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STK-0050 replacement for SX-780 and others

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dr*audio said:
I do want to try the discrete replacement parts but there is a substantial price difference and most of my customers who have units with STKs in them would not want to pay for the better replacements, especially because I would replace both modules with the discrete parts so they match.
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Our new stk-0050-c0 design needs someone to try it out in a sx-780 or something similar since we do not have one. Without the heatsinks it's a cost reduction exercise. built up two of them but it's possible to send the blanks,parts? and someone can solder them up. the op devices use the existing STK mounting hole centers so a jig was made to do that. Others would have to do the same if soldering one up or use the existing STK heatsink but that can be cumbersome. PM me if you are interested.
 
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rcs16 said:
Their has been a bit of interest for a replacement of what was the original Sanyo STK-0050 module used in a SX-780 receiver. Many question the integrity of what can be obtained these days as STK-0050 modules.
I decided instead of sending these files to individuals or trying to make a buck from folks needing them, I thought that it would be better served if I make a contribution to the community.
The design was simulated, so I will include the ltspice schematic. If someone wants the .asc file to play with I can provide that as well.
There were some earlier threads where I introduced this design, you can follow them for some background and pics of one implementation.
The pcb fab files use pcbway naming conventions. You can change them if you chose to use a different fab.
.GTL Gerber top layer
.GTO Gerber top overlay
.GTS Gerber top solder
.GBL Gerber bottom layer
.GBO Gerber bottom overlay
.GBS Gerber bottom solder
.GKO Gerber keepout layer
.DRD Excellon drill file or rename to .XLN for JLCpcb (rev A1 is for JLCpcb)

BOM:
863-MJE15032G MJE15032G ON Semiconductor Q3
863-MJE15033G MJE15033G ON Semiconductor Q2
863-NJW1302G NJW1302G ON Semiconductor Q1
863-NJW3281G NJW3281G ON Semiconductor Q4
80-R82DC3470AA60K R82DC3470AA60K KEMET C2
594-SFR16S0003929FR5 SFR16S0003929FR500 Vishay R9
594-SFR16S0004708JR5 SFR16S0004708JR500 Vishay R1,R5
594-5073NW4R700J PR01000104708JR500 Vishay R3,R4
594-SFR16S0003901JA5 SFR16S0003901JA500 Vishay R8
594-SFR16S0001211FR5 SFR16S0001211FR500 Vishay R6
833-RL202-TP RL202-TP Micro Commercial Components (MCC) D1,D2
534-9902 9902 Keystone Electronics Screw for Q1-4
534-9901 9901 Keystone Electronics Screw for Q5
534-4692 4692 Keystone Electronics for Q1,4
594-SFR16S0007509FR5 SFR16S0007509FR500 Vishay R2
951-SPK10-006-00-104 SPK10-0.006-00-104 Bergquist Company Ins for Q1,4
512-BD13910STU BD13910STU ON Semiconductor Q5
652-3362P-1-501LF 3362P-1-501LF Bourns R7
534-3049 3049 Keystone Electronics For Q2,3
567-120-SA 120-SA Wakefield-Vette
594-K221J15C0GH5TH5 K221J15C0GH5TH5 Vishay C1,3
532-53-77-4G 53-77-4G Aavid Ins for Q2,3

Mouser BOM upload:
863-MJE15032G|1
863-MJE15033G|1
863-NJW1302G|1
863-NJW3281G|1
80-R82DC3470AA60K|1
594-SFR16S0003929FR5|1
594-SFR16S0004708JR5|2
594-5073NW4R700J|2
594-SFR16S0003901JA5|1
594-SFR16S0001211FR5|1
833-RL202-TP|2
534-9902|4
534-9901|1
534-4692|1
594-SFR16S0007509FR5|1
512-BD13910STU|1
652-3362P-1-501LF|1
534-3049|2
567-120-SA|1
594-K221J15C0GH5TH5|2
532-53-77-4G|2

Link to shopping cart:
https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=976621ac80

The docs and fab data are in one zip file, stk-0050-8.zip

You are responsible to build it all yourself. I am here only to help, answer questions. I encourage others to help the ones that are doing this for the first time.
I did think about adding the protection circuitry (mtf mentioned it one time) as was done in the sx-880, but that I will leave for now as it requires further mod to the design (new pcb) and some extra wiring to match the sx-880 design.

