Power Transformer


I’ve this blackheart power transformer in my junk cabinet. It’s rather interesting because in spite that it was used in a simple single ended EL84 tube amp it has several odd things. It , clearly , wasn’t designed specifically for this amp.

The primary show different wires to make the transformer usable everywhere on the planet . The different wires corespond to the different main voltage (230V for Europe, 110V for USA and so on). It’s a common way to avoid the building process of 2 or 3 transformers for the same product (obviously the connexions have to be changed before)


The more odd comes at the secondary . It shows three windings. The High voltage is a center tap  winding , there’s the 6V3 heater winding but also a 5V one. Beside there’s also a big 5W 470R ceramic resistor to drop 40V of the HT ! This make me think that this power supply wasn’t specifically designed for this amp but borowed from a tube rectifier amp . It could even be used for the all blackheart line.


I’ve no idea of the maximun current this puppy could give . Nonetheless, it seems pretty massive for a single ended.  The 5V winding , if rectified,   can be nice for switching system or tremolo solid state circuit !

It appears that Crate decided to end the blackheart line . It’s sad because it was pretty good and quite well build .

the blackheart little giant schematic :

blackheart 5W little giant


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