KR Audio
tube tradition since 1928
As an authorized KR service partner, we can deliver the complete KR product lineup on request.
1. Tubes Create a Natural Sound
At the beginning, Dr. Ricardo Kron had a vision of an amplifier capable of reproducing live emotions - even at concert volumes. The amplifier was to set a new benchmark in naturalness, impulse response, and spatial imaging. Based on his extensive experience, only a single-ended triode tube amplifier came into consideration.
From countless experiments, he knew that a natural and realistic sound could only be achieved using audio tubes with minimal components in the signal path. Using as few tubes as possible, the goal was to reach a previously unattained level of performance in distortion-free single-ended Class A operation. At 100 watts of continuous power, the amplifier should achieve a signal-to-noise ratio over 100dB and ideal harmonic distortion characteristics.
It became immediately clear to him that the tubes available on the market did not meet his standards, and that he would have to develop his own audio tube. Most commercially available tubes were not designed for audio use and could not optimally amplify music signals. To achieve high-end performance levels, many tubes would have to be run in parallel. However, a large number of tubes is problematic because no two tubes sound exactly the same, and drift over time is inevitable.
In 1995, he began developing the SUPER AUDIO TRIODE T1610. The specifications read like an audiophile’s dream: up to 160 watts of dissipation per tube, super linear amplification (low distortion) across a frequency range of at least 0Hz to 100kHz. After two years of development, the unique Super Audio Triode T1610 was born. Utilizing new technologies and materials, a true masterpiece was created.
Thanks to a uniquely high number of up to 32 cathodes (patent pending), electron emission could be drastically increased. The result: optimal power output with extended long-term stability. This innovation, along with the gold-plated grid of the T1610 tube, ensures exceptional durability: over 12,000 hours of operation - a world record!
Through novel processes and the use of highly specialized vacuum pumps—developed exclusively for KR Audio in Switzerland - the vacuum inside the tubes was improved by a factor of 10,000 over standard tubes. Only a special hand-blown Bohemian lead crystal glass could withstand the high vacuum pressure.
All tube manufacturing takes place in-house, by hand. This also allows the tube body to be fixed at several points within the crystal glass cylinder. This alone massively reduces microphonic effects and shields the music signal from external influences.
The extremely high vacuum and a special degassing procedure for all tube components ensure a true vacuum with no residual oxygen inside the tube. This allows the music signal to flow and be amplified without any external interference.
2. Short Signal Paths and Purist Signal Amplification
More than 15 years of research and development have gone into this exceptional tube amplifier. Countless listening hours were dedicated to selecting the right materials and developing the Super Triodes. Just the development of a suitable driver stage took five years, during which countless tube driver stages were analyzed for their audiophile properties. Unfortunately, no existing driver tube was capable of fully exploiting the sonic potential of the T1610 linear audio triode.
Because the KR T1610 can deliver not only high voltage but also a relatively large current, it requires high input power at the tube’s grid. Insiders say: “The tube needs to be properly fired up!” It was a real dilemma - how to unlock this potential and achieve maximum performance.
After two additional years of development, the solution was found: a purist driver stage with remarkable capabilities. Here are just a few key specs: maximum dynamics thanks to a transmission bandwidth of over 250kHz without feedback, optimal harmonic distortion behavior, and a signal-to-noise ratio of over 120dB—all with the sound character of a tube!
The two-stage driver section is based on a high-level JFET input stage. This world-first input stage, operating at 100V, consists of selected JFETs and ensures an immense noise margin while delivering the same sonic signature as a tube, but with incredible dynamics. Thanks to their extremely high input sensitivity, JFETs can follow even the most delicate and nuanced music signals and amplify them without distortion.
The JFET input stage’s uniquely high 100V supply voltage delivers insatiable dynamic reserves. The downstream selected MOSFET provides only slight amplification and primarily serves as a current supplier to the T1610 tube grids. Built entirely in Class A operation with an ultra-short signal path (around 10 cm), this ensures absolutely lossless signal transmission.
Only carefully selected components are used. We consider Mundorf silver/gold foil capacitors and WIMA capacitors as standard in the signal path. Special high-speed mica capacitors developed specifically for us in SMD design are used in parallel to transmit even the smallest impulses.
In the signal path, highly precise non-magnetic metal film resistors from Vishay and Welyvn are employed. The extremely sensitive JFET input stage is additionally shielded with copper plating to protect against even the smallest interference. Music, in its most purist form!
3. Audiophile Materials
Optimal material use in the respective components is the most important cornerstone of the KR Audio philosophy. As mentioned earlier, only the most necessary components should be used in the signal path. Every additional component - no matter how expensive - noticeably degrades sound quality. Naturally, the components in the signal path must be strictly selected based on audiophile criteria, with no economic compromise.
