BLOCK AUDIO Mono, Power a Line


Power amplifiers

Searching the archives of Audiodrom brings up the recollections of several  powerful and well designed power amplifiers - to move around the  monuments like the Bryston 28B-SST2, the Musical Fidelity Titan or the Accuphase A-200 monos is not a job for a single guy. The Block Audio Monos are one step further - it is  next to impossible to lift them, I had a constant feeling that someone had bolted them to the floor. That raised my interest about their  performance and they did not disappoint - these amps proved  to be the best amplifiers that I had ever auditioned.

100% reference

Function and form

Ease of use

The MONO BLOCK is - spoiler coming - a mono block capable of delivering 1x500W (1x250W into 8 ohms). The first 200 watts are pure class A operation, the rest switches to AB. Aesthetically it is an amp of prey with a modern clean cut facade that brings to my mind another monster - the M.U.T.O. from the latest Edward's Godzilla movie (did you know the abbreviations stand for winged Massive Unidentified Terrestrial Organism?). Alike this organism the MONO BLOCK is somewhat energy hungry - it draws 500W of juice at idle. There is a possibility to switch it to the ECO mode, however, yet it remains to draw 100 watts. If you do not cover the energy consumption by your own powerplant in the backyard then it is recommended to switch the unit off to STAND BY (0.5W). 

The rest of parameters made me hungry: 90 kilos of net weight, powerful low-noise and low-radiation 2.1kVA toroid transformer, 500,000 µFof power supply-filter capacitance at each channel, more than 120dB of signal to noise ratio and brutal damping factor of 5000 (by the way, it is twenty times more than that of the Musical Fidelity Titan). All these numbers mean control - the pair of the MONO BLOCKs can easily drive any speakers on the planet.

The use of MONO BLOCks is conditioned by the use of the LINE and POWER blocks at the same time. There is no freedom in combination of the power amp with other preamps or vice versa - all Block devices are interconnected including the protecting circuits communication. Do not even dare to think about acquiring just one BLOCK and match it with your existing gear. For example, the LINE BLOCK preamplifier switches the MONO BLOCKs on and off and controls their internal temperature through a communication link. The MONO BLOCKs sense the load at their speaker terminals - if the speakers are not connected then the power amps would not power up.

The LINE BLOCK is of a strictly dual mono design - in fact the preamp consists of two separate chassis (one channel each) that are held together by a joint display unit at the front and a headphone preamplifier (class A again) at the back. The headphones may be connected through XLR or 6.3mm jack. A phono preamp is on request. The LINE BLOCK's connectivity provides 4 pairs of balanced XLR inputs and 5 pairs single ended RCA inputs. There are 2 pairs of XLR and RCA outputs too.

To feed the electricity to the amplifiers the POWER BLOCK is needed. The power supply is based on battery cells - each channel has its own pack. The capacity of the batteries allows for approximately 15-20 hours of operation. Once running low the power supply switches automatically to a recharge mode. The trick is that even during the recharging, when the listener can listen to the music normally, the POWER BLOCK isolates the amplifiers from mains and works like an energy buffer reservoir. So, the power filtration is made redundant with the BLOCKs. There is a software option to reprogram the devices to draw the juice directly from the mains, although the vulnerability to external noise increases.

Bass management


The menu of the LINE BLOCK, that is the main control unit, has three levels with many options. One can choose the default class of operation, A or AB or A-ECO that switches the amp into AB after being idle for more than 15 minutes). The DOT display has smooth intensity regulation. The phase can be reverted by 180°. The automatic switch off timer can be set. The default power up volume can be set (good if your kids love to play with volume controls). By the way, on powring up or down the potentiometer automatically fades in and fades out the signal - a very nice touch. If you need you can deactivate selected inputs or set the individual gain for them. It is also possible to use external processor to control the volume of the AV installations with BLOCKs. The remote control can be deactivated. A lot of cool stuff is happening in the control menu of the combo... And if get lost then it is easy to reset the devices to factory settings.

