AVM Ovation A 6.2 ME integrated amplifier Measurements

Sidebar 3: Measurements

I tested the AVM Ovation A6.2 ME with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). I preconditioned the amplifier by following the CEA's recommendation of operating it at one-eighth the specified power into 8 ohms for 30 minutes. The manual states that the A 6.2 ME can get warm. At the end of the preconditioning, its heatsinks were very hot, at 132.3°F (55.8°C), and the top panel's temperature was 110.4°F (43.6°C). Operating the amplifier at the older IHF recommendation for preconditioning—both channels driven at one-third power for 60 minutes—the temperatures increased slightly, with the heatsink measuring 140°F (60.5°C) and the top panel measuring 113.9°F (45.5°C). Be sure to give this amplifier plenty of ventilation.

I looked first at the AVM's behavior via its line inputs, mostly with the volume control set to its maximum of "99.5," then at lower settings. With the optional attenuation bypassed with the menu, the maximum gain at the loudspeaker outputs was a high 47.8dB for both the balanced and single-ended inputs. With the attenuation switched into the circuit, set to 6dB, the gain was reduced by exactly 6dB. (I didn't investigate other attenuation values.) The maximum gain at the headphone outputs was 21.75dB without attenuation, 15.75dB with 6dB attenuation. At the preamplifier output, the maximum gain was 12.2dB with and without attenuation. The Ovation A 6.2 preserved absolute polarity at its loudspeaker, preamplifier, and headphone outputs (ie, was noninverting) for both balanced and single-ended line inputs.

The Ovation A 6.2 ME's single-ended input impedance was 10k ohms at low and midrange frequencies, dropping slightly to 9.4k ohms at 20kHz. The balanced input impedance was lower, at 6.8k ohms across the audioband. The single-ended preamplifier output impedance was a low 46.8 ohms from 20Hz to 20kHz. The balanced impedance was exactly twice that value, as expected. The headphone output impedance was a very low 0.5 ohms at 20Hz and 1kHz but rose to a still-low 7.6 ohms at 20kHz. The AVM should not have problems driving low-impedance headphones (though see later).

The amplifier's output impedance was a very low 0.07 ohms at 20Hz and 1kHz, rising slightly to 0.09 ohms at 20kHz. (The measured values include the series impedance of 6' of spaced-pair speaker cable.) The modulation of the amplifier's frequency response, due to the Ohm's law interaction between this source impedance and the impedance of our standard simulated loudspeaker, was minimal (fig.1, gray trace). The small-signal bandwidth into resistive loads with the volume control set to its maximum was flat to 20kHz, not reaching –3dB into 8 ohms until 120kHz (blue and red traces), although a slight, 0.15dB channel imbalance can be seen in this graph. This wide small-signal bandwidth was preserved at lower settings of the volume control. The amplifier's reproduction of a 10kHz squarewave (fig.2) featured very short risetimes. A slight amount of overshoot can be seen, but there was no ringing. A 1kHz squarewave was perfectly square (fig.3).


Fig.1 AVM Ovation A 6.2 ME, frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), 2 ohms (green) (0.5dB/vertical div.).


Fig.2 AVM Ovation A 6.2 ME, small-signal 10kHz squarewave into 8 ohms.


Fig.3 AVM Ovation A 6.2 ME, small-signal 1kHz squarewave into 8 ohms.

The Treble and Bass controls each offer seven steps of boost or cut. Their effect set to "+7" and "–7," with the volume control set to "79.5," is shown as the blue and red traces in fig.4. Each step of the Treble control boosts or cuts the output above 10kHz by 2dB. The Bass control operates in smaller steps, but instead of a conventional Baxandall-type control, it boosts or cuts the output between 50Hz and 500Hz and rolls off the output below 50Hz. The Contour control provides a traditional "Loudness" function for low-level listening and has 10 settings. The green and gray traces in fig.4 were taken with it set to the maximum. The treble is boosted by 5.5dB and the 50–500Hz region by the same amount as when the Bass control was set to "7." With the Contour set to "3," the treble is very slightly attenuated, and the bass boost peaks just above 4dB.


Fig.4 AVM Ovation A 6.2 ME, response with Treble and Bass controls set to "0"and "±7" and Contour set to "Off" (left channel blue, right red) and with Contour set to "10" (left green, right gray) and "3" (left cyan, right magenta) (5dB/vertical div.)

