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more cabs to one amp

Posted: Tue Nov 14, 2017 1:16 pm
by bloodstoner
Hello

I have an Orange OR100 and I have 3 16 ohm cabs atm. One 4x12 and two 2x12.

The question is, if I had 4 16 ohm cabs, could I use 2 daisy chains, and connect them to the two 8 ohms outputs? So I could play through 4 cabs, or would that hurt my gear?

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 2:11 pm
by Rlw59
Standard daisy chain is parallel (like if your cabs have two jacks, and you connect one cab to the amp then run a cable from that cab to another cab).

Four 16 ohm cabs all in parallel is a 4 ohm total load. Most Oranges don't have 4 ohm outputs, I'm not familiar with the OR100 but I'm going to assume it doesn't do 4 ohms.

You need either a series connector box, or a series splitter cable, so you can run the four cabs in series/parallel.

Plug the input of the series box into the amp's 16 ohm jack. Run a cable from one of the box's outputs to one cab, then daisy chain from that cab to another cab.

Do the same with the box's other output - box to third cab, third cab to fourth cab.

Any external series connection carries some risk. If a cable gets unplugged or a cable fails internally, none of the speakers will work and the amp will see an open load/infinite load (very very bad for the output transformer).

_______________

The two 8 ohm jacks on your amp are connected together in parallel. Together, they're connected to the output transformer's 8 ohm tap. That tap needs to see an 8 ohm total load. Either one 8 ohm load plugged into one jack, or two 16 ohm loads using both jacks.

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 2:37 pm
by Rlw59
As long as you get the ohms correct, the amp doesn't work any harder driving 10 speakers, 12 speakers, 1 speaker, 100 speakers. So no worries for the amp. It doesn't care as long as the ohms are correct.

But the more speakers, the less power each one gets. The amp puts out 100 watts (a bit more at max volume) so with 10 speakers each one will only get about 10 watts. Speakers sound different the harder they're pushed.

And a further complication. Let's say you run your 412 and a 212 together. Both are 16 ohms so you plug them into the amp's two 8 ohm jacks (or daisy chain them together and plug into one of the amp's 8 ohm jacks).

Because both cabs are 16 ohms, the amp's power will be equally divided between them. 50 watts to the 212 (25 watts for each speaker), and 50 watts to the 412 (12.5 watts for each speaker).

If you have 20 watt greenbacks or 15 watt blues, you have to consider the power distribution to keep from blowing speakers.

And then there's speaker sensitivity. If the 212 has V30's and the 412 has greenbacks and you run the cabs together, the 212 will be significantly louder than the 412.

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 2:54 pm
by Rlw59
Sorry to keep blabbing, way more than you really wanted to know.

Orange is very conservative. They say you must match impedances. Period. No exceptions.

Some amp companies say 2:1 and 1:2 mismatches are ok. Some amp companies even encourage experimenting with mismatches - changes the tone and distortion characteristics.

People have accidentally mismatched Oranges with no ill effects.

It's possible you could daisy-chain four 16 ohm cabs and have no problems. You'll scratch your head and say "that blowhard didn't know what he was talking about".

I'm just a poor boy who's afraid of blowing up $1000 amps. If Orange says "don't do that", I don't do that.

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 4:53 pm
by Boy_Narf
Yea don't mess with it. Run the 412 and one 212 together, that's what I do. Sounds great! Best idea is to just buy another orange amp so your spare 212 doesn't get lonely :)

Perhaps a micro dark for some compact impress your friends tone?

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 5:25 pm
by Rlw59
Boy_Narf is the voice of reason. You could buy a CR120H and an a/b/y splitter and run a stereo rig for less than the cost of some cabs.

With much less ohm confusion.

Re: more cabs to one amp

Posted: Tue Nov 14, 2017 7:28 pm
by bclaire
Here's what I posted to technical before I realised you had duplicate threads. Only one thread is ever necessary so I deleted it.

No. That would be TWO 8 ohm loads together making for a 4 ohm load total.

Which will probably blow your output transformer. If the OR100 had a 4 ohm option, yes, but otherwise, no.

Re: more cabs to one amp

Posted: Wed Nov 15, 2017 5:49 am
by afjungemann
If you have a TV200, you can run 4 ppc412’s with a single head. I have zero reason to need that but that alone makes me want it.

