Hello guys. Do you think that 40w guitar tube head through 2 x 12'' cabinet with Celestion G12N-65 Super speakers will be loud enough for 4x5 meters room? Also, will it be a problem that the head works on 6/12 ohms and the cab is 8 ohms?

The music I play is mainly doom metal (using very extreme fuzz pedal) and psych rock. The doom band contains only me and a drummer, and the psych rock band (using mainly clean tones) contains me, drummer, bassist and keyboardist.
Last edited by Imraotnh at Sep 24, 2014,
That will be loud enough for playing gigs & jamming with drummers!
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If it's not something is dreadfully wrong.

What head is 6/12 ohms?
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Something is weird with the impedance. I'd suggest the matching cab to this head but as long as impedance on cab side is not lower in value, and it's not huge difference say 12 on head and 16 on cab, or 6 on head vs 8 on cab you should be OK.
Wattage is fine....it'll be able to shake the walls.

However the impedance seems a bit of an issue, can you not get a matching cab or is there a different version of the head that has the correct impedance?
Thank you guys... the head is 6/12 ohms indeed - it's "home-made" in Bulgaria a long time ago (at least 10 years, maybe more).
Can I take the head (or the cab) to a guitar tech who can change the impedance?
A 25% mismatch to 8 or 16 shouldn't be an issue, but there's no way for us to be certain.

You would have to replace the output transformer.
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It would be interesting to see what the amp looks like, I'm curious.

I'm guessing it is probably PA.

I was running a Peavey 50/50 power amp (tube) at 8 bridged mode into 2x12 16 ohm cab, without any issues for years. Actually you might not even have that much of a problem since impedance fluctuates somewhat, it is possible the Bulgarian/Soviet era measures to be a bit different. I'd suggest for you to ask an amp tech locally, someone that has worked with these when you narrow down cab choices. Probably the 6ohm setting with 8ohm cab wouldn't pose a problem, although I don't think the 12 into 16 would either.
yes. plenty loud.
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That will peel paint in a room that size. I gigged with a JCM 900 SLX and a 4x12 and I always used my 50w half power switch and I could get crazy loud.. 40 tube watts is louder than you think.
Plenty loud enough. An 8 ohm cab on the 6 ohm output or a 16 ohm cab on the 12 ohm output should be fine. I used to run that sort of mismatch all the time when I ran a 6x12 (10.3 ohms off the 8 ohm output of my JCM900)
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Wattage doesn't really mean crap, your speakers will determine how loud it is. Every try a micro terror with its matching cab its not that loud. Use the same amp in with a good. 4x12 it suddenly becomes a hell of a lot louder. Not all amps are created equal, my ampeg pretty much crushes everything. 40 wats pushed by a fuzz should more then get you there.
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The ohm ratings are probably recommended minimums so an 8 ohm cab on a 6 ohm (min) amp should be fine. 40w into quality speakers equivalent to V30s will be loud enough to cut people in half.
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An 8 ohm cab with a 6 ohm amp should be fine. You don't want the speaker impedance to be lower than the amp.

Speaker volume is mainly affected by the efficiency rating of the speaker, which is why some will be louder plugged into the same amp than others. A speaker with a higher efficiency rating will be the louder one. Wattage will affect it too, but it take a lot more wattage to make a big difference. To get a noticeable difference in volume, you would have to go from a 30 watt amp to a 100 watt one with the same speakers. The difference between a 30 watt amp and a 60 watt one would be minor, you might not even be able to tell it. 30 to 45 watts, you'd never know it. The Peavey Classic 30 can stay onstage with my Fender Super Reverb at 45 watts quite easily. Been there done that...

With a 40 watt amp you should be able to handle anything but really large clubs, and maybe even those, especially if you mic into the PA. I've played my Super Reverb with some pretty loud bands, it's always held up fine even with a 100 watt guitar amp onstage too. Lots of times I've seen pro bands with 50 and 100 watt amps onstage, Tom Petty has used a pair of Marshalls, probaly 50 watters, while his lead guitar player, Mike Campbell, had a Fender Princeton as part of his rig, it's 18 watts I think. I don't know what other amps Mike used, they never showed a good enough shot of them on the video I have. Johnny Winter used 3 Fender Super Reverbs for years, Derek Trucks still uses one. Those are 40-45 watts depending on the model.
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