Bottlehead Forum

General Category => Technical topics => Topic started by: johnsonad on November 11, 2016, 12:20:39 PM

Title: New DC board max current
Post by: johnsonad on November 11, 2016, 12:20:39 PM
Team BH,

What is the maximum current that one side of the new Kaiju DC board can handle without overheating? 

My hair brained idea is to run two type 27 tubes off of half of a board.  Total current draw of the two tubes would be 3.5 amps.  I would use a 6 amp Hammond transformer to feed the board.

If it's too much for one side, could I get away with it with one tube per side?

Thanks,

Aaron

Title: Re: New DC board max current
Post by: Paul Joppa on November 11, 2016, 01:55:01 PM
I cannot recommend more than 1.2 amps.

The chip itself is rated 3 amps maximum, but in my experience it's tempting fate to use more than half of the maximum current.

The heat sink is running at maximum with 1.2 amps. Any increase would need a larger heat sink.

Incidentally, power transformers vary in their open circuit voltage and DC resistances. The board works with the Kaiju power transformer, but other transformers with the same spec may or may not be able to offer enough voltage headroom.

In other words, it was never designed as a general-purpose filament power supply.
Title: Re: New DC board max current
Post by: johnsonad on November 11, 2016, 01:58:40 PM
Thanks Paul.  Another dream shattered but my wallet thanks you :)