In circuits that are not directly involved in the audio signal, the use of components is maximized - for example, to ensure a very stable and low-noise power supply. The Kronzilla Purist Edition adheres to this principle in every situation. An amplifier that sets such high standards must draw from full power. The Kronzilla DM Purist features four power supplies per monoblock and additional buffering of the supply voltage in each stage.
The entire amplifier is built around a special stainless steel frame made from a thermally resilient alloy. The output transformer is intricately hand-wound in several opposing layers and contains a total of three internal shields. This highly specialized winding technique enables the transmission of extremely low to very high frequencies with an exceptionally linear frequency response.
The electrolytic filter capacitors used meet the highest standards and are especially durable. In the Kronzilla DM, extreme foil capacitors combined with mica capacitors are used in the fixed bias section. All materials undergo rigorous quality testing to ensure maximum performance and long-term reliability.
4. Distortion-Free Class-A Operation (Single-Ended)
This should really be the first commandment. The extremely linear KR Audio T1610 super triodes and the driver stages are, of course, operated in pure Class A. The KR Audio development team considers this circuit design to be, without debate, the only correct solution in the audiophile sense. All other operating modes simply do not deliver the same results. Period.
5. Zero Feedback - Maximum Dynamics
One of Dr. Ricardo Kron’s core design philosophies is the complete absence of feedback - both global and local - throughout the entire amplifier. While this type of circuit design demands substantial know-how from the developer, the result is something you can truly hear. We eliminate any signal distortion that could be caused by feedback. Our testing showed that feedback negatively impacts dynamic performance. Dynamics - the ability to follow musical signals quickly - is crucial for achieving a natural and realistic sound impression. At KR Audio, dynamic behavior takes absolute priority. Depending on the type and strength of feedback, the sound loses its sense of live presence and emotional impact.
While, in theory, feedback should positively influence amplifier performance, the reality proves otherwise. Feedback relies on a phase-shifted signal being reintroduced at -180 degrees - but this only works with purely resistive loads. Unfortunately, a loudspeaker is anything but a purely resistive load, meaning the signal never arrives perfectly phase-shifted at the amplifier’s input. The result is actual signal distortion. And when the music really wants to come alive, the feedback steps on the brakes. As it says in the Bible: “Thou shalt not feed back” - we want to hear it live!
6. Wide Bandwidth and Optimal Transient Response
The choice and matching of components - and the right materials - have a profound impact on sound quality. Different materials significantly influence sonic characteristics, which is why we engage in deep material science for both active and passive parts. We custom-produce special alloys for tube manufacturing and pay attention to even the smallest detail. The result is a sum of many micro-optimizations that create an impressive whole.
We match and select tubes more rigorously than any other manufacturer, holding ourselves to the highest quality standards. Our output transformers are meticulously hand-wound in multiple counter-wound layers and feature three internal shields. This complex winding technique achieves extremely linear transmission across a wide range - from very low to very high frequencies - even at output power levels of 100W, with a bandwidth of over 40 kHz at -3 dB and up to 80 kHz at -6 dB.
The JFETs in the input stage are selected for multiple parameters. In the signal path, we use non-magnetic metal film precision resistors from Vishay, paired with Mundorf Silver/Gold Supreme capacitors. Additionally, high-speed mica capacitors are combined with WIMA FKP and more Mundorf capacitors. We apply the best audiophile-grade materials where they matter most-performance trumps cost. Only music sets the benchmark.
7. Clean Power Supplies
The massive toroidal transformer ensures that ample energy is always available to unleash the amplifier’s full sonic potential. The oversized power supply is designed for high continuous loads and maximum peak performance. A highly sophisticated, multi-stage filtering and buffering system guarantees an optimal and stable power supply. Ultra-clean power delivery is a cornerstone of the KR Audio philosophy.
The amplifier’s transistor-free circuit design achieves maximum noise reduction and plays a key role in delivering the legendary dynamics of KR Audio tubes.
The Powerhouses of the Kronzilla:
Main power supply with buffering for the anode voltage
Dedicated power supply for the CPU-controlled monitoring board
Two separate heater power supplies—one for each tube
Multiple buffer stages for the two-stage driver circuit
8. Smart Use of Cutting-Edge Technology
A modern microprocessor controls and monitors the amplifier. To extend tube lifespan, the supply voltage is gradually increased using a soft-start process. The controller also monitors the warm-up phase of the tubes. After powering on, the tubes are tested, and once the warm-up and checks are successfully completed, the signal path is enabled.
If any measurement deviates from optimal conditions, the controller indicates this via a red LED on the front panel. In the Kronzilla DX model, the Auto-BIAS circuit is also monitored and managed.
The microprocessor ensures a completely maintenance-free tube amplifier with full oversight of all relevant components. Manual tube matching is entirely unnecessary, and the need to replace a tube is visually indicated.
