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Old 14th April 2020, 04:34 PM
bikerhifinut bikerhifinut is offline
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Join Date: Jan 2006
Location: Penrith, Cumbria
Posts: 1,089
Default Re: PSU II & III transformer rating.

Hi bob,
Well you'll Know its 1.5A heater draw for 5 x ECC8x valves.

As memory serves the current draw for the Phono is very low, not much above 5mA which a quick rough look at worst case circuit values confirms.

Again Pre 3 draws around 25mA so that's a total of 30mA on the HT.

You are using a Pair of ECC88 in your CF so You'll need to work out the current draw through the unit which I guess is ascertained from the cathode voltages on the bottom valves. I am not sure but I think the ECC88/6DJ8/6922 draws a wee bit less than ECC82/12AU7/5814 types which is a fairly current hungry device.

if I taught granny to suck eggs, sorry bob.

The WD transformer is rated at 2 A on the heater secondary and that's the reason I'm going to need extra heater amps when I knock up the 2 x 6SN7 line preamp as they are 600mA heater draw which takes the heater draw for phono and pre to 2.1A which might maybe perhaps be ok but it's going to run a bit 'ot! and not worth the risk.

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