Good Luck
Rick

Index: (thanks to Zeb)

Al Plate Page3, post #54
Using the sub to replace the pair of STK0080's. Page 6, post# 107
Bias procedure for a .22 ohm emitters. Page 6 post #115.
Alternate outputs, Would FJP1943 / FJP5200 work? Yes, page 7 post# 123
Is there a way to set the idle current with these new modules? Yes
Procedure for idle setting on DBT. Page 23 Post# 451
Making the heatsinks ready for component install. Page 26 Post# 518
Will it replace the STK-0050II? Page 31 Post# 607
Fisher CA-800 sub install. Page 7 Post# 134
Fisher RS-2010. Page 29 Post# 576
Pioneer SX-680: Post #428, #571 in http://audiokarma.org/forums/index....lacement-for-sx-780-and-others.721181/page-29
Technics SU-V2 (STK-8040). Page 30 Post# 569
Speaker fuse size. Page 7 Post# 140 – 142
Fusing the circuit. Page 21 Post# 419
Current protection. Page 11 Post# 203
Other Output subs. Page 13 Post# 248
Alternate trimmer. Page 28 Post# 552-555
Q2 alternates. Page 25 Post# 495
R2 alternates. Page 13 Post # 259
Initial checks. Page 14 Post# 280
Installing the transistors. Page 15 Post# 281
Bias setting for the SX-780. Page 16 Post# 301
Does the sub work for a STK-0059? Yes. Page 17 Post# 329
More about the sub circuit design from Rick. Page 18 Post# 359
Technics SU-V4? Will it work? It should. Page 20 Post#386 and Post #410
Use in a SX-580. Page 21 Post# 417 and Post# 424 - 428
Some extra assembly notes: Page 48, post #490
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Hi I am tying to track down PCB docs for STK-0050 module replacements I`m new here so please excuse ignorance/errors I want to replace said devices in a JVC mint amp ( apart from blown STK`s) I understand the file can be uploaded to one of the Chinese PCB manufactures? Thanks in advance John
 
Hi John,
Recently I discovered that someone was selling these PCBs on eBay. The premise was that this was made available for personal use only. The only way I determined to try to put an end to this was to kindly ask Heather to remove the files, in which she obliged. Sorry but you're one week late in a ~ 10 year run.
 
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@rcs16

Using the work of others for personal gain is terrible.

However, taking the Gerbers down actually helps the eBay seller, because hobbyists like @jowinst - who this project was intended to help - are left with no choice but to purchase the illicit eBay boards... the opposite of the intended effect.

Just my 2 cents, obviously.
 
the boards are sold on ebay if anyone wants a set for $20 cdn and you get the links to buy the current revision of parts.
the new -c0 design is being tested in a sx-780 and it will be offered as above without needing the heatsink (cost reduced),
only use the HS design for hi powered applications, stk-0070,80+, it has mounting hole positions for all STK package types.

The ebay seller was asked to de-list and he complied. Suggested to him to give them away to others for free or at his cost.
Once I expire all our designs will be put out for free for the world to use as they like, I doubt the grandchildren want to take it on.

Damn this site has become annoying, I am typing away and the ads keep popping up stopping my key entry.
Does it do the same to subscribers? Zeb was saying the same thing a few days ago.
 
Well, correction: Ads appear on Firefox, but not on Brave.

Brave browser blocks ads right out of the box. I've been using it ever since it came out and I highly recommend it.
 
