son of Zen-lite

[PedroPO]

After 2 hours of operation without the cover, the left channel is at 50ºC and the rigth one is at 44ºC.

 

[AudioFreak]

well given that R3 and R4 are in parallel according to the original schematic, then if one of the bulbs fails it is in effect the same as replacing the parallel combination of R3 and R4 which is a nominal 4 ohms with a single 8 ohm resistor. Of course that assumes that you replace R3 and R4 separately, if you replace them with a single set of series connected bulbs then if one fails it is the same as disconnecting the -ve rail.

 

[Variac]

Congratulations Pedro- I will be asking your advice when I make my X SoZ lite (getting to be a long name!! 😉

So you are running 24v/ rail? or at the transformer? - what does that come out to-about 16 watts audio output a channel? Does that mean the bulbs are dissipating about 80 watts?

 

[PedroPO]

variac:

no, no, no

I replaced R3 and R4 with 3x12V50W bulbs in series, so I got a 4 ohm equivalent resistor.

I didn't replaced each resistor with 3x12V50W.

I'm running this SOZ with 12V+12V @ the transformer.

The voltage drop between in R3 is 8.71V.

with the lamps is 8.72V.

The current flowing is 1.8A, so P=R . I^2 =V.I=8.72 *1.8=15.7W

15.7W is the power dissipation of the 3 bulbs that substitut R3 and R4. Not the output power of the amp, wich is +-5W.


Audiofreak:

if you replace them with a single set of series connected bulbs then if one fails it is the same as disconnecting the -ve rail./

yes that is it, but what wappens? do I burn anything or not?