McIntosh MPM4000 Power Meter Review

[jamescarter1982]

how wide is this thing ? if it was the standard width of a stereo component that would be so cool ?

 

[KEFCarver]

Seems like McIntosh gets everything right except speakers. They always look great too—any and every vintage I’ve seen.

I have only heard their XRT18's and myself and several others really liked them.....

 

[GXAlan]

how wide is this thing ? if it was the standard width of a stereo component that would be so cool ?

It is for car audio, so unfortunately just 7 inches.

 

[peng]

Can't they just measure across a small in-line resistance to get the power accurately? Or am I missing something obvious?

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.

 

[jamescarter1982]

It is for car audio, so unfortunately just 7 inches.

real shame the full quoted price for a full width one would almost be worth it

 

[EJ3]

This is a review and measurements of the McIntosh MPM4000 Power/dB vintage stereo meter. It is on kind loan from a member and costs used from US $500 to $999.
View attachment 424110
It had come out in 1997, aimed at automotive market so requires 12 volt power. As you can see in this sample though, it can be readily used in home systems with a case and external power supply.

Unlike every other VU meter we have tested so far which are just for show, the MPM4000 is supposed to be calibrated for a 4 ohm speaker. The purpose of the review then is to see if there is an impact on the fidelity and accuracy of its markings.

FYI the sample I have has very dim lighting. I suspect the originals were brighter.

McIntosh MPM4000 Power Meter Measurements
For testing, I configured the Purifi reference amplifier for 1 watt output. Here it is by itself:

View attachment 424111
As we expect, distortion is vanishingly small. Let's now connect the MPM4000 in parallel to left (1) channel:

View attachment 424112

There is no impact whatsoever which is a relief.

Now let's test for accuracy. I measured the above on the meter and it was accurate, subject to optical error. I then jumped to 10 watts and it too was accurate:
View attachment 424113

I then went up to 100 watts and it too was accurate. So mission is accomplished!

Conclusions
We have had many discussions of vintage meters on power amps being accurate (or not) in the context of new versions which clearly are not. I did not know what to expect but was pleasantly surprised to see that not only is it transparent but that it is also accurately showing power output of the amplifier.

The only negative is the astronomical pricing of it. I guess half of that is for the "status" sake.

I am going to recommend the McIntosh MPM4000 power meter if you don't have to tap into kid's college education fund to buy it!
------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

I recently saw one in the dash of a car that had a McIntosh amp in the trunk. It came from the Callaway factory that way in a:

C9 (Callaway Impala SS)​

[edit]
The Callaway SS integrated the 400 bhp/383 cid SuperNatural engine used in Callaway Corvettes and Camaros with the impressive Chevrolet Impala SS. The Callaway SS also included suspension, braking, wheel and tire enhancements.
There were 3 produced with the Tremec 6 speed manual transmission and one of those was produced with the 450 bhp/383 cid SuperNatural engine.
That was the one that I saw for sale in Charlotte, NC with the McIntosh gear in it. It only had 52,000 miles.
If I had only had an extra $50,000 handy, I would have bought it.

For those that don't know about this car company:
Callaway Cars Inc. is an American specialty vehicle manufacturer and engineering company that designs, develops, and manufactures high-performance product packages for cars, pickup trucks, and SUVs. They specialize in Corvettes and GM vehicles. New GM vehicles are delivered to Callaway facilities where these special packages and components are installed. Then the vehicles are delivered to GM new car dealers where they are sold to retail customers, branded as Callaway. Callaway Cars is one of four core Callaway companies, including Callaway Engineering, Callaway Carbon and Callaway Competition.

B2K Callaway Twin-Turbo​

[edit]
1990 Chevrolet Callaway Corvette Convertible
The B2K was a high-performance alternative to the standard Corvette offered by Callaway Cars under license from Chevrolet from 1987 to 1991. It was available at Chevrolet dealers if the customer selected the "RPO B2K" option on the order specification sheet. Chevrolet approached Callaway to offer such an option after seeing the power output the tuning company was able to extract reliably from modified twin-turbocharged Alfa Romeo V6 engines. The car came with normal Chevrolet warranty as well as an additional one year 12,000-mile warranty from Callaway Cars. The conversion cost an extra US$26,995 over the price of a base model Corvette. The conversion consisted of taking the engine out of the car and performing a thorough set of modifications along with installing two turbochargers. The result was the engine rated at a reportedly conservative 382 hp (285 kW). The car was classified as a standard Corvette by the EPA, so it wasn't subject to additional registration requirements. Over 500 cars were subject to the conversion.

A derivative of the Twin Turbo Corvette, the 880 hp (656 kW) Callaway SledgeHammer, recorded a speed of 254.76 mph (410.00 km/h) on Ohio's Transportation Research Center track in 1988, making it the fastest road-going car at the time.
From 1988 until 1991, the Callaway Sledgehammer Corvette held the World Street Legal speed record of 254.76 mph (410.00 km/h).

C5 (Aston Martin Virage V-8 & AMR-1 Group C Engine 1989)​

[edit]
Aston Martin retained Callaway to help it re-engineer its then 30-year-old Tadek Marek-designed, two-valve V8 engine for the upcoming Aston Martin Virage. Callaway's brief was for four-valve cylinder heads, increased power, and single configuration worldwide emissions compliance. The Virage road car debuted in 1989 and the project was successful enough that Aston chose to rely on Callaway to supply a race version of the road car engine for their 1989 Group C prototype, the AMR-1. It finished eleventh in its first and only appearance at Le Mans.

