Another project, all digital DDX amplifier

[hifimediy]

Hi, everyone.
This is a new 2.1 channel amplifier project. It's a power DAC, directly input digital signal, no analog signal process before output to speaker.
In my plan, a mcu and HID like LCM, remote receiver and rotary encoder and so on will be added.
May be some of you have finished similar or anyone have better idea? Any suggestion will be valuable for me.
The design:

Test by wiring.

based on my AMT2050 v2 board.

 

[teamacc]

So basically the DAC replaces the TC2000 in the tk2050 board?
Could it be used with the new T3 boards too then?

Any chance you could include some analog input too, as most people that build such a amp would want to keep their ipods connected.

 

[hifimediy]

I call it AMu320, and the coming version will be 1.0.
It's a digital(S/PDIF) input and PWM output IC replace TC2000, and a mcu is added to handle the system, so it will be more interesting to use. I think T3 is a analog input class-T amplifier which is different.
We can add a ADC module to AMu320 to receive analog input.

 

[jtjy]

I call it AMu320, and the coming version will be 1.0.
It's a digital(S/PDIF) input and PWM output IC replace TC2000, and a mcu is added to handle the system, so it will be more interesting to use. I think T3 is a analog input class-T amplifier which is different.
We can add a ADC module to AMu320 to receive analog input.

dear sir, any idea when you are selling this board? sounds interesting to me

 

[teamacc]

So the chips used in the AMU320 are tp2050 chips?
If so, can the tc2000 of the t3 boards be cut out and replaced by the amu320 pwm converter?
That way, T3 will have digital input too.

 

[udailey]

A suggestion would be to offer in modules. Maybe I require 5.1 system or 5.3. Rotary volume would be a master and each module a slave. Subwoofer module would have adjustable gain, perhaps each has adjustable gain. Subwoofer module should be able to be hacked into to provide digital or active crossover.
Uriah

 

[Solve]

Great idea with 2.1!
Not many offers that possibility, modules as udaley say is even better!

 

[udailey]

Just read the STA320 intro on the datasheet. Nice choice as it already has capability for adjusting gain and frequency.

 

[hifimediy]

dear sir, any idea when you are selling this board? sounds interesting to me

I will make the first sample this week, but need more time to finish the software.

So the chips used in the AMU320 are tp2050 chips?
If so, can the tc2000 of the t3 boards be cut out and replaced by the amu320 pwm converter?
That way, T3 will have digital input too.

Right, remove the TC2000 and connect the signal from AMu320, you can do that.

A suggestion would be to offer in modules. Maybe I require 5.1 system or 5.3. Rotary volume would be a master and each module a slave. Subwoofer module would have adjustable gain, perhaps each has adjustable gain. Subwoofer module should be able to be hacked into to provide digital or active crossover.
Uriah

I think 5.1 will be a next project, a added decoder(support DTS, AC-3 etc.) is needed for 5.1 system, so will be more complicated than 2.1.

 

[Cyan]

So is the subwoofer out amlified, or just signal? If signal, does it have a crossover? And what crossover order?

 

[udailey]

APWorkbench from ST is free of charge. If you added USB capability to communicate with the chip, even us DIYers could put whatever crossover we desired into it. You would rule the DIY world

 

[SoldierAnt76]

APWorkbench from ST is free of charge. If you added USB capability to communicate with the chip, even us DIYers could put whatever crossover we desired into it. You would rule the DIY world

The board has a USB port, so this might work as long as the STA320 chip is compatible with APWorkbench. But most people will probably want to use the hardware-based crossover, since software adds another layer of complexity.

From the diagram, it looks like the subwoofer-out is amplified (100w). I'm not sure how well this configuration will work in practice, since quite a few subwoofers will need more power than that. It might be better to make the subwoofer output non-amplified (signal level), and use the second power chip to provide dual 100w outputs to the main speakers.

 

[teamacc]

The board is fully digital, so the sub out has to be connected to some chip that accepts PWM signal like stuff, like the tp2050 or the sta517b (chip from the T3 board).

I would love the moduled building

 

[SoldierAnt76]

The board is fully digital, so the sub out has to be connected to some chip that accepts PWM signal like stuff, like the tp2050 or the sta517b (chip from the T3 board).

I would love the moduled building

I'll second (third?) the idea of a modular solution, so people can mix and match parts according to their needs. Say, 2.1 and 5.1 audio controller boards, a variety of power stage boards (2x50w, 1x100w, etc.), and a front panel device. Add a selection of power supplies and/or transformers, and you've got a product line.

 

[udailey]

Check out what Hypex is doing
http://www.hypex.nl/docs/AS2.100/Manual AS2.100 V1.2.pdf
Page 11
Uriah

 

[Boss187]

Looks good! I reckon dont complicate things, make the 2.1 perfect, then release a 5.1 version at a later stage.

 

[hifimediy]

So is the subwoofer out amlified, or just signal? If signal, does it have a crossover? And what crossover order?

It has a 2nd-order low path crossover(soft configurable). This is a all-in-one and will drive subwoofer itself.

APWorkbench from ST is free of charge. If you added USB capability to communicate with the chip, even us DIYers could put whatever crossover we desired into it. You would rule the DIY world

Good idea. For this version usb is for audio only(USB to S/PDIF).
I add a LCM, and many configuration can be handle by diyer. but I still think your suggestion is very valuable.

The board is fully digital, so the sub out has to be connected to some chip that accepts PWM signal like stuff, like the tp2050 or the sta517b (chip from the T3 board).

I would love the moduled building

If working with T3, have to remove some chips and do some wire work.

I'll second (third?) the idea of a modular solution, so people can mix and match parts according to their needs. Say, 2.1 and 5.1 audio controller boards, a variety of power stage boards (2x50w, 1x100w, etc.), and a front panel device. Add a selection of power supplies and/or transformers, and you've got a product line.

yes. We seperate the front pannel now, and we can support STA505~STA517 on this board.

 

[teamacc]

It has a 2nd-order low path crossover(soft configurable). This is a all-in-one and will drive subwoofer itself.

Does it have a high pass filter too, for the other channels?

 

[hifimediy]

Does it have a high pass filter too, for the other channels?

The high pass filter is used for DC block, so the output DC offset will be very low(about 1mV in my test).
There is tone(Treble/Bass) and EQ controller can be used.

 

[kc7wdg]

I cannot wait to see it but I hope it isn't to $$$$ this is a hobby I save money to indulge in.