STK-0050 replacement for SX-780 and others

Discussion in 'Pioneer Audio' started by rcs16, Jun 18, 2016.

  1. Bassblaster

    Bassblaster Super Member

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    for the STK-0050 most likely, now when used for the 0080...i dont know. i still wonder what the power output is when used to replace a 0080. maybe HBrown can test that if he has the gear to do so. i have a scope coming in the mail and 8ohm 100W resistors aren't that expensive
     
  2. rcs16

    rcs16 Super Member

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    The amp is spec'd for 19Vrms into a 8 ohm load (45W), so that works out to ~2.4A, 5A is double that, you are fine. If you are going to drive 4 ohms or 2 sets of speakers, you might want to bump it up to 7A. The bjts are 15A devices.
     
  3. HBrown

    HBrown Active Member

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    I don't have any actual output measurements, but it hits the meters on the pioneers and fishers a slight bit harder than the stock channels do. How hot you have it biased seems to make some difference in output. I haven't fused any of mine, nor done any fuse testing. It would be a good idea I suppose. I just don't intend to short the outputs- if I do, then, Oh Well, I'll rebuild it.

    I haven't really pioneered the upper limits of output. On an SX-780 with a set of vintage 3-way speakers with 12" woofers it gets way loud with the knob at about 12-1 O'clock. I haven't felt the need to try to blow something after working to get them installed and operating. You'll see what I mean after you get it going.
     
    Last edited: Feb 26, 2017
  4. petehall347

    petehall347 the brandy coffee man

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    would it not be better to fuse the speaker output rather than the rails as the main fuse should blow anyway if it gets that bad ?
     
  5. rcs16

    rcs16 Super Member

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    speaker fuses add distortion, so generally not recommended by the experts.
     
  6. klitzy13

    klitzy13 AK Subscriber Subscriber

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    Thanks for the info HBrown and for your help Rick.

    If it were mine I probably wouldn't worry about fusing it either for the same reasons (on my SX-850 with my HPM-100's I can hardly make it to 12 o'clock because its so loud in the space I have them) but its for my friend and he somehow killed both STK-0050's so I'm just trying to think of fool proofing it in a way.

    My main concern would be if he hooked up two sets of speakers to get the impedance down to 4 ohms and turn it to 13... Doing the calculations for 4 ohms at 45W it would be around 3.4A so a 5A fuse would potentially still be a decent amount of protection but increasing to 7A as Rick suggests may be the route to go.
     
  7. paultlaw

    paultlaw AK Subscriber Subscriber

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    Can someone provide the dimensions of the board in mm please?

    Is it 56mm high x 46 wide and 1mm thick?
     
  8. rcs16

    rcs16 Super Member

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    If you are asking about the stk-0050-8 pcb, this info is detailed in the STK-0050-8.pdf drawing
    It is 2.45" x 1.425"= 62.23 x 36.12 mm
    Also it is the standard pcb thinkness, 1/16" = 0.0625" = 1.6mm
     
  9. paultlaw

    paultlaw AK Subscriber Subscriber

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    199
    Perfect, thank you!
    Imperial metric confusion there. The BOM that you have shared on Mouser Rick, is that still current or is there an updated one?
     
  10. rcs16

    rcs16 Super Member

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    The Mouser BOM is current. 863-MJE15033G is on back order, so you can use one of the subs listed in the notes. For you to see the notes, I have to add you, so PM me your name and email address, so I can add you to the Mouser project list.
    I also see the nylon shoulder washer 532-7721-7PPS is on back order as well, so I will look for a second source for them as well. And it to the notes if I find one.
     
  11. rcs16

    rcs16 Super Member

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    2,912
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    In case you want to order these pcbs and have never done so before, here are the instructions,

