JPJ Posted August 6, 2012 Share Posted August 6, 2012 Just a thought, but why cant more amp manufacturers adopt Oranges trick of the 4/8 ohm switch on the Terrorbass allowing you to get maximum output from their amp with either a 4 or 8 ohm load. Given that the Terrorbass is hardly in 'boutique' territory price-wise, I'd guess this must be a fairly easy thing to do? Just a thought but I couldnt imagine our six string brethren settling for an amp that only put out a 1/4 or 1/2 its stated output in one cab. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted August 6, 2012 Share Posted August 6, 2012 Kind of wonder if the switch even does anything at all, not like anyone would know. Switch and a dymo labeller is all it takes. Quote Link to comment Share on other sites More sharing options...
AntLockyer Posted August 6, 2012 Share Posted August 6, 2012 two sets of windings or a tapped winding on an output transformer for a valve amp = economics or a solid state amp that doesn't really care what your impedance is = economics. Quote Link to comment Share on other sites More sharing options...
icastle Posted August 6, 2012 Share Posted August 6, 2012 (edited) I don't think that's what the switch was intended for. It's more of a by product of having to have the correct set of output transformer windings 'engaged' to match a given speaker impedance. If it wasn't there then your cab options would be impacted and you'd be on first name terms with your local amp tech. Edited August 6, 2012 by icastle Quote Link to comment Share on other sites More sharing options...
JPJ Posted August 6, 2012 Author Share Posted August 6, 2012 [quote name='icastle' timestamp='1344293860' post='1762512'] I don't think that's what the switch was intended for. It's more of a by product of having to have the correct set of output transformer windings 'engaged' to match a given speaker impedance. If it wasn't there then your cab options would be impacted and you'd be on first name terms with your local amp tech. [/quote] But most tranny amps are capable of carrying 4 or 8 ohm loads (some even 2 ohm) without needing a switch, so why does Orange have the switch? Quote Link to comment Share on other sites More sharing options...
JPJ Posted August 6, 2012 Author Share Posted August 6, 2012 [quote name='Mr. Foxen' timestamp='1344292095' post='1762481'] Kind of wonder if the switch even does anything at all, not like anyone would know. Switch and a dymo labeller is all it takes. [/quote] Good point, didnt really try mine as I set it to 8 ohms to match the Schroeder and left it that way. I think OBBM may have looked at a circuit diagram and he seemed to think it did something Quote Link to comment Share on other sites More sharing options...
icastle Posted August 6, 2012 Share Posted August 6, 2012 [quote name='JPJ' timestamp='1344294712' post='1762531'] But most tranny amps are capable of carrying 4 or 8 ohm loads (some even 2 ohm) without needing a switch, so why does Orange have the switch? [/quote] I thought the Terrorbass was a valve amp? Quote Link to comment Share on other sites More sharing options...
JPJ Posted August 6, 2012 Author Share Posted August 6, 2012 [quote name='icastle' timestamp='1344295430' post='1762542'] I thought the Terrorbass was a valve amp? [/quote] Nope, 2 valves in the front end, class D solid state power amp Quote Link to comment Share on other sites More sharing options...
icastle Posted August 6, 2012 Share Posted August 6, 2012 [quote name='JPJ' timestamp='1344295804' post='1762546'] Nope, 2 valves in the front end, class D solid state power amp [/quote] Ah. I'm no mega expert on this, but it's something to do with the impedance of the speaker being used as part of a filtering circuit on the rear end of the amp. There's a set of manufacturer notes [url="http://www.wolfsonmicro.com/documents/uploads/misc/en/WAN0200_1.pdf"]here[/url] regarding speaker selection that gives a full set of technical reasons pointing at why your amp has an impedance switch. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted August 6, 2012 Share Posted August 6, 2012 Using the speaker as an inductor for the low pass filter that takes out the switching noise from the class D output saves components and makes the amp cheaper. Cheaper to make at least. Quote Link to comment Share on other sites More sharing options...
icastle Posted August 6, 2012 Share Posted August 6, 2012 [quote name='Mr. Foxen' timestamp='1344296737' post='1762557'] Cheaper to make at least. [/quote] You old cynic you... Quote Link to comment Share on other sites More sharing options...
