Feedback resistor smokes up

[lsabourin]

Hi all, I've setup the BA283_AM portion of a Neve-style 1073 preamp on breadboard just to test voltages (schematic attached). Problem is that I smoked the 47 ohm R tied to the 2N3055 emitter and to 5k trim on startup. I've got the 5k trimpot all the way down (it clicks). Any clues?

L

[Audioguru]

The schematic does not say and does not show what the lettered terminals are for or their voltages. The 47 ohm resistor cannot smoke because it is connected to nothing.
Why would a preamp use a 2N3055 power transistor and a transformer? Transformers have not been used for audio since about 1960.

[lsabourin]

It is connected to the emitter of the 2N3055 and the trimpot and ground. Transformers are being used regularly in vintage audio applications.

[Audioguru]

"Vintage" means old antique stuff. Hey, I am vintage. I am old but I am not an antique yet.
Maybe you have the transistor pins mixed up.

[Seekonk]

First off, NEVER start with the pot all the way down.  This is a bad design just because you can do that.  That sends the output transistor into maximum current.