Silicon Chip is an Australia Electronics Magazine has just released their World first DIY high-power high-performance Class-D amplifier called “The Classic-D”.
It’s rated at 250W into 4ohms & 150W into 8ohms.
The magazine publish part 1 3 days ago, but their web site Silicon Chip still shows October issue.
Like with most designs/kits it pays to wait after part 2 the construction issue in case there’s any errata or changes to components due to availability.
I must say it looks like good project to sink your teeth in.
Normally Altronics and Jaycar Electronics are kit reseller and PCB’s and layouts from Silicon Chip downloads & online orders.
It’s rated at 250W into 4ohms & 150W into 8ohms.
The magazine publish part 1 3 days ago, but their web site Silicon Chip still shows October issue.
Like with most designs/kits it pays to wait after part 2 the construction issue in case there’s any errata or changes to components due to availability.
I must say it looks like good project to sink your teeth in.
Normally Altronics and Jaycar Electronics are kit reseller and PCB’s and layouts from Silicon Chip downloads & online orders.
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The protection circuit
Are talking about the dc offset which is monitored by Q7 & Q8, which goes through RC filter to remove the frequencies above 0.3Hz on the amps output, if it occurs it the mosfet short circuits and the IC1 can't shut down, the full supply voltage will be applied to the speaker.
So the backup optional speaker board kicks-in triggering the relay to break the connection between the failed module and speaker the two boards work in conjunction to protect the speaker, this my understanding as quoted the designer.
Are talking about the dc offset which is monitored by Q7 & Q8, which goes through RC filter to remove the frequencies above 0.3Hz on the amps output, if it occurs it the mosfet short circuits and the IC1 can't shut down, the full supply voltage will be applied to the speaker.
So the backup optional speaker board kicks-in triggering the relay to break the connection between the failed module and speaker the two boards work in conjunction to protect the speaker, this my understanding as quoted the designer.
I think I need a little help here.
Where are Q7 & Q8? ("...dc offset which is monitored by Q7 & Q8...")
The schematic of the "CLASSiC-D Loudspeaker Protector" shows protection from one polarity of catastrophic failure for two channels. This I can see...sort of.
What happens if the output transistor in the negative rail develops a short circuit?
With loud music (output greater than the 4V needed to turn on the opto-isolators) wouldn't the transistor outputs turn on enough to discharge the 4.7uF capacitor through the 1K resistor faster than the 100K resistor could charge it back up?
This could be a great SPL limiter.
Where are Q7 & Q8? ("...dc offset which is monitored by Q7 & Q8...")
The schematic of the "CLASSiC-D Loudspeaker Protector" shows protection from one polarity of catastrophic failure for two channels. This I can see...sort of.
What happens if the output transistor in the negative rail develops a short circuit?
With loud music (output greater than the 4V needed to turn on the opto-isolators) wouldn't the transistor outputs turn on enough to discharge the 4.7uF capacitor through the 1K resistor faster than the 100K resistor could charge it back up?
This could be a great SPL limiter.
There is a schematic of the dc protection circuit missing from the op. the dc protection is very conventional and should work just fine.
The design seems to be close enough to the reference design from IR. There are some additional details and measurements in this PDF: http://www.irf.com/technical-info/refdesigns/iraudamp7s.pdf. Same with no SMD components: http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
I have had that for some time, and it does sound nice. I use it with a Hypex SMPS400A180.
I have had that for some time, and it does sound nice. I use it with a Hypex SMPS400A180.
An interesting part of the reference design is its scalability. The reference design documents discuss in detail how the same schematic and PCB can be used to build a 25W, 60W, 125W or 250W (into 8ohm) amplifier. The principal difference is the rail voltage (from 2x25V to 2x70V), which requires right power FETs and some other minor adjustments. This means that the SiliconChip design can easily scale up or down as well.
Yes the scalability is a good feature, designed to operate in the range of +/-40-60V.
A supply of +/-57V will produce 150W into 8ohm & 250W into 4 ohm with THD of 1%, but the filter capacitors used are only rated 63V which gets close or past that value with mains variation.
The another feature, is to bridge two modules to get 500W into 8ohms and run them of one of single supply with a transformer rated at 500VA or more.
If you add mosfet gate drivers you can get well over 250 watts.
I have a design that will output 750 watts into 2 ohms.
I use the TC4420 mosfet gate drivers with 2 pairs of irfb4227's.
I have a design that will output 750 watts into 2 ohms.
I use the TC4420 mosfet gate drivers with 2 pairs of irfb4227's.
Mosfet gate drivers
Hi Nigel, can you post a schematic of your circuit?
Interested amps that can drive difficult speakers with low impedance.
Hi Nigel, can you post a schematic of your circuit?
Interested amps that can drive difficult speakers with low impedance.
ITS JUST THE APPLICATION NOTE CIRCUIT WITH tc4420 GATE DRIVERS.
I ALSO SCALED THE OVER CURRENT VOLTAGES TO GET MORE POWER.
D-Class Kit for Sale
Altronics have the kits in stock. Selling for AU$69.95 complete one channel less power supply.
Altronics - K5181 Classic 250W Class D Audio Amplifier Kit
Altronics have the kits in stock. Selling for AU$69.95 complete one channel less power supply.
Altronics - K5181 Classic 250W Class D Audio Amplifier Kit
Whilst it's nice to post what we see on the forum, this is the parts forum - why not post it in the Class D forum?
The other no-no is that this is copyright material from recent magazine issues! Guys, there are definite rules about that.
The other no-no is that this is copyright material from recent magazine issues! Guys, there are definite rules about that.
Follow up
Originally I posted it under Class D section, but due to the copyright images the Web-Master move it to the parts section.
I've order two kits, and hopefully if I've receive them early 2013, I can start the building the project and post the result.
Originally I posted it under Class D section, but due to the copyright images the Web-Master move it to the parts section.
I've order two kits, and hopefully if I've receive them early 2013, I can start the building the project and post the result.
Just built one of these little buggers, assembling the power supply tomorrow.
Its going to be the bass amp for my computer amp. (5xLM3875) and this Class D module.
Got a 2x10inch sealed sub enclosure already built (4ohms total). I expect lots of boom 🙂
I am not using the speaker protected for this module, but making one using arduino. It will also control soft on, remote on / auto power on/off.
Its going to be the bass amp for my computer amp. (5xLM3875) and this Class D module.
Got a 2x10inch sealed sub enclosure already built (4ohms total). I expect lots of boom 🙂
I am not using the speaker protected for this module, but making one using arduino. It will also control soft on, remote on / auto power on/off.
This is true. You just have to change a few resistors and zener diodes to get the different operating voltages.
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