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Thermal paste

A

aurora01

Active Member
I’m restoring a Fisher amplifier with the Darlington. Power packs what do you recommend for thermal paste, there is a metal heatsink that these get screwed too.

also I’m replacing the 2Sa798 transistors I found Mitsubishi 2SA798 but I’m also buying Matched pairs of the replacements just to have, are you all using thermal paste between them before you heat shrink them together?
 
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use heat sink compound not thermal paste. when you say thermal paste it makes me think you will use cpu thermal paste.

i like:


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lots of opinions, honestly most of them are pretty much the same thing, a mixture of silicone grease and zinc oxide. Being basically the same thing, they perform basically the same, so use whatever is available to you. Without looking I couldn't even swear what I've got, other than it comes in a small plastic jar. At some point someone will come along with a warning about the silver stuff causing shorts, but if you read the datasheets it does say that it is non-conductive. I just don't like it because it doesn't spread nicely.

and yeah, thin coating is all you need. I usually spread it with a razor blade. You want just barely enough to coat the surface evenly. The goal is to fill in tiny gaps and surface imperfections, not to lay it on there like cake icing.


For the heat shrink question, I'm assuming you're replacing a dual transistor diff pair with two individual transistors stuck together? Last time I did that I did use a teeny bit of heat sink compound but I honestly don't know how necessary it is.
 
I used this...
GowizDream High Performance Thermal Paste (3g) for Cooling All Processors (CPU, GPU - PC, PS4, Xbox),12W/mK High Conductivity Heatsink Paste,Long Durability, Non-Conductive, Non-capacitive (3 Grams) https://a.co/d/7AajFlI
 
gadget73 said:
lots of opinions, honestly most of them are pretty much the same thing, a mixture of silicone grease and zinc oxide. Being basically the same thing, they perform basically the same, so use whatever is available to you. Without looking I couldn't even swear what I've got, other than it comes in a small plastic jar. At some point someone will come along with a warning about the silver stuff causing shorts, but if you read the datasheets it does say that it is non-conductive. I just don't like it because it doesn't spread nicely.

and yeah, thin coating is all you need. I usually spread it with a razor blade. You want just barely enough to coat the surface evenly. The goal is to fill in tiny gaps and surface imperfections, not to lay it on there like cake icing.


For the heat shrink question, I'm assuming you're replacing a dual transistor diff pair with two individual transistors stuck together? Last time I did that I did use a teeny bit of heat sink compound but I honestly don't know how necessary it is.
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I’m found new 2SA798 Mitsubishi transistors but i bought the replacement ones as well from Mouser just checking if it’s wise to add so thermal conductance between them.
 
Blue Shadow said:
60 Gs will last through a lot of transistors. I bought the tube of 249 at least a decade ago but I'm not inside gear every day and mess with tts a lot, too and they don't need that stuff.
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Bring it over! It can have a play-date with my (equally old..) toothpaste tube of 340:p
 
arts said:
Bring it over! It can have a play-date with my (equally old..) toothpaste tube of 340:p
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Thanks for the invite. Maybe we can talk about me thinking of moving away from the SP-3a and getting an SP-6 or SP-8 while the tubes are playing, both kinds.
 
Blue Shadow said:
Thanks for the invite. Maybe we can talk about me thinking of moving away from the SP-3a and getting an SP-6 or SP-8 while the tubes are playing, both kinds.
Click to expand...

I have been looking for an SP-8 (unsucessfully) for quite a while myself. I have taken a couple of SP-6 models (B&C) for a spin, and (with the tone controls "Out") still preferred the SP-3A-1. And as I still occasionally need the tone controls and the contour feature for low-level listening, I can't see myself replacing it with a 6 (or an 8) anytime soon. I really didn't find the SP-6's to be any better, just different. The SP-8 may be another story...
 
I've used the white zinc oxide paste with good results. There are also mess-free preformed thermal silicone sheet material couplers called Sil Pads, which work well. No paste or goo to worry about.
 
I've assembled computers for 20 years as a hobby. I use Artic Silver thermal compound on them. I'll wipe the heatsink with alcohol, then rub in some compound using a coffee filter, then wipe it off. I put a small amount on the die, and spread it as thin as I can on the die, then put on the heatsink.
 
quote didn't come out right

I think that MG 860 is what I have, or at least its in a jar that looks just like it.
 
Since mouser will not ship Wakefield 120 to Canada anymore I’ve been using chiplock brand from Digikey. It’s more viscous than 120
 
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