Orange Bass Terror - Ohms question

[rOB]

Ok quick question about the ohm-switch at the back.

If I switch it to 4 ohm would it function like a normal 4 ohm amp in that if I plugged in 1 8ohm cabinet would the cabinet receive just 250W?

Sorry if I haven't explained that well.

Thanks, Rob

[icastle]

[quote name='rOB' post='1246048' date='May 26 2011, 06:46 PM']Ok quick question about the ohm-switch at the back.
If I switch it to 4 ohm would it function like a normal 4 ohm amp in that if I plugged in 1 8ohm cabinet would the cabinet receive just 250W?[/quote]

True up to a point, but the impedance switch on the back selects a different set of output transformer taps.
Using the wrong setting won't do your amp a lot of good...

[obbm]

[quote name='icastle' post='1246060' date='May 26 2011, 06:59 PM']True up to a point, but the impedance switch on the back selects a different set of output transformer taps.
Using the wrong setting won't do your amp a lot of good...[/quote]


Careful. Terror Bass is a Class D solid state amp with no output transformer. According to the block diagram the switch
controls a limiter which drives the Class D output modules.


As far as the OP goes, I'm not sure I follow the reasoning behind the question. If you have an 8-ohm cab then switch to 8-ohms. If it's too loud then turn it down.

[Bass Awkward]

The OBT has a nasty little distorted side to it, and that engaged, you wouldn't really be able to hear the speaker distortion, right?

And you have a cab rated 300w@8ohms, I assume?

Mmmm.....

I don't know how much harm it would really do - certainly I'd imagine that the amp should be up to it - it's not like it'll screw its output stage like a tube amp, and these things have fans, thermal cutoffs and (presumably) components selected to deal with the different tolerances implied by an 8ohm load...

A lot depends on what the 'limiter' affects.

And on the other hand, these things look like laptops on the inside, and repairs to modern amps are nowhere near as easy, or as cheap, as with old equipment.

I have absolutely no idea - but you could take a hit for the rest of us, and try it..

[alexclaber]

My best guess is that the switch changes the output limiter threshold, similar to what the biggest Genz head has (though I believe that drops the rail voltage too but I think that's unlikely with a class D module). Anyway, running an 8 ohm load with the switch at 4 ohms won't be a problem, you just get a bit less power but I doubt you'll notice much difference.

[rOB]

[quote name='obbm' post='1246106' date='May 26 2011, 07:24 PM']Careful. Terror Bass is a Class D solid state amp with no output transformer. According to the block diagram the switch
controls a limiter which drives the Class D output modules.
As far as the OP goes, I'm not sure I follow the reasoning behind the question. [b]If you have an 8-ohm cab then switch to 8-ohms. If it's too loud then turn it down.[/b][/quote]
Normally that's exactly what I'd do but the dirty amp sound might well cover the speaker distortion.

[quote name='Bass Awkward' post='1246165' date='May 26 2011, 08:05 PM']The OBT has a nasty little distorted side to it, and that engaged, you wouldn't really be able to hear the speaker distortion, right?

And you have a cab rated 300w@8ohms, I assume?

Mmmm.....

I don't know how much harm it would really do - certainly I'd imagine that the amp should be up to it - it's not like it'll screw its output stage like a tube amp, and these things have fans, thermal cutoffs and (presumably) components selected to deal with the different tolerances implied by an 8ohm load...

A lot depends on what the 'limiter' affects.

And on the other hand, these things look like laptops on the inside, and repairs to modern amps are nowhere near as easy, or as cheap, as with old equipment.

I have absolutely no idea - but you could take a hit for the rest of us, and try it..[/quote]

Almost- its a 250W at 8 Ohms (for whatever the rating is worth) cabinet and don't want to damage the speakers. True, don't much fancy damaging the amp for the sake of curiosity

[quote name='alexclaber' post='1246290' date='May 26 2011, 09:34 PM']My best guess is that the switch changes the output limiter threshold, similar to what the biggest Genz head has (though I believe that drops the rail voltage too but I think that's unlikely with a class D module). Anyway, running an 8 ohm load with the switch at 4 ohms won't be a problem, you just get a bit less power but I doubt you'll notice much difference.[/quote]

Mmm that sounds ok. Might give it a go on low gain, keep an ear out for any speaker distortion and see how it goes.

Thanks for all the advice chaps.

[rOB]

[quote name='icastle' post='1246060' date='May 26 2011, 06:59 PM']True up to a point, but the impedance switch on the back selects a different set of output transformer taps.
Using the wrong setting won't do your amp a lot of good...[/quote]
In what way?

[alexclaber]

I doubt your cab can handle much more than 100W in the lows without the drivers exceeding Xmax, just be sensible! No output transformer on the Terror - don't use the 8 ohm switch with a 4 ohm cab but the reverse will be fine.

[rOB]

[quote name='alexclaber' post='1246386' date='May 26 2011, 10:41 PM']I doubt your cab can handle much more than 100W in the lows without the drivers exceeding Xmax, just be sensible! No output transformer on the Terror - don't use the 8 ohm switch with a 4 ohm cab but the reverse will be fine.[/quote]

Right ok, I'll be careful.

Thanks everyone. As always, your advice is much appreciated.