You need a soft start to limit the transformer start up current.
If you plan to fit secondary fuses you MUST CHECK the output offset if ONE, or other, fuse ruptures.
That may demand a speaker protection system.
If you plan to fit secondary fuses you MUST CHECK the output offset if ONE, or other, fuse ruptures.
That may demand a speaker protection system.
How do achieve a soft start? If I could do that then maybe I can get away with a 2A or 1.5A fuse? Or maybe a 1A fuse?
your 300VA on a 110/120Vac supply would normally need a T3A fuse, but may run on a T2.5A fuse because you will not be drawing much power. It might even run on a T2A fuse, but I think that would be unreliable.
Read all about soft starts on this Forum. And use a proper timer. Not an RC that may, or may not, trigger on very variable mains supply.
Read all about soft starts on this Forum. And use a proper timer. Not an RC that may, or may not, trigger on very variable mains supply.
Are any of the following good locations for speaker terminals? Does it matter how close they are to AC main? IF not, I prefer the first one, to allow more room for taller and wider heatsink later on. EDIT: Actually the third one would work fine as well becasue I don't think I need taller.. I just might add 3/8" thick aluminum bar to the heat sink between the chip and the heatsink.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Any of those will work.
Leave enough room between terminals to insert spades or wire ends. And twisted pairs are resistant to emitting & receiving interference.
What about Speakon sockets?
One hole supplies both poles of a speaker.
Leave enough room between terminals to insert spades or wire ends. And twisted pairs are resistant to emitting & receiving interference.
What about Speakon sockets?
One hole supplies both poles of a speaker.
Any recommendations of gauge of wire to use and whether I should use solid core or stranded for:
1) dc supply to amp boards
2) internal speaker output wires
1) dc supply to amp boards
2) internal speaker output wires
I actually have 4 wires coming from dc supply board:
+ve, -ve, ground for +ve and ground for -ve.
Should I braid the 4 of them together as one?
or since they each have thier own ground, twist them in pairs and run in parallel?
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Hi Jennifer,
I also love to recycle old equipment.
My headamp ended up in an old computer tape backup case see here.
Keep up the good work!
Cheers,
Jacques
I also loved to recycle or make my own chassis - I even made my own steel brake brake.
But then i found these
Steel Enclosure Half Shell, Black, 250 x 200 x 70 mm from Conrad.com
But then i found these
Steel Enclosure Half Shell, Black, 250 x 200 x 70 mm from Conrad.com
Cool what is a Brake Brake? What all have you made with those conrad enclosures? They look pretty nice.
post number 1149
http://www.diyaudio.com/forums/class-d/87913-class-d-amp-photo-gallery-23.html
This is made with my simple metal brake ans some aluminium sheet (white on one site). The total cost is a little less, then the cheap steel enclosure in the other link from conrad.com. But you save the freight.
http://www.diyaudio.com/forums/class-d/87913-class-d-amp-photo-gallery-23.html
This is made with my simple metal brake ans some aluminium sheet (white on one site). The total cost is a little less, then the cheap steel enclosure in the other link from conrad.com. But you save the freight.
Here is a brake. You can make one much cheaper if you have some ordinary tools
36" Sheet Metal Bending Brake Bender Aluminum Steel Trim 30 Free Shipping | eBay
36" Sheet Metal Bending Brake Bender Aluminum Steel Trim 30 Free Shipping | eBay
My brother had a scrap piece of aluminum bar and machined it to the dimensions of the heatsink. The heatsink is plenty thick enough now 🙂
Don't braid them.
Twist them for smallest loop area.
Consider one supply.
If it has +ve , Zero Volts and -ve, then twist all three as a triplet.
Minimise the loop area at the terminal connections.
Repeat for the other supply.
It's all about surface area not thickness. It will probably cool a bit worse than without the extra aluminum. It depends on how efficient the heat transfer is between the joints
I agree, there is a risk this solution will be worse than without.
I explained that in an earlier post and gave amethod that is more likley to improve on the added plate.
But she has ignored that advice.
I didn't ignore it. You said yourself it would be a bit tricky to implement yourself.. the bar over the top of the chips. I agreed and didn't do that.
The transfer between the heatsink and the bar is actually quite good. They were both machined perfectlly flat and there is thermal compound between them, with six bolts holding them together! BriantGT from chipamp.com said that aluminum bar itself was enough for these chips. Now it has fins as well AND ventiliation from the bottom and top with airflow between the vent and bar. I think it'll cool quite sufficiently./
I'll find out tomorrow how well it works, will have it up and running by then.
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