Audio Hungary Qualiton A50i | Used Class A Tube Amplifier
An exceptional opportunity to own a handcrafted Hungarian integrated amplifier, combining 50 watts per channel of Class A tube power with precision-wound output transformers and automatic bias control.
Condition: Pre-Owned, Excellent Power: 2 × 50W Class A Output Tubes: KT120 standard configuration Speaker Connections: 4Ω / 8Ω Finish: Polished Stainless Steel Price: €3,900
Watch our original Qualiton A50i listening demonstration on the Chameleon Audio YouTube channel.
International shipping quotations available on request.
Audio Hungary Qualiton A50i Integrated Tube Amplifier – Used
50 Watts of Pure Class A Valve Amplification. Handcrafted in Hungary.
The Audio Hungary Qualiton A50i is a premium integrated vacuum tube amplifier designed for music lovers seeking the natural tonal richness, refinement and musical involvement of genuine Class A valve amplification.
Delivering 2 × 50 watts of stereo power, the A50i combines four KT120 output tubes, custom-wound output transformers, automatic bias control and a beautifully polished stainless-steel chassis.
This carefully used Qualiton A50i is offered by Chameleon Audio in excellent condition, providing an opportunity to own a distinguished European tube amplifier at an attractive pre-owned price.
Special Price: €3,900.
About This Pre-Owned Qualiton A50i
This listing concerns one specific Audio Hungary Qualiton A50i integrated amplifier.
According to the Chameleon Audio product listing, the amplifier has seen relatively little use and is in excellent condition.
Its distinctive polished metal chassis and exposed valve architecture make it an impressive centrepiece for a dedicated high-end stereo system.
The actual unit is shown in the WooCommerce product gallery.
Contact Chameleon Audio for confirmation of the installed valve set, remote control, supplied accessories, packaging and applicable warranty before ordering.
Pure Class A Tube Amplification
The Qualiton A50i was developed to combine the musical character of valve electronics with the power and control required by modern high-fidelity loudspeakers.
Its output stage uses four KT120 power tubes operating in a Class A push-pull configuration.
The manufacturer specifies a rated stereo output of 2 × 50W, making the A50i a particularly substantial design within its category.
Class A operation maintains the output devices in their intended active operating region throughout the signal cycle.
This approach requires careful thermal management and power supply engineering, but is valued by many listeners for its potential to deliver smooth and coherent musical reproduction.
KT120 Power Tubes
The A50i uses four KT120 output tubes in its standard configuration.
The KT120 is a powerful vacuum tube developed for demanding audio amplification applications.
In the Qualiton A50i, these valves operate together with the manufacturer’s own output transformers and automatic bias control system.
Audio Hungary has documented compatibility with certain alternative output tube types, but any substitution must be confirmed for the individual amplifier and performed in accordance with the manufacturer’s instructions.
The specific tubes installed in this pre-owned unit should be verified before purchase.
Automatic Bias Control
One of the A50i’s most practical engineering features is its automatic bias control circuit.
The circuit monitors the quiescent current of the power output tubes and adjusts the operating conditions towards the manufacturer’s preset values.
Maintaining appropriate bias is important for consistent valve operation, amplifier performance and component reliability.
The automatic system also simplifies ownership compared with designs that require frequent manual bias adjustment.
The performance of a valve amplifier depends heavily on the design and quality of its output transformers.
Audio Hungary develops and manufactures its own precision-wound output transformers for the Qualiton range.
These transformers are central to the A50i’s ability to transfer power from its KT120 output stage to compatible loudspeakers.
The amplifier provides dedicated connections for nominal 4Ω and 8Ω loudspeaker loads.
Using the appropriate output connection is essential for correct matching and reliable operation.
Three RCA Inputs and One Balanced Mini-XLR Input
The Qualiton A50i offers flexible connectivity for a dedicated two-channel music system.
Its input arrangement comprises three stereo RCA line inputs and one stereo balanced mini-XLR connection.
This allows users to connect suitable analogue sources, including:
Digital-to-analogue converters
CD players and digital sources with analogue outputs
Phono preamplifiers
Compatible music streamers
Other line-level audio components
The front panel provides input selection and volume control.
The mini-XLR connection uses a specialised connector format. Standard full-size XLR cables are not directly compatible without an appropriate adapter or cable.
Line-Level Output
The A50i also provides an unbalanced line-level output.
This connection may be useful for suitable recording or signal distribution applications, subject to its specified operation.
It is not a dedicated subwoofer-management or digital output interface.
Elegant Stainless-Steel Construction
The Qualiton A50i combines traditional vacuum tube engineering with an unmistakably contemporary appearance.
Its polished stainless-steel chassis reflects Audio Hungary’s emphasis on mechanical construction and finish quality.
The exposed valves create a visually striking design, while the substantial transformers contribute to the amplifier’s overall weight of approximately 25kg.
The chassis should be installed on a stable, ventilated shelf with sufficient clearance around the hot vacuum tubes.
Precision Volume Control
Audio Hungary pays particular attention to the mechanical and electrical implementation of the amplifier’s volume-control and input-selection systems.