    I never had pcbway make this particular design for myself, so I do not have an order number for you to reference. Others have had pcbway.com make this design,more than once, so we know it is good. I have had them make other designs,so that is what I was showing as my costs, using the same 100x10mm quote
    As far as ordering, get a login, provide your billing/shipping address, complete the online ordering form, and state that the pcb size is 2.45"x1.425"(62.3x38.2mm) which qualifies for the 100x100mm deal, so that you get the $10 quote, for quantity, use 10.
    Best is to pay using your paypal account, so you will need one of them if you do not have one.
    For the pcb ordering options, leave them as default, which means, green solder mask, HASL(Hot Air Solder Leveling using leaded solder) finish, soldermask top and bottom, white silkscreen on top, 1oz copper,1.6mm(1/16",0.0625") pcb thickness.
    I noticed recently that they have a check box asking if you give them approval to substitute a higher performance plating, ENIG(Electrolysis Nickel Immersion Gold plating), so check that box as being okay. When you place the order, attach the zip file that contains the gerber,cnc drill data. You do not need to include a BOM, since you only want the pcb's made and do not want them to buy parts, assemble the pcb's, that is your job to do.
    I used HK post shipping method, as it was the cheapest, I was in no rush, you can select another shipping method if you wish, but you will pay much more for faster shipping.
    If they reply back, after they review the information and say that there are 4 holes outside the pcb outline, tell them that it is okay and to disregard them.
    That should cover it, if not let me know.


    Good Luck
    Rick
     
    Last edited: Mar 17, 2017
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  12. zebulon1

    zebulon1 Back repairing the PL's Subscriber

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    I just ordered 10 so there's a lead time.
    I'll send some at cost to any who are looking for them.
     
  13. Bassblaster

    Bassblaster Super Member

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    Still planning on using these on my Fisher CA-800. since i finished up a sherwood i was working on last week. i think its about time i pull the fisher out. Rail voltage on the CA-880 is +/-55V. i doubt its any different in the CA-800. rcs16 you think you can run that through your simulation program and see what it says with that rail voltage?
    Man this CA-800 is about to be my most expensive project yet!
     
  14. HBrown

    HBrown Active Member

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    Location:
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    Bassblaster, as long as everything else in the 800 is ok, there shouldn't be any problems. As well as multiple SX-780's, I have installed the modules in the Fisher 880 (~57V rails), and now also a Fisher RS-2004a- which has a single amplifier board for both channels like your 800 does. The 2004a had suffered a major failure in the amp/driver circuits in one channel that had to be sorted before I could attempt the modules, but it turned out well. I had to modify the heatsink mounting screw locations and enlarge the window in the back panel of the unit to make the modules fit side by side- time consuming, but I like mechanical projects such as that.

    In this case, I opted to make the adapter plates work instead of drilling the heatsinks and installing the devices directly to it. I would have still had to enlarge the window in the back panel, and accurately locate & drill/tap 10 holes in the heatsink. Making the adapter plates work in this case was easier. You will need to do something similar on your 800.

    IMG_20170315_123708330.jpg
     
    Last edited: Mar 18, 2017
    eizner23, Bassblaster and rcs16 like this.
  15. rcs16

    rcs16 Super Member

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    If I had a schematic of a Fisher CA-800, that might help :) Without seeing a CA-800 schematic, I can not confirm nor simulate that the module would work. It is a chance that you are taking. I am fairly confident that it should work, if these Fisher designs are similar enough but can not be 100% sure without having a schematic to review and sim against.
    As HBrown has already done a build and tested it out on a CA-880, the CA-800 supply voltage of +/-55V is not a problem.
    Good luck and here's hoping all goes well.
     
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  16. Bassblaster

    Bassblaster Super Member

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    Sooo i got a package in the mail today...
    EDIT: Ok so comparing the schematic for the CA-800 to the 880. the amplifiers are mostly the same. only differences are the emitter resistors in the 800 are .22 5W where the 880 are .47 7W.
    That's it.
     

    Attached Files:

    Last edited: Mar 23, 2017
  17. rcs16

    rcs16 Super Member

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    The 0.22ohm emitter R's are insignificant and the same as is used on the SX-780.
    If/when you have the time, scan/post the CA-800 schematic for my library. If you want, you can PM or email it too me.
    Did the service manual cost about the same as the parts for the STK-0050 modules? :)
    Where are you at with the build, parts, pcb, Al plate?
     
  18. Bassblaster

    Bassblaster Super Member

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    i think ill send it in to HiFi engine, then everyone can download it.
    Manual only cost me 58 cents ;) i still had a half spent eBay gift card laying around i used.
    None of those. i figure first ill get the boards and plates, then all start redoing the amplifier with some new caps and other goodies. someone was inside of it before i got it, we got shorted caps in the pre amp, a replaced op amp along with some blobby solder work on some wires. and of couse one of the STK-0080's have been swapped out.
     
  19. rcs16

    rcs16 Super Member

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    2,912
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    Great idea.
     
  20. Bassblaster

    Bassblaster Super Member

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