Preamplifier ELRAD "RÖHRLING" using ECL86 - what value is the best for An. Voltage ?

[tiefbassuebertr]

Preamplifier ELRAD "RÖHRLING" using ECL86 - what value is the best for An. Voltage ?

In the German magazine ELRAD (Jul/Aug 1989) was published a large preamplifier - go to the attachments.
Unfortunately no exact value is mentioned in the text for the adjustment the serial voltage regulator - go to first image.
Thank you for an advice concerning best voltage value for longest life expentancy of the ECL86.

P.S.: An overview of this magazine is here:
Seite nicht gefunden - Musikelektronik

 

[artosalo]

It should work fine with 250...300 Vdc.
This value is not critical.

 

[thimios]

The same circuit was published in Elektor Magazine.
The protection circuit is a bit more complex.