TWF6 desktop speaker

[tomzarbo]

Looking Good!
I'm jealous of your woofer recess, that's nice.

TomZ

[dirtbike]

I thought I should finish this build diary, so here are some more pictures and details.

[dirtbike]

Base module for the Bluetooth amp, batteries, charger, and battery status panel.

[dirtbike]

Front panel battery monitor display and ON/OFF

[dirtbike]

Bluetooth amp
Volume control

[dirtbike]

The finished base with all the parts fitted - a bit tight!

[dirtbike]

Schematic of complete speakers.

TWF 6 speaker schematics.pdf

[dirtbike]

The finished speakers, taking pride of place on my desk.

[djg]

Nice results, nice documentation, thanks.

[tomzarbo]

They're beautiful. That's some next-level engineering going on there in my opinion. I'd botch the electronics in that all up guaranteed. I especially like the integration of the electronics into the bases. Nice work!

You've nearly doubled the interior volume, I wonder how do they sound?

TomZ

[3rutu5]

Pride indeed, they look great. are you charging them off USB?

Edit, i completely forgot you already answered the USB thing. I would be keep to know how you managed to do this as i've heard mixed outcomes about overloading a wall wart which can cause a short\fire etc. I really want to do somethng similar with an upcoming 2 builds so very very keen to know how you did it.

[Wolf]

A couple queries...
Shouldn't you have current limiting resistors on the LEDs? IME, even being a low draw at 5V will overcurrent them. I blew 2 sets of LEDs over this learning experience.
I see you have amplifier outputs labeled as HP +/- and LP + and HP - in the schematic.
So, you are biamping the drivers, and using a passive xover. Why did you go this route over DSP/active solutions? Just curious...

You clearly know more than me about the active side of electronic things to do this, so please correct me if I'm wrong.

Looks great!
Wolf

[randyohoh]

Red. Orange, yellow, & yellow-green LEDs need 1.8 - 2 volts while white, blue, and deep green LEDs need around 3 volts to light them up. These small LEDs can only handle 10 - 20 mA of current and the higher the voltage supplied the more current the LED will draw. Running a 2 volt LED at 5 volts will fry the LED, it's only a matter of time and it could be within seconds.

[wogg]

Red. Orange, yellow, & yellow-green LEDs need 1.8 - 2 volts while white, blue, and deep green LEDs need around 3 volts to light them up. These small LEDs can only handle 10 - 20 mA of current and the higher the voltage supplied the more current the LED will draw. Running a 2 volt LED at 5 volts will fry the LED, it's only a matter of time and it could be within seconds.

This

I'll add explanation. A diode, LED or any type is effectively a near short circuit above it's threshold voltage. A current limiting resistor is 100% required in series with the diode. The current the diode will see is calculated by (applied voltage - diode junction voltage) / Series resistor. Target ~10mA for that current based on whatever input voltage you apply.