Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Starving Student PCB's
New Posts  All Forums:Forum Nav:

Starving Student PCB's - Page 3

post #31 of 222

Fred, got them a couple weeks ago but forgot to say here :) they look very nice. Thanks

post #32 of 222
Mine just arrived in the mail today. Needless to say I'm very excited to place an order at Mouser and hunt for some cheap tubes on eBay smily_headphones1.gif Thanks again, Howard!
post #33 of 222

My package just arrived today, thanks Howard for fast shipping. Soon me and my friends will buid it..beerchug.gif
 

post #34 of 222

I put my amp together today, everything was looking great , I'd even found a working power supply in a junk bin for $2 and some nice 1960's tubes ..... final job mounting the Mosfets to the heatsinks .... Doh! I realised that I don't have any of the ceramic mounting kits. Does anyone know where I can buy them or have any to sell? or maybe there is a work around? I can't find any on ebay and Mouser are really expensive for shipping to Japan.

 

Thanks, Andy

post #35 of 222
Quote:
Originally Posted by Frodo View Post

I put my amp together today, everything was looking great , I'd even found a working power supply in a junk bin for $2 and some nice 1960's tubes ..... final job mounting the Mosfets to the heatsinks .... Doh! I realised that I don't have any of the ceramic mounting kits. Does anyone know where I can buy them or have any to sell? or maybe there is a work around? I can't find any on ebay and Mouser are really expensive for shipping to Japan.

 

Thanks, Andy

 

You mean a TO-220 insulation kit? Like a mica and a plastic shoulder washer?

 

Here you get 10 kits for 3.50 USD. I'm sure the shipping from Hong Kong to Japan would be reasonable.

http://www.ebay.ca/itm/TO-220-Transistor-Mica-Insulation-full-set-for-TO-220-Transistor-X-10-/261144589902

 

Otherwise simply search for "to220 insulation" or similar keywords.

post #36 of 222
Thread Starter 
Quote:
Originally Posted by Frodo View Post

I put my amp together today, everything was looking great , I'd even found a working power supply in a junk bin for $2 and some nice 1960's tubes ..... final job mounting the Mosfets to the heatsinks .... Doh! I realised that I don't have any of the ceramic mounting kits. Does anyone know where I can buy them or have any to sell? or maybe there is a work around? I can't find any on ebay and Mouser are really expensive for shipping to Japan.

 

Thanks, Andy

 

Dont forget you only need to insulate the heatsinks if they are grounded, if you dont ground them and use a wooden or ABS type case it's not a problem

 

cheers

FRED

post #37 of 222
Quote:
Originally Posted by Fred_fred2004 View Post

 

Dont forget you only need to insulate the heatsinks if they are grounded, if you dont ground them and use a wooden or ABS type case it's not a problem

 

cheers

FRED

 

I beg to differ. Here's two reasons:

 

First, there can possibly be some 50 volts on these. With the amount of capacitance on the rail, it can be quite a dangerous zap if conditions are met (you just got out of the shower, your feet are wet and your arm brushes the heat sink...). It's simply not something that should be left to chance. Oh and you don't want to be responsible for someone's cat getting killed by such an advice. Not good for business.

 

If the sinks are not grounded, they become antennas. They'll pick all sort of RF crap that could then be induced on the gate of the fet. Not good. If you ground them, they become shields that actually block RF from reaching the transistors. Much better.

 

It is therefore preferable to ground the heat sinks and then electrically insulate the transistors from them. It's not that hard to do, and the only argument I can see for not doing it is laziness... at the risk of your own safety... and your cat's.

post #38 of 222
Thread Starter 

I've never had any problems, but if you want to take the precautions , fair enough

 

cheers

FRED

post #39 of 222

Got mine today. Looks good. Thanks!

post #40 of 222

Got mine too, thanks a lot Howard !!
Very fast shipping too :)


Edited by marcus76 - 7/1/13 at 11:15am
post #41 of 222
Thread Starter 

everybody seems happy no losses so far :-)

post #42 of 222

I'm happy with the board that I got.  It looks great.  Can't wait until work slows down a bit and I'll solder it up.

post #43 of 222
Thread Starter 

Bump :-)

post #44 of 222

Hi Fred, these sound great, do you have any idea of the shipping time to Italy?

 

Cheers

Chris.
 

post #45 of 222
Thread Starter 

Hi Chris

Italy is a challenge it seems to take 2-3 weeks as a letter,

but there is no hard and fast rule they are all over the place :-)

 

FRED

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Starving Student PCB's