's why two '69 Fridges were required to handle 300 watts without farting out. Many guitar drivers sound good on bass, they just don't have the ability to go loud while doing it.
If you want to see what was used for drivers back then have a look here. The same drivers were used in both guitar and bass cabs.
[Invalid or Expired Link Removed]

 

[Calaverasgrande]

IIRC the Marshall Stack was intended for bass. The guitar amps of the day being open back combos with 2x12" or maybe 4x10. So 8x12 with 50-100watts would have been adequate. 50 watts divided among 8 speakers is hardly going to blow any of them.

 

[billfitzmaurice]

IIRC the Marshall Stack was intended for bass.

It was. I don't think more than ten had been sold before guitar'd players started using them.