A local store had a Boxing Day sale for a "Special Buy" of a name-brand 2.1 Speaker system for only $24.99CAN.
It has a 5inch "sub-woofer" (it lights up with blue LEDs) and two satellite speakers each with two 1.5" mid-range speakers and what looks like a 1" soft-dome tweeter. It sounds great and goes very loud.
On the internet it got good reviews. It is rated at 150W. On the box and in its owner's manual it is rated at 75W RMS.
BUT ... its sensitivity is a little low so I took it apart to see if I can easily increase it gain.
1) Its amplifier is two 16 pins DIL ICs with a small piece of aluminum glued on top. 3W each?
2) Its little power transformer is labelled 9VAC/1.1A. That is 9.9W and only about 6W goes to all the speakers.
Maybe one 3W IC powers the sub-woofer and the other 3W IC powers the satellite speakers.
The advertised output is 150W or 75W RMS but the actual output to the speakers is only about 6W so the lie is 25 times or 12.5 times wrong.
3) The "soft dome tweeters" are actually ports for the satellite speakers with a passive soft dome covering the holes.
4) The 5" sub-woofer measures only 4.25" and its moving cone measures about 3".
It has bass and treble tone controls but has no transistors nor opamps to do it.
I measured the frequency response with my old ears and it works well from 40Hz to 18kHz.
I don't know which Chinese power amp ICs it uses. Since its actual power is much less than advertised then adding more gain might blow it up. I will not modify it.
It sounds great! It sounds great! It sounds great!
It has a 5inch "sub-woofer" (it lights up with blue LEDs) and two satellite speakers each with two 1.5" mid-range speakers and what looks like a 1" soft-dome tweeter. It sounds great and goes very loud.
On the internet it got good reviews. It is rated at 150W. On the box and in its owner's manual it is rated at 75W RMS.
BUT ... its sensitivity is a little low so I took it apart to see if I can easily increase it gain.
1) Its amplifier is two 16 pins DIL ICs with a small piece of aluminum glued on top. 3W each?
2) Its little power transformer is labelled 9VAC/1.1A. That is 9.9W and only about 6W goes to all the speakers.
Maybe one 3W IC powers the sub-woofer and the other 3W IC powers the satellite speakers.
The advertised output is 150W or 75W RMS but the actual output to the speakers is only about 6W so the lie is 25 times or 12.5 times wrong.
3) The "soft dome tweeters" are actually ports for the satellite speakers with a passive soft dome covering the holes.
4) The 5" sub-woofer measures only 4.25" and its moving cone measures about 3".
It has bass and treble tone controls but has no transistors nor opamps to do it.
I measured the frequency response with my old ears and it works well from 40Hz to 18kHz.
I don't know which Chinese power amp ICs it uses. Since its actual power is much less than advertised then adding more gain might blow it up. I will not modify it.
It sounds great! It sounds great! It sounds great!