#1
Hi guys I've trawled the forums for a good couple of hours and can't find information specific to my question.

I now realise that when running two speaker cabinets (at 16ohms) they need to be plugged into the 8ohm output, not the 16ohm. The problem is I've just come back from a band practice where I've run them through 1 16ohm output and then linked them together. Is it possible I've just fried my amp?

(Background)

Hayden MOFO 30 -> 2x 1X12 cabs @ 16ohms each. Both cabs have an input and a 'link' input. What I've done for this practice is gone:

Amplifier -> 16ohm output, first cab (input), out through first cab 'link' into input of second cab, End.

Am I even setting up my stack right and have I just broken all my gear basically?

Thanks in advance.
#2
Is the amp not working or are you just wondering?

I'll give you my opinion and then let others weigh in.

Your Hayden should have fairly robust transformers (output transformer specifically) so unless your amp is making weird sounds or no sound at all I wouldn't worry about it too much - at least up until this point.

That said, I would stop doing it potentially.

Your amp wants to see a load (resistance) of 16 ohms and you are giving it 8.

If this was reversed and your amp was at 8 and your cabs were at 16 total I'd be less concerned. Someone can correct me or provide a different answer if they like. The reason this gets somewhat ambiguous is because part of the equation depends on the quality of the amp and the components (transformers and such) it uses. Some amps can handle this kind of mismatch with no problem.

I'd contact the manufacturer and then consider either getting a different cab/cabs or some kind of resistance/reactance 'matcher' - like a Dr Z ohm matcher, Weber Z-matcher, etc .

Like this: http://www.tedweber.com/z-matcher-50
Last edited by 311ZOSOVHJH at May 18, 2016,
#3
Hmm that doesn't sound too good. If you only used the one 16 ohm to run 2 16 ohm speakers you could have produced an 8 ohm load or a 32 ohm load but not 16 ohms. From my understanding of tube amps neither would be good for it, but im a solid state guy. It's possible you blew a fuse if the amp is not working now. With 2 16 ohm outputs each 16 ohm speaker would be plugged into its own output or 1 8ohm speaker would be plugged into both 16ohm outputs. In the case of plugging a 32 ohm load in the sound should have been very quiet but still work and in the case of an 8ohm load the amp might have been very loud for a split second and the quit working,or possibley just quit without making a sound. Did you try it again with just one speaker attached?, or did it actually play with this setup?
Last edited by geo-rage at May 18, 2016,
#4
If it still works you did no damage. Output transformers stop functioning altogether when damaged.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#5
Quote by Cathbard
If it still works you did no damage. Output transformers stop functioning altogether when damaged.


And they smell all melty.
#7
You can lose a tube sometimes, yes.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#8
Thank for everyone's replies so far.

After plugging in my amp today in the 8Ohm output it still works as it did, now the head runs slightly cooler so how on earth I haven't damaged anything is a miracle. I wish the manual had made it clear how to set up the head with two cabs and not just one.

Other than that though the amp is playing exactly the same as it was when I was connected to the 16ohm output.

So long term damage wise, I will have to replace the tubes and transformer sooner than I would normally? What kind of cost would I be looking at for that?

Thanks
#9
OT's rarely go bad in my experience.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#11
Most amps will tolerate a 2X mismatch without issue.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band