Re: more cabs to one amp

Posted: Wed Nov 15, 2017 1:02 pm
by a.hun
Get an OR120 - they had a 4 ohms output tap! :D

Rlw59 wrote:
Tue Nov 14, 2017 2:54 pm
Orange is very conservative. They say you must match impedances. Period. No exceptions.

Some amp companies say 2:1 and 1:2 mismatches are ok. Some amp companies even encourage experimenting with mismatches - changes the tone and distortion characteristics.

People have accidentally mismatched Oranges with no ill effects.

It's possible you could daisy-chain four 16 ohm cabs and have no problems. You'll scratch your head and say "that blowhard didn't know what he was talking about".

I'm just a poor boy who's afraid of blowing up $1000 amps. If Orange says "don't do that", I don't do that.
Fair enough, but generally valve amps with healthy power valves and output transformers (OTs) will tolerate a 1/2 to 2x range impedance mismatch. The known Orange exceptions were the '90s reissue ORs which had good sounding but less robust OTs which did often die when mismatched.
You are right, always best to correctly match output impedance, but it is also (frankly) good to know that it can usually be safe enough to try, especially if not running an amp at full whack.

bclaire wrote:
Tue Nov 14, 2017 7:28 pm
No. That would be TWO 8 ohm loads together making for a 4 ohm load total.

Which will probably blow your output transformer. If the OR100 had a 4 ohm option, yes, but otherwise, no.
Actually no Billy! :shock:
It is high direction mismatches which are risky for the OT. Low direction mismatches (like a 4 ohm load from an 8 ohm output) are harder on the power valves which are more likely to fail, especially any weaker ones. Failing output valves could in theory lead to OT damage, but if the correct HT fuses are fitted this should protect them adequately in any decent amp design, so that actually almost never happens.
It can definitely happen with high direction mismatches though as very high voltages can develop in the OT and burn across between windings.

I have pointed this difference out so many times here. Search my name (or Andy H. :wink: ) and 'mismatch'...
Example:
viewtopic.php?f=3&t=47083


Andy.

Re: more cabs to one amp

Posted: Wed Nov 15, 2017 2:01 pm
by Rlw59
Ohms taken to the logical extreme:

Classic Fenders use shorting jacks for their outputs. With no speaker connected the transformer secondary sees zero ohms, a dead short.

Classic Marshalls use open jacks for their outputs. With no speaker connected the transformer secondary sees infinite ohms, an open connection.

Fender's shorting jacks are a safety feature. The transformer might overheat eventually with no speaker, but it willsurvive the occasional whoopsie.

The Marshall transformer might survive an ooops, or it might start arcing internally before you even realize what you did.

So, yeah, low mismatches are a bit safer.

Re: more cabs to one amp

Posted: Wed Nov 15, 2017 8:37 pm
by bclaire
a.hun wrote:
Wed Nov 15, 2017 1:02 pm
bclaire wrote:
Tue Nov 14, 2017 7:28 pm
No. That would be TWO 8 ohm loads together making for a 4 ohm load total.

Which will probably blow your output transformer. If the OR100 had a 4 ohm option, yes, but otherwise, no.
Actually no Billy! :shock:
It is high direction mismatches which are risky for the OT. Low direction mismatches (like a 4 ohm load from an 8 ohm output) are harder on the power valves which are more likely to fail, especially any weaker ones. Failing output valves could in theory lead to OT damage, but if the correct HT fuses are fitted this should protect them adequately in any decent amp design, so that actually almost never happens.
It can definitely happen with high direction mismatches though as very high voltages can develop in the OT and burn across between windings.

I have pointed this difference out so many times here. Search my name (or Andy H. :wink: ) and 'mismatch'...
Example:
viewtopic.php?f=3&t=47083
Andy.
You get it and I get it. The issue is, you don't encourage anyone (could be 12 years old- could be 60) to mismatch impedances. I don't care if it won't blow their amp - but if they think THAT'S ok they may go the other way and one of us said it was ok to do so. Let's err on the side of caution not encouraging forum members to go against what the manuals say.

Re: more cabs to one amp

Posted: Fri Nov 17, 2017 4:40 am
by Sooner
:lol:

Re: more cabs to one amp

Posted: Fri Nov 17, 2017 11:09 am
by adkguy07
Billy's statement carries weight when one recognizes how expensive it is to replace Orange amps.
About now, I don't think I can afford repairs or replacement for my Dark Terror.


adkguy07