McIntosh MPM4000 Power Meter Review

[soundofsilence]

A good enough reason for me, and thats certainly why I am considering it, but is that why they are actually manufactured too?

 

[amirm]

Technically they tell you how many watts you are really using to get the level of loudness you are hearing. If you are maxing out the power of your amp, you will know it.

 

[beagleman]

Technically they tell you how many watts you are really using to get the level of loudness you are hearing. If you are maxing out the power of your amp, you will know it.

I would also add, without ANY meter, one is simply taking a wild guess. I know many are unable to see any use for meters such as this, but....

A fairly close approximation (due to resistive speaker loads) has always been Far closer than a wild guess in my mind.

And from some of the comments I have read across many audio forums I have frequented, it seems many or most sincerely have no idea the actual average power needed for normal listening. I have seen guys claim to NEED several hundred watts, and supposedly oblivious to the fact that "normal" listening in a mid sized room tends to often be a few watts or less.

 

[music4cities]

This product makes me rethink Bose’s acquisition of McIntosh! There was a bit of Bose-osity bidding at McIntosh all along! . I can’t wait to see this product resurrected and placed in the empty expanses of todays car dashes where every control has been consolidated into a single touch screen. except one would need 6-12 meters to accommodate all the amps in a modern car stereo. But I think the Tesla models have enough blank space for at least six.

That this was designed for use in cars is, to me at least, very funny. If only this was proportioned to fit where cars from the mid 90s to 201x had sd card navigation screens (Now obsoleted by smart phones) !

 

[music4cities]

Wow!

The screen is pokey but I gotta hand it to Mc. It's a vectorscope! Awesome. I've been messing around with Signalizer which is cheaper than anything Mc and has more even knobs.

Ok now I want 4” diagonal pairs of these vector scope sorts or meters instead of just bouncing needles.

Fosi Audio: are you listening? Get right on thing. I’d be fine with a hires OLED screen instead micro cathode ray tubes so long as it can look close to the crt, monochromatic. No tacky RGB for me. I like my audio bling classy. I’m waiting for the Fosi Vectotscope speaker or line level switch box! In brushed silver please.

 

[music4cities]

Something like that but probably more complicated than just a resistor to minimize the side effects of the voltage drop however low it is, and accuracy as well. The root of the issue, imo, is not so much about accuracy, but the real meaning of the indicated "watts" for real world applications when loudspeakers are used, not load resistors or inductors.

As to accuracy, don't really need it to be high, take a look of the following I took in a dealer where the amp was driving a pair of Sonus Faber flagship towers:

The needle stayed mostly in the decimal watt range, rarely peaked above 35 W. So who care if accuracy is say +/- 25%? I also have a bunch of videos taped in dealer/trade shows demo rooms, it is always the case (except one that I can remember) that, even at insane spl, those hug 4 ohm nominal giant towers or bookshelves never seemed to need more than 100 W peak!

Back to the root, or nature of the beast, as we all know, speaker loads are not resistors. The impedance and phase angles are time and contents dependent varying, the speakers simply would produce sound and the SPL does not correlate all that well with the "power" dissipated in the speaker's crossovers and voice coils, or the power dissipated in the amplifier's output devices. You give it 2.83 V, it gives you X dB @1m, that's it. That's why I prefer to see V, I, and THD indication simultaneously. Then we don't have to forever debate whether the reported (by forum members) deficiency of their amp is "power" or "current" related.

View attachment 424253

The Krell style rack handles” ruin the look of that unit. I’m not a fan of the McIntosh retro design language at all, but at least be consistent. what were they thinking…

 

[Cbdb2]

Technically they tell you how many watts you are really using to get the level of loudness you are hearing. If you are maxing out the power of your amp, you will know it.

Its a first approximation, without measuring the current the speaker impedance and music content can cause large errors. Does it show clipping? Vu meters are too slow to show fast clips, the reason pros like to use PPMs as well.

Dorrough Stereo Meter Plugin - Waves Audio

When it comes to a stereo meter plugin, you want readability. You want musicality. And most of all, you want accuracy. You want The Waves Dorrough Meter Collection.

www.waves.com

 

[amirm]

Does it show clipping?

Clipping? What clipping would it show? It is not inside the amp to have a single for that.

 

[amirm]

Its a first approximation, without measuring the current the speaker impedance and music content can cause large errors.

And what approximation would you have if you had no meter?

 

[GXAlan]

So…

Based upon this ad for spare parts…

https://www.usaudiomart.com/details/649999848-power-output-watt-meter-for-mcintosh-ma7000/images/4557113/

Sifam Analogue Panel meters for Industrial, Audio & Broadcast

This is the manufacturer of McIntosh’s meters.

