Category: Audio Products Published: Monday, 26 October 2020 Written by Richard Hoogeveen

2A3 /300B SE tubeamplifier SELiiX


These are the HMR-audio Single Ended Class A monoblocks called SELiiX.



This set is completely CNC and handcrafted by HMR-Audio from mostly 10mm thick 6082 aluminum used in the industry. Each case weighs 8kg. The total weight is 24kg each complete mono block. The 2A3-40 tubes you see here are equal to the 300B from JJ, but has its filament half of that of the 300B. The Coleman DC DHT filament regulator for the 2A3 can be "easily" configured for a 300B filament by changing a resistor.

The driver tube sitting behind the front plate is the 6H30P double triode tube, chosen for its linearity, little distortion and gain and it is actually quite good in driving a 2A3 or 300B. This tube is connected to the HMR-audio MOSFET MU-stage and HMR-audio voltage regulator driven by a Mullard GZ34. The bias current regulation is a conventional one with bias pots.

The amorph output transformers, chokes and power transformers are famous Tribute ones. This is a expensive handmade set by Piet Treurniet

You need to drive these amplifier with a volume regulated pre-amp like the HMR-Audio PRELUX pre-amp or other sources with a volume regulation like a media player. In the front you see a part of the HMR-audio tube amplifier controller. It is a Nextion touch panel and the cpu/software of the controller is capable in controlling the amplifier. The amplifier tube controller has specific software built for this model.

You can turn it On or Off, measure bias current, temperature, measure high voltages, keeps track of tube hours and you will have audio detection for automatic shutdown. The measures can be used to take action, warn or shutdown the amplifier.


Single Ended SE monoblock 8.7Watt class A output

Tubes, 2A3-40 JJ / Sovtek 6H30 / Mullard GZ34

230V / 80Watt, standby 0.9 Watt

Case temperature max about 45 degrees Celsius

GZ Uk about 390 Volt

Ureg about 360 Volt

Uref about 185 Volts

Ug 2A3 about -70 Volts

75mA biascurrent

4 and 8 Ohm output terminals

THD+N @ 1 Watt 0.71%

PCB's from HMR-Audio and high quality components

DHT regulator from Rod Coleman (really good and no plans to design my own)





These special high performing amplifiers (and CNC/PCB parts) can be made for you, you can contact me with the contact form.





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