Channel separation (not shown) was excellent, at 100dB in both directions below 1kHz and still 80dB at the top of the audioband. With the unbalanced input shorted to ground, the volume control set to its maximum, and attenuation bypassed, the wideband, unweighted S/N ratio was 59.1dB (average of both channels), ref. 2.83V output into 8 ohms. Restricting the measurement bandwidth to the audioband increased the ratio to 68dB, while switching an A-weighting filter into circuit further improved the ratio to 70.3dB. Activating the attenuation increased all these ratios by around 3dB. The level of the Ovation A 6.2's noise floor depended on the volume control setting. Even with the control set to its maximum, no supply-related spuriae were present in the amplifier's low-frequency output spectrum (fig.5, cyan and magenta traces). When the volume control was set to –20dB (blue and red traces), the random noise was lowered by 20dB, which shows that the source of the noise, which in any case is probably inconsequential, is before the volume control.


Fig.5 AVM Ovation A 6.2 ME, spectrum of 1kHz sinewave, DC–1kHz, at 1W into 8 ohms with attenuation active and volume control set to –20dB (left channel blue, right red) and its maximum (left cyan, right magenta, linear frequency scale).

To reduce the influence of the random noise floor on the distortion measurements, I performed all of these with the attenuation active and the volume control set to –20dB. AVM specifies the Ovation A 6.2 ME's maximum power as 300Wpc into 4 ohms (21.75dBW). With both channels driven and using our definition of clipping, which is when the output's percentage of THD+noise reaches 1%, the amplifier clipped at 190Wpc into 8 ohms (fig.6, 22.8dBW), 315Wpc into 4 ohms (fig.7, 22.0dBW), and 505W (21.0dBW) with one channel driven into 2 ohms (fig.8). The headphone output clipped asymmetrically at just over 1V into 300 ohms under all circumstances measured: with attenuation active or bypassed, with both balanced and unbalanced input signals, and regardless of the volume control setting. This will not be an issue with high-sensitivity headphones, but it correlates with Herb's observation that the AVM couldn't drive his low-sensitivity HiFiMan Susvaras to appropriate levels without clipping.


Fig.6 AVM Ovation A 6.2 ME, distortion (%) vs 1kHz continuous output power into 8 ohms.


Fig.7 AVM Ovation A 6.2 ME, distortion (%) vs 1kHz continuous output power into 4 ohms.


Fig.8 AVM Ovation A 6.2 ME, distortion (%) vs 1kHz continuous output power into 2 ohms.

As the distortion at low powers was very low, I measured how the Ovation A 6.2's distortion changed with frequency at 20V, which is equivalent to 50W into 8 ohms, 100W into 4 ohms, and 200W into 2 ohms. The THD+N percentage was very low into all three impedances at low frequencies (fig.9), but the increase in the treble implies a relatively restricted open-loop bandwidth. (As the signal frequency increases, correspondingly less negative feedback is available to reduce distortion.)


Fig.9 AVM Ovation A 6.2 ME, THD+N (%) vs frequency at 20V into: 8 ohms (left blue, right red), 4 ohms (left cyan, right magenta), and 2 ohms (left green, right gray).

The distortion was predominantly the third harmonic (fig.10), with the higher odd-order harmonics all lying below –100dB and decreasing in a linear manner with frequency (fig.11). (Other than the third, which remained at –80dB/0.01%, these harmonics all lay below –110dB at the same drive voltage into 8 ohms, not shown.) The reduction in high-frequency linearity seen in fig.7 led to the production of high-order intermodulation products with an equal high-power mix of 19kHz and 20Hz tones (fig.12). The difference product at 1kHz lay at a low –86dB (0.005%), however.


Fig.10 AVM Ovation A 6.2 ME, 1kHz waveform at 20W into 8 ohms, 0.024% THD+N (top); distortion and noise waveform with fundamental notched out (bottom, not to scale).


Fig.11 AVM Ovation A 6.2 ME, spectrum of 50Hz sinewave, DC–1kHz, at 100Wpc into 4 ohms (left channel blue, right red, linear frequency scale).


Fig.12 AVM Ovation A 6.2 ME, HF intermodulation spectrum, DC–30kHz, 19+20kHz at 100Wpc peak into 4 ohms (linear frequency scale).

