it's probably a metric conversion thing. .

I have just posed this same question to Vox's importer here in New Zealand. Will post here if I get a response.

And if anyone from Vox is listening, please update the contact details on your website for the New Zealand Vox dealership. "www.korg.co.nz" no longer exists, and nor does the email address you have listed.

No response yet from Vox USA or the local distributor here in NZ - not even an acknowledgement of receipt of my emails. Nice customer service guys!

A little further investigation shows that the 54 watt figure isn't a simple misprint in the manual, because the same figure appears on the back of the amp itself. Contrast it with the Fender Mustang III, which is sold as 100 watt amp and was the other one I was considering buying. It has a power consumption of 310 watts RMS, which is far more believable for a 100w RMS output, particularly when you consider some of the power is needed to drive the preamp and all the modelling electronic wizardry. Even the little 20watt Mustang I consumes 70watts, 16 more than the VT80+. If the 54 watt consumption figure is correct, there is no way that the VT80+ can produce a CONTINUOUS 120 watt RMS or even 80 watt RMS output - if it can then Vox have solved the world's energy crisis by creating something that outputs more power than it consumes. I suspect that the continuous RMS capability is more like 35-40 watts, and the "120 watts RMS" quoted in the manual is more of a momentary peak figure. I love the amp, I think it sounds great, but one of the main reasons I bought it was to get significantly more power than my Mustang II, and I'm just not convinced it gives me that. I am left feeling that I have been misled, which taints the whole experience for me.

Really? I've not heard that before. Is that documented anywhere?

Every other guitar amp I've ever owned, and every hi-fi amp, and every home cinema amp (we're talking a lot of gear here by the way) has had a quoted power consumption figure that is significantly higher than the quoted RMS power output, in many cases it's double or more. This Vox amp is the only exception to this I have ever seen. That's why I'm questioning it. Believe me I'm happy to be proved wrong about this. If only someone at Vox in the US or the local NZ distributor would repsond to my emails....

I emailed the online retailer I bought the amp from, and got a response in 10 minutes. That's more like it! However, the response doesn't make a lot of sense.... "Basically the VT80+ has up to 120 watts of useable power because of the tube pre amp in it". And also "The Mustang III consumes a lot more power then the VT80+ because it has a screen on it".

Given that the tube in question is only a small pre amp tube (about 1 watt I believe), and that the small screen on the Mustang III will only consume a very small proportion of the amp's power, these statements are clearly not valid or sensible. However, to this guy's credit, when I pointed all this out he accepted it and promised to pass my question on on to their technical guy. Watch this space......

Thanks for pursuing this. . .as much as we love the Vox sound, having the facts is vital. .

These VT+ amps are not as loud as the numbers suggest. I have the big VT120+ and it is as loud as a set of drums, but the 1 12 and 1 10 amps might not cut it, I figure a 50 watt Marshall is louder tha your VT 80+.The 120+ I have sounds good, but with a ton of bass.

Vox should really be giving away free cans of contact cleaner with every one of these amps they sell....

Nope..They should just be using better quality jack socket inputs that don't oxidise/stick!!

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Another response from Vox Support in the UK. It was pretty brief, but they did answer almost all of my questions. Here's the detail, point by point:

1. I asked them to absolutely confirm that 54 watts is the maximum power consumption for this amp. Their response: "Yes, this is correct."

2. I asked them to confirm whether the quote 120 watts RMS is a continuous figure or more of a momentary peak figure. Their response: "RMS is an average, the figure is normally quoted when a sine wave is injected into the circuit. As you are from an engineering background, you will be familiar with the math’s and methods involved in reaching this figure http://en.wikipedia.org/wiki/Root_mean_square." This response actually didn't answer my question, or tell me anything I didn't alreayd know.

3. I asked that, if the 120 watts RMS is a momentary figure rather than a continuous one, what is the actual continuous RMS output figure for this amp. Their response: "120 watts RMS".

4. I said I agreed with their earlier point that amplifier output depends in part on the efficiency of the circuit design, but asked them whether or not they agreed with me that no amplifier design is more than 100% efficient. They chose not to answer that one.

They restated what they told me in their previous email - that the VT80+ does produce 120 watts RMS into a 4 ohm load (although I note they don't use the word "continuous").

They closed the email by saying they would not discuss this issue with me any further, and if I felt they were misleading customers, I should take this up using whatever method was appropriate in my country (I'm in New Zealand). I plan to do so, as I believe they are in breach of consumer law here.

To sum up: If what they say is correct, this amp can produce a continuous output of 120 watts RMS while consuming no more than 54 watts of power. Am I the only one on here who thinks they're breaking the laws of physics here? Interested to hear what you all think.

On a side note, I was in my local music shop yesterday. They are not a Vox dealer, but they do sell amps from Marshall, Fender, Mesa Boogie, Orange, Line 6, Soldano, Gallien Kruger and others. We did a quick, unscientific survey of about 15 different amps of all shapes and sizes. Every single one has a rated power consumption that is significantly higher than the quoted RMS output, and in some cases it is three times or more. Is anyone aware of any amp builders other than Vox who are claiming more power output than power input? I know it's not just the VT80+, their figures for the whole Valvetronix range are similarly supicious.

Don't get worked up. It's the way of the world, unfortunately.
1 - it's just marketing numbers
2 - you can tell because if the watts "output" is more than the watts "consumed" it is physically impossible. Only sales people can come up with that.
3 - Korg/Vox is not the same as Vox back in the sixties. All these guys currently care about is profit, no matter how much crap you have to put in the sales brochures.
4 - you can see for yourself: ask them a question. Do you get a sensible answer? There you go!
5 - if you want to know the output of your amp, do the following.
= connect an oscilloscope to the speaker.
= play as loud as you can. The output voltage will "clamp" to the max voltage the power supply can produce.
= that gives you a good idea of how much power you get out of the amp at most.
6 - and, finally, forget about output power. If it sounds loud enough, it's good enough. Period. End of story.