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rcs16 said:
Damn this site has become annoying, I am typing away and the ads keep popping up stopping my key entry.
Does it do the same to subscribers? Zeb was saying the same thing a few days ago.
Click to expand...
It seems it has become significantly worse just this past week. I don't get the ads due to my browser securty settings, however I do get the pause that stops my keystrokes and blank segments/gaps on the response pages.
 
rcs16 said:
the boards are sold on ebay if anyone wants a set for $20 cdn and you get the links to buy the current revision of parts.
the new -c0 design is being tested in a sx-780 and it will be offered as above without needing the heatsink (cost reduced),
only use the HS design for hi powered applications, stk-0070,80+, it has mounting hole positions for all STK package types.

The ebay seller was asked to de-list and he complied. Suggested to him to give them away to others for free or at his cost.
Once I expire all our designs will be put out for free for the world to use as they like, I doubt the grandchildren want to take it on.

Damn this site has become annoying, I am typing away and the ads keep popping up stopping my key entry.
Does it do the same to subscribers? Zeb was saying the same thing a few days ago.
Click to expand...
I had the ads for a few days but they've been gone for a few days.
 
I should also clarify my own position on sharing design files.


There is a reason why I do not publish my Gerber files. I have shared detailed photos, PCB layout images, and schematics to help the community understand the approach and design philosophy. That, in my view, is a fair level of openness.


However, this project represents a significant investment of my own time, money, prototyping effort, and testing. I personally repair STK-based amplifiers using the modules I manufacture myself. If someone wants to build their own version based on the schematics and photos, they are absolutely free to do so — but they will need to put in some effort of their own to realize it.


In real life, development work takes time and resources. I do not sell these modules commercially on eBay or advertise them publicly. I have only produced small batches (typically 6–8 units at a time) because the demand is limited and I don’t want large amounts of money tied up in inventory.


Occasionally, if someone contacts me privately and I have spare boards available, I may provide one. But I do not distribute Gerber files, partly because that is the only practical way to protect my work from being mass-produced by third parties without any involvement on my side.


If someone takes the time and effort to design their own PCB implementation from the schematic and successfully produces a working module, that is entirely their right — and I respect that.


And of course, if anyone has technical questions about building similar modules, I am always willing to help.
 
rcs16 said:
Hi John,
Recently I discovered that someone was selling these PCBs on eBay. The premise was that this was made available for personal use only. The only way I determined to try to put an end to this was to kindly ask Heather to remove the files, in which she obliged. Sorry but you're one week late in a ~ 10 year run.
Click to expand...
Thanks for coming back to me. Only wanted to fix my amp, no intention of selling boards for profit as not my intellectual property..... Fed up of fake Chinese parts........

Take care John
 
Good grief. I was just seeking advice on stk0050 packs for my newly acquired sx780 and I stumbled onto this 10 year compilation of research on the subject! I just want to know best Chinese ebay version to buy for now. Any current top contenders? I have not read all 70 pages of this thread…
 
ducati2 said:
Good grief. I was just seeking advice on stk0050 packs for my newly acquired sx780 and I stumbled onto this 10 year compilation of research on the subject! I just want to know best Chinese ebay version to buy for now. Any current top contenders? I have not read all 70 pages of this thread…
Click to expand...
Try the seller located in Florida
 
ducati2 said:
Good grief. I was just seeking advice on stk0050 packs for my newly acquired sx780 and I stumbled onto this 10 year compilation of research on the subject! I just want to know best Chinese ebay version to buy for now. Any current top contenders? I have not read all 70 pages of this thread…
Click to expand...
I pick them from aliexpress based on the number they have sold
Pick a seller that has sold a large number of the module you want
 
Hello everyone. I ordered some boards from a member in the past, way back in the past. I would like to get ahold of some more unpopulated or populated boards. I don't have the wherewhithall to download the zip file and have the boards made to order. I also don't see any on ebay. Although I remember they were available on ebay at one time.

If anyone has some boards please PM me. Thank you.
 
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