Q-tron Audio PA12B 2x25W Push Pull Vacuum Tube OTL Power Amplifier

Q-tron's Output Transformer Less (OTL) amplifier provides a clearer and wider sound quality compared to other vacuum tube amplifiers. By eliminating the output transformer required by a normal vacuum tube amplifier, it avoids the distortion and frequency characteristics limitations caused by the transformer and improves sound transparency and response. The Futterman circuit, designed specifically for low impedance without the use of transformers, achieves low output impedance and excellent balance. In addition, active noise cancelling technology to reduce noise below 100dBA and design to achieve very low distortion without excessive feedback. The use of minimal vacuum tubes has proven reliable and long life. All parts are designed and manufactured in Sweden and use high quality components to maintain high performance over a long period of time.

The OTL amplifier with two PA12 vacuum tubes in each channel is a unique driver circuit that reduces distortion to one-tenth of a 6C33C than other OTL amplifiers. This unique driver circuit allows 25W output. The distortion rate is less than 0.1% even at the output of the 10W, which is very good for vacuum tube amplifiers. In addition, the distortion rate at 1W is even lower at 0.01%, and ham and noise are very low by active noise reduction technology.

Although the amplifier is built on a large PCB, point-to-point (PtP) technology is used for important components. Ceramic solder support is used to withstand 5kV, and the chassis is made of 10mm thick aluminum, providing excellent mechanical stability and completely eliminating noise caused by vibration.

Q-tron PA-12 is a vacuum tube amplifier with an innovative push-pull design that redefines the possibility of OTL amplifiers. In addition to the reverse-phase Futterman circuit, we adopt our own distortion and noise removal circuit to achieve unprecedented pure and transparent sound. It provides a sound quality comparable to a Class A amplifier and performs well beyond that area.
The charm of the PA-12 lies in its distinctive texture purity and rich tone. It brings out the essence of 6C33C power triad, the high range is sparkling with a sense of life, and the low area is strongly expressed while maintaining very accurate pitch control. Unlike conventional vacuum tube amplifiers, it avoids crossover distortion problems and provides deep sound fields and three-dimensional sound images.
Another noteworthy point of PA-12 is its speed and high-range delicacy in response to transients (instantaneous sound changes). Since there is no DC blocking capacitor in the signal path, natural and organic details are reproduced fully controlled. The bus line is also very clear and conveyed with a wonderful sense of definition. In order to capture the minute nuances of music and to solve the details of any recording, we will impress the listener and provide a technical and excellent listening experience.
PA-12 is a true reference grade amplifier that has a very low noise floor and reproduces very precisely low levels of detail. It captures the essence of music, realizes sound with excellent transparency and clarity, and eliminates excessive secondary and tertiary harmonic distortion.
For those looking for the purity of the sound of a vacuum tube amplifier but looking for the transparency and resolution equivalent to the best solid state design, the Q-tron PA-12 is definitely the top choice. If the 25W/ch output is a suitable system, this amplifier is a game changer that demonstrates the true potential of OTL technology and provides the musicality and accuracy that audio files require. We highly recommend you to all who wish to take your listening experience to a new level. * "Enjoy The Music』参照

This device is composed of 11 vacuum tubes: 2 x 6H6Pi, 5 x 6H2n-EB, and 4 x 6C33C. The miniature tubes are generally similar to the 12BH7A and 12AX7 models. The output tubes were originally designed for regulation and are impressively large. There are three corners on the head. When you press the power switch on the front panel, a light click of the relay is heard after 1.5 seconds, and the current of the large toroidal transformer slowly ramps up. After 90 seconds, a second click is heard, and the plate voltage is applied. Another 45 seconds later, the short circuit in the speaker is released, allowing you to listen to music. Only at this time does the edge of the switch light up green. It also monitors DC leakage, protecting the precious speakers. Be careful not to turn on the power without connecting the speakers, as the protection circuit will activate. Since the 6C33C takes about 10 minutes to stabilize per specifications, it will likely take over 30 minutes for the sound to stabilize. The sound I heard during the listening test was astonishing. Whether classical or jazz, the realism is incredible. Regardless of what sound is played, it is quite stable even in transient areas. The fullness of the mid to low frequencies is just right and feels pleasant, and there is a sense of expansion. Additionally, the complex sounds of plucked instruments like the guitar and shamisen were reproduced accurately, and I was impressed by the high frequencies of the trumpet. This must be influenced by the rise time of 0.5 microseconds.

Although the sound is precise, I think it is not a monitor sound like listening in a pro studio, but a sound that can enjoy music. I used it for listening in Valencia of Artec with high efficiency and . I started MC240 Yamaha's B1 and Mackintosh with a number of amplifiers, but as soon as I thought that the sound I sounded in this Q-Tron was the best I've ever heard, I felt happiness when listening to music on this speaker. I wonder if the compatibility was so good. However, when I listened to the ME of the TAD (1 efficiency is 82dB in 4 ohms), I could not get the feeling of happiness to that point. Of course, there is no difference in being a good power amplifier to play music. The output of this OTL amplifier is 25W, so if you sound with a low-efficiency speaker, you may feel a little scarce. However, I think that if you have more than 90dB speakers, you can secure enough volume. You can choose between balance and unbalance.

It was an amplifier that brilliantly broke the preconceived concept that "a good amplifier is like this." He taught me that there are still things I do not know in the world. * See Radio Technology