ohms scare me

[nomis]

can i run a 4ohm cab and two 8 ohm cabs at the same time from my ad200? i dont have that amount of cabs, im just wondering?

if so what will it do? kill people?

[MythSte]

The orange website says it has 2 4ohm outputs on the back, I would presume you could run the 40hm cab from one output and then daisychain (Amp->8ohmcab1->8ohmcab2) the 8ohm cabs from the other.

It will be loud.

[nomis]

it has one 4 ohm and 2 8 ohm outs

at the moment i only use the 4 ohm with my 8x10 but for arguments sake say i bought a 115 and it was 8 ohms could i run that at the same time?

[MythSte]

On further inspection it seems the minimum ohmage for the Orange is 4, So no, I'm afraid you couldnt!

[mart]

[quote name='therose789' post='1241807' date='May 23 2011, 04:15 PM']it has one 4 ohm and 2 8 ohm outs
...[/quote]

From the manual on the Orange website I don't think it'll cope with a 4 ohm cab and 2 8 ohm cabs at the same time. The manual says it can handle 1 8 ohm cab (plugged into the "8 ohm" output), or 1 4 ohm cab (plugged into either of the "4 ohm" outputs) or 2 8 ohm cabs (each plugged into one of the 2 "4 ohm" outputs). So it looks like the 2 4 ohm outputs are designed for a TOTAL load of 4 ohms, not for 4 ohms in each output.

So I read that as saying that it'll happily work at 8 ohms or 4 ohms. But you'd need it to cope with 2 ohms in order to run the 3 cabs you suggest, and I don't think the head is designed for this.

Edit: Oh, it looks like MythSte beat me to it!

Edited May 23, 2011 by mart

[razze06]

[quote name='therose789' post='1241807' date='May 23 2011, 04:15 PM']it has one 4 ohm and 2 8 ohm outs

at the moment i only use the 4 ohm with my 8x10 but for arguments sake say i bought a 115 and it was 8 ohms could i run that at the same time?[/quote]

That suggests that it really wants a 4 ohm load.
I don't know the actual layout, but I'm pretty convinced that you shouldn't put a 4 ohm cab AND a 8 ohm cab at the same time. That would result in an impedance of 2.67 ohm (if the outs are in parallel), lower than what the is amp is designed for, resulting in an expensive bang and puff of smoke...

[nomis]

smashing, not actually going to do it, just wondered!

[alexclaber]

The AD200 is a valve amp so the rules are totally different to the solidstate amp ones. It looks like it has both an 8 ohm tap and a 4 ohm tap on the output transformer and you can use either one but not both. You could safely run three 8 ohm cabs on the 4 ohm tap, that won't bother it at all as valve amps are sensitive to overly HIGH not low impedances. Likewise I wouldn't envisage a problem running all those cabs you describe off the 4 ohm tap.

[razze06]

[quote name='alexclaber' post='1241870' date='May 23 2011, 04:57 PM']The AD200 is a valve amp so the rules are totally different to the solidstate amp ones. It looks like it has both an 8 ohm tap and a 4 ohm tap on the output transformer and you can use either one but not both. You could safely run three 8 ohm cabs on the 4 ohm tap, that won't bother it at all as valve amps are sensitive to overly HIGH not low impedances. Likewise I wouldn't envisage a problem running all those cabs you describe off the 4 ohm tap.[/quote]

Oh? I thought impedances below the recommended level would essentially draw too much current through through the OT and the valves, potentially frying them. Maybe that's true for transistor amps?

[JTUK]

Stick to what the manual suggests and don't mismatch cab impedances..

[obbm]

From Adrian Emsley - Tecnical Director at Orange Music Electronic Ltd - 24 April 2008 in answe to my question.

It confirms what has been previously said.

1 x 8 ohm cab = 8 ohm socket

2 x 8 ohm cabs = both 4 ohm sockets

1 x 4 ohm cab = either 4 ohm socket


Regarding the original post

Run the 2 x 8-ohm cabs in parallel

Put these in series with the 4-ohm cab to make 8-ohms.

Run the lot from the 8-ohm output.

[flyfisher]

Or, for more power output, connect an 8 ohm cab and the 4 ohm cab in series, giving 12 ohms, then run these two in parallel with the other 8 ohm cab, giving an overall load to the amp of 4.8 ohms.

It won't harm the amp but I doubt it's worth faffing around with the cabling.

