Sankin VS OnSemi

[LBPete]

For what it's worth, I noticed the temp difference after it was running with a load. Didn't notice what it was doing with no load.

As far as the onsemi cross reference it is still screwed up for the SA909, it crosses it to a MJ15003 which is a PNP transistor.

- Pete

 

[DanTana]

For $2.00 or even $4.00 each I can't see why all the TO-3's weren't replaced at the same time. Just makes sense unless it's not econically feasible.

 

[rstsgsas]

I have seen the same.

Recently repaired a pioneer sx-1250 and at no load with bias and dc-offset adj the channel with original sankens got noticably hotter than the one with on-semi transistors .I swapped the originals with another set of on-semi's and had to adjust bias and dc-offset just a tweak.Now both run cool at idle .I figured there was some leakage of the old transistors.I use the mj21193/94 as replacements.They really sound great too.MJxxxxx outputs is all I use now.I have a 9090db i used them in also.I have never had any problems with on-semi transistors.

 

[Yamaha B-2]

Makes me think of what ilimzn stated earlier. Good mica and/or thermal paste used so that the heat is actually getting into the heatsinks or are you heating up the cans and using them as the heatsink?

 

[LBPete]

When I swapped the Sankins from right to left, I cleaned all the old grease off the left side micas and used new grease. I left the old grease and micas in place on the right side, since I’m planning to use the Sankens on that side too. Even with the new grease, the Sankens were warmer. I’ll double check the offset and bias today.

- Pete

 

[Yamaha B-2]

Times like these it's nice to have an IR laser thermometer.

Have you got any inexpensive recommendations on these? Last ones I bought were on the order of $3K/each to look at epi wafers during process and temp profiles on the wafers and reactors.

 

[EchoWars]

Any number of inexpensive ones out there...I'd go for this one, but only because it seems to have a lot of features for $100.

http://www.tempgun.com/order.html#pe3

 

[Yamaha B-2]

Amazing advancement in the state-of-the-art in only six years. But have to admit I've never looked before. Those Chinese. They are so clever. Thanks for the lead.

 

[ilimzn]

When I swapped the Sankins from right to left, I cleaned all the old grease off the left side micas and used new grease. I left the old grease and micas in place on the right side, since I?m planning to use the Sankens on that side too. Even with the new grease, the Sankens were warmer. I?ll double check the offset and bias today.
- Pete

Hold on, are you checking the heatsinks or the transistors themselves?
If the latter, it is normal for the Sankens to be warmer as they use different case technology and have a higher thermal resistance of the case, but IIRC they have a copper slug embedded between the pins.
If we are talking the total heat produced by the transistors, it is exactly the same, and when I say heat, I mean Watts. As for temperatures, that depends on thermal resistance.

And do PLEASE call them Sanken... having had my name said wrongly for umphteen gazzilion times makes one really sensitive to this. I'm sure you would be slightly annoyed if someone called your receiver a Sonsui, or call you Pite, or call this board Audiokerma... :scratch2:

 

[Eggman]

Hey LBPite, what was the number on those Sankins again? I nead some fer my Yomaha.

 

[RocknRoll]

I just thought about it they must have combined Sansui with Kenwood to get SanKen. Or Kinwood to some folks.

 

[Eggman]

Amazing advancement in the state-of-the-art in only six years. But have to admit I've never looked before. Those Chinese. They are so clever. Thanks for the lead.

I need this IR Thermometer, and thats all I need! <Steve Martin talking from The Jerk.

 

[LBPete]

Today’s update.

I rechecked the offset and bias. They had drifted a little but not much. The bias on the right channel was about 25 to 30 mV the spec is 10 +/- 5. Even though it was off, it still ran cooler with the OnSemi than the left channel with the Sankens.

I swapped the OnSemis for the second set of Sankins, rechecked the offset and bias and ran the unit for a couple hours. The left channel is still warmer than the right channel. When I get a chance I’ll swap the Sankens from left to right and see if the set in question stays warmer.

- Pete