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STK-0025 substitution

nabeelsayegh

nabeelsayegh

AK Subscriber
Subscriber
Morning everyone. I have a basic Technics SA-101 that uses a pair of these STK-0025 modules. I know that for some of them, you can replace them with a higher model (like being able to replace an STK-0040 with a 0050.) I was wondering if the same is true for this 0025. I found this datasheet snippet and if i follow it correctly, the 0025 should be able to be replaced by a 29, 39, 49, 59 or 105. Am I correct in this assumption?

STK.jpg
 
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So let me ask this question, looking at the internal circuit design between the STK-0025 and say the STK-0050...couldn't you technically use an STK-0050 in place of the 25? It seems to have the same overall mappings in regards to pin function.
 
(I have a few of these STK-0050's I've harvested from hanger queens in the past, but don't want to put them at risk.)
 
rcs16 said:
Electrically a stk-0050 will sub for a stk-0025, I think the package is the same
Click to expand...
i've still got one of your kits that i intend to replace a couple stk-0039s one day , which would be the same thing. i'll report my findings when ever i get around to it. or if i get around to it. i've got a pretty full plate for at least a year or 2.
 
It’s great if everyone posts there success and experience along with a few pics to help others.
Sometimes there are mechanical challenges with sub using the heatsink plate but I’ve seen folks get creative
 
Agreed. I got lucky and found another SA-101 tucked away in my inventory. I got even luckier to find that one of it's two modules was still good, so i was able to repair the Customer unit with the exact part. NOW...i have a Guinee pig to see if the STK-0050 works in it. I may not get to it right away, but once I have free time (yeah, right), I will clean it up, see what else it may need and drop in the 50's (as I have a bunch of them to work with). Will report back when I can.

Incidentally, i heard that there were circuit boards you could get that were designed to replace these STK modules that you assemble the components on yourself. I have not tried to do this on any unit yet but I am curious if anyone has had experience with them and how "universal" are they?
 
Beware that the STK-0025, 0029 and 0039 has one pin connected to the collector of the driver transistor on the negative supply side. This is pin #4 on the datasheet, but pin #5 according to the Technics SA300 service manual. This pin is not always connected in the actual amplifier or receiver circuit. So the STK 0050 is not always a sub for these STKs (0035, 0029, 0039)
 
nabeelsayegh said:
Incidentally, i heard that there were circuit boards you could get that were designed to replace these STK modules that you assemble the components on yourself. I have not tried to do this on any unit yet but I am curious if anyone has had experience with them and how "universal" are they?
Click to expand...

that is what i was speaking of and @rcs16 is the designer

https://audiokarma.org/forums/index.php?threads/stk-0050-replacement-for-sx-780-and-others.721181/

so far i've used them on stk-0040,0050 and 0080 but those are the same family. the stk-0025,0039 are cousins as are the stk-0xx0ii, which are also supposed to be compatible but i have not verified that yet personally.

thanks for the heads up @ecluser my 0039 is in an mcs 3835 int. amp. i did buy a service manual for it so i have the schematic. i'll tag you if i ever get around to trying it.
 
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