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 or from .

Customerspecific transformers are available from .

The fast-recovery-diode BYV96E is available from .

The pf-condensators in the amplifiers must be silver micas from Do not use ceramic types.

Resistors from vishay, I used in the signal path are also available from .

Elkos of the product line 057 from BC is supplied by . 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.
For the first stages I recommend Svetlana, Tungsram, Siemens or EI (Yugoslavia).
For the 6S4A I recommend RCA.

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 . Ordering number is 2508709806.

Boards can be manufactured by for low cost.

Did I forget something? If you have questions then email me at Tips, suggestions, opinions are welcome too.