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Chinese MiniPA-100 Kits
- Thread starter Rick Miller
- Start date
Hello Rick. I really appreciate the info and images which make perfect sense and are totally clear. I do apologise for it taking up your time. These things always seem to take longer than we expect unfortunately.
Your help has been amazing. I very much look forward to building my units. I have ordered what appears to be a suitable heatsink from china - nicely oversized !
and also one locally to give me another option.One last question if I may ?. Are you connecting the main PCB directly to the heatsink or are you using some form of insulation between the underside of the board and the heatsink ? (not the PA - the actual PCB) The reason I ask is that although the traces that are non GND are coating in some kind of white substance, I am not sure of the insulating properties of such. It does seem fairly resilient material but I would be interested to know your thoughts.
Thank you again. 73 DE G4XRZ - Joe
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The PCB should mount directly to the heatsink. The white masking on the bottom of the PCB should insulate just fine. I've heard others have tried to add a bit of insulating material only to discover oscillations. I suppose if you're worried about it you could use some nail polish to thicken up the masking, but I've not had any issues with this.Hello Rick. I really appreciate the info and images which make perfect sense and are totally clear. I do apologise for it taking up your time. These things always seem to take longer than we expect unfortunately.
Your help has been amazing. I very much look forward to building my units. I have ordered what appears to be a suitable heatsink from china - nicely oversized !
One last question if I may ?. Are you connecting the main PCB directly to the heatsink or are you using some form of insulation between the underside of the board and the heatsink ? (not the PA - the actual PCB) The reason I ask is that although the traces that are non GND are coating in some kind of white substance, I am not sure of the insulating properties of such. It does seem fairly resilient material but I would be interested to know your thoughts.
Thank you again. 73 DE G4XRZ - Joe
Thanks Rick.
I may put a very piece of Kapton on the non GND tracks only. (the white coated parts). The Kapton is incredibly thin.
I can imagine people using small heatsinks having issues with thermal transfer from sink to PCB / components. The heatsinks they show in the images on ebay / ali etc are crazy small though. The ferrites can have quite varying properties with differing temperatures, The temperature variations from an adequate heatsink should definitely not cause an issue but some places are selling these units on a heatsink the size of the PCB ! - yikes !. That will certainly cause many issues only one of which is ferrite stability.
Many thanks again.
Joe.
I may put a very piece of Kapton on the non GND tracks only. (the white coated parts). The Kapton is incredibly thin.
I can imagine people using small heatsinks having issues with thermal transfer from sink to PCB / components. The heatsinks they show in the images on ebay / ali etc are crazy small though. The ferrites can have quite varying properties with differing temperatures, The temperature variations from an adequate heatsink should definitely not cause an issue but some places are selling these units on a heatsink the size of the PCB ! - yikes !. That will certainly cause many issues only one of which is ferrite stability.
Many thanks again.
Joe.