Can an octave pedal damage yer amp?

skunkwerx

Became curious, n worried after having thoughts.  

Remembered hearing that a bass through a guitar amp is bad bad bad. 
But I often use an octave pedal to go down 1 octave.. which is what a bass is isnt it? 

Only, became concerned for my lil Katana 50, as I dont want to end up killing the amp or speaker. 
Most of my pedals are more bass heavy too, like the russian muff pi reissue. Some sound ok with the octave, some dont.. like the amps just overloaded. Could sound ok in its own way, but I dont know if its damaging. 

Is it a matter of keeping the tone knob on any drive/distortion pedals I use after the octave more toward the treble, if its sounding too bassy and or like its just flabby?

I often use the octave pedal an octave down on clean or high gain channels, which come to think of it are eq’d with the bass up. 

The last rambling is, I get some fairly bassy/muddy tones from using the neck pickup with some of the muffs/drives. 
Same question, can these low/deeper tones harm the amp/speakers? 

Cheers all. 

Late night anxiety ey. Gotta love it!

p90fool

The effects on my Katana include an octave pedal as a factory default, so Boss are obviously not that worried. 

It should be fine as long as you don't run a ridiculously bass heavy EQ or the volume flat out. 

ICBM

Yes it can, especially combined with heavy fuzz at higher volume. At lower volume it will be fine, but be careful.

It will usually be the speaker which limits how loud you can get away with it, but it is possible for the amp to be damaged as well if you go too far. As long as you keep to sensible levels and don’t push the power stage too hard it should be OK though.

Kalimna

Out of interest, would that go for od pedals and valve amps? And just at higher volumes?

ICBM

It’s probably safer with a valve amp because the frequency range is limited by the output transformer to some extent, but you can still generate enough excess power in the low frequencies to damage both the speaker and sometimes (but rarely) the amp, if you go too far.

To be safe you need to be sure the power stage isn’t being overdriven and that the speakers are rated for at least twice the maximum output of the amp - at that point you won’t do any damage from the power alone, although sometimes low frequencies can damage speakers even below that point.

Voxman

Interesting @ICBM ; - what about an octave effect built into an amp (where you'd assume the amp and effects were specifically 'set' to work together) e.g. my 'blue' AD120VTX Valvetronix (speakers are 2 x 80w version of Celestion Neodymium G12 Century Vintage)

ChuckManual

I send the output of my TC Sub'n'Up to a separate bass amp.  Sounds great!

skunkwerx

Damn. Was hoping my woes were needless. 

Thanks for the replies. 

Looks like I might have to have a play around and reduce some bass and/or octave level. 

Maybe because the amps channel is set fairly bassy AND the pedal is set to noon rather than bright, theres too much low end especially with the octave.. 

I never touch the octave 2 knob, keep that off, so I am only ever 1 octave lower. 

Amateur question now, but what is the power stage and how do I keep it in safe levels?

If I use any pedal dirt, the amp is set to clean, gain very low, around 9 o clock if that high at all, channel volume maybe 12 o’clock and master anywhere between 10-11 o clock. The pedal is then set to unity gain or thereabouts so no big volume boost.
This is on the half a watt setting. 

If I use amp dirt the distortion is maxed, channel volume maybe a touch lower than 11 or 12 o clock, and master around 10-11 o clock. 

I think from memory the octaved sound sounds better through the amps distortion rather than through a dirt pedal into a clean amp. Whether thats because the dirt pedal is set too bassy in combination with the clean tone being a bit bassy, I dont know.

 

p90fool

Doesn't your Katana have a built in octave pedal? The 100 does. 

antifash

If it can, then how do people like Tom Morello go about mashing up concerts when pitch shifting? Why would they sell these pedals in the first place? I had a bassist who used sub frequencies and he never blew up an amp - ever! I wouldn’t worry too much about it, personally. 

