Class D amp module build, silly power...

[Reid Malenfant]

Well as i posted in the Class T thread earlier i received the pair of silly power class D modules in kit form, the only thing that was kind of put together was all the small diodes (1N4148, 2 x 5v6 zener diodes & 1 x 15V zener) were pre fitted to the PCBs but not soldered. They do look alike & the text on each component is tiny - so i hope they got it right

As i really want to get to hear what these things actually sound like i proceeeded to start assembling them in short shift These things are tiny, it just doesn't make a lot of sense in all honesty... Each one is more than capable of over 200W RMS with a 8 ohm load on it's own or 400W RMS with a 4 ohm load They just need a big PSU

If bridged this equates to 800W RMS 8 ohm load, they won't like 4 ohm bridged as the power mosfet (two in one die) won't be able to handle the current... But i tell you this is still mad as you are about to see, i have seen bigger 10W amplifiers

Ok, here is one of the PCBs as received with fitted diodes.



Thanks to MartinT for a rather sensible suggestion of a blob of glue on the bottom of the control IC, ok i didn't go with that but it gave me the idea of holding it in place with good old selotape Cheers Martin notworthy.gif I soldered the leads at both ends on this side & then removed the selotape to do the opposite pins... Then did one at a time to allow the poor thing to cool down, it never felt warm - good news



Now you really have no idea how to gauge scale here so here is a pic of the control IC & my shaky soldering next to a £1 coin, yep these things are kind of small



Where i am now before i had a phone call & vistit from a friend, nearly all resistors fitted. The second PCB is in the same state, so it looks like i'll be carefully initially testing one or both amplifiers this coming weekend, well i'm hoping at least lol..



I'm fairly sure i have a nice big fat toroidal transformer (from a Pioneer 120W RMS 8 ohm channel) that should be ok with these PCBs, though i'll check as the voltage will be at the top of the range & possibly marginal. Initial testing will be done with a much lower supply voltage & with resistors in both + & - rails to restrict current incase something is up. Once all has been established as well with both amps they can be connected to the big supply

More coming shortly...

[MartinT]

Very nice so far, Mark. Keep us informed

[MartinT]

Very nice so far, Mark. Keep us informed

[John]

looks like fun...enjoy

[biggzy]

Looking great, will keep an eye on this thread, maybe in 10 years time i will be at this stage of doing DIY hi-fi, that board looks so small for the amount of power it will push out, what case you putting these into Mark?

please keep post updated with pics as this not only looks great/cool but also learns us noobs a thing or two.

Will be nice seeing the final working product

Adam.

[Reid Malenfant]

Looking great, will keep an eye on this thread, maybe in 10 years time i will be at this stage of doing DIY hi-fi, that board looks so small for the amount of power it will push out, what case you putting these into Mark?

I guess one that is big enough for the power supply Honestly the amps are tiny, while i'm sure that the heatsinking is also adequate for general musical listening i'll be fitting a nice fat right angled alloy bracket to the power mosfet & attaching this to a reasonably sized heatsink

You see what they don't tell you is that conduction losses increase with the mosfet die temperature as the resistance of the mosfet (RDS on) increases. Keeping it cool will yield more power & higher reliability at the end of the day

At a guess both amplifier modules & PSU could be fitted into a case a little bigger than one of your Teac amplifiers No kidding...

[biggzy]

I guess one that is big enough for the power supply Honestly the amps are tiny, while i'm sure that the heatsinking is also adequate for general musical listening i'll be fitting a nice fat right angled alloy bracket to the power mosfet & attaching this to a reasonably sized heatsink

You see what they don't tell you is that conduction losses increase with the mosfet die temperature as the resistance of the mosfet (RDS on) increases. Keeping it cool will yield more power & higher reliability at the end of the day

At a guess both amplifier modules & PSU could be fitted into a case a little bigger than one of your Teac amplifiers No kidding...

That sounds good, really can't wait to see the end product now, that sort of power in such a small box is mad, now i don't understand why most the hi-fi companies still produce 43cm wide units when we could have nice small units with huge power and great sound.
how long do these kits take to build mate?

Adam.

[Reid Malenfant]

About 6 hours if you know what you are doing to build a pair, maybe less.. It's the control IC that is the pain to solder as it's tiny as you can see compared to that £1 coin

This is the first time i have tackled them as well, given practise (that i'm not likely to gain) 4 hours might be realistic to build the modules.

No idea what they sound like, but i'm hopeful which is why i decided to buy them I just couldn't be doing with 20 or 40W, i want realistic volume levels so these caught my eye, as well as that looking at the specification it looks like a realistic power level to given the possible supply voltages. Can't say the same for some of the stuff i have seen out there

[Mark Grant]

Looks fun and they must be really small looking at the size of the pound coin.

Another tip to hold components in place such as the chip is PVC insulation tape as it peels off easier than sellotape or try a blob of blutac, allows easy repositioning before soldering.

[Butuz]

Looks like a real fun project!!

I do have one q though - if you are using 120w transformer how can you expect this to supply 200w?

Butuz