So we definitely have the opportunity to get someone to start adding cool meters to stuff. Maybe @Buckeye Amps?

 

[dualazmak]

And, as I have already shared here...
The pro-use VU Meters/Monitors manufactured by YAMAKI Electric Co., Ltd. would be of your nice reference, I believe.
https://www.yamaki-ec.co.jp/
https://www.yamaki-ec.co.jp/product_cat/vu-meter/
https://www.yamaki-ec.co.jp/product_cat/vu-monitor/
They also accept "Entrusted Design and Manufacturing" (maybe including OEM manufacturing too?) as well as "Technical Supports in Design and Manufacturing" as we can find here;
https://www.yamaki-ec.co.jp/service/

I actually saw several times some broadcasting studios and recording studios are using Yamaki's VU monitors, like the TV screen capture (sorry for the low quality image) I shared here.

 

[dualazmak]

So we definitely have the opportunity to get someone to start adding cool meters to stuff. Maybe @Buckeye Amps?

Edit: Please refer to my post #130 for the revised/updated version!

In case if @Buckeye (and/or other companies) would/will be seriously interested in designing/producing such a VU/PP meter, I do hope they would take my dream VU/PP meter in consideration which I shared here.

 

[soundofsilence]

Thanks for the insight guys What are the consequences of when you exceed the power that the amp can provide? Sorry for the ignorant question.

So if I have a 200w power camp and I turn the volume up to the meter reading more than 200w what is going to happen?

 

[soundofsilence]

Technically they tell you how many watts you are really using to get the level of loudness you are hearing. If you are maxing out the power of your amp, you will know it.

Thanks for the insight! What are the consequences of when you exceed the power that the amp can provide? Sorry for the ignorant question.

So if I have a 200w power camp and I turn the volume up to the meter reading more than 200w what is going to happen? Is the result 'merely' clipping? I also don't fully understand clipping and would be super grateful of an explanation as to what it means!

Sorry if this is an ignorant question!

 

[Doodski]

Thanks for the insight! What are the consequences of when you exceed the power that the amp can provide? Sorry for the ignorant question.

So if I have a 200w power camp and I turn the volume up to the meter reading more than 200w what is going to happen? Is the result 'merely' clipping? I also don't fully understand clipping and would be super grateful of an explanation as to what it means!

Sorry if this is an ignorant question!

I'll give it a try.
If you exceed the power amplifier ability then you cause clipping. Clipping is where the output of the amplifier meets or exceeds the positive and negative voltage rails of the amplifier. Clipping sends DC power to the speakers and this can cause damage and often or always does depending on the degree of clipping.

A basic class AB schematic showing the positive and negative voltage rails of a theoretical number of +/- 30 Volts DC. It also shows the Rload which is the speaker shown as a resister. When the signal input/volume control shown as Vs in the schematic is turned too high then the amplifier clips and send DC 30 volts positive and negative to the speakers. DC overheats speakers and causes damage.

 

[antcollinet]

I'll give it a try.
If you exceed the power amplifier ability then you cause clipping. Clipping is where the output of the amplifier meets or exceeds the positive and negative voltage rails of the amplifier. Clipping sends DC power to the speakers and this can cause damage and often or always does depending on the degree of clipping.

A basic class AB schematic showing the positive and negative voltage rails of a theoretical number of +/- 30 Volts DC. It also shows the Rload which is the speaker shown as a resister. When the signal input/volume control shown as Vs in the schematic is turned too high then the amplifier clips and send DC 30 volts positive and negative to the speakers. DC overheats speakers and causes damage.
View attachment 425831

This image shows what a clipped ouptut waveform will look like with servere clipping (where the target output waveform is about 2x what the power supply can support).

In between, as the voltage increases from the left hand side, to the right hand side, there is increasing amount of the peaks of the waveform clipped off, starting with just the smallest amount of distortion with just the very peak of the waveform flattened off - up to the gross almost square wave you see on the right hand side.

 

[Cbdb2]

Clipping? What clipping would it show? It is not inside the amp to have a single for that.

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.

 

[Cbdb2]

And what approximation would you have if you had no meter?

The point is that these meters arnt accurate.

 

[beagleman]

The point is that these meters arnt accurate.

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

But I also think its possible through some experimenting and usage to "Find" an average level where a meter is relatively close at least or "trim" it to at least get it in the ballpark, assuming the speakers load does not vary too wildly.

Put it this way, the meter can be far more accurate than my "Guesstimation" of how many watts an amp is putting out.

 

[beagleman]

Clipping? What clipping would it show? It is not inside the amp to have a single for that.

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.