240V Paramount on Low Line Voltage - Modification

[Paul Birkeland]

It has come to our attention that a 240V Paramount operated under 230V may not produce sufficient filament voltage (2.4V DC for 2A3, 4.75V DC for 300B between pins A1 and A4). 

If you observe this issue, a capacitor can be added on the FC-1, between terminals 5 and terminal 10, with the striped lead on 5 and unstriped lead on 10.  This capacitor should be rated at 6.3V or more, and sized around 4,700uF to 10,000uF.

Do not add this capacitor if your filament voltages are within tolerance stated above.

[ToolGuyFred]

Off topic but:

This is usually only an issue on mainland Europe. When Brussels decided we should have a "harmonized" voltage (at the time mainland Europe was mostly 220V and the UK was 240-250 depending where you live) by and large nothing changed. Voltage tolerances were tweaked so that the mainlanders could call their voltage 230V (minus 5% or so) and we Brits could call our supply 230V (plus four to eight and a bit percent).

This is a source of confusion to anyone either non-electrical or from outside the EU (and the reason the adaptor which came with my Bottlehead DAC overheats and shuts down after four tracks - not a problem - my NiCad setup sounds better).

[mcandmar]

Thankfully we still use 240v here in Ireland, which makes more sense to me as it allows for dual voltage equipment to work better being double 120v.  I.e. transformers with two 120v primary windings are still within spec running on 240.