B-15N Power output mesurement

[simondolanbass]

Hi,

I've checked the power output of my B-15N and I was suprised that it deliver only 18W.

This is my procedure

Jump pin 2 and 3 of the 4 pin speaker output. Plug pin 1 and 4 to a 8 ohm dummy load. Feed a sine wave into the amp. Watch the sine output on a scope. Raise the level until sine wave is still perfect. Mesure the AC voltage with a DMM on the dummy load.

Vout= 12 VAC

P= V2/R
P=144/8
P=18W

I'm surprised that It don't go up to 25W.

Comments?


Thanks

Simon

[Hangman]

Hi,

I've checked the power output of my B-15N and I was suprised that it deliver only 18W.

This is my procedure

Jump pin 2 and 3 of the 4 pin speaker output. Plug pin 1 and 4 to a 8 ohm dummy load. Feed a sine wave into the amp. Watch the sine output on a scope. Raise the level until sine wave is still perfect. Mesure the AC voltage with a DMM on the dummy load.

Vout= 12 VAC

P= V2/R
P=144/8
P=18W

I'm surprised that It don't go up to 25W.

Comments?


Thanks

Simon

push the sign wave on the output to clip, then bring it back a bit until its just ever so slightly distorting at the peaks.

its a bit subjective, the power rating usually has an accompanying THD%.

lets see what it measures with a very slight clip.

[simondolanbass]

Hi,

With a light clipping on the top of the sine wave, I reach 13,5 VAC. That gives me 23,125 W! This is pretty close to 25W!

Thanks!

Simon

[simondolanbass]

UPDATE!

I restored the full 25W power by changing the two cathode bias capacitors that were dead!



Simon

[Hangman]

Nice! good work. glad it is back up to snuff.