Dykem or magic marker on base of washer and on device. Fine file or diamond lapping stone (best) to remove stain. Install with Belleville Lock Washers.Trying to finish the Boards and mount them on the heathsinks today, while choosing the washer I found something interesting, see the picture so I’m debating between 16mm and 20mm, what do you think?
They were all tightened up to 9nm.
Adding a second picture, in this one you can see the damage that the pads took with the different washers, clearly the biggest the washer the least the damage.
When lapping is used the stress on the bolt assembly will drop the high torque wasted on flattening the device and washer for more useful contact.
There really is no other way to do it.
Most manufacturers have application notes on this - some are below. I think Mr Pass mentioned once that Pass Labs tightens the mounting screw on the TO247 Fets to 1.2nM.
You will find they use different units to specify torque, but when converted to nM, they are lucky to reach 1nM.
https://www.infineon.com/dgdl/Infin...n.pdf?fileId=db3a3043429a38690142a3a1f142107f
https://www.ti.com/lit/an/snoa460/snoa460.pdf
https://www.renesas.com/us/en/document/apn/247plus-package
https://aosmd.com/res/application_notes/package/AN101_TO220_Guidelines.pdf
https://www.ti.com/lit/an/snoa460/snoa460.pdf#:~:text=The maximum recommended torque force to mount a,device, render it non-functional, and is not recommended
You will find they use different units to specify torque, but when converted to nM, they are lucky to reach 1nM.
https://www.infineon.com/dgdl/Infin...n.pdf?fileId=db3a3043429a38690142a3a1f142107f
https://www.ti.com/lit/an/snoa460/snoa460.pdf
https://www.renesas.com/us/en/document/apn/247plus-package
https://aosmd.com/res/application_notes/package/AN101_TO220_Guidelines.pdf
https://www.ti.com/lit/an/snoa460/snoa460.pdf#:~:text=The maximum recommended torque force to mount a,device, render it non-functional, and is not recommended
Depending on manufacturers specs on flatness, if the pieces are not, torque will rise. Heat transfer suffers.
Simple to check as this is DIY and parts wil not come to user in best possible condition. Simple to check this up front.
Can anyone elaborate on this.. Obviously with more output devices you get more power, but do you not also get more noise (generally)?
I'm just wondering if these is some characteristic of BJTs that lowers the overall THD when lots of them are in parallel? Perhaps a stupid question.
My assumption was that devices had to be matched and selected for gain/ lowest noise.
Thanks
Hi Nelson,
Gary S has been guiding me on a rebuild of my Stasis 2 , I’ve basically replaced everything internally bar the transformer .
I’m now at the stage of biasing the amp but I’m not get any voltage ( mv ) at the 1 ohm resistor ?
When I turn the P2 pot nothing happens, it does give a variable voltage at D+ and D- .
I’ve checked over everything over and over , no shorts etc and I’m getting 72v at the rails .
Any ideas please?
Btw I’m a complete amateur ( never done this before)
Gary S has been guiding me on a rebuild of my Stasis 2 , I’ve basically replaced everything internally bar the transformer .
I’m now at the stage of biasing the amp but I’m not get any voltage ( mv ) at the 1 ohm resistor ?
When I turn the P2 pot nothing happens, it does give a variable voltage at D+ and D- .
I’ve checked over everything over and over , no shorts etc and I’m getting 72v at the rails .
Any ideas please?
Btw I’m a complete amateur ( never done this before)
no need to bring that in this thread, when you already have your own dedicated thread
everyone will help you as much they're able to help, better to keep all info in one thread
.............in fact, good that you asked for help here, some of members actually building this one could chime in your thread and offer some measuring data of their amps
everyone will help you as much they're able to help, better to keep all info in one thread
.............in fact, good that you asked for help here, some of members actually building this one could chime in your thread and offer some measuring data of their amps