The Australian magazine Siliconchip has published an amplifier SE using tubes 6L6.
<<< To overcome this, we have used an output configuration that has become known as "parafeed". This uses a relatively low-cost high impedance choke as the load for the plates of the output valves and a capacitor couples the audio signal to the primary of the output transformer. As a result, there is zero DC in the primary winding, so the output transformer can be much smaller and lower in cost without sacrificing quality.>>>
<<< The plate current for the two valves passes through a 9H (nine Henry) choke – essentially three standard compact fluorescent ballasts connected in series – and this provides a high AC impedance but low DC resistance to supply the HT to the plates. >>>
www.siliconchip.com.au/cms/A_105000/P_2/article.html
http://www.siliconchip.com.au/cms/A_105172/P_2/article.html
The choque is 3 standard compact fluorescent ballasts connected in series?????
Somebody has used this?
best regard
Jaime
<<< To overcome this, we have used an output configuration that has become known as "parafeed". This uses a relatively low-cost high impedance choke as the load for the plates of the output valves and a capacitor couples the audio signal to the primary of the output transformer. As a result, there is zero DC in the primary winding, so the output transformer can be much smaller and lower in cost without sacrificing quality.>>>
<<< The plate current for the two valves passes through a 9H (nine Henry) choke – essentially three standard compact fluorescent ballasts connected in series – and this provides a high AC impedance but low DC resistance to supply the HT to the plates. >>>
www.siliconchip.com.au/cms/A_105000/P_2/article.html
http://www.siliconchip.com.au/cms/A_105172/P_2/article.html
The choque is 3 standard compact fluorescent ballasts connected in series?????
Somebody has used this?
best regard
Jaime
Hello Jaime! What a beautiful name 
I've tried. Their inductance is pretty low (don't expect 3H from each of them, 1 seems more realistic), but the problem is that they aren't gapped so even with small DC currents they saturate and the inductance goes down.
I can't see the problem, chokes are pretty cheap, cheaper than neon ballasts (not if you already have them).
My transformers source has 10H 100mA chokes for 16euro each.
I've tried. Their inductance is pretty low (don't expect 3H from each of them, 1 seems more realistic), but the problem is that they aren't gapped so even with small DC currents they saturate and the inductance goes down.
I can't see the problem, chokes are pretty cheap, cheaper than neon ballasts (not if you already have them).
My transformers source has 10H 100mA chokes for 16euro each.
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