JPJ Posted August 7, 2012 Author Share Posted August 7, 2012 So does this mean that the marketing stating that the full 500 watts into either 4 or 8 ohms is a complete fabrication then? The impedance switch is merely there to ensure the correct filtering load for the class D amp? Quote Link to comment Share on other sites More sharing options...
bremen Posted August 7, 2012 Share Posted August 7, 2012 [quote name='Mr. Foxen' timestamp='1344296737' post='1762557'] Using the speaker as an inductor for the low pass filter that takes out the switching noise from the class D output saves components and makes the amp cheaper. Cheaper to make at least. [/quote] You'd still need a sizeable inductor to filter the output before it leaves the box, otherwise the emissions would be horrendous and it'd never pass EMC (and CE) testing. Even if this was the reason, what would the switch do? There must be another reason. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted August 7, 2012 Share Posted August 7, 2012 [quote name='JPJ' timestamp='1344360441' post='1763356'] So does this mean that the marketing stating that the full 500 watts into either 4 or 8 ohms is a complete fabrication then? The impedance switch is merely there to ensure the correct filtering load for the class D amp? [/quote] Watts is pretty much a fabrication, since it's dependent on outside influences, and only quotes a nominal one. The correct filtering load would influence the watts too though, since the purpose of the filter would be to remove the distortion from the amp, although I don't know if it counts as harmonic distortion for the THD figure, which is necessary to quote to give a useful output figure. Quote Link to comment Share on other sites More sharing options...
obbm Posted August 7, 2012 Share Posted August 7, 2012 As far as I can remember the switch has something to do with the input limiter of the Class D power amp, certainly nowhere near the output stage. Quote Link to comment Share on other sites More sharing options...
bremen Posted August 7, 2012 Share Posted August 7, 2012 [quote name='Mr. Foxen' timestamp='1344363849' post='1763470'] Watts is pretty much a fabrication, since it's dependent on outside influences, and only quotes a nominal one. The correct filtering load would influence the watts too though, since the purpose of the filter would be to remove the distortion from the amp, although I don't know if it counts as harmonic distortion for the THD figure, which is necessary to quote to give a useful output figure. [/quote] No, the filter wouldn't remove (for example) the harmonic distortion from a 1kHz signal. The stuff that a class D output filter removes is 400kHz-ish. Still a mystery. I like your Octobass. Quote Link to comment Share on other sites More sharing options...
bremen Posted August 7, 2012 Share Posted August 7, 2012 [quote name='obbm' timestamp='1344364332' post='1763481'] As far as I can remember the switch has something to do with the input limiter of the Class D power amp, certainly nowhere near the output stage. [/quote] That'd work. You could design an output stage that'd go 'bang' into a 4 ohm load were it not limited. Flick the switch to '8' and it'd be unleashed. Bit risky though, what happens if you run it into 4 ohms on the '8' setting? Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted August 7, 2012 Share Posted August 7, 2012 [quote name='bremen' timestamp='1344364602' post='1763490'] That'd work. You could design an output stage that'd go 'bang' into a 4 ohm load were it not limited. Flick the switch to '8' and it'd be unleashed. Bit risky though, what happens if you run it into 4 ohms on the '8' setting? [/quote] User error invalidates your warranty. Plus Orange cabs will pretty much all be into fart territory before 500w hits them, except maybe the big ones that will have levelled the room by then. Quote Link to comment Share on other sites More sharing options...
Dood Posted August 8, 2012 Share Posted August 8, 2012 [quote name='obbm' timestamp='1344364332' post='1763481'] As far as I can remember the switch has something to do with the input limiter of the Class D power amp, certainly nowhere near the output stage. [/quote] Yes, I remember reading this too. The amp is actually capable of peaks of 900W at 4 ohms. Somewhere (maybe in the Bass Gear Magazine review?) they detailed that the impedance switch just throttles the amp back to around 500W in each position. Quote Link to comment Share on other sites More sharing options...
obbm Posted August 8, 2012 Share Posted August 8, 2012 [quote name='dood' timestamp='1344417491' post='1764031'] Yes, I remember reading this too. The amp is actually capable of peaks of 900W at 4 ohms. Somewhere (maybe in the Bass Gear Magazine review?) they detailed that the impedance switch just throttles the amp back to around 500W in each position. [/quote] My reading of this would be that by running it with the switch at 8-ohms into a 4-ohm cabinet should give a lot more oomph. Quote Link to comment Share on other sites More sharing options...
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