9. In the End, Only the Ear Decides
Purist-grade materials, optimal technical specifications - but ultimately, it is the ear that makes the final judgment. After extensive measurements and calibration of all parameters, the most decisive measuring instrument is used: the human ear. Our many years of listening experience allow us to fine-tune each product in comprehensive listening tests. During these sessions, further refinements are made for optimal sound. Every amplifier in the Purist Edition is tested in an acoustically optimized room and, if necessary, modified once again. Only after this rigorous process does the production of a Kronzilla begin.
10. No Matter How Hard or Impossible the Path May Seem—Never Break the 10 Commandments
We remain true to our principles and develop only uncompromising high-end solutions - for you.
Kronzilla DM purist oder DX purist?
KR Audio Electronics is the world’s only manufacturer that designs and produces audio tubes using innovative materials and pioneering manufacturing processes.
The technical distinction between the Kronzilla DM purist and the Kronzilla DX purist lies in their output power. Visually, both products are identical except for the nameplate. The difference in performance is due to the way the operating point is configured.
The Kronzilla DM Purist achieves 70 watts of continuous (sinusoidal) power at 8 ohms per monoblock via a so-called “fixed bias” circuit. The Kronzilla DX Purist, on the other hand, delivers 100 watts of continuous power at 8 ohms per monoblock using a completely newly developed “auto bias” circuit.
You may ask: why are there two variants? Quite simply, among industry insiders, the fixed bias approach has been traditionally favored—but they likely haven’t yet heard the new auto bias technology from KR AUDIO Electronics. We want you to decide for yourself by listening. We look forward to your opinion.
I am continuing the principles and tradition of Ricardo Kron with full consistency, setting aside all economic considerations to create the Purist Edition. In addition to Mr. Kron’s vast experience, I have contributed my own professional background and over 25 years of expertise in high-end audio. The result is the Purist Edition of KR Audio products.
Kronzilla - For the Love of Music!
Kronzilla - Relentless by Principle!
- Your purist, Andreas Milkovits
Kronzilla SX- und SXI purist
Stereo amplifier, Single-Ended Class-A
SXI: Stereo integrated amplifier, Single-Ended Class-A, Auto-BIAS
2 x KR-T1610
2 x 50 watts (continuous sine power)
4 or 8 ohms (adjustable)
20 Hz to 40 kHz (-3 dB), up to 80 kHz (-6 dB)
> 100 dB
None
2 x RCA (optional: 2 x XLR) SXI: 4 x stereo RCA channels (optional: phono input)
500 VA at 230 V / 50 Hz
1 VRMS / 47 kOhm for 2 x 50 watts
Approx. 3
5 – 30° C (avoid heat buildup)
Approx. 46 kg
Approx. 38.5 x 41.5 x 55 cm (W x H x D)
SXI: Channel selection and volume control
Kronzilla DM purist
Two monoblocks, Single-Ended Class-A Fixed BIAS
4 x KR T1610 (2 x KR-T1610 per monoblock)
2 x 70 watts (continuous sine power)
4 or 8 ohms (adjustable)
20 Hz to 40 kHz (-3 dB), up to 80 kHz (-6 dB)
> 105 dB
None
2 x RCA (1 x RCA per monoblock) 2 x XLR (1 x XLR per monoblock)
500 VA per monoblock 1000 VA at 230 V / 50 Hz
1 VRMS / 47 kOhm for 2 x 70 watts
Approx. 5
5 – 30° C (avoid heat buildup)
Approx. 36 kg
Approx. 38.5 x 41.5 x 55 cm (W x H x D)
None
Kronzilla DX purist
Two monoblocks, Single-Ended Class-A Auto BIAS
4 x KR T1610 (2 x KR-T1610 per monoblock)
2 x 100 watts (continuous sine power)
4 or 8 ohms (adjustable)
20 Hz to 40 kHz (-3 dB), up to 80 kHz (-6 dB)
> 100 dB
None
2 x RCA (1 x RCA per monoblock) 2 x XLR (1 x XLR per monoblock)
500 VA per monoblock 1000 VA at 230 V / 50 Hz
1 VRMS / 47 kOhm for 2 x 100 watts
Approx. 6
5 – 30° C (avoid heat buildup)
Approx. 36 kg
Approx. 38.5 x 41.5 x 55 cm (W x H x D)
None
Technical specifications subject to change for all models.
Warranty: 2 years on all tubes! 4 years on all other electronics!
Models KR VH 680, KR SDI, KR VA355I are available on request.
Music servers and amplifiers for audio purists
Our aim is to reproduce recordings exactly as captured. We believe every component in the signal path can alter the original sound. By investing in superior circuit technology and ensuring optimal power supply performance, we let the ear make the final decision.
