[SoundDouble]

This is for those of you, like myself, that are starting to build a home system piece by piece and don't want to spend a bunch of money up front on a part you're going to get rid of.

So this is probably one of the cheapest setups available, courtesy my best friend the thrift store.

Recently got a pair of JBL speakers, simple full range 4 1/2" driver, for $6. I have an audio-technica record player $99 and needed an amp to complete the system.

It then dawned on me that these bose companion 2 series 2 active pc speakers I got at the thrift store $25, have an amp inside. So here comes the tools.

I chopped off the front panel, because the only screw was in the back holding the rca connections. Pulled out the sound absorption material and 2.5" speaker. Soldered maybe 3ft speaker wire for the right channel and connected my JBL.

Turns out the bose speaker goes on eBay for $10-$30. Has a class a-b amp ~30w, and a headphone amp(w/ automatic switch) possible of 70mA into 150ohm.

BTW everything will be replaced/modded in the near future.

 

[SoundDouble]

This is what the bose speakers looked like inside the companion 2 housings.



Had a some weight for the size but probably cause the shielding.

Apparently similar circuit design to bose car amps. Same proprietary eq chips and a-b amp.

 

[SoundDouble]

So heads up on the progress.




For all the engineers and guys that mess with things like myself. It has:

TDA7377 for the power amp
4556AD for the headphones
And 3 TL072CN

Already got some TI2072, and 2068DD to try out. Just waiting on the sockets.

Eventually I'll make a box and maybe take the components I want to keep to do a completely different amp.

 

[SoundDouble]

Sockets came in.

Swapped out the TL072 for the 2068 on speaker preamp side and seemed a little warmer, but there was oscillation/audible noise at about 3/4 volume. Must need more filtering.

Then swapped the tl072 for the TI2072. And no noise/oscillation. Sounds a little more shimmer. Supposedly direct upgrade part for part. Higher slew rate, lower thd, higher bandwidth.

I also did some swaps on the headphone side but I need more revealing hp to tell the difference.

Any suggestions, been looking at the opamp thread also?