Peleus Posted July 7, 2014 Report Posted July 7, 2014 I draw the schematics to show my modified version of the T2 psu for megatron below. Dose the modified schematics work? Any comments will be welcome. Thanks!
kevin gilmore Posted July 7, 2014 Author Report Posted July 7, 2014 (edited) NO. you are missing the point. The point is a fair bit MORE current. one 10m90s is not going to handle that. you would need 3. and you need 3 x fqpf8n80c. other than that, both supplies are about the same in cost and performance ksc5026 works fine as 2sc3675 or 2sc3840 replacement and is a current part ksa1156 works fine as 2sa1486 replacement with the 270V zener and is a current part Edited July 7, 2014 by kevin gilmore
JoaMat Posted July 7, 2014 Report Posted July 7, 2014 (edited) Why three fqpf8n80c? Shouldn't even one do if proper heat sinked? Edited November 11, 2015 by JoaMat
Peleus Posted July 7, 2014 Report Posted July 7, 2014 NO. you are missing the point. The point is a fair bit MORE current. one 10m90s is not going to handle that. you would need 3. and you need 3 x fqpf8n80c. other than that, both supplies are about the same in cost and performance ksc5026 works fine as 2sc3675 or 2sc3840 replacement and is a current part ksa1156 works fine as 2sa1486 replacement with the 270V zener and is a current part Thanks KG！ I'll be back to the kgsshv psu while you give me the information of the fets replacement. Thanks!
kevin gilmore Posted July 7, 2014 Author Report Posted July 7, 2014 you are going to need a bunch of heatsink. use the off board power supply version.
Peleus Posted July 7, 2014 Report Posted July 7, 2014 ksa1156 works fine as 2sa1486 replacement with the 270V zener and is a current part Ask a question: KG point to use 270V zener while use ksa1156 to replace 2sa1486. Where is the exact component that KG mean? Would anyone like to provide photos to explain for me? Or using this part of kgsshv psu schematics explain for me. I'm truly newbie indeed !
luvdunhill Posted July 7, 2014 Report Posted July 7, 2014 Why three fqpf8n80c? Shouldn't even one do if proper heat sinked? If you do the math you will see why this is a bad idea. Use more devices to spread out the heat.
spritzer Posted July 7, 2014 Report Posted July 7, 2014 Are you running 10M90's at 500V in the KGST? That's not the best of plans...
Victor Chew Posted July 8, 2014 Report Posted July 8, 2014 this should handle the power angle bracket to big heatsink and 3 x fet per side http://gilmore.chem.northwestern.edu/kgsshvpsminiexternal.jpg Perhaps to add a delay start and 300v section as well?
mypasswordis Posted July 8, 2014 Report Posted July 8, 2014 Referring my post #129. I did build a PSU for both Blue Hawaii and Megatron. I choose an off board heat sink approach just like the excellent DIY T2 PSU. I run everything I build at 500 V - even the KGST. Did some of the magic smoke seep out?
eggil Posted July 15, 2014 Report Posted July 15, 2014 This is the way I am thinking about offboarding the transistor. I haven't done it since still waiting for the chassis with the external heat sinks
eggil Posted July 18, 2014 Report Posted July 18, 2014 (edited) What would work better for heat transfer to the heat sink?: a. L shaped aluminum piece like the one shown above b. solid aluminum cuboid/rectangular piece Edited July 18, 2014 by eggil
johnwmclean Posted July 18, 2014 Report Posted July 18, 2014 (edited) http://sound.westhost.com/articles/diy-heatsink.htm Edited July 18, 2014 by johnwmclean 1
eggil Posted July 18, 2014 Report Posted July 18, 2014 Thanks John. I had read the article before. He used for a heat spreader ether a 25x25 mm aluminum rod or an aluminum sheet with a thickness of 10 mm. I guess an L shaped flat aluminum piece is as good as a cuboid shape. No discussion of this in Westhost.
niner Posted July 29, 2014 Report Posted July 29, 2014 Thanks! It is my very first tube amp. Thank you, Kevin and the team, to share your work. You guys made the world better! I also have the KGSSHV 500V. I prefer the Megatron, especially with SR-009. Now only if I can locate Tran, then I can finish my T2 build.
kevin gilmore Posted July 29, 2014 Author Report Posted July 29, 2014 very nice job. you are ready to do the T2.
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