Hi there!
I finally finished my quest for a new amplifier for Reference 9 K speakers.
Been listening to them with my new T+A PA 2000 R amplifier for about two or three weeks now. Balanced connection. Fully broken-in after the first week or so.
Well, long story short, they sound like a mono brand system together
I heard three pairs of other brands acoustics on T+A and it only confirms that statement.
And with the following lines I will try to put down some of my thoughts about why it happens and why I've chosen this machine.
The most special features of this amplifier are speed, resolution and power. It's build with a switching power supply, which may not sound very sexy, but it has 700 W of continuous power and 1200 W peak. The amp itself provides 60 V/µs slew rate. The manufacturer claims 100/200/300 W into 8/4/2 Ohm. Real tests show (on average from different tests) 130/240/390 W into 8/4/2 and even 1 Ohm. All of that in a very slim case. And that means control. Mind You, it's not a clas D or Hypex amp. Analogue power. The unit runs rather warm even with inexisting volume levels so I suspect some bias towards class A for the first 10 or 20 watts. It also doesn't have a first watt problem (no additional distorsion at extremely low power output fugures).
The schematics is based on their flagship HV series (high voltage). The idea was to use higher voltages (360V in HV and 180V in R series) with transistors to have the benefits of tube designs. Pre amplifier and power amplifier are built on a single compact boards (for each channel), volume control is a resistors ladder (vishay-dale cmf55) switched with relays. The circuit topology of the input stage is based on a cascoded differential amplifier with J-FET transistors and stages of discrete construction. The voltage amplifier stage and current amplifier (MOSFET) are isolated from each other galvanically. They also use 5-pin thermaltrak transistors with built-in thermal sensors.
The amplifier has a built-in VU-meter, which has digital display and is rather fast. Is also shows the peak value for some time. This thing is interesting too. With music I rarely go beyound 10-20 Watts and it becomes too loud. But watching cinema (hello Blade runner 2049) it easily peaks to 100 W for shooting or explosions.
The results are quite impressive to my ears.
Speaking of simple and obvious things, this new device eliminated any boomy and uncontrolled bass, but added precise and dynamic power where it really exists in a record. It also has resolution, that eliminates any harsh one-note screaming sounds. No more one-note instruments. Even the sharpest voices, guitars or trumpets have complex timbres with many layers of sound informatin. Especially the vocals became airy and smooth. Most instruments have "visible" size, not only localization on a stereo image.
Another rather unexpected effect was too much focus with my old speaker placement (the speakers were "looking" directly on the listener). I never thought that there can be too much localization with stereo image, but that definitely was the case. On a flat and poorly recorded vocals it really sounded from a tiny spot, which isn't fun. I turned them out a little bit and for now I ended up with a toe-in when a listener is around 10 to 15 degrees from speakers axis. The stereo image is still focused, bus images are more airy and bigger in size. For a context, I use equilateral triangle speakers placement and listen in the near-field (2m).
Speaking of musicality, fast power gives music life and emotions. Any music. I couldn't find any genre preferences. Jazz or rock, classics or electronics. I can listen to rock again without falling asleep (was rather bored with some simple genres recently). Electronics is remarkable too. I never heard Kraftwerk like this before. Their records are very demanding with all these "square" sounds without compression. It's very difficult for a sound system.
Another changes that I did even before the amp change was to my listening environment.
I've rebuilt my listening room, adding a lot of acoustic treatment. Don't ask me to describe the solutions, it would be impossible with my english. Some of them can be found on acoustic-group.ru site, but it's in russian. Solutions use Sylomer (from Getzner) and floating ceiling, floor, wall. Heradesign panels for absorbtion etc.
And then I bought a measuring microphone and used free Audionet CARMA application to localize and fix some problems. It's sad that this company went bankrupt and the site is not even working anymore, so I don't know where to download this application now
.
Well, the results are interesting too. These "bookshelf" speakers play in a real life room from 30 Hz. Not -10 or -6 db, no, they REALLY play from 32-34 Hz in a room of almost 20 square meters. Also, I had a huge bass lift (10+ db) in my right channel in a range of 50-70 Hz. Measuring showed, that in can be easily fixed by closing the speaker's bass reflex port. Or almost closing it (with acoustic synthetic winterizer). Which I did and then it was a question of adjusting of doors position (it affects a lot
) and other minor things.
What it shows, IMHO, that these speakers are made with no compromises in bass response. Even bookshelf versions should be taken seriously and ideally not be placed closer than 1 meter to any wall. Ideally....