Allowed the guitar notes to become forte
As far as the quality of our products is concerned, we do not make any compromises. Appliances launched under the brand name UNIVOX consist of electric circuits
made of selected high-quality components. They are placed in solid and carefully conceived metal frames. We are working on developing durable power amps and integrated amps,
designed for the Hungarian and international market, as well as in addition to vacuum tube amps on designing hybrid constructions using semiconductors.
Finally, we hope that our appliances, made to meet with high technical demands, will be to the liking of all the visitors of our products it is a preamp or a power amp, a hybrid amp or a full tube amp.
The launching of the vacuum tube stereo power amp Qualiton APX 200 entailed the demand for developing a thoroughly classic vacuum tube preamp.
The vacuum tube preamp Qualiton APR 204 is meant to meet this demand by not wanting to seem to be more than it is: it is in fact one indispensable element of the
sound chain which was developed based on clear guiding principles and is able to evoke the classics of tube electronics.
At the same time, three audio sources with line level output signals as well as one signal source with MM phono output signal level can be connected to the RCA connectors at the rear panel. With the help of the audio source selector switch at the front panel, the user can determine, out of these four audio sources, which one of the relay-switched, volume-controlled signal should reach the output RCA connectors.
If the input selector unit is in P, i.e. PHONO position, the signal to be processed gets on the grid of the first voltage-amplifying vacuum tube through RCA connectors marked PHONO - thus, through the shortest possible signal paths. From here, in the before-mentioned classic way, the signal component gets on the grid of the second voltage-amplifying stage through a passive correction network between stages according to RIAA standard, realised exclusively with passive elements. We use both in the first and in the second voltage-amplifying stage double triodes ECC83/12AX7. Through an appropriate tuning circuit and volume control potentiometer, the output of the PHONO stage is connected to LINE stage, consisting of double triodes E88CC/6922.
As the successor of the former amp BEAG APX 100, we have created the vacuum tube stereo power amp Qualiton APX 200 which is able to operate
low impedance speakers. As opposed to the previous model, in the case of the Qualiton APX 200 we did not insist on the monoblock design. Instead,
we regarded it as more favourable if we used a more compact and economical stereo version compared to the previous design.
The power of the appliance was set as 2 x 100 W, consequently it is able to dynamically operate even more insensitive speakers. The frequency response of the power amp is fully linear in the audio-frequency range, at nominal, i.e. 100 W output power, measured with sinusoidal waveform. The low frequency breakpoint of the frequency response is 15 Hz, the upper cutoff frequency is 100 kHz (-3 dB points). In the entire audio-frequency range, the total harmonic distortion is less than 1% and the signal-to-noise ratio of the appliance is typically higher than 101 dB. While developing this product, the listed technical parameters were attained due to carefully designed circuit arrangements, a selected set of vacuum tubes and an accurately dimensioned and a manufactured output transformer.
The protection of the vacuum tube set is handled with special care. The lifespan of the tubes can be drastically reduced by uncontrolled transient surges of current at the moment of power-on. Similarly, suddenly switching high anode voltage on non-preheated vacuum tubes can have an adverse effect on the lifespan. In order to eliminate those effects, the appliance is equipped with a slow-start circuit and an anode voltage delay circuit.
Dynamic Solutions, Westkanaaldijk 18, 3606AL Maarsen, tel +31-621593460