Another (my first) Class D DIY amp

[babadono]

59 minutes ago, CECAA850 said:

The PS starts to de-rate at 105 F.

Please point me to data. I see that it has Over Temp Prot. on main power switch(transistor) which will supposedly shut it down and recover automatically.....we'll see.

[CECAA850]

24 minutes ago, babadono said:

Please point me to data. I see that it has Over Temp Prot. on main power switch(transistor) which will supposedly shut it down and recover automatically.....we'll see.

See the de-rating curve at the bottom of the page.

 

https://www.meanwell.com/productPdf.aspx?i=469

[babadono]

Thanks. That's just a warm day here in Murrieta.

And this is with the fan operating I would have to assume.

[CECAA850]

9 minutes ago, babadono said:

Thanks. That's just a warm day here in Murrieta.

It's a dc fan.  Should be nothing to replace it.  You could throw a resistor in line also and slow it down if you didn't want to swap it out.

[babadono]

You're Mister Magic or I am blind. It's a DC fan? Did you already take one apart? Ok finally I see it--at the top in "features". You know sometimes those lie

 

[mike stehr]

On 7/1/2020 at 7:49 PM, mike stehr said:

After borrowing/listening to a Schiit Loki for a week, I'm going to purchase a Loki for my TI 3255 eval board.

I'm using a SYS passive volume control at the moment.

 

I bought a Loki...

Having a tone control with some slight gain in combination with the passive volume control, sounds rather good to my ears parked in front of the 3255 eval board.

 

I listen to compact discs. It is nice to use the tone controls to add a bit of bass to dead CDs, or tip up the top-end a bit. Or turn down overblown bass CDs, or turn down a hot top-end. Some CDs can't be helped...

The tonality of the 3255 eval board with my speakers when just using a passive volume control, (between CDP and amp) has a overall dark sort of sound while having lots of resolution and black background. The Loki takes nothing away from the black background and high resolution, and adds a bit more open sound to the overall tonality.

 

I'll always prefer my 2A3 DHT SET amp, and my Altec 345A EL34PP amp, but this set-up is a daily driver...

Sorry about the dust...need to do some housekeeping...

[CECAA850]

21 hours ago, babadono said:

You're Mister Magic

You can call me Mr Copperfield.

[babadono]

Got into the amp and then into the P.S. last night. Disabled(unplugged) the fan. Ran it lid less, with the top down as it were but only for about 5 minutes at moderate volume. Heatsink in P.S. was still at ambient it seemed like to my touch. I had/have no way to measure temp unless I take some equip. home from here at work. I think I'll remove the fan and see if an exact size but quieter is avail. Meanwhile button it back up fanless and see how it goes.

[CECAA850]

On 8/7/2020 at 6:49 PM, babadono said:

. I had/have no way to measure temp unless I take some equip. home from here at work. 

You dont have an infra red temp gun at the house?  They're cheap and handy to have around.

[babadono]

No I font

[babadono]

On 8/7/2020 at 8:33 PM, CECAA850 said:

You font have an infra red temp gun at the house?  They're cheap and handy to have around.

Are you talking about the kind like the one that I have to point at my forehead everyday when I come to work?

[CECAA850]

1 minute ago, babadono said:

Are you talking about the kind like the one that I have to point at my forehead everyday when I come to work?

Something similar to THIS.

[Pete H]

20 hours ago, CECAA850 said:

Something similar to THIS.

That's one that I have and has been very accurate and really cheap.  Not to be confused with the ones that take your temperature as they typically don't have the range you need. 

[babadono]

So I finished up a meter(as promised) and metering circuit for this amp. Its pretty cool. Wish I could post a short vid of it in action. Its based on China acquired 60 led per channel bar graph type meter. I added the driving circuitry for it and a 4 position sensitivity switch. So full scale on the meter can be 0.1W, 1.0W, 10W or 150W. (into 8 ohms)

With the 10W sensitivity selected and the meter pretty active it is hard to stay in the same room

[babadono]

On 7/21/2020 at 5:18 PM, babadono said:

This is my first Class D amp, so let me ask this. I see about 2 volts peak to peak signal @450 kHZ with no signal being output. This is the residual switching frequency that makes the amp work? Or is my amp really screwed up?

OK so this maybe in the "you get what you pay for" column. Because I now have another commercial Class D amp on my bench. It is a Crown K2. I see no or very little residual switching noise on the output of this beast.

And man this thing is a beast, so far I've had it putting out 400w RMS into 4 ohms both channels and it is not even breaking a sweat.

[CECAA850]

35 minutes ago, babadono said:

OK so this maybe in the "you get what you pay for" column. Because I now have another commercial Class D amp on my bench. It is a Crown K2. I see no or very little residual switching noise on the output of this beast.

And man this thing is a beast, so far I've had it putting out 400w RMS into 4 ohms both channels and it is not even breaking a sweat.

That's what I use on my 686 sub.  One channel per driver.