Vacuum tube amplifiers are used as guitar amplifiers by musicians (due to their specific characteristics and higher price) after semiconductor amplifiers became main stream. A transistor is a semiconductor component controlled by the current as opposed to a voltage-controlled vacuum tube, so the frequency spectrum is different, particularly in the overload area. There lies the origin of the often used term "vacuum tube sound". We currently produce:
It is a tube stereo amplifier that uses customized wiring from the Tesla 4243 - Spoletto television set, manufactured in the 1980s. The amplifier is complemented by a fluorescent excitation indicator and by an up-to-date BLUETOOTH electronic circuit.
The amplifier has two identical low-frequency channels with 2 x 5W of output power. The immediate amplifier power and its excitation is indicated by a tape indicator. Two independent potentiometers can be used to control the gain. The low-frequency signal can be connected via the CINCH connectors (a high quality connection), or the BLUETOOTH connection can be activated to connect the amplifier wirelessly to a signal source, (e.g., using a mobile phone) or to turn it off. In case of a BLUETOOTH deactivation,the amplifier switches to a standby with a minimal power consumption after 5 minutes have elapsed. Since the vacuum tube connection is used (amplifier works in a class A), it is necessary to take into account the consumption of about 30W even if the amplifier is without signal. The device is housed in a wooden cabinet (solid wood) and is fitted with a front glass wall that allows the device to be observed during its operation (a shine of the vacuum tubes glowing).
Informs: Doc. Ing. Josef Šandera, Ph.D., Date: 03/2019