Other than the random noise that comes before the volume control and the reduction in linearity in the treble octaves, the AVM Ovation A 6.2 ME did well on the test bench, slightly exceeding its specified power. I was puzzled by the headphone jack's limited output voltage, but that might well be a sample-specific problem.—John Atkinson

AVM Audio Video Manufaktur GmbH
US Distributor: Bluebird Music Ltd.
1100 Military Rd.
Kenmore, New York 14217
(416) 638-8207

tonykaz's picture

I don't need the Phono although Re-Sale residuals will kinda demand Phono MC/MM.


Power Switch on the Rear?, at this price?? Noooooooooo way. ( sure Schiit still gets away with giving everyone the finger on this issue and yet still sells 10X more Gear than they can build )

These AVM folks started-up around the time ( 1986 ) Vinyl died it's painful death so they are solidly digital, they even make a CD player, god bless em. My kind of people and Germany is my kind of Manufacturing Paradise that discourages the importing of Chinesium Land filler for the local retail outlet bargain shelves.

Well, AVM seems to at least compromise with a little shinny on-off button on the front that is actually stand-by or some other 'silencing' device.

Robust beauty seems hard and purposeful, I wonder if women can live with this type of simplicity: turn it on & adjust the Vol. ? ( even Car Radios are more complex nowadays )

Tony in Venice

MZKM's picture

Why does that matter? You put it into Standby using the front controls. So unless you really want to save like $5/yr on electricity, it’s fine.

tonykaz's picture

Hello Mr.MZKM,

Well, they have to put the Switch somewhere, don't they?

Why choose quirkiness ?

Why on the rear where you can't see it, where fearful people won't reach around the Wires & etc...?

Way back in the past decades we needed to preserve Tube life and we needed convenience so the Power Switch was on the Front and clearly labelled.

Nowadays, SS devices have a near infinite useful life ( we are told by authorities like Nelson Pass who puts all his power switches on the customary front panel )

Designers allege that noise is the justification for power switch location on the back panel, why not have no power switch. ( just get rid of the Power Switch )

Overall, I suppose that you are right, it doesn't matter all that much. Certainly the integrity of the AVM Company is far more important that an unimportant design feature.

You're Right!

Tony in Venice Florida

Charles E Flynn's picture

Years ago, a magazine titled "ID: Industrial Design" (later "ID: International Design") had a rare feature about especially egregious examples of design that were not just incompetent, but downright malignant. The title of the feature: "From the Devil's Workshop". The only example that I can recall today is the CD jewel box.

If the magazine were still in business, it might consider the case of a series of stacking components, each of them a good design, and good value for money, all from the same manufacturer, having rear panel power switches that are not in a single vertical line. The manual makes no reference to the possible installation of a mirror behind the components to aid in turning on the components.

tonykaz's picture

Quite some time ago ( mid 1980s ), I represented JVC ( Japanese Victor Company ) who designed their Audio Gear to have the switches do multiple functions. A person could turn the wrong switch and disable the device. Dealer Call-backs were a nightmare for Sales Staff because they too couldn't recall all the functions. JVC gear did work well and had plenty of gizmo appeal.

Today, Car Radios can be over-the-top as can navigating the unlimited functionality of iPhones.

We can't go back to simpler times, even the Amish in Florida are driving Cars and have given up farming 40 Acres using work Horses.

Tony in Venice Florida

ps. White House has discontinued Trump 2017 Chinese plywood tariffs , expect wood building product supplies to start dropping in price. ( fingers crossed ) phew!!

Anton's picture

I guess there were no clouds for you to yell at today?

For a guy who has such disdain for vinyl, you sure can't stop talking about it.

The vinyl segment of the hobby is living rent free in your head, Tony.

tonykaz's picture

It's just sooooo overpriced now. A nice AcousticSounds costs $100! A proper Vinyl front end is well over $20,000!

Vinyl was everything for 35 years of my early life, 3-1/2 Decades.

I don't have disdain, I'm disappointed in vinyl promotion, it was never all that good.

Someone has to call-out all the Gaslighting going on here!

Thanks for writing,

Tony in Venice

ps. the Audiophiliac just presented a 3 Part Series with a Recording Studio Owner, it is well worth watching

liguorid42's picture

" A nice AcousticSounds costs $100! A proper Vinyl front end is well over $20,000!"

