ive noticed amps such as glockenklang can run at 2.7 ohms.does anyone run their amps at this impedance.how would the mesa d800+ operate at this impedance and would you select the 2ohm setting.im putting together a modular rig involving up to 3 cabinets to cover all my sizes of gigs.ive had my existing amps for over 30 years but am a little out of touch with modern gear.can modern valve amps run at this low impedance.?thanks for any help.
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2.7 ohms
- Thread starter black cat bone
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- ohms
- Feb 12, 2006
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- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
With the Subway, anything below 4 ohms would use the 2 ohm position.
Please clarify. When you say "Valve Amps" I normally think of a tube amp. (Brits, etc. frequently use this term for tubes)
IF you are questioning the use of a tube amp at this load I STRONGLY advise against experimenting with this without consulting the amps manufacturer. Most tube amps I'm aware of don't like a load below 4 ohms. (Though they may still function) There are exceptions of course. Be careful.
IF you are questioning the use of a tube amp at this load I STRONGLY advise against experimenting with this without consulting the amps manufacturer. Most tube amps I'm aware of don't like a load below 4 ohms. (Though they may still function) There are exceptions of course. Be careful.
Actually, tube amps are opposite to solid state. They are much happier with a lower load than a higher one. Further, two of the four tube amps I currently own have 2 ohm outputs anyway - Ampeg V4b and Fender Super Bassman - plus off the top of my head you can add Ashdown CTM, Fender 100T and Ampeg SVT to that. My Orange AD200 and Trace Elliott V4 are rated for 8 and 4 ohms only though, IIRC. So to answer the OP, there are plenty of modern valve/all-tube amps which are rated for 2 ohms, and all-tube heads are safer with a lower ohmage than a higher one, unlike solid state. Obviously it is preferable to keep within the manufacturer's specs.
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- Aug 3, 2007
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- Current: Blackstar, DR strings, Nady. Previous endorsements with: GK, Rotosound, Ernie Ball, Cleartone, EMG, Dean, Dava Picks, Rebel Straps, Dickies
I smell what you're stepping in, but this statement isn't accurate. Ohms law is.... a law. Not a suggestion, hypothesis, or theory. There aren't exceptions to Ohms law when it encounters different amplifier designs.
Back to basics for electricity: ohms is a measure of resistance. Voltage is voltage, current is current, and watts are watts regardless if it's tube or ss. ANY electricity is looking for the path of least resistance straight to a ground source.
If an amp is designed to be ran at 2 ohms regardless of its tube, as, or hybrid makeup, then by default the electricity will be "happier" with less resistance than a higher resistance.
- Feb 12, 2006
- 61,045
- 5
- 220,994
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Tube amps with transformer coupled outputs are generally more tolerant of a lower impedance load than higher but not because of ohm's law. Another principle comes into play which is back EMF of the transformer, especially under overdrive operation into a higher impedance load.
Sorry, totally not what I have read and understood for years. Plenty of posts from amp designers on this who would concur and can explain it to you if you are struggling. Read Agedhorse's contribution above for an example.
I do support your right to express your opinion.
Back to the topic, if I was the OP and wanted a versatile amp that is speaker ohms tolerant I would have the Mesa 800+ high on my list of solid state designs.
That's because tubes & transistors act like a valve. The original signal voltage is sent in which operates the "gate" of the valve, which controls the flow of the electricity through the tube:
It begs the question though, why don't Britons call Transistors valves also?
The ohms of a cab and heads are not ohms of resistance. They are ohms of impedance, a very different thing.
- Feb 12, 2006
- 61,045
- 5
- 220,994
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Early text books used hydraulics or water flow examples to explain the operation of the tube/valve. A VOLTAGE change on the gate alters the current flow between the cathode and anode.It begs the question though, why don't Britons call Transistors valves also?
With a junction transistor, it's not quite as easy to explain using hydraulic examples (though it certainly can be). A CURRENT through the base-emitter junction controls the current through the collector-emitter junction.
I keep wading through this current of knowledge thinking I will somehow be anointed with the ability understand it. Oh well, I'll just keep paddling and try to absorb what I can.
Is it a current of knowledge, or a voltage of knowledge?
Thanks for your replies.some quite technical responses a little beyond me.ive used solid state for over 30 years and been very happy with the sound .previous valve or tube amps were a british matamp style amp and a rare marshall major(should have kept that one).the d800+ is definitely one i have in mind as well as a glockenklang but i keep watching mesas utube video on the prodigy. I may have to rethink my cabs if i go for that.thanks.
If you measure the average eight ohm bass speaker at 1 kHz it will read around 60 to 100 ohms, depending on the voice coil inductance. The standard for the rated impedance for a speaker is a bit vague, but on average it's the DC resistance multiplied by 1.5.
Amps aren't designed to be run at any resistance. They are designed to work within a range of nominal impedance loads. As Tim said tube and SS are opposites. You should run a tube amp with a speaker impedance equal to or lower than the tap rating, you should run an SS amp with a speaker impedance equal to or higher than the minimum load rating. In both cases there's no need for an exact match, because the impedance ratings themselves aren't exact.
Is it tube or SS?Is it a current of knowledge, or a voltage of knowledge?
There are a few replies here who say it is fine to run a tube amp at a lower impedance than the rating on the amp.would a mesa prodigy be ok at 2.7ohms and would the warranty be honoured in the event of a problem.they are expensive amps to take a chance with.cheers.
