WTB Thick Ceramic TO-220 Insulators

Zero Cool · 07:21 PM

I am looking for some Thick TO-220 Ceramic Insulators. I am working on an amp that uses these 2-3mm thick ceramic pieces as insulators. some of them are broken and i need to replace them. I have only seen the mica, kapton or sil-pad type insulators.

Anyone have a source for these??

They must be using these thick insultors due to the high voltages involved. many of these parts have 440V on them and or 70khz high frequencies.

Zc

Magura · 21st December 2009, 07:22 PM

Sure, just search for aluminum oxide.

Digikey sure has them.

Magura

Magura · 21st December 2009, 07:40 PM

My mistake.

Farnell is where I saw them:

AAVID THERMALLOY|4180G|Thermal Insulator | Farnell Danmark

Magura

stoc005 · 21st December 2009, 08:20 PM

Let's hope the ones you have are NOT beryllium oxide. DO NOT broke them into pieces and create dust. It is POISONOUS. Better to use Aluminum oxide or kapton-like (K-10) or sil-pads. See Digikey for examples of this. Use the one with the lowest thermal resistance.

Zero Cool · 21st December 2009, 09:00 PM

The ones i have are white ceramic. they were broken when i removed them. the second i loosened the screw, the broken pieces fell out.

Zc

llwhtt · 22nd December 2009, 12:22 AM

You are probably looking for the beryllium oxide type. I stocked up on the TO-3 type a few years back, got them from Hosfelt Electronics in OH. I found the part number on the Thermalloy or Wakefield site, then searched that number and came up with Hosfelt. They ARE the best if you have to use an insulator. I also bought a torque screwdriver so I don't break them, 6 in/lbs is all that is needed for TO-3s. You can download a whitepaper from ON Semi about transistors and mounting, also the torque specs for all types of transistor cases. Yes they are poisonous so take heed and don't stick 'em in your nose or mouth. I used many of them in the military and I'm still kickin', for now at least. I'm using them on my Sumo Andromeda II rehabbed into a Pass A40.

Craig

llwhtt · 22nd December 2009, 12:50 AM

Digikey has all of the part numbers for the Thermalloy aluminum oxide insulators but none in stock and very high minimum order. Use the part numbers and search the internet. I couldn't find them on the Hosfelt site now.

Craig

llwhtt · 22nd December 2009, 12:58 AM

Just found some aluminum oxide type for TO-220 at Mouser, in stock at a whopping 50 cents each. Part number 532-4170.

Craig

21st December 2009, 07:18 PM	#1
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	WTB Thick Ceramic TO-220 Insulators I am looking for some Thick TO-220 Ceramic Insulators. I am working on an amp that uses these 2-3mm thick ceramic pieces as insulators. some of them are broken and i need to replace them. I have only seen the mica, kapton or sil-pad type insulators. Anyone have a source for these?? They must be using these thick insultors due to the high voltages involved. many of these parts have 440V on them and or 70khz high frequencies. Zc Last edited by Zero Cool; 21st December 2009 at 07:21 PM.

21st December 2009, 07:22 PM	#2
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	Sure, just search for aluminum oxide. Digikey sure has them. Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

21st December 2009, 07:40 PM	#3
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	My mistake. Farnell is where I saw them: AAVID THERMALLOY\|4180G\|Thermal Insulator \| Farnell Danmark Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

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21st December 2009, 08:20 PM	#4
stoc005 diyAudio Member Join Date: Feb 2007 Location: Midwest in the USA	Let's hope the ones you have are NOT beryllium oxide. DO NOT broke them into pieces and create dust. It is POISONOUS. Better to use Aluminum oxide or kapton-like (K-10) or sil-pads. See Digikey for examples of this. Use the one with the lowest thermal resistance.

21st December 2009, 09:00 PM	#5
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	The ones i have are white ceramic. they were broken when i removed them. the second i loosened the screw, the broken pieces fell out. Zc

22nd December 2009, 12:22 AM	#6
llwhtt diyAudio Member Join Date: Jun 2008	You are probably looking for the beryllium oxide type. I stocked up on the TO-3 type a few years back, got them from Hosfelt Electronics in OH. I found the part number on the Thermalloy or Wakefield site, then searched that number and came up with Hosfelt. They ARE the best if you have to use an insulator. I also bought a torque screwdriver so I don't break them, 6 in/lbs is all that is needed for TO-3s. You can download a whitepaper from ON Semi about transistors and mounting, also the torque specs for all types of transistor cases. Yes they are poisonous so take heed and don't stick 'em in your nose or mouth. I used many of them in the military and I'm still kickin', for now at least. I'm using them on my Sumo Andromeda II rehabbed into a Pass A40. Craig

22nd December 2009, 12:50 AM	#7
llwhtt diyAudio Member Join Date: Jun 2008	Digikey has all of the part numbers for the Thermalloy aluminum oxide insulators but none in stock and very high minimum order. Use the part numbers and search the internet. I couldn't find them on the Hosfelt site now. Craig

22nd December 2009, 12:58 AM	#8
llwhtt diyAudio Member Join Date: Jun 2008	Just found some aluminum oxide type for TO-220 at Mouser, in stock at a whopping 50 cents each. Part number 532-4170. Craig

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