 

[GXAlan]

McIntosh - Automotive: The Story

Perhaps no environment is more challenging than the automobile, but we’ve never shied away from a challenge. McIntosh is proud to announce our long-awaited return to the automotive industry.

www.mcintoshlabs.com

Subaru was one of the first OEM McIntosh setups! Nowadays, it’s only found in Jeep.

The old ones were Clarion era products, but clearly measure well, and the new ones are from Alpine.

I don’t know what will happen with the Bose acquisition of McIntosh. Interestingly, while B&W/Harman/Dirac is the flagship for Volvo’s EX90, Bose was able to secure a spot as the mid tier upgrade.

 

[antcollinet]

Of course.

I'm guessing though that it is actually only responsive to voltage. So will show double the real power with an 8 ohm load.

EDIT : or some random multiple of actual power with any real speaker, due to the impedance characteristic.

 

[jeffaegrim]

I sent this in to Amir.

It’s exactly that. Status symbol or more specifically, eye candy. It did help me understand exactly how many watts I was using when listening in my own setup. I previously had the MC2105 and MC2102 and the meters are a fun part of McIntosh products. It’s why the MC2100 just isn’t worth as much as the MC2105. When I sold off my McIntosh gear, and then Accuphase gear, I missed the “style” that the VU meters offered.

What we see with a lot of VU meters with labeled power output is just random numbers. It is nice to have accurate numbers if you are going to have numbers.

For speaker switching, I previously sent in three Luxman speaker selector.

Audio jewelry or “collectible” widgets like this:

75th Anniversary Limited Edition Ornament

A unique collectable for any McIntosh fan. Limited Edition - order yours before they are gone. Made in USA from fine pewter.

shop.mcintoshlabs.com

…are just things for fun, not driven by technical rationale. For those that celebrate Christmas and celebrate it with a home decorated tree, why pick the specific ornaments that you pick? That’s the rationale for picking some of the audio gear we pick…

You have sent in so much cool stuff over the years! It’s greatly appreciated. I also find it funny that we own(ed) so many of the same, or similar, „toys“ - I have that Luxman switch in passive (AS-55), there was the JBL UT405 / Baby Everest, and I happen to own a product similar to the one reviewed here - the Technics VU meter that I like to mention so much - sh 9020. It features both line level and a speaker (power) input, providing accurate readings. The latter is a one - way connection, so there isn’t even a possibility for the device to interact with the signal. I love this thing, it’s so versatile and cool. They need to start making equipment like that again.

Thanks for the review, @amirm

 

[amirm]

EDIT : or some random multiple of actual power with any real speaker, due to the impedance characteristic.

Vast majority of speakers have their minimum impedance around 4 ohm. So they are smart in targeting this value as it is likely close to be accurate with real speakers.

 

[RogerSmith]

Looks nice, but how does it sound?

 

[amirm]

Looks nice, but how does it sound?

Sounds nice and sharp with my glasses on. Without, it blurs the details....

 

[Andysu]

£999 daylight mac robbery

okay here's tandy realistic a power meter that is light years cheaper
vu and led

 

[JSmith]

McIntosh MPM4000

I've been intending to buy one of these for some time, so thanks for testing this as great to see no impact on signal.

Being old and 2nd hand, they're not easy to find and quality varies unfortunately.

Operation manual;

MCINTOSH MPM4000 OWNER'S MANUAL Pdf Download

View and Download McIntosh MPM4000 owner's manual online. Power Output Meter. MPM4000 measuring instruments pdf manual download.

www.manualslib.com

I was not able to locate a service manual or schematic unfortunately.


JSmith

 

[JSmith]

Yep, know of these... cheaper than the Mac, but not much less in most 2nd hand cases and also hard to find, various conditions etc.

I really don't see why a company can't make a proper power meter like these, even incorporated into a nice integrated (for a reasonable price), properly referenced to 4/8 Ohm.


JSmith

 

[Andysu]

Yep, know of these... cheaper than the Mac, but not much less in most 2nd hand cases and also hard to find, various conditions etc.

I really don't see why a company can't make a proper power meter like these, even incorporated into a nice integrated (for a reasonable price), properly referenced to 4/8 Ohm.


JSmith

bundles of them , you can make them into an atmos array to make your atmos home theatre great again

 

[Serg]

Sounds nice and sharp with my glasses on. Without, it blurs the details....

Sounds like you need something to "lift the veil"!!

 

[GXAlan]

I really don't see why a company can't make a proper power meter like these, even incorporated into a nice integrated (for a reasonable price), properly referenced to 4/8 Ohm.

I keep tagging the various companies like Fosi and Douk to try to convince them to make these.

They have speaker switchers but I actually think something in parallel is fine and avoids the need for relays and remotes.

I would much rather have accurate results rather than pretty results. The other idea would be a line level referenced to dBu like

Technics SH-9020 Review

The TC Electronic Clarity is also tempting if you had multiple digital outs but it’s less attractive for eye candy and perhaps too technical. I don’t think you can go full screen for the visualization

 

[torgeirs]

I find it facinating how the electical motor power engeeneers has solved the current measurment problem in a cheap and accurate way for motor control.
Warning: reading this and your head might start to spinn: https://www.ti.com/lit/ug/tiducy7/tiducy7.pdf?ts=1738066318483

 

[Sokel]

I find it facinating how the electical motor power engeeneers has solved the current measurment problem in a cheap and accurate way for motor control.
Warning: reading this and your head might start to spinn: https://www.ti.com/lit/ug/tiducy7/tiducy7.pdf?ts=1738066318483

Even easier,this one and some code:

Adafruit INA260 High or Low Side Voltage, Current, Power Sensor

This breakout board may well be the last current sensing solution you every need to buy. Not only can it do the work of two multimeters, but it can do it with amazing precision and ...

www.adafruit.com

That's for DC of course.