The tactile front-panel controls are designed to complement the polished finish while providing straightforward everyday operation.
The following image illustrates the manufacturer’s volume-control construction.
Remote Control Convenience
The Qualiton A50i was designed with a dedicated remote control for convenient volume adjustment and mute functionality.
The manufacturer’s metal remote follows the same polished aesthetic as the main amplifier.
For this particular pre-owned unit, please confirm whether the original remote is included in the sale.
Vacuum Tube Complement
The manufacturer’s original A50i configuration specifies:
4 × KT120 output tubes
4 × E88CC / 6922 driver-stage tubes
2 × ECC83 input-stage tubes
The original design uses Tungsram ECC83 input valves, with E88CC/6922 types providing the driver-stage functions.
Replacement valves may have been fitted during the amplifier’s life. The installed complement of this pre-owned unit should be confirmed independently.
Amplifier and Loudspeaker Matching
The Qualiton A50i is suitable for use with appropriately matched loudspeakers presenting nominal 4Ω or 8Ω loads.
With 50 watts per channel, it can provide a serious foundation for a high-quality stereo system, particularly when paired with loudspeakers of suitable sensitivity and impedance characteristics.
Final matching should take into account the listening room, preferred playback level, loudspeaker impedance behaviour and desired musical balance.
Chameleon Audio can offer individual matching advice based on the customer’s existing system.
Explore Qualiton Components at Chameleon Audio
Audio Hungary offers a range of specialist vacuum tube amplification products.
Customers assembling a complete analogue system may also be interested in suitable Qualiton phono preamplifiers and matching source components.
Independent Reviews
High Fidelity Poland – Qualiton A50i
High Fidelity Poland published a detailed review of the Qualiton A50i, examining its design, construction, valve configuration and musical performance.
The review explores Audio Hungary’s engineering philosophy and its approach to Class A tube amplification.
Discover the Qualiton A50i in an original Chameleon Audio listening demonstration.
The video was recorded in the Chameleon Audio demonstration room using AudioSolutions Figaro S loudspeakers, SOtM digital audio components and selected high-end cables.
It provides an introduction to the amplifier within a complete music system and allows visitors to experience the atmosphere of our listening demonstrations.
Technical specifications refer to the original Qualiton A50i design. The exact valve brands and supplied accessories of the available used unit should be confirmed with Chameleon Audio.
No. This is a pre-owned unit offered by Chameleon Audio in excellent reported condition.
What is the amplifier’s output power?
The Qualiton A50i is specified at 50 watts per channel in Class A operation.
Which power tubes does it use?
The original design uses four KT120 output tubes. The installed valves of this particular used unit should be confirmed before ordering.
Does it need manual bias adjustment?
The A50i incorporates automatic bias control for its output tubes.
Can it drive 4Ω loudspeakers?
Yes. The amplifier provides dedicated output connections for nominal 4Ω and 8Ω speaker loads.
Does it have balanced inputs?
It includes a mini-XLR balanced input connection, in addition to three stereo RCA line inputs.
Does it include a built-in phono stage?
The documented inputs are line-level connections. A separate phono preamplifier is required for a conventional turntable without its own phono stage.
Does it come with a remote control?
The A50i was designed for remote operation. Please confirm whether the original remote is included with this used unit.
Can I replace KT120 tubes with KT150 tubes?
Alternative output tubes have been discussed for the A50i, but suitability must be confirmed with Audio Hungary for the specific hardware revision before any substitution.
Are independent reviews available?
Yes. Reviews and technical features are available from High Fidelity, Positive Feedback and HomeTheaterReview.
Can I watch the amplifier in action?
Yes. Chameleon Audio has published an original listening demonstration and an unboxing video on YouTube.
Can it be shipped internationally?
Contact Chameleon Audio for a destination-specific shipping quotation and confirmation of suitable packaging, insurance and delivery arrangements.
Why Choose the Qualiton A50i?
The Qualiton A50i represents a distinctive combination of classic vacuum tube design, advanced bias management, precision transformer engineering and exceptional European craftsmanship.
Its 50-watt Class A stereo output, KT120 valve architecture and elegant polished chassis have made it a memorable model within the Qualiton range.
For listeners looking for a substantial high-end integrated tube amplifier at a second-hand price, this Chameleon Audio example deserves serious consideration.
Hungarian Craftsmanship. Class A Valve Power. A Special Pre-Owned Opportunity.
Availability and International Orders
This used Audio Hungary Qualiton A50i is offered by Chameleon Audio in Greece, subject to prior sale.
Contact us for additional photographs, current availability, tube-condition information, compatible loudspeaker recommendations and worldwide shipping options.
Specifications
Name
Value
Rated output power
2 x 50 W, stereo
Total harmonic distortion
< 0.75% (f = 1 kHz, rated output power)
Frequency response
30 Hz – 100 kHz (-3 dB, rated output power)
Input sensitivity
425 mV, unbalanced input
Number of input ports
3 unbalanced input per channel, 1 balanced input per channel
Number of output ports
1 output terminal pair per channel, 1 line level output per channel