ICBM

Voxman said:

Interesting @ICBM ;;; - what about an octave effect built into an amp (where you'd assume the amp and effects were specifically 'set' to work together) e.g. my 'blue' AD120VTX Valvetronix (speakers are 2 x 80w version of Celestion Neodymium G12 Century Vintage)

You would hope it would be OK! I would still avoid pushing it too hard though.

skunkwerx said:

Amateur question now, but what is the power stage and how do I keep it in safe levels?

If I use any pedal dirt, the amp is set to clean, gain very low, around 9 o clock if that high at all, channel volume maybe 12 o’clock and master anywhere between 10-11 o clock. The pedal is then set to unity gain or thereabouts so no big volume boost.
This is on the half a watt setting. 

If I use amp dirt the distortion is maxed, channel volume maybe a touch lower than 11 or 12 o clock, and master around 10-11 o clock.

This should all be fine - on anything other than the full power setting there's no risk at all. You would know if you were pushing the power stage too hard - which means more than the maximum clean power - firstly it would be very loud, and secondly you would most likely hear extra (and not necessarily good-sounding) distortion.

antifash said:

If it can, then how do people like Tom Morello go about mashing up concerts when pitch shifting?

Morello uses a Marshall JCM800 50W head into a Peavey closed-back 4x12" cabinet with G12K-85s, ie a 340W cab. So the speakers are at no risk at all, and the JCM800 Marshalls have good big transformers too.

antifash said:

Why would they sell these pedals in the first place? 

Because when used carefully, they're fine.

antifash said:

I had a bassist who used sub frequencies and he never blew up an amp - ever!

Bass gear is specifically designed to handle low frequencies.

antifash said:

I wouldn’t worry too much about it, personally. 

You should at least learn what the potential problems are instead of just dismissing it. I've personally blown up two amps - not the speakers - using a fuzz and an octaver.

It's true that one of them was a Fender Twin with most likely knackered valves - it blew the valve and fried the socket - and the other was a Trace Elliot Super Tramp, which are notoriously unreliable anyway... but both of them died when I turned on the octaver with the fuzz already on, which I don't think is a coincidence.

antifash

@ICBM You know your stuff, dude. 

ICBM

antifash said:

@ICBM You know your stuff, dude. 

As a repairer I tend to see the results when things go wrong rather than when they go right, so I can tend to be a bit pessimistic sometimes . And I've been doing this a long time . 

If you're using gear 'normally' you don't really need to worry about any of this, it's just when you do something a bit out of the ordinary that you can sometimes come unstuck...

ecc83

In THEORY OP valves can be damaged by bass frequencies outside the design range of the OPT because it is equivalent to running the valves into a very low load, like putting 2 Ohms on an a eight Ohm tap. I have not had it happen and 'we' have loaned out an S1 200 for bass duty.  But then I do not have ICBM's vast experience!

The main danger I would say was to the speaker. Guitar speakers are just not built for the mechanical overload. Note as well that a sealed box cab style will be safer for the speaker than an open backed jobbie.

The other problem is that both speakers and our ears are much less sensitive at bass frequencies so 'loud enough' can be a LOT of extra power input!

Softly, softly cahchee coney!

Dave.

Voxman

@ecc83 said:

Note as well that a sealed box cab style will be safer for the speaker than an open backed jobbie.

Why is that Dave?

ecc83

Voxman said:

@ecc83 said:

Note as well that a sealed box cab style will be safer for the speaker than an open backed jobbie.

Why is that Dave?

Because the air in the box provides a "load" and helps prevent over excursion. Counter-intuitively, small boxes give greater LF power handling than big ones(but a higher system resonance and faster roll off)

Note too that ported speaker cabs also leave the cone unloaded below resonance but usually the frequency is low enough that a valve amp delivers little power there. DC coupled Sstate amp DO! It is a good idea IMHO if messing with DCC/SS amps and an add hoc cab to fit a 1000mfd 63V cap as an output coupler for a sixer and 2200 mfd for bass. Check the existing offset voltage for polarity, do not assume it is positive of jack sleeve.

Dave.

olafgarten

ICBM said:

Yes it can, especially combined with heavy fuzz at higher volume.

While this is true, I don't think it caused Jack White any problems.