Orange AD200 and 2.6 ohms advice please

[Tim1]

I have an Orange AD200 which I normally run into a 4 ohms Berg NV215 cab. Sounds wonderful. Since I also own an 8 ohm Berg NV115 I would like to try the two together (Berg NV315) which would be a 2.6 ohm load. The Orange has only an 8 and a 4 ohm speaker output. The last thing I want to do is risk any damage to the amp, especially since I am quite happy with just the 215, so does anyone know whether it would be safe to do this - and which output would you recommend? I certainly won't be doing it if there is any risk of damage to the amp.
Naturally it would be a vertical 315 stack

 

[CL400Peavey]

Run it on the 4 Ohm tap. Might stress your tubes a little harder, but those are supposed to be replaceable components.

 

[TMARK]

My tech says this will burn out the output transformer if run like that for an extended time.

 

[B-string]

My tech says this will burn out the output transformer if run like that for an extended time.

Get a new tech. The OT is fine, the tubes will just run a little hotter. Tube amps can survive very well into a direct short (0 ohms), but without a load the high voltage can punch through the insulation in the OT killing it. As you can see from this, your "tech" has it backwards and should not be working on tube amps without supervision. Not being nasty here, just truthful. I have more education than I care to talk about and well over 40 years of hands on experience.

 

[TMARK]

Your point is taken B-String.

 

[B-string]

Your point is taken B-String.

Apologies if it brought out the impersonal, direct. engineer response. Tired from yesterday's gig.

 

[Chris 'Wighat' Jordan]

Won't the 8 ohm 115 be contributing very little next to the 4 ohm 215?

 

[B-string]

Won't the 8 ohm 115 be contributing very little next to the 4 ohm 215?

Chances are extremely good the 215 also uses 8 ohm drivers so all three will be in parallel just like if they shared the same cabinet space. 1/3 power to each.

 

[Tim1]

Won't the 8 ohm 115 be contributing very little next to the 4 ohm 215?

I am assuming that that the 215 has two 8 ohm speakers in it wired in parallel, so my somewhat uneducated and rather intuitive thought is that each of the three speakers will share the power equally. I am happy to be corrected on this.
Of course, my main reason behind the post is to seek reassurance that doing this for a three hour gig is not going to destroy the amp. I doubt whether I would do it very often, but it would be nice to know it is possible and in the armoury. Have always loved my AD200, sold one a while ago and just had to buy another six months later to replace it - the last thing I want to do is risk any damage.

 

[Chris 'Wighat' Jordan]

Chances are extremely good the 215 also uses 8 ohm drivers so all three will be in parallel just like if they shared the same cabinet space. 1/3 power to each.

Um, yeah, I guess that's right!

 

[Tim1]

So... the consensus seems to be that I won't do any damage running my all tube Orange AD200 into 2.6 ohms for a gig, but use the 4 ohm output. It may shorten tube life but I would be unlikely to notice if I only do it at the occasional gig.

 

[Mr. Foxen]

I am quite happy with just the 215

No point in messing about if happy as is.

 

[waltdogg]

You can always run a tube amp into a lower load safely, not so much into a higher load without stressing the transformer. The opposite with solid state amps, go below the minimum impedance and the amp blows up, go over and you lose power.

 

[Tim1]

You can always run a tube amp into a lower load safely, not so much into a higher load without stressing the transformer. The opposite with solid state amps, go below the minimum impedance and the amp blows up, go over and you lose power.

This is what I have always understood. I was hoping someone with specific technical knowledge of the AD200 could confirm for me that it is definitely safe with this head.

 

[waltdogg]

To be honest, two ohms is pushing it with any amp. Your best bet would be to put a multimeter on your speaker cabs, and get the exact impedance of both cabs in parallel. It might be closer to 4 ohms than 2 anyways. FWIW I do run my Hellhawk at 8 ohms into 5.3 (16 ohm and 8 ohm cab, for guitar).

 

[Mr. Foxen]

Multimeter won't tell you impedance. The 4/8/16ohm is a nominal figure. Which is to say made up.

 

[waltdogg]

That's what I'm saying. None of this is accurate, it's all rule-of-thumb.

 

[eyeballkid]

I would add that while this may be theoretically safe with a tube amp that it may not be a good idea with this specific tube amp because as pointed out it will cause the tubes to run hotter and the one recurring issue known to cause failures in Orange amps is excessive heat build up.