Depends on your definitions of "nice" and "proper", I guess.

hb72's picture

Consumption of <0.5W in standby says the manual. So, why not?

tonykaz's picture


less than .5w Standby ! Sure!

I'm complaining about putting the Power Switch on the Rear, that's all! Seems the worst place to put an important function , it shows Bad Design from folks trying to say that they are Superb Designers.

Since Print Reviewers won't say anything about it, I will !

Tony in Venice

liguorid42's picture

...the main power switch is *not* an important function, because you simply put it in "standby" when you're not using it. But you're right about reviewers often missing egregious ergonomic designs. For example I'm using a well reviewed universal disc player with an otherwise useful disc resume feature, but in order to use it and be able to cancel the resume in order to play part of a CD then put it away you have to go through a well-timed sequence, available on the remote only. Much more significant than having to reach in back in order to save half a watt, in my opinion (I give off far more than half a watt of CO2 by virtue of being alive).

By your logic, you would want all the inputs and outputs in front too, to save the trouble of disconnecting and reconnecting things in the back. Connectivity is, after all, a pretty important function.

tonykaz's picture

Ergonometric Complaints are legitimatte especially coming from customers.

Some Outfits intentionally snub their Customers, so figure!

Tony in Venice

liguorid42's picture

I agree with your first statement. Regarding your second, they may disregard some customers' complaints about ergonomics, but I doubt it's just to piss them off. Complaints many users agree are legitimate are often addressed by good companies.

tonykaz's picture

I suppose that I agree with you.

Still, Audio Gear Outfits will present Black Gear that has printing that can't be read easily as well as a range of other things that make the item difficult to use and/or understand.

Tony in Venice Florida

ps. my most serious gripe is sourcing from impossible to locate 'unknown' little manufacturing contractors in Asia instead of using Local Loyal Employees who build quality for a fair price.

liguorid42's picture

One of my pet peeves too. Blue print on black boxes. Not so much on mid to high end audio components in my experience. Yes, the little Asian companies are the worst offenders. Along with little instruction sheets that lose nearly everything in translation--and with pictures that, however many words they were originally worth, look like fourth generation photocopies. Good luck with writing to any of them and asking them to mend their ways.

hb72's picture

..the option to delete duplicate posts of mine...

AaronGarrett's picture

Jimmy Martin in an audio review! Art Dudley would be very happy.

johnnythunder1's picture

I wish I could actually audition it. Luxmans are too large for my space. The Sugden doesn't have enough muscle for my speakers. Herb's review is very enticing. It checks every box that is important to me. And he likes it more than the Pass (also too large.) And German engineering? I'm going to start saving.

Long-time listener's picture

But can anyone explain the logic behind the weird curve on the bass tone control? It used to be that the bass mirrored the treble response curve; now we get this weird stuff, here and on Marantz's Model 30 too.

What the heck is going on? How does that give you good bass?

DougM's picture

There's one thing that Herb said in this review that made him my new hero, because I believe there are two types of audio equipment, which I find even more obvious among speakers than among other components. There's the kind that is all bright and shiny, and is trying too hard to call attention to itself and is screaming at you "listen to me, I'm SO hi-fi", and then there's the kind which is very smooth, relaxed, natural, and realistic sounding, which just disappears, as if to say "I'm not even here, listen to the music". In my experience, far too many audio lovers fall into the former category, and too few fall into the latter category. Too many are listening to the "the sound" instead of the music. And, I confess that I fall prey to this too many times myself, but, as of late, I find the more natural sound, while maybe less impressive on first listen, is ultimately the most satisfying. Perhaps the best gear is that which successfully straddles the fence between the two, and if it errs in any way, hopefully errs on the side of the natural over the bright and shiny hyper detailed kind of sound.

liguorid42's picture

Well, I think there are a lot of shades of grey in between the poles you describe. I happen to be a detail freak. I like to hear every note in a musical performance, and listen very intently. Too bright is one thing, but I don't consider revealing of detail to be "too hi fi". Of course if it creates its own detail ("etched") that's another thing.

One of my favorite tee shirts that's getting too ragged to wear says "There are 10 types of people: those who understand binary and those who don't".

liguorid42's picture

Either Herb is a very young looking 100 or he is once again demonstrating his penchant for hyperbole.