STK0039 - Suitable Replacements - Unobtanium in 2016??

[PTL-Pioneer]

Hi all

As the title suggest i have a question about the STK0039 modules in a SX-690.
I have ordered one off the ebay, reason being it was cheap, and it lights up but no sound.
Bear in mind it is not here yet, but i do hear they are a real failure point in these units, and i suppose my question is whether or not there are any sources of these around nowadays. Plenty on ebay, all chinese and fake etc.

I know Sanyo stopped making these in 95 or whatever (correct me if i am wrong), but do any of you know if there are any near acceptable equivalents that can be procured nowadays, lots of old threads with links etc but kinda hard to find. Larry had pointed to audiolab as a source and they have them in stock, but shipping etc bumps price up considerably. And correct me if i am wrong but they are just good fakes??

I know i am jumping the gun completely, don't worry i am not going to run off and buy a bunch thinking i have diagnosed a unit before it has even got here, i suppose i just wanted to get some experienced input and advice about the topic.

Thanks

 

[Awesomeaudio]

STKs it seems is a hot topic.
Yes there are the Chinese "Fakes" which are cheap and nasty but I wonder if there are companies that actually reproduce them and put some R & D into them.
We all know the Originals are all gone, with the exception the rare NOS pops up, but if there are decent reproductions available then I'd give it a shot.
I have a couple of 39s on the way from a mob in Germany.

 

[rcs16]

Its 2017 btw

but I wonder if there are companies that actually reproduce them and put some R & D into them.

I doubt that, as their is no ROI, (return on investment). I certainly would not invest in making any, since who am I going to sell them too? A couple of customers wanting to fix their sx-680, pretty small numbers to work with for a business case.

I am not certain, but you might be able to use the STK-0050 module that I have designed for the sx-780. You would have to verify if it fits. I do no have a good detailed pics of the inside, to see if there are any interference points. If you do that, I could simulate the design to see if it would work in a sx-680. From what I see in the schematic, I do not see any show stoppers.

Rick

 

[PTL-Pioneer]

I would be interested in that, but if it meant i would have to modify the circuity i would get lost pretty quick, i do not have the knowledge and no matter how hard i try, these things take a long time to sink in with me.
Would voltages not be too high with a STK-0050 equivalent? Sorry now if thats a stupid question Rick

HAHAHHA yes it is 2017, as they say stop looking back, your not going that way

 

[rcs16]

I looked further, there is another thread on sx-680 with what was diagnosed as a stk-0039 issue.
So based on that pic it looks as if my module might fit.
I do not think anything need for ckt modification, the issue is if you can make it fit?
Easy enough to try, print out a pic of the pcb and see if it fits.

Those stk-0050's should run off any reasonable +/- supply from say +/- 20 to +/- about +/-40V being around the max, since it is only one pair of o/p's in a TO-3P package (200W devices). They only supply a V from what they are operating from, they do not generate any voltage themselves, they just pass the supply to the load, just like a water tap or valve.
I know my friends Sansui G-7500 (rated for 90W/ch into 8 ohms) ran off of +/-50V supplies and used ~150W bjts, it smoked those devices so many times, a total under designed amp.

 

[PTL-Pioneer]

Cool send on a picture! I'll see if it fits when unit arrives, if you could pm me what they cost too that would be great Rick, thank you!

 

[rcs16]

All the documentation is in the STK-0050 thread. To make it easy for you, I will include it here.
I do not sell them it is for you to make them up yourself. Parts costs are around ~$25-30 each iirc. read the thread.

 

[Awesomeaudio]

Well, If and when my replacement 39s get here, I'll try them out and if they work ok I'll just leave it until such time they cause issue.
I would also consider making and installing the work around you have rcs16.
Thanks for providing us the opportunity for this option.
Well done

 

[PTL-Pioneer]

Might be all a bit over my head to be honest. I am going to study this one for a while, it certainly looks like the best option, permanent fix and an upgrade of sorts.

 

[Awesomeaudio]

My "replacement" STKs finally arrived from Deutschland. I ordered 4 items to keep so i have spares.. (saves on postage)
Seems too that are all from the same batch of manufacture. That can't be a bad thing I guess.

 

[Tangerine]

T

My "replacement" STKs finally arrived from Deutschland. I ordered 4 items to keep so i have spares.. (saves on postage)
Seems too that are all from the same batch of manufacture. That can't be a bad thing I guess.
View attachment 880161 View attachment 880162

Through eBay or directly?

 

[Awesomeaudio]

From the bay yes. The vendor is in Germany though.

 

[PTL-Pioneer]

Let us know how you get on with these!

 

[dbxdx5]

From the bay yes. The vendor is in Germany though.

Any update on your experience? I need a pair myself and don't want to throw good money at bad modules.

 

[chaosreigns]

Any update on your experience? I need a pair myself and don't want to throw good money at bad modules.

Also inquiring as I need a pair myself.

 

[MyLastWord]

have you tried pacificsemi dash usa dot com. I got mine pair from there and seem to be good.

 

[Watthour]

There are "generic" replacement modules for sale on Amazon, which may or may not provide some measure of fraud protection. They are almost certainly replica modules.

 

[arcorob]

I know this is an old thread but curious How different is the STK-0039 from the STK-0050? From the hard to get data sheets its seems that the 50 can tolerate more input voltage (which makes sense because its for a higher wattage amp) but other than that it seems the same. In fact, would you actually net more output watts since the darlington packs are the power amp section or would the input voltage to them need to be different ?

 

[larryderouin]

Topology is quasi comp in 0039. Full comp in 0050. They are different, but it's way above my paygrade. Lower input voltage = lower output power for the 0039 vs. the 0050. Ricks' (RCS16) board can electrically handle all the way up to a 0105 setup in a FISHER 100+Watt amp. See the spec's on page 1 for the 0039, 0050 and 0105.

Also see the AF Amp diagram on page 2. It's basically the same circuit for all 3. Some fine tuning may be needed.