-1

I have an old sony str-d911 some pics

I know the str-d911 is a receiver and not an amp but the specs say 100 watts per channel I tried using a 40 watt and 100 watt light bulb (as a test/dummy load) connected to the left speaker channel playing 60 Hz but it doesn't seem to be putting enough power out to light it. What am I missing?

Here's The Spec sheet

Front-1

Back

Video of using a light bulb as a load below.

1
  • You're missing about 100 volts. – Tetsujin Nov 12 '20 at 8:59
0

What am I missing?

Use a 24 V lamp instead.

Back of an envelope calculation. The formula I use is P = U * U / R.

Your amplifier: 100w in 4 Ohms --> cirka 20V output. Put 20 V into a normal 110V / 100W lamp (around 110 Ohms) gives you about 4 W = not enought to light it. Even worse with a 40W lamp (about 320 Ohms) --> about 1.3 W.

The Peavey in the video gives 650W in 4 Ohms --> about 50V --> 20 W or so = enough to light the lamp. Or they might have it bridge coupled, which would give about 100V across the lamp.

Not the answer you're looking for? Browse other questions tagged or ask your own question.