A4.5

The VALVET A4.5 monoblocks are currently the final development stage of power amplifiers in our program. Their roots go back to the 90s. As always, long-term satisfaction, value and longevity count here. Anyone who owns these power amplifiers can put the issue of power amplification aside for a long time. The musical information the A4.5 conveys is simply thrilling! Feel free to compare with so-called global brands and then decide which rendition resonates with you more. The A4.5 power amplifiers are extremely fast, controlled and powerful. They don’t put their own  stamp on the music, but rather support flow and involvement. Immerse yourself in “your” music!

The A4.5 monoblocks have an output power of 60 Watts/channel into 8 ohms (100 Watts/channel into 4 ohms). In our opinion, the desire for even more performance will not arise so quickly. Like all VALVET power amplifiers, the A4.5 power amplifiers have an enormous power supply capacity thanks to the stable power supply and have a “firm grip” on practically every loudspeaker on the market. The monoblocks work in push-pull A mode and only with a single pair of power transistors in the output. We are of the opinion that connecting several power transistors in  parallel to increase performance results in sound disadvantages. For those interested in technology: a very quiet 500 VA toroidal transformer, 4 ultra-fast 60 A individual diodes as rectifiers and a filter with 4TTN electrolytic capacitors from Supertech ensure ultra-stable operation. No  capacitor in the signal path of the amplifier (DC – 100 KHz), extremely short (pure silver) signal paths.

The sound: dynamic, neutral, balanced, very musical, powerful with a lot of blackness and control in the bass and simply harmonious. In the current version, detailed improvements in mechanics, technology and sound ensure an even more harmonious package. “The Power and the Glory”  – that’s it!

