GREATech µVAC Stereo Amplifier Review By Steven R. Rochlin

March 2006

GREATech µVAC
Stereo Amplifier

Review By Steven R. Rochlin
Click here to e-mail reviewer

They say if an amplifier does not get the first watt right, then many more make no difference. It matters not if it is a 100 watt per channel unit or the single watt GREATech µVAC. Loyal readers know full well i am not of the 'bigger is better' camp. Huge coffin-sized loudspeakers that demand 1.21 Gijawatts of power need not attend my funeral. Give me that single tube, pure Class A triode amplifier and a pair of loudspeakers that present an easy load. High efficiency is, of course, a must. Perhaps those guys who like huge speakers and amplifier, like Fabio, are making up for other, eh hem, shortcomings?

My first encounter with this amplifier was years ago at the High End Society show in Germany. It was in prototype form under the Kolibri nameplate. At the 2005 Munich show i once again saw the unit in production form by GREATech, and under the official name of µVac. Frankly, i have always had a soft spot in my heart for chachkies. In the 1980's it was the Sony D-88 3-inch CD player. Eventually came the Lehmann Audio Black Cube phonostage, which has just been released in a 2006 version by the way. Next up was the 47 Labs Gaincard, and many of you know the outcome from that review. The Gaincard spurred many imposters to the point of virtual downright design theft! They say imitation is the sincerest form of flattery, though stealing a design and selling it to others is downright inexcusable! With that said, i have a feeling that GREATech has no worries in that regard.

As seen in the photo, the µVac is very small. A puny 140 x 85 x 75 mm for amplifier and 140 x 85 x 90 mm for the external power supply. The box of wooden matches gives you some idea. To the right is a photo i took while covering a European show in 2005. Note the chassis color and Kolibri name at that time.

So what is it with the fascination of small chachkies? The heck if i know, other than perhaps i am the type of guy to cheer for the little engine that could. GREATech's µVac is a stereo amplifier with volume control and external power supply. Single source systems can use this as a preamplifier/amplifier, thereby saving money on interconnects and the like. Tube compliment is a High-Rel MIL subminiature beam power pentode 5902 for amplification and high-mu UHF triode 5744 for pre stage. Frequency response is claimed as 25Hz to 30kHz with weight being a mere 2.5 kg in total. The internal power supply senses power voltage and therefore can handle from 115 to 230. So how many watts does this €940, limited production of only 250 pieces produce? Glad you asked!

Remember at the beginning of this article where i said the first watt is the most important. Well, that is all you get with the µVac. A single, one, uno, ein.... Just one watt! This amplifier almost personifies the meaning of the first watt, because that is all it can produce. Not that the Song Audio's 4 watts is some big, beefy amplifier in the watt-producing game of life. i mean, here it is 2006 and we have amplifiers that produce well over 1,000 watts per channel. What the heck am i doing playing around with such small wattage units? Ahhh, we must remember the saying about the first watt. As for build quality, the µVac is almost toy-like, yet the tubes are nicely surrounded in an almost jewel-like gloss black chassis.

Cables Make A Difference

Dual COnnect DCS 200 Loudspeaker Cable For the µVac, this cable was the clear winner! Just wait until to hear my feelings about the GREATech unit. As for loudspeaker cable, the winner was the new Dual Connect DC-S200 (€1,389 for single run) solid silver, with two runs of wire per channel (bi-wire). They are a combination of gold plated solid silver wires in a dual configuration per electrical run that are held in a thin tubing of PTFE (Teflon) insulation. With these cables the bass and highs were as good as it gets for this review. Perhaps it is the very low capacitance between adjacent wires that did the trick compared to other cables on hand? Frankly, i admit cables make a difference yet hate to review cables so below is some technical mumbo-jumbo for those geek types in the audience:

High power transfer capacity: 5000 Watts into 4 ohms
Low conductor resistance with only 0.0033 ohms/meter
Low audio frequency attenuation of 0.03 dB/meter
PTFE insulation with low dissipation factor of 0.0002

The Sound

GREATech's cute little µVac was a revelation! For only a single watt this baby produced the single best rendition of microdynamics my ears have ever heard! Add to that overall dynamics came from a pure black background; instruments each had their own space in an awe-inspiring 3D soundscape. For a mere single watt, bass was very deep, tight, and tuneful. Usually bass sucks up the watts, or watt in this case, as the larger motor (woofer driver) needs more power than a smaller motor (tweeter dome/cone).

