The Qtron OTL PA12B examined!

On a rainy day January 31th 2020 a big package of 45 kg arrived delivered by UPS. The driver from UPS had some problems dragging it into my room for unpacking. However, after he went on, I started unpacking this large wooden box. As the box was split in 3 different spaces I first took out all the tubes 6C33C x 4, 5 x Russian Voshod Rocket 6N2P-EV and 2 x Reflector 6N6P. All tubes were carefully screened and given a number.


Secondly I removed the big power amp weighting almost 21 kg! And finally the pre map PRE14B with already mounted tubes Mazda ECC82 x 2 and 4 x 6N6P from Reflector NOS stuff. Hans Beijner told me I had to remove the protective padding in the pre amp before operating it! So I screwed it open en saw I very big 600VA toroidal transformer and the intelligent volume solution (no Alps here!). This pre amp consisted of 2 x Mazda ECC82 / 12AU7 as a kind of V1 position and 4 x 6N6P.


After reading both manuels I installed the tubes 6N2P-EV x 5 in the right positions and also the 6C33C from Uljanovsk and the Reflector 6N2P x 2 on top of the amp. When viewing the amp you see 1 cm thick aluminium plates building a sturdy housing for the PA12B. You also can see porcelain sockets for all tubes and a pair of XLR input and 1 pair of RCA inputs golded, good but no WBT's. The amps build shows no screws or transformers. Inside there are 2 transformers. After connecting the pre amp and the power amp and installing a source I connected also the speaker cable and speakers before switching on by using the button on the back of both amps. Then after a few seconds you can press the buttons on the front to start a 90 second softstart proces which ends with a firm 'click'. The amps are now ready to play. It's lovely to see how the amp glow in the dark. After a few hours the amp surface gets a little warm but not hot.


Next week I will write more on the sound of the PA12B and the PRE14B. Just playing for 5 minutes I realised this amp is quiet in my 105dB Jericho 08 horn loudspeaker, due to the very high bandwith of 10-150.000 Hz you get all the details which you normally don't notice, especially the midrange is a little higlighted and incredibele dynamics and the feeling a couple of layers are removed from the recording process. My Line Magnetic 219 surely is very good but this is so much better! See you next time!