@birdbox
See here: https://www.diyaudio.com/community/threads/f5m-kit.408290/page-18#post-7610843
Papa was just making sure we are awake! 😉
Best,
Anand.
I was looking for specs on the thermal pads supplied, they are listed as BER1340-ND.All that comes up and close is BER134ND.It is black and proper dimensions.Its name is Bergquist Q3.The specs for it on Digikey say it is non insulating,which can't be a good thing I'm thinking.Reason I'm looking for specs is I have a bunch of mica pads and was trying to decide between the 2.
The data sheet on digikey say insulating in the first paragraph
https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/852/cpu_pad.pdf
https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/852/cpu_pad.pdf
This Berquist product is electrically insulating:
https://www.digikey.ca/en/products/...MIwP_p4KSDhQMVLCatBh0TNQ9aEAYYASABEgL59PD_BwE
https://www.digikey.ca/en/products/...MIwP_p4KSDhQMVLCatBh0TNQ9aEAYYASABEgL59PD_BwE
The drain of the mosfets is connected to the metal shell.Therefore there is very little dc volts on the shell.However the ac output voltage is on the shell so depending on your volume level you can have up to watt or two dissipated by the pad.
Has someone reached out to the store to ensure this thermal pad issue @oreo382 brought up is addressed? I can if needed, but no need to double down if someone else has. I had asked the question about pads a couple weeks ago and it seemed like there were no concerns brought up at that time.
Impressed by the dynamics of this amp through LaScalas and a B-1 original version . Good enough volume for most listening. Very revealing little amp. I think I will keep it. One of the best I've heard. Now I need a spare.
Good dynamics you say.... well, Nelson decided to give us a PS PCB with (besides all other goodies that come with this PCB of his) - a proper placement of the earthing NTC on the PS PCB. I think everyone reported reduced noise floor - no wonder!!! I've finally seen (from the photos posted here in this thread) the margin for error reduced to ... a very small number. Of course, we may still have members who may decide to become creative and place the PS PCB on the opposite side of the IEC inlet...
Well, my bias was too high at 1.7A, I have the 10ohm thermisters when I should have bought and installed 4.7ohm thermisters, and I used the thermal pads in the completion kit which appear to be non-electrically insulating....call me a "Foolish Amp Builder" because I turned it on, hooked up the Iron Pre SE SMD and played music....
🎶 !! Glorious Music !! 🎶
Amps sounds amazing!
I wish I didn't have to take it all apart now to make the fixes. It'll be good practice at least.
Thank you to everyone on this thread who has freely given their knowledge, pointed out my many errors, given me a little razzing from time to time, and shared their build experience! Very generous group of people here!
🎶 !! Glorious Music !! 🎶
Amps sounds amazing!
I wish I didn't have to take it all apart now to make the fixes. It'll be good practice at least.
Thank you to everyone on this thread who has freely given their knowledge, pointed out my many errors, given me a little razzing from time to time, and shared their build experience! Very generous group of people here!
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Don't tell anyone, and I don't recommend it but.... my early amp configuration just relied on the anodizing for isolation. Just thermal grease (pigeon poop) and a no-continuity verification check..
I wonder if it's such a bad thing if the pad itself dissipates some power as the MOSFET is a lot hotter? Did I cry wolf here?
I can confirm that the specified (black) pads are indeed conducting. I measured 75 ohms (using my trusty AVO 8) with the pad sandwiched between two steel washers.