VALVET A4.5 Classe-A mono power amplifiers - FOCUS ON THE ESSENTIALS
When mono power amplifiers were offered to me as test objects, the thought of a
package that probably weighed 50 or more kilograms and the resulting back pain
went through my head. However, I was relieved to find that they were manageable,
albeit extremely massive, power amplifiers that “only” weighed 13 kilos each. Even
during installation, the VALVET mono blocks made an excellent impression. The
perfectly crafted housing of the A4.5 exudes solidity. The black anodized, 15
millimeter thick aluminum front and the massive cooling fins are particularly
impressive. The latter form the flanks of the compact amplifiers. The silky, shiny,
brick-red anodized cooling fins gives them a smart, elegant touch. I'm not a fan of
colorful hi-fi equipment per se, but I find the design irresistible, especially with
the"V" (for VALVET) milled into the front and backlit in red during operation.
A look at the back and underneath will also satisfy the high-end gourmet. WBT
NextGen speaker terminals and cinch sockets, Neutrik XLR inputs, Furutech
rhodium mains input (with marked mains phase) and absorber feet from Alto
Extremo demonstrate high quality standards down to the last detail. I really like the
fact that the mono blocks stand on three feet, as this is the safest way to ensure a
tilt-free stand.
Dipl.-Ing. Knut Cornils is the owner, managing director and developer of the audio
manufacturer “VALVET High-End Amplification”. He manufactures every single
device in his portfolio himself, which includes a preamplifier and three power
amplifiers. In this way, he is able to respond to special customer requests.
When developing his amplifiers, he follows a clear strategy: simple circuits that are
implemented with a few but high-quality components. A philosophy that I like. A bit
like the really great art of cooking, which brings the taste to the point without any
fashionable accessories through perfect cooking times and a few, finely balanced
spices.
Cornils uses valves and semiconductors in their best application area in a
completely non-dogmatic manner. Therefore, only transistors in Class A operation
are used in the output stages. Another feature of his amps is their sensationally
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oversized power supplies. The gigantic toroidal transformers (2 x 270 W) in its
preamplifier – yes, you read that correctly, “preamplifier!” – would look good in
many a stereo power amplifier.
Back to the test objects. The VALVET's A4.5 mono blocks are the fifth development
stage of the A4 amplifier series, the first version of which celebrated its debut on the
HIGH-END stage in Munich in the early 2000s. Unchanged from its predecessor,
the A4 MKII only uses one pair of power transistors in push-pull Class A operation.
According to Cornils, this increases performance, while the inevitable parallel
connection of several power transistors results in sound disadvantages.
The A4.5 achieve a higher output compared to its predecessor, with 60 watts/
channel at 8 ohms or 100 watts/channel at 4 ohms. That sounds pretty
unspectacular at first, but I've never even come close to reaching their performance
limits. This control can probably be attributed to the generously sized power supply.
The transformer output has been increased to 500 watts per block, and the rectifier
diodes were replaced by “fast” 60 A types.
The toroidal transformers are manufactured by a North Rhine-Westphalian
specialist according to VALVET's specifications. In general, Cornils attaches great
importance to ensuring that his suppliers are as close as possible to its production
location (the tranquil Bargteheide, northeast of Hamburg). Cornils discovered that
the motto “more is better” is not always justified when he discovered the electrolytic
capacitors used in the A4.5 for the first time. Although the Guided Current 4TTN
electrolytic capacitors provide less capacity, they sound better in his ears. Cornils
said that enthusiastic customers had their power amplifiers retrofitted with the new
capacitors. He selects the components based on extensive listening comparisons.
For this reason, the internal cables are made of pure silver, although no relevant
difference compared to copper can be detected, according to the engineer. The
impression created by the outer shell is confirmed when you look inside the power
amplifiers: everything top notch! Of course, that's no guarantee
for highest euphony per se, but it did give rise to a certain level of expectation. The
operating instructions say that you have to give the power amplifiers around ten
centimetre of space on all sides when placing them. The power amplifiers can get
up to 60 degrees due to Class A operation. Accordingly, I placed the amplifiers in
the rack with plenty of room for air to circulate. The “hard” power switches are
located at the front right underneath the power amplifiers. The optimal solution: If it
were placed at the top or even on the front panel, the simple design would be lost
and operation on the back would be awkward.
The Alto Extremo feet create a comfortable distance from the surface, making the
switches easy to operate. After a satisfying ‘clack’, the A4.5 purred briefly and
contentedly and the valve “V” indicated operational readiness in bright red. A blue
light shimmered through the vents. What I first thought was a design feature similar
to the underbody lighting popular in the car tuning scene has a completely technical
purpose: These are LEDs that serve as the base load for powering the input stages.
If desired, Cornils can adapt the color of the luminous V on the front panel or dim it
completely using the remote control.
My fear that the VALVET mono blocks would not harmonise with my
Electrocompaniet preamplifier turned out to be unfounded. After a warm-up phase
of about 30 minutes they played as if from one piece.
Every now and then I enjoy wallowing in complete harmony. What is better suited to
this than an ACT production like Wolfgang Haffner's Kind Of Spain? Immediately
after the first sounds flooded the room, the special abilities of the compact blocks
became clear.
The complete clarity of the music as well as the holographic stage presentation
make you forget that it is a reproduction.
Speed, resolution, dynamics, impulse resistance – the A4.5 easily fulfils all these
requirements. Even in records that were technically unremarkable, the monos
brought out a liveliness that had previously remained hidden from me. Solo voices
and instruments were not pushed over the edge of the stage into the foreground;
they remained in a realistically integrated position on the stage. Attributes such as
clarity, tonal purity and smoothness kept coming to mind.
After my usual suspects (well-produced but overused recordings) had done their
duty, I set out on a long musical journey through neglected slices. Denez Prigent,
an artist hardly known in this country, is considered in his Breton homeland as one
of the best interpreters of the traditional song forms Kan ha diskan (dance song)
and Gwerz (lament). He mixes traditional sounds with modern elements without
fear of contact to create an exciting brew. In “E trouz ar gêr” the Breton singing is
accompanied by bombarde and binioù (traditional wind instruments with a sound
that penetrates to the core). Deep synth basses and drum beats stand in stark
contrast to this and provide a basis reminiscent of Techno. This exotic mixture
increases, supplemented by a variety of instruments and sound effects,
to a hurricane-like roar. The A4.5 remain completely unaffected by this. They give
each sound layer the necessary space, with a clear structure and seemingly
limitless dynamics.
What I heard piqued my curiosity in the VALVET preamplifier. Knut Cornils reacted
immediately, and two days later there was another device in the listening room. Just
minutes later, the soulshine2 MKII was part of the test setup. Is it any wonder that
this combination played together even more coherently? Fine dynamics and
transparency benefited particularly. This realisation provoked an excursion into
early music. I'm not a big opera lover, but when Roberta Invernizzi sings Vivaldi
arias, the sun rises for me.
The Valvet combination managed to reproduce the crystal clear yet warm voice
extremely naturally. The accompanying baroque orchestra La Risonanza is
presented perfectly in all proportions, both tonally and spatially. Molto bellissimo!
Cornils reduced formal language, in combination with the stringently designed
circuitry is reflected in the performance of the A4.5 mono blocks. I have rarely
experienced such confident and natural playback, and when I did, it was only with
setups that cost many times more.
The VALVET A4.5 are “final” amplifiers in a double sense: They are not only at the
end of the amplification chain, but they can also represent the end of the search for
audiophile nirvana.
VALVET's A4.5 is pure perfection: stylish, compact, perfectly
crafted, outstanding in every respect - the definitive amplifier!