Clarity & delicacy


David Grisman and his mandoline in Sway (The Hot Club of San Francisco, Yerba Buena Bounce) are quite demanding track - the mandoline is a transient freak. It should not be of a wardrobe size, it hates to sound steel or thin, it likes to sound wood, hollow and stringy. The BLOCKAUDIO combo portrayed the tonal balance of the mandoline right plus it maintained it in separation with the rest of the instrumentation on the track. There was no preference to any audioband heard from BLOCKs, no apparent signature. The MONOs were lliterally like two boulders next to the speakers, inert, rock-hard, neutral. Do whatever you want and they just keep the grip on the speakers with an immense sense of control. At one moment through the review I played Metallica's Black Album, not a landmark for audiophile sound. You know what I heard? Not a landmark for audiophile sound. The BLOCKs will not save the compromise program material from imperfections, they are honest, no cheating.

Tonal accuracy

Temporal resolution

Let's move on with vocals. How about Suzanne Vega's a cappella Tom´s Dinner from Solitude Standing? Amazing. Natural and clean vocal with beautifully conveyed added studio reverberation and with accurate and timely phrasing. There is a kind of excellency in how the BLOCKs master the midrange so it was not surprise when I checked another vocalist, Mari Boine, this time backed by the native instruments (Goaskinviellja, Verve World). The flute, big shamanic drum, bass and cowbell unleashed a maelstrom of sounds across the width of my room and beyond.

There was another partcularly strong accent that nailed me to my armchair: huge uncompressed dynamic swings. There were moments that, with some really dynamic material, the amps forced the Dynaudios to hit their stops. From that time on I had to be careful - it is not an issue with "standard" recordings but if you treasure things from Reference Recordings or Sheffield Labs that are recorded at low average loudness and feature high dynamic peaks then be careful not to crank up the volume too much. Goaskinviellja of Mari Boine was like a trip to the studio with all the glory but also the issues, like the tortured vocal mike that ran to limitation. The power reservoir of the MONO BLOCKs seemed to be endless, on the other side.

Spatial resolution

Soundstage width
Soundstage depth

How about Dick Hyman and Fats Waller (Reference Recordings), year 1989, the hiss of tape and the fat Bosendorfer sound? It was like a documentary with resolved fingers dancing on the keyboard and spatial information on the strings laid in diagonal arrangement from the mike. After two hours of listening the cooling fins of the MONO BLOCKs are getting really hot on touch, the preamp stays cool and indifferent.

The power is in simplicity - spoken word of Bob Anders (Chesky's Jazz Sampler) is a real reference in the most sensitive frequency bands. Through the BLOCKs the speech of Bob was saturated, rich, defined and detailed as if he was in the room with me. It was pleasure to see the sound travelling left and right and beyond the speakers, still keeping the amazing articulation with no sibilance naughtiness and, of course, no coloration. The only coloration I could hear was that introduced by smoothly rolling off silk domes of Dynaudio's Esotar drivers.

The amps preserve the original depth of the soundstage, the tap of a tambourine is precisely tracked as it recedes further and further away from a microphone. Again, the simple things are easy to test even at home - take a tambourine (or a small box filled with grains) and check for yourself. Very often such a simple sound ends up as muddy, hollow, thin, steely and whatever else. The full definition of the tight skin and rattling jingles is not an easy task for all amplifiers but the best. The trinity of BLOCKs passed with flying colors.

Price as reviewed:1 890 000,- Kč

Recommended resellers

Blockaudio s.r.o., Olomouc, tel. +420 604 514 282

Associated components

  • Sources: Yamaha CDS3000
  • Amplifiers: Plinius SA-Reference
  • Interconnects and speaker cables: Furutech Lineflux and Speakerflux, Kimber Kable Silver Streak
  • Loudspeakers: Dynaudio Confidence C4 MkII Signature
  • Power conditioning: Block Audio Dog Block, Furutech Powerflux



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