EL84 SET class A amplifier

 

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I have build an EL84 SET class A amplifier in triode configuration for my computer- and bedroom. The amplifier has a very nice soft warm sound, with a good amount of bass.
The amplifier however has some blue light in the EL84's. I have mounted grid stoppers on the ECC83 grids and have read on the web that it is normal for pentodes as EL84 and EL34 to have some amount of blue light, it is also common for old NOS tubes like mine to have some blue light. The amplifier also hum a little bit (100Hz), I will not do anything about this. At last I have added a small 30 sec. delay circuit to delay the high voltage switch on.

The schematic that inspired me to build the amplifier, from http://www.jogis-roehrenbude.de/ under Leserbriefe in Deutsch!
Picture of the EL84 SET taken during test. Pcb file updated 2007.01.24
Picture of the finished EL84.
Picture of the 30 sec. delay circuit. Pcb file updated 2007.01.20
Picture of the blue light in the EL84's.
Front of the finished amplifier.  
Back of the finished amplifier.  
CAD files for the cabinet. CAD files updated 2007.12.02

This page was last updated 2009-09-13.