Remember that you are handling with high voltages that can be dangerous to life. So if you are working on powerd on devices use only one hand in order to prevent electrical shock.
The indicated supply voltages, especially the values for the main supply must be considered as maximum values for that the amplifier works proper. Do not exceed these values.
Provide sufficient cooling for the power semiconductors or tubes.
All parts are carefully selected and should be used as listed in the partslist.
Measure your semiconductors and tubes and pair parts with same Hfe. The 2SJ74 JFETs must be matched at 1,5mA. The measured difference should be <50mV.
All transistors are available from Gerwert Electronic firstname.lastname@example.org or from http://www.sh-halbleiter.de/ .
Customerspecific transformers are available from http://www.top-print-pcb.de/ .
The fast-recovery-diode BYV96E is available from http://www.conrad.de/ .
The pf-condensators in the amplifiers must be silver micas from http://shop.frihu.com/. Do not use ceramic types.
Resistors from vishay, I used in the signal path are also available from http://shop.frihu.com/ .
Elkos of the product line 057 from BC is supplied by http://www.schuro.de/ . Depending from the type of 220µF elko in the power supply it can be advantegous to switch a 0,22µF tinfoil capacitor parallel. It can change the sound dramatically!
Tubes from different manufacturers are sounding different. It is worth carrying out a comparison.
If you want to use melting fuses in your power supply, only use PADIS fuses.
Headphone sockets for STAX 78-S6S can be found at http://www.rsonline.de/ . Ordering number is 2508709806.
Boards can be manufactured by http://www.platinenbelichter.de/ for low cost.
Did I forget something? If you have questions then email me at email@example.com. Tips, suggestions, opinions are welcome too.