McIntosh MPM4000 Power Meter Review

[GXAlan]

Well to be more to the point, NO meter can show accurate wattage across a reactive load. (due to varying impedance and phase)

This unit was intended for use with McIntosh car audio amps.

For their home amps, they talk about these being true power meters that uses both the voltage and amperage outputs to display the real watts output by the amp. So, in my mind, if you have an ammeter and a voltmeter, you should be able to instantaneously report what the true power output is independent of the complexity of the load.

 

[amirm]

You said "If you are maxing out the power of your amp, you will know it." I took "maxing out the amp" as clipping. And as you say, you will not now it.

Not all amplifiers clip. Also, the meter can tell you that you are playing near max power already so if you have aspirations to either play louder or get a less sensitive speaker, you will know it.

 

[Cbdb2]

This unit was intended for use with McIntosh car audio amps.

For their home amps, they talk about these being true power meters that uses both the voltage and amperage outputs to display the real watts output by the amp. So, in my mind, if you have an ammeter and a voltmeter, you should be able to instantaneously report what the true power output is independent of the complexity of the load.

Too be accurate the phase between V and I matters, and that depends on the speaker load. At 60 degrees (not that drastic) the real power is only 1/2 of V times I. Thats the power into the speaker.

 

[Cbdb2]

Not all amplifiers clip.

If your talking about input limiters, (the only way to prevent amp clipping) thats rare and miss leading.

 

[Cbdb2]

Also, the meter can tell you that you are playing near max power already so if you have aspirations to either play louder or get a less sensitive speaker, you will know it.

These have VU ballistics. If your peak to average (vu) difference is 10 db (not that much) your 100 watt amp could be clipping when this meter is only showing 10 watts, not "near max power".

 

[amirm]

If your talking about input limiters, (the only way to prevent amp clipping) thats rare and miss leading.

It can be that or protection circuit:

 

[amirm]

These have VU ballistics. If your peak to average (vu) difference is 10 db (not that much) your 100 watt amp could be clipping when this meter is only showing 10 watts, not "near max power".

And the inverse? The meter showing you 100 watts when your amp is 120? Stop arguing for the sake of arguing. This is not an instrument. It is a consumer power indicator.

 

[Ropeburn]

And the inverse? The meter showing you 100 watts when your amp is 120? Stop arguing for the sake of arguing. This is not an instrument. It is a consumer power indicator.

Yeah seriously. For a "lol meters" thingie such as this - and let's make no mistake, there is no point beyond "lol meter" for a device such as this - it's pretty damn accurate. About as accurate as the average 90s car speedometer on the Autobahn. +10 or 20% have to be expected, and everyone knows it.

It's just old, which explains the nowadays ridiculous price. At least you got a halfway accurate 4 Ohm calibration for your money back then. Nowadays you get the same for 200 or less (the usual Fosi amp/speaker switches with meters etc.), so you decide what is really the goal. My wild guess is: pretty backlit analog jumping needles for lols and giggles. So it doesn't really matter.

 

[gordoste]

I am not even positive how to implement a clipping light or what have you.

I remember back in my sales days NAD and HK had clipping lights (among other I am sure) but never really thought about how the circuit would be.

Here is one with a comprehensive explanation.

 

[dualazmak]

I just updated my "dream" VU/PP meter (ref. my above post #112) so that it has USB (ASIO) IN/THRU-OUT as follows:

We need dedicated ASIO driver in Windows PC (and Mac PC?), and of course I know well this dream VU/PP Meter unit and subsequent any USB device would not be completely in-sync because of the ASIO routing in case if the USB THRU OUT would be utilized.

On the other hand, AES/EBU as well as S/PDIF COAXIAL and OPTICAL signals have sync timing markers within them for synchronization with the subsequent gears connected to the THRU OUTs. I know little about HDMI THRU OUT feasibility/possibility and synchronization thereof, though.

 

[Ropeburn]

I just updated my "dream" VU/PP meter (ref. my above post #112) so that it has USB (ASIO) IN/THRU-OUT as follows:
View attachment 425933

We need dedicated ASIO driver in Windows PC (and Mac PC?), and of course I know well this dream VU/PP Meter unit and subsequent any USB device would not be completely in-sync because of the ASIO routing in case if the USB THRU OUT would be utilized.

On the other hand, AES/EBU as well as S/PDIF COAXIAL and OPTICAL signals have sync timing markers within them for synchronization with the subsequent gears connected by the THRU OUTs. I know little about HDMI THRU OUT feasibility/possibility and synchronization, though.

Using ASIO, this software solution including its inherent latency would probably still faster and more responsive than any physical meters, with their meter delay...

 

[dualazmak]

Using ASIO, this software solution including its inherent latency would probably still faster and more responsive than any physical meters, with their meter delay...

