2. amps-preamps
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Power consuption of an amplifier

Hi, friends!

Maybe you can help me to figure out the peak power consumption of my amp.

I have bought Micromega M-150 from USA, but I live in Europe now. The amp's voltage is 120v, but I have 230v in socket here. So, I'm going to buy a step-down coverter 230v to 120v. Each step-down converter is designed for some maximum load, 150W, 450W, 600W, 1500W etc. So I need to know how much power my amplifier consumes from a socket to choose a coverter.

The problem is that I found three different points of view:

1) The Micromega's manual says: 

Power consumption: Standby : 1W

2 channels -1/8 Pmax under 8 Ohms : 185W

The seller says this is the maximum and I should take converter with double reserve, let it be 450W

2) Hi-Fi News Lab Report says:

Power consumption (idle/rated o/p): 40W / 480W (3W, standby)

I was told in another audiophile forum that 480W is maximum. So we can take with reserve 600W converter.

3) On same forum another guy counted this way:

You should take the dynamic power for two channels and multiply it by two. It means like 300W*2*2=1200W. And as the dynamic power of this amp on 1Ohm is 690W you showd take at least a 1500W conerter.

So I'm confused... The converter I want (Krieger) is 1150W maximum available and costs too much with shipping.

Amp specs:

Power by channel: 150W for 8Ohms, 300W for 4Ohms (I have 4Ohms speakers)

Efficiency 95%

Two power supplies - one for each channel

I wrote to Micromega, but they were bought by another company three years ago and stopped support.

I hope someone here could help me with this problem.

128x128iad
mikhailark
278 posts
 

So, here is what I found

Power output: 150 watts per channel at 8 ohms (300W at 4 ohms), both channels driven

Thus, what speakers are you planning to use? Check impedance and not just rated resistance - if 8 ohms speaker actually drops to 4 ohms, count it as 4. So you need 300x2x2 - 1.2 KW transformer. Yes, transformer, NOT switching supply.

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cleeds
5,957 posts
 

The power output of the amplifier is irrelevant to this discussion. What matters is its power consumption, tested by Hi-Fi News at 480 watts. There’s no need to make this complicated.

iad's avatar
iad OP
53 posts
 

I'm using 4 Ohms Buchardt S400 MK2 speakers 

gs5556
1,235 posts
 

In the US, when you plug an appliance into an outlet, that appliance cannot draw more than 1800 watts because the receptacle is rated at 15-amps. The closest equivalent power source is the 1500 watt transformer.

Keep in mind the transformer wattage is the maximum it can handle and therefore you can go for a bigger VA or watt rating than the amplifier. Going smaller will affect the amp's performance as it will sag voltage at low impedance loads.

(That wall outlet that is rated for 1800 watts is fed by a pole transformer that can deliver hundreds of thousands of watts to your house yet your appliances don't care).

iad's avatar
iad OP
53 posts
 

gs5556, thanks for your advice.

If I understand right, if power consumption will exceed max power of transformer, the transformer will just turn off because of built-in protection.

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