Talk about cold hearted killer amp (when its OFF). If the amplifier with these boards installed is ON, the boards then becomes warm, is the heart then considered to be alive? What happens when the amplifier is off, is it cardiac arrest ? (maybe I should have punctuated it with a "," coma, get it?). Will it need Atorvastatin as it aged?
Very nice boards ElliJ with a tasteful personal touch! Congrats!
Very nice boards ElliJ with a tasteful personal touch! Congrats!
Thanks for all the positive comments. Just finished the second board, need to give them a clean and I was short of a 221ohm resistor (I know, who doesn’t have a few of those lying about!). I used lead free solder because I am messy and have a kid and pets, not quite as easy as leaded. I will post more when I get them mounted on heatsinks (300x150x83).
Hi,
I have 2 questions:
1. For the MOSFETs of the Aleph J, what is the exact insulator (or dimensions) needed? Is it TO-3P?
2. I noticed that the orientation of the Aleph J PCB, when mounted, is that the MOSFETs are on the bottom (lower) side of the board when installed. I understand that for the DIYstore chassis such as 4U/5U/etc, it is because the mounting holes are oriented as such.
My question is:Is there any problem if the PCB was mounted the other way around or inverted (the MOSFETs are on the top/upper side of the board when installed) ? I am thinking that this might be a better orientation to better hide the power wires at the bottom of the chassis (hidden) since the power wires will be situated already at the bottom
I have 2 questions:
1. For the MOSFETs of the Aleph J, what is the exact insulator (or dimensions) needed? Is it TO-3P?
2. I noticed that the orientation of the Aleph J PCB, when mounted, is that the MOSFETs are on the bottom (lower) side of the board when installed. I understand that for the DIYstore chassis such as 4U/5U/etc, it is because the mounting holes are oriented as such.
My question is:Is there any problem if the PCB was mounted the other way around or inverted (the MOSFETs are on the top/upper side of the board when installed) ? I am thinking that this might be a better orientation to better hide the power wires at the bottom of the chassis (hidden) since the power wires will be situated already at the bottom
Thank you for your reply.
"best place for mosfets is 1/3 of height, looking from bottom of hsink"
- Is there any practical/technical reason for this? Is this heat (transfer) related?
Isn't it "hot air tends to rise"?
But with the MOSFETs directly attached to the heatsink, shouldn't the "absorbed" heat of the MOSFETs scatter at all directions in the heatsink (equilibrium)?
I'm a bit confused 😀
just believe in said
plenty of places on internet where you can find hard-backed data and info, no reason to include it here
EUVL published his article in Linear Audio, for instance
plenty of places on internet where you can find hard-backed data and info, no reason to include it here
EUVL published his article in Linear Audio, for instance
Yes, look up heat sink conduction and convection. Heat sink orientation and natural or forced air convection make a difference. The one third placement is for natural convection and vertical fin oriented heat sinks.
I like pics of FW assembled channels, in dozen layin' on the shelf
doesn't matter did I seen it or dreamt
doesn't matter did I seen it or dreamt
A bit further with my build. Drilled and tapped one of the heatsinks, surprised at how un-square my drilling is but it was good enough. I got 300x100x83mm heatsinks 0.12c/w. I am waiting for spring washers and slow blow fuses.
I wish the ModuShop would include better heatsinks (your heatsink looks nice 🙂) with their cases... I find ModuShop heatsinks minuscule, compared to the size of the cases.
My heatsinks were about £70 each. I’m just going to bolt the top, base, front and back to my heatsinks to create the case. It took me a while to find them and they should be able to passively cool my amp easily.
I have been putting off powering up my boards but this afternoon I did. I assembled a quick psu, used a 1.25amp fuse and went for it. I switched it on and absolutely nothing happened, no lights, no smoke but then after a couple of seconds it lit up. The bias was a bit high 0.85 and the offset was 250mv. I set the bias to 0.5 and adjusted the offset and it seems pretty stable, I only ran it for 5 minutes. I am very happy even though I have not listened to it yet. As this is my first amp build and pcb layout I was not that confident it would work. My amp will have an external psu connected using a Speakon power connector, only xlr inputs and Speakon outputs.
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I ran one of my boards for an hour with the bias at 400mv and the heatsink was at 49c. I have to tap my other heatsink to test the other board. I have ordered the metal and paint for the case so I have no excuses to finish this project and listen to something.
My external psu is a 500w llc soft switching smps. I am going to have 3 CL60 thermistors in my grounding, I hope this looks ok?
My external psu is a 500w llc soft switching smps. I am going to have 3 CL60 thermistors in my grounding, I hope this looks ok?
nope
common PSU for two channels means Common Audio GND for two channels
means no NTC in channel ground leads, just one between Audio GND and Safety GND/Case
even in dual mono setup, NTC is having place only between Audio GND(s) and case
common PSU for two channels means Common Audio GND for two channels
means no NTC in channel ground leads, just one between Audio GND and Safety GND/Case
even in dual mono setup, NTC is having place only between Audio GND(s) and case