Yes, agree, and I have been understanding your point well!

Usually such out-of-synchronization (in less than 10 msec order), however, would be well below the level of VU/PP Meter's ballistic behavior/specification (10 - 100 msec order).

I actually use two different ASIO routings (with KORG DS-DAC-10 and OKTO DAC8PRO) for driving my 12-VU-Meter Array (ref. here and here) with no "visible" out-of-sync issue.

In case if you would be further interested in the "start-up/kick-off" timing-discrepancies of multiple ASIO drivers within a PC, my posts under the below spoiler cover would be of your reference, I assume.

Spoiler

- Can I (we) temporarily synchronize outputs of multiple DAC units (each of them has own independent ASIO driver) in 10 micro second (0.01 msec) precision in DSP-based multichannel audio setup?: #783
- Can I (we) temporarily synchronize outputs of multiple DAC units (each of them has own independent ASIO driver) in 10 micro second (0.01 msec) precision in DSP-based multichannel audio setup? Part-2: Simplified experiments without using audio mixer: #804

In any way, VU/PP Meters are only our eye-candies (I still love them, though), and we do not need (0.1 - 10 msec precision) full synchronization!
The use of USB THRU OUT of my "dream" VU/PP Meter for further listening/audio-processing purposes would not be recommended, of course.

 

[Cbdb2]

And the inverse? The meter showing you 100 watts when your amp is 120?

??? all I was getting at is these meters dont actually show when you run out of power, clipping. Am I wrong?

 

[Cbdb2]

Stop arguing for the sake of arguing.

Likewise.

 

[Holmz]

??? all I was getting at is these meters dont actually show when you run out of power, clipping. Am I wrong?

It is like asking your tachometer in a diesel truck to show 12000 RPM. Just because the motor cycle does it does not mean that the car or truck should.
You want a clipping light on the amp, or maybe an understanding of how much power you nominally are using.

 

[dualazmak]

It is like asking your tachometer in a diesel truck to show 12000 RPM. Just because the motor cycle does it does not mean that the car or truck should.
You want a clipping light on the amp, or maybe an understanding of how much power you nominally are using.

Yes, I agree with you!
Just for @Cbdb2's reference, I have this thread;
- Apparent power consumption of whole audio system during daily audio listening sessions: how SDGs-friendly is it? (not the idle power, please.)

 

[HaveMeterWillTravel]

Thank you for your review Amir.

The only negative is the astronomical pricing of it. I guess half of that is for the "status" sake.
Maybe, or it's too McIntosh's owner who for example bought a McIntosh MC1502 tube amp for $12,000.00 no astronomical price to just to add a MPM4000?

A new VU /Power/dB stereo meter from McIntosh costs $1,800.00. Wait it was "just" a mantle clock:

MCLK12 Clock

Illuminated meters for ease of sight Temperature compensated Quartz movement ----SPLIT---- The McIntosh MCLK12 mantle clock is a celebration of time while being a tribute to classic McIntosh design. Constructed with the signature McIntosh blue watt meters, the MCLK12 demonstrates the same easy...

shop.mcintoshlabs.com

If enough customers are willing to buy it at that price, then its the correct price!

 

[HaveMeterWillTravel]

But specifying it is accurate into exactly 4 ohms, while great in one way, speaker loads are very reactive, so in reality it can not by its very nature be any more accurate then any power meter.

Are we saying it does a "Good job" of measuring a 4 ohm dummy load, or a good job of showing the power while connected to a speaker?

In actuality, this and most like it are voltage meters. Since it can't response fast enough to the real time voltage waveform, it will inherently have some type of averaging. Typically it will be ~proportional to RMS voltage over a set period of time. Play a low enough frequency and one may actually see the needle oscillate with the voltage waveform.

That's true for how much "power" an amplifier will deliver into a speaker load. One tests it at "4Ω" or "8Ω".
We talk about "watts" but that's really only the real component of power. There is also the reactive power. One than can use the Pythagorean theorem to calculate the apparent power.

 

[HaveMeterWillTravel]

View attachment 424199

Audio Classics - MI3

Audio Classic's buys and sells the finest in home audio/video equipment

www.audioclassics.com

Dang it, beaten to the punch.
I actually have used on in the distance past.

I swear Star Wars stole their targeting display concept from it!

 

[HaveMeterWillTravel]

Agreed, but then if you are that serious about real world accuracy, then we need something more outside the box, that is, we need one that can display instantaneous, average, and RMS voltage and current (programmable, selectable by push buttons, apps etc.) rather than a single popular yet anecdotal metric, i.e. average power, one (there are more) reason being such meters will most likely be used with loudspeakers, not dummy resistor loads. Those Mc meters are just nice and fun to look at.