PA12B, (balanced and unbalanced input)

Backside PA12B

Front PA12

2 x 25W OTL power amplifier


10 times lower distortion than other OTL amplifier thanks to unique driver circuit. 


PA12 is an OTL amplifier that is equipped with 2 6C33C tubes per channel that is driven by the unique driver circuit to 25W output power. Even at 10W output power the distortion is less than 0.1%, a very good figure for a tube amplifier, at 1W distortion is as low as 0.01%. Hum and noise reach very low values as active noise reduction is used. 


PA12 is the amplifier that was reviewed by Dick Olsher in Enjoy The Music and was described as "A tube amplifier that redefines what is possible in a push-pull design."Q-tron PA-12 beats them all" see review here:

The amplifier is built on a large PCB except for critical parts that are built using so called Point to Point, (PtP) technology, ceramic solder supports are used that can withstand 5kV.  The chassis is made of 10mm aluminium which gives extraordinary mechanical stability and completely remove vibration induced noise. 


We now have a variant of PA12, PA12B that is equipped with balanced input using XLR connectors and can also be used unbalanced through RCA phono connectors.


We can offer versions of PA12 and PA12B with higher output impedance if requested, this as some speakers work better when driven by a higher impedance 




Output power                                   



Distortion at 1kHz, 1W                  

Distortion at 1kHz, 10W                 


Frequency response                

Power bandwidth                   


Rise time


Hum and noise                        


Output impedance

Input sensitivity 


Input connectors   PA12








25W in 8 ohm at less than 1% distortion

20W in 4 ohm at less than 1% distortion


< 0.01%

< 0.1%


 5 - 100kHz - 1dB

10 - 100kHz - 1dB


< 0.5us


< -100dBA


0.4ohm or 1.5ohm, (see text above)

2.5 V for full output power


RCA Phono


XLR + RCA Phono


430 x 250 x 290 mm, (B x H x D)


21 kg

© 2017 by Q-tron Audio. All rights reserved.