| Jean |
I just read many threads and couldn't find what I needed. I am looking for heatsinks that I can order from Digikey (thats where I am ordering my irfp9610s and zeners from) that will fit BrianGT aleph 2 boards.
Thanks ! |
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| Jean |
| Will vertical mount 294-1034-nd or 294-1024-nd fit ? Trying to locate something that will fit right in on the board w/o getting in the way of other components. |
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| BDP |
I believe the digi-key number that would work is HS107. My voltage rails were -\+ 33 volts. As you can see the differential pair didnt need heatsinks.
BDP |
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| moe29 |
i don't use heatsinks for the 9610's on my Aleph 2 at all...
guess it just depends what you are comfortable with. |
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| jwb |
| None of those transistors need heatsinks but you may get better performance if the diff pair is thermally coupled on the same heatsink. |
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| Jean |
I went ahead and ordered 20+ small heatsinks from digikey, maybe a few will match and fit good on the board.
Thanks! |
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| Brian Donaldson |
I used a peice of L extrusion to connect diff pair. Small whatever for ccs from surplus shop
The chokes started to stink. They were replaced with big 2 ohm resisters. |
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| nbaula |
| HI! Brian I see that you did a good job doing the point to point connection of the CCS and the output FETS. How did you connect the CCS and the output FETS ( Source of the CCS to the Drain of the output FETS ). Thank you for your'e input . |
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| Brian Donaldson |
They connect on the board through the 12 ga yellow wires.
Here's a better pic of point to point with the turret terminals Mark Gulbranson ( I hope i didn't butcher his last name too badly) used on his Aleph 2
OOps, That was the wrong pic. Here I'm swapping blown fets. They are sooooo sensitive to static without the rest of the circiut. |
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| nbaula |
| H! Brain is you're driver board from Dale's group buy, if so please help me understand. Refering to Kristijan site (http://web.vip.hr/pcb-design.vip/) there are six FET output and CCS , The CCS FET ( source is connected to a one ohm resistor )to the output FET( Drain). These connection is only connected by that yellow wire am i right? |
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| Brian Donaldson |
Correct. All 12 fets (6 via source resistors) all connect together through the yellow wire in Dale's Aleph boards. I added a peice of 12 ga solid copper wire over the trace that connects the sources on one side to the drains on the other.
I was after a little more power, so I have 16 fets and .68 ohm source resistors to give around double the bias barring ang other component changes. I also installed a pot for r19 to adjust the bias. |
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| tomchaoda |
| quote: | | The chokes started to stink. They were replaced with big 2 ohm resisters. |
Brian:
Can you elaborate a little bit about this? I thought the CLC is always the better way to reduce the AC ripples!
Thomas |
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| Brian Donaldson |
But it's hard for a choke to dissapate 50 watts and not self destruct. They had a little over 2 ohms resistance and 5A flowing through.
I've been toying with the idea of using a source follower Zener diode regulator like the zen preamps(I don't remeber which one). but since the amps pull a constant current, the resistor will do for now.
I Know I'm a dumb *** some times. I thought that since they were air cores, they couldn't saturate. But I forgot to consider the ESR would mean 10v drop at 5A. |
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| Jean |
| Brian, what ga inductors did you use ? I plan on using Solen 14ga inductors. |
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| nbaula |
| Thanks!Brian I think I understand it now. |
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| Brian Donaldson |
| I Think they were 16 ga. I remeber thinking "yea, 16 ga can carry 6 amps, no problem. The problem is 100' if 16 ga rolled up so there is no surface area exposed to the air for cooling. I would guess that you need to see less than .75 ohms or so to keep the temp down in the core. I also would not recomend home wound units because the layers are not rolled tight enough to cunduct the heat from the middle layers to the surface. Or maybe pot them in some thermally conductive epoxy to a heat sink? |
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