Glorious midrange. i swear this amplifier has swooned me big time! My wife, upon hearing the µVac on the Hyperions, was smiling ear to ear. Have you ever had one of those components where upon installing it and first hearing it you went into your music collection to enjoy disc after disc? Well, the µVac is precisely one of those units. As much as i tried to find fault in this little bugger, the only real thing i could come up with was the lack of very, very high frequency extension (over 12kHz) that is the very last sheen/shimmer. Do not expect extremely high sound pressure levels (SPL, or volume) unless you have highly efficient loudspeakers. Of course playing Reference Recordings Pomp & Pipes [RR58-CD] had limitations, especially on the Hyperions, as the pipe organs' deep bass caused the amplifier to go into clipping at basic listening levels. To its defense, the Hyperions are not ultra-efficient loudspeakers like the Avantgarde Acoustic Duos (reviewed here) with their 103dB/W/m rating. But do not fear as...

i like to rock, so on came Rush Signals remastered [Mercury 314 534 633-2] and yes this is the little amplifier that could at sane volume levels. David Chesky's Club de Sol [JD33] had a delicacy that most amplifiers only hint at. i find that when an amplifier produces incredible resolution and dynamic portrayal, the music sounds more relaxed. Yes, this little bugger has relaxed down in spades! There is more natural space as each instrument floats within the room. An oldie but a goody is Sonny Rollins Way Out West [Analog Productions CAPJS 008] had just the right horn balance of reed, breath, and metal resonance. My wife and i danced to certain song on Madonna's The Immaculate Collection [Sire/Warner 9 26440-2]. So where is the Achilles heel?

Other than that very last smidgeon of ultra-high frequency sheen, nothing. Yes, you read that right, nothing! Am i saying the µVac is perfect? Hmmm... after a very long time thinking this out i would have to say it is the best damn amplifier i have ever heard in my life. Oh, and i did try it as a headphone amplifier with the Sennheiser HD600 with Stephan Audio Art cable (reviewed here) and if you are a Head-Fi kinda person this may be just the ticket to erotica! Forget those other headphone amplifiers, who shall remain nameless. Get yourself a µVac!

We are in single digit wattage territory here so i have a feeling this review will only be good for headphone guys and those with over 95dB/W/m sensitive loudspeakers. Well, leave it to me to spend vast time and effort in hopes of reaching a niche, of a niche, within a niche market!

Final Results

My ratings below speak for themselves. If you took the time to read the review, and not skipped down to this conclusion first, you are probably asking yourself if Steve is off his rocker. Far from it! This is why i dragged my wife into this mess. My wife is kind, patient, and appreciates music as she has played the violin for many years. Besides, scientific fact is that women generally have better hearing than men. If you love headphones, if you have highly efficient speakers... please do me this favor and buy the µVac. This is a huge and bold statement. Perhaps i am putting my reputation on the table and that is fine with me. My confidence with this little single watter is that strong. Never before have i went out and said BUY THIS THING, but this is precisely what i am saying. Of course the choice is ultimately yours, but don't be a turkey. Dare to go the extra mile here. Well, i am doing that here and now.

All i ask is one favor. When you buy the unit and give it a good listen within an appropriate system, please e-mail me your comments. i truly want to know what others think of this thing. Color me amazed, enthralled, astonished, and stunned at how much sheer dimensionality and definition this baby can find within the music i have enjoyed for many years. All this for only €940 too! Like Bill and Ted would say, "Like, no way dude!" And with that said, of course in the end what really matters is that you...

Enjoy the Music (Madonna "Justify My Love" right now),

Steven R. Rochlin

"I wanna kiss you in Paris
I wanna hold your hand in Rome
I wanna run naked in a rainstorm
Make love in a train cross-country
You put this in me
So now what, so now what?

Wanting, needing, waiting
For you to justify my love
Hoping, praying
For you to justify my love...

Yearning, burning
For you to justify my love

What are you gonna do?
What are you gonna do?
Talk to me -- tell me your dreams
Am I in them?
Tell me your fears
Are you scared?
Tell me your stories
I'm not afraid of who you are
We can fly!..."

Tonality
Sub-bass (10Hz - 60Hz)
Mid-bass (80Hz - 200Hz)
Midrange (200Hz - 3,000Hz)
High-frequencies (3,000Hz on up)
Attack
Decay
Inner Resolution
Soundscape width front
Soundscape width rear
Soundscape depth behind speakers
Soundscape extension into the room
Imaging
Fit and Finish
Self Noise
Value for the Money

Specifications

GREATech µVAC

Type: Tube stereo amplifier

Power Output: 1 watt per channel

Tube Compliment: High-Rel MIL subminiature 5902 for amplification, high-mu UHF triode 5744 for pre stage. Pure Class A operation.

Frequency Response: 25Hz to 30kHz

Weight: 1kg for amplifier, 1.5kg for power supply

Power Supply: handles 115 to 230 Volt

Dimensions: 140 x 85 x 75 mm for amplifier, 140 x 85 x 90 mm for power supply

Price: €940