Newbie needs advice: F5 Build parts
Hello everyone! :wave:
First time poster and novice builder here. I have ordered the F5 and Universal Power Supply PCB from DiyAudio, along with a 4U Deluxe chassis.
I need some advice and verification on picking parts for both the F5 and Universal PSU, especially for the BOM for the PSU as i find it confusing.
Here's the Matched Semiconductors I have ordered.
This is my Mouser cart.
This is my digi-key cart. Sorry i dont know how to link it, so here's a pic.
<a href="http://tinypic.com?ref=24dq0rn" target="_blank"><img src="http://i43.tinypic.com/24dq0rn.jpg" border="0" alt="Image and video hosting by TinyPic"></a>
Main things I'm needing help with:
1) What Input snubber resistors and capacitors for the PSU? I will be using a SumR 400VA with 18v secondaries.
2) The PSU calls for .47R-1R PI resistors. I have .47R in my cart, do I need these at all or a different value by chance?
3) Do I need those Vishay rectifiers if I'm building this PSU?
4) Do I have the proper Thermistors for TH1&TH2 in my mouser cart?
5) What's the recommendation for wiring all this stuff up, i.e. gauge, length, colors, etc.
6) Can someone provide links for proper silpads/mica, mounting hardware and grease along with how many i need of each?
7) Can someone provide links to proper standoffs and hardware to mount my kits to the UMS chassis and how many i would need?
I can't thank you guys enough for all the support. Looking forward to replies!
You should have asked here first. I'm willing to bet at least the J fets are fake. (2SJ74) Test them before installing on your boards.
Would you be able to provide some answers to my questions? It would be much appreciated :)
Yes, the 174 Jfets are likely fake. Contact spencer (search the forums) to get the real deal. This is perhaps the most important part in the amp. You don't want to risk it.
You have read this? This will answer a lot of your questions.
1 & 2) The .47 3W Vishay resistors in your cart are fine for the PSU. You need 4 per rail (8 total) for just the PSU, plus 2 for each channel on the amp board. 12 total. The snubber cap value would technically depend on what caps you are using in the PSU. I am using a 50V 4.7uf WIMA for each rail. But I am not using the DIYaudio psu board.
3) I couldnt see your Digikey cart. You will need rectifiers though. Either discrete for the diyaudio board or the "block type" chassis mount kind.
4) Yes, those would work but make sure the sensor is not conductive, so if you lay it on the bolt holding the mosfet down it wont short.
5) I used 14G to wire the PSU to the boards and 10G from the rectifiers to the PSU board. 18G for the speaker outs and small 26G for the signal.
6) If you use silpads use the K-10 variety. Or order the Kapton insulators from the diyaudio store. That's what I would do.
7) don't know. I drilled and tapped my chassis.
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Now you can see the caps im using to help me determine the snubbers.
You say that i will need rectifiers, i guess im confused (newbie) on that part because i thought the universal PSU board has that included?? So how many would i need, just 2? Mind giving me a link for your recommendation?
Where can i find K-10 silpads?
Thanks so much for your help!
The first item in your digikey cart are the rectifiers. They go on the PSU board. They need to be heatsinked or mounted to the chassis.
I believe the .1 cap in your digikey cart is the snubber.
You can get K-10 silpads from mouser. You need them to fit a to220 device. Just search Berquist K-10 and choose the to220 size.
But I would order the Kapton pads from the diyaudio store or use mica and grease. You need 8 pads for the diode rectifiers if you mount to the chassis and 4 pads for the mosfets.
R11 & 12 are the snubber resistors on the PSU schematic. 1 ohm, 3 watt. You have them in your digikey cart.
Cx1/CS1 and CX2/CS2 are the snubbing caps for the diodes. As for the value...I don't know. Maybe someone else can chime in?
You have read the diyaudio build guide PDF, right? it will guide you. Memorize it.
7, check out the back panel parts kit in the store, it contains the mounting hardware.
2) 4pc 0.47ohm pr rail is a good start.
3) no. you can use what ever you want, as long as they do the job.
7) check out this store: GBP UK Items, 5W Metal Oxide Film items in Electronics-Salon store on eBay! for hardware.
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