Are you interested to improve cheap amplified speaker?

[destroyer X]

These toys are around costing 20 USD or less... and offering MP3 player reader and encoder.... accepting pen drives, SD and MMC inputs, line inputs (stereo), FM radio receiver and playback equalizer (6 preset position).

Radio is sensitive, has more than 23 memory positions, manual adjust and frequency scan.

So, a cheap thing that can be improved having a simple Dx Amplifier, the old standard one simplified to use darlington output transistors...a small supply included in the stereo pcboard...all in one board, to be installed internally into these popular toys.

I know the modifications needed and i can develop and test the project myself depending forum friend's interest on that stuff.

We can install plugs to external speakers and pump out more than 20watts RMS each channel, to 8 and 4 ohms speakers having distortion smaller than 0.1% THD (0.039% at 10 Watts RMS - 8 ohms).

I can provide prototype tested, schematic, layout and help people to modify (not publishing the modifications into the Chinese toys in order to avoid them to copy)....but i will explain directly to you how to make these modifications.... in confidence.

The amplifier layout and schematic opened to whole world.....except gerbers.

This way we can use them to our own purposes instead to be used by them....they make and we go improving without let them know the tips and tricks.

I have tested something....with secret modifications i have matched (almost) the Ipod sonics (reasonable)...Here you see:

Everything sounds good with a Dx amplifier - 1 - YouTube

I will look forward by your opinions, support and interest... please publish what you think about....the idea is a super cheap system built by you, using Dx Amplifier to our fun and enjoyment and to give one on pirates.... you know.... let them feel what we are feeling because of them.... now we copy....we use...we pay cheap and we make it better!

I can put the "Corporation" guys in movement to make this come true.

regards,

Carlos

[destroyer X]

And you can see them here:

destroyersoueu's Channel - YouTube

regards,

Carlos

[Jay]

Do you mean everyone must buy the same amplified speaker to work with? Doesn't sound like a good idea, unless for local project.

A small module capable of processing various input (including radio) is common. Costs around $10. I have worked with cheap things like these and the sound quality was not as good as I wanted it, of course

If big size is not an issue (adding a DX amp will increase the size anyway), a cheap DVD player is a workable DIY alternative. They consists of (usually) switching supply that should be replaced with transformer based supply and a mainboard with MPEG/DSP. Some have USB capability (which requires additional 2 ICs if not yet supported). I think certain decoder can accept modification for additional input type (Mine is a robust CS98201).

For small speaker desktop system, a blameless amp is too big. 10W is more than enough, and I prefer the John Broskie-McAulay 12W Opamp Darlington amplifier.

[destroyer X]

modification can be done in one model and will he good for all models...there is clearance, room, internal size to install a Dx amplifier (or other) inside..also the power transformer.

I have not the idea to use the MKIII Hx...it was the one available to test purposes...of course it can melt the small speakers you have inside.... the transformer will not fit the box....this means to install the Titanic inside a beetle car...no way..this is not my idea.

Any amplified speaker that has this size (several models available) will fit....all then have the same circuit board inside.

I have already developed a simple Dx amplifier, made to 10/20 watts RMS with small distortion, using darlington output (avoiding chips the sound became better as we do not have the several troubles IC construction have).

About Audio Integrated circuit issues i can write a book...or two books...but this is not the subject here...i am sure discrete has better performance..this is based in the technology used to make integrated circuits.

Thank you by your opinion... despite i disagree, i respect and was helpfull to start some discussion about the stuff.

regards,

Carlos