Power Amplifier Octave MRE 220 in the Test

The new Monos octave can reinforce fantastic. In the test, they impressively show what is currently possible with tube technology.

Octave MRE 220: Technology

The intro of the instructions, the reader demanded a portion of expertise. Explained on these pages the company from Karlovy Vary in the northern Black Forest, through galvanic coupling sneak ground loops, how to avoid this inconvenience can be and why the inputs of MR. 220 highly balanced instrumentation amplifier of type INA134 used does not directly come in, whose negative connection for coaxial control but is located via 22 Ohm resistor to ground.

The bipod-XLR connection the already very high common-mode rejection of the Studio-ICs is not enough, must the MRE 220 place order for 16,500 to 17,000 euros. A small octave input transformer increases the galvanic isolation to virtually infinite and the distance to potential litter errors via broadband on over 80 decibels. Sapperlot, that you can handle so out sophisticated. The technician bows and mutters about the world record.

That is not enough. Because on the other end of the amplifier works physically as technically even bigger transformer Marvel. Not only that octave probably afford the good sow and boar expensive Swiss transformer iron plates with Philbert cut and the toil associated bending their way as the only manufacturer (while an EGG nucleus is simply pushed together). It had to be this time a new wrapping technology. One, in which only the half position of the wrap Gets a certain strength wire and the other half another. Layer by layer is created as a kind of cross nested transformer, that can score with an order of magnitude better symmetry. “Hmm”, should that mischievous grin octave Chief Andreas Hofmann: “We need this, because you can build better counter clock amplifier with higher symmetry only.”

Stereoplay readers of other octave models know the principle of double power supply, that extra sure prepares the high voltage into two halves and saves with Siemens EPCOS electrolytic capacitors. The 6SN7 input of MR 220, the two-stage driver arrangement with counter clock counterpart and equal to four KT 120 in the output: The other assembly points on quality – as on replenishment.

Octave MRE 220: Sound

And what a sound! The laboratory identified a sensational for tube amps value of 170 Watts per block. And a wonderful constant harmonic at various frequencies and loads – much more sensational – distortion. As long as the first and the second harmonic not disturb, measurements show that a MR. 220 cleaner than a transistor amp acts!

The stereoplay logistics Chief Kristian Rimar deceived is not, even cleaner than the Ayre MX-R took when he the octaves in the chain with the AVM PA 8 (for testing) and the Sonics Allegra. He liked the objection that the transistor reference Monos to a morsel more finely draw, let not apply. Quite so: Americans diversified while background violin locally better, but MR 220 countered with more substance for the instruments: with a Ross hairier recalcitrance in the painting, with more body, more varnish and more airiness. The semiconductor slipped, however, apparently some across, as would have too much oil in your transmission.

Usually, the crisp bass as Pro-transistor argument comes now. Difficult in this case. Because MR 220 held against it: with a bass, which can be hardly to surpass in color, shape, and ELAN.