[nomis]

the main reason i was asking in the first place is becasue im thinking about etting two smaller cabs to make practices easier and then i have a mamoth for live,

just spoke to matamp about a 2x15 which im very interested in.

it can be made in either a 4 or 16 ohm version say i was gonna get another cab to go with that what should i do? like something for the top end (i dunno a 2x10)

[obbm]

[quote name='flyfisher' post='1241926' date='May 23 2011, 05:33 PM']Or, for more power output, connect an 8 ohm cab and the 4 ohm cab in series, giving 12 ohms, then run these two in parallel with the other 8 ohm cab, giving an overall load to the amp of 4.8 ohms.

It won't harm the amp but I doubt it's worth faffing around with the cabling.[/quote]


Why would you deliberately wnat to create a miss-match?

[flyfisher]

[quote name='obbm' post='1241933' date='May 23 2011, 05:44 PM']Why would you deliberately wnat to create a miss-match?[/quote]
Where's the mismatch?
Speaker impedances are only nominal so what's the problem with connecting a combination of speakers totalling 4.8 ohms into a 4 ohm output?

[obbm]

[quote name='flyfisher' post='1241943' date='May 23 2011, 05:51 PM']Where's the mismatch?
Speaker impedances are only nominal so what's the problem with connecting a combination of speakers totalling 4.8 ohms into a 4 ohm output?[/quote]

I know that. Your method just seems a rather cack-handed way of getting there. Each to their own I suppose.

[flyfisher]

[quote name='obbm' post='1241949' date='May 23 2011, 05:53 PM']I know that.[/quote]

Then why try to imply there was a mismatch problem?


[quote name='obbm' post='1241949' date='May 23 2011, 05:53 PM']Your method just seems a rather cack-handed way of getting there.[/quote]

Just trying to explain all the options. I thought I was quite clear about it being a bit messy.


[quote name='obbm' post='1241949' date='May 23 2011, 05:53 PM']Each to their own I suppose.[/quote]

Quite so.

[alexclaber]

If you're thinking about two smaller cabs why not get two 1x15"s? It isn't like a 2x10" will get you any more top than a good 15" will with a bit of treble boost.

[Musicman20]

[quote name='therose789' post='1241931' date='May 23 2011, 05:43 PM']the main reason i was asking in the first place is becasue im thinking about etting two smaller cabs to make practices easier and then i have a mamoth for live,

just spoke to matamp about a 2x15 which im very interested in.

it can be made in either a 4 or 16 ohm version say i was gonna get another cab to go with that what should i do? like something for the top end (i dunno a 2x10)[/quote]

Just get one 4 ohm cab or two 8 ohm cabs..thats about it

Personally, I can see exactly why you would want to spend time thinking about....but please give things a try to see if you like them. Sometimes we get swallowed up in specs and it turns out to be nothing like we expected.

[Musicman20]

PS = Two Orange OBC115s make for a very nice stack!

[Big_Stu]

[quote name='MythSte' post='1241804' date='May 23 2011, 04:13 PM']The orange website says it has 2 4ohm outputs on the back, I would presume you could run the 40hm cab from one output and then daisychain (Amp->8ohmcab1->8ohmcab2) the 8ohm cabs from the other.[/quote]

Not contradicting this; I just want to be clear for future reference, I would have thought that daisychaining two 8ohm cabs one into the other would have made them in series & therefore make 16ohms, or do those daisychaining jack sockets make it "see" them as parallel?

[obbm]

[quote name='Big_Stu' post='1242115' date='May 23 2011, 07:34 PM']Not contradicting this; I just want to be clear for future reference, I would have thought that daisychaining two 8ohm cabs one into the other would have made them in series & therefore make 16ohms, or do those daisychaining jack sockets make it "see" them as parallel?[/quote]

When looping from one cab to another you are putting them in parallel, so 2 x 8-ohm cabs will make a 4-ohm load.

To put two cabs in series, and hence sum their impedances, a special cable is required.

[Big_Stu]

[quote name='obbm' post='1242142' date='May 23 2011, 07:52 PM']When looping from one cab to another you are putting them in parallel, so 2 x 8-ohm cabs will make a 4-ohm load.

To put two cabs in series, and hence sum their impedances, a special cable is required.[/quote]

"Looping"?, so it's a circuit within itself, as though you were wiring them as you would in one cab? *sigh* it was so much easier in my day

[obbm]

[quote name='Big_Stu' post='1242149' date='May 23 2011, 07:56 PM']"Looping"?, so it's a circuit within itself, as though you were wiring them as you would in one cab? *sigh* it was so much easier in my day [/quote]

Looped inputs is a term used in electronics where an input has 2 sockets, passively conected that allows a signal to loop out and onto another piece of equipment. Most speaker cabs have this. When you connect the 2 cabs together you are putting both sets of speakers in parallel.

[markstuk]

It's pretty easy to check with a cheap multimeter...

Something like this ..:-)

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