Friday, 27 January 2017

Follow the heat waves

Big thanks to a friend who owns a Flir E4 Thermal Imaging camera and lent it to me for the weekend.

After warming up the amp, I used the camera to measure the envelope temperature of the big KT88 valves.


Not surprised at the 172º reading. (340ºF)



Strangely this one runs a little cooler than the rest. Its bias current is the same, 50mA


From the KT88 Datasheet:

Phew!


The question you may be asking: what was playing through the amplifier during this photo session? Glad you asked. Icehouse... Man of Colours. Since I'm going to be seeing them live tomorrow.

Wednesday, 18 January 2017

New beginnings


The beginning...


Next one on the way... this one will be an EL84-based PP with fixed bias and a phono stage...

Starting to collect parts