REVIEW: Meier Audio Concerto headphone amp - Page 5

Is Orpheus the newest amplifier from Meier ?

The Orpheus is produced by a company in Taiwan called Music Hi-fi.
Meier only acts as a dealer or something like that.

Dear headfellows,

A few people have asked me to answer some of the questions in this thread and to add my own comments. So here we go.

“I have always thought of the Phoenix as being on the slightly dark and smooth side. And traditionally, I have actually felt the same way about most Meier amps I have heard. The Concerto, on the other hand, was a little lighter and brighter”

“While this is not a big deal or a defining character, it does represent a bit of a departure from Meier amps in the past”

It is true that old models like the CANTATE and the OPERA had a slightly warmer and slightly less detailed sound than the current CONCERTO and the SYMPHONY models. The main reason for this sonic change is in the volume control. While designing/testing/prototyping the SYMPHONY I found that the use of the classic ALPS blue potentiometer does add its own specific sound signature. Using a chain of discrete resistors and switching relays in the SYMPHONY clearly improved detail and neutrality. The relays on the SYMPHONY are selected using a rotary decoder switch for volume control.

The CONCERTO does not use such a decoder switch but an analog (mono) potentiometer whose position is measured by a DAC-chip. The output of this DAC-chip is then used to select the appropriate relays. This not only gives volume control a more analog feeling but also allows for more discrete steps and a smaller step size. Technically a very elaborate solution but the sonic results are well worth the efforts.

“ Instead of the use of the LM6171 op-amp in the SYMPHONY, the CONCERTO uses AD797 opamps.”

The LM6171 and the AD797 indeed sound a little bit different, but these differences are surprisingly small. Both use bipolar inputs and I’ve always felt that FET opamps in comparison sound relatively veiled. The reason for dropping the LM6171 is not its sonic quality but has a more technical nature.

And as for the A- or B-versions of the AD797. The B-version is no longer available through regular channels in DIP-format (there still seems to be some old stock around) and I wanted the opamps to be socketed.

And are there really sonic differences between the two-versions? My own testing showed that the A-version is already very sensitive to the quality of the power-supply (more then any other opamp I have been using before, hence 85000 uF capacity using Nichicon audio-grade capacitors as well as extensive regulation and filtering).

Since the B-version has a much lower power-supply-rejection-ratio the characteristics of the power supply may well add a different sonic flavor to the sonic result. Whether better or for worse, that probably is a matter of personal taste and will strongly depend on the power supply used.

To be honest, I find that statements like “opamp A sound much better than opamp B” should always be read with much care. The sonic results of an opamp can strongly depend on its technical implementation and simply swapping opamps in a single setup may well result in very misleading results. This aspect is very much overlooked in many of the discussions in this forum.

“ Rob, do you know if the power supply is linear or switching.”

I always use linear power supplies. This simply prevents any high-frequency noises pollution.

“ are the case dimensions the same as the stageDAC?"

Height and depth are the same. The STAGEDAC is just a little bit wider because of the many control elements.

“ how does the new crossfeed circuit sound by the way compared to the ones found on a headfive for example"

The sonic differences are very small and only noticeable in test situations.

The situation is different with the crossfeed on the STAGEDAC though. This implementation is far more complicated than those on all other CORDA amplifiers and has better positional imaging. But even then, major differences are only heard in specific situations and using very trained ears.

“ Which output impedance have Concerto?”

The CONCERTO has a low output impedance jacket only.

“ Grace use the crossfeed from Jan.”

True, but they use the original version that has no psychoacoustic bass-compensation. The versions on the current CORDA amplifiers all have this compensation.

“ So the top case in final product will be different?”

The toroidal transformer in the CONCERTO is pretty large and almost touches the top case. The case of the prototype is made of iron and thus starts to swing in the magnetic field. The amp produces a small mechanical hum. The series product will have a top case made of aluminum and thus will be quiet.

“6moons always pops open things for an internals look.”

Actually they do have one of the two prototypes made for a review. So hopefully pictures will be up soon. The second prototype is in Robs possession so I can’t produce any pictures myself right now. Of course I don’t mind if Rob produces some pictures himself.

Cheers

Jan

Thanks for the very informative response Jan

Oh one other question, the Concerto has the balanced ground thingy the rest of the amps have right? just curious since the technical details isnt up for the amp on the meier site

i just realized that was in the first sentence of your review...sorry, itd been since the day the review was launched since i read it

Absolutely!

Concerto will be my next purchase - for sure

Hi Skylab,

Interesting to hear that you decided to purchase the Concerto. I wonder, is difference between the two quoted above the only reason you decided to add it to your amp collection? Or are there also other ways in which the Concerto differs from (or even bests) the Phoenix. I'm deliberating between these two amps for a next purchase (and who knows, might end up getting both ). Of course it is difficult to fairly compare the performance of an SE design with one that is balanced.

Some pictures of the internals are here on 6moons.com.

Man, Jan Meier's amps have gotten considerably more component-heavy since the days of the Corda Opera!

Thanks for the info, that's really helpful!

Actually, we could use some nice high-resolution ones. (kidding )