KSA1220 Transistor out of stock

Discussion in 'Solid State' started by dave404, Jan 13, 2019.

  1. dave404

    dave404 New Member

    Messages:
    34
    Location:
    Whiteford, MD
    Hi all
    In the process of a rebuild, I found I needed a KSA1220 transistor. However, both Mouser and Digikey don't have any in stock. Does anyone know a a source or of a good substitute?

    Thanks
     

     

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  2. slimecity

    slimecity Super Member

    Messages:
    3,242
    Location:
    New Zealand
    How many do you need? I have a few and can send them to you - but unfortunately it will cost you the price of postage from NZ.
     
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  3. dave404

    dave404 New Member

    Messages:
    34
    Location:
    Whiteford, MD
    Slimecity
    I need two.. and let me know what that would be.. and how can I pay you?
    thanks for the offer :)
     
  4. EastPoint

    EastPoint Factory Code No. 4200 Subscriber

    Messages:
    4,818
    Location:
    Milwaukee, WI
    I think a KSA940 should be ok as a sub in most situations.
     
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  5. LesE

    LesE 110284 Subscriber

    Messages:
    944
    Location:
    Ontario, Canada
    Depending on the application, a Toshiba TTA004B may be a good sub.
     
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  6. quaddriver

    quaddriver 120 What's per channel Subscriber

    are you using the 1220 as a compliment to the 2690? that makes things harder but as mentioned the 940 might fit (and its 2073 compliment) if that is what is needed.
     

     

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  7. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    22,223
    Location:
    Glen Burnie Md.
    PM on the Way. I've got some still sealed in the Mouser Bag. And I'm right down the road in Bel Air.
     
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  8. slimecity

    slimecity Super Member

    Messages:
    3,242
    Location:
    New Zealand
    I will assume that larryderouins offer is a better one for you to take!
     
  9. dave404

    dave404 New Member

    Messages:
    34
    Location:
    Whiteford, MD
    Slimecity, yes he is A LOT closer than NZ, however, I want to publicly say you and your kind offer is one of the reason's why forums like this are so cool.. you don't know me from Adam but are willing to help.. says a lot about the quality of people here.

    Cheers
     
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  10. slimecity

    slimecity Super Member

    Messages:
    3,242
    Location:
    New Zealand
    No probs.

    Just paying it forward - I have had a ton of help from some of the great members here too.
     
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  11. craig elder

    craig elder New Member

    Messages:
    16
    IF THIS IS FOR YOUR MAIN AMP SECTION. SWITCH TO MJ21193G AND MJ22294G. THESE ARE VERY LINEAR AND CAN HANDLE THE POWER. PLEASE CHECK THEM OUT. A LOT OF PEOPLE USE THEM INCLUDING MYSELF ON A STA 2100. MOST GOOD TECHS SHOULD AGREE.https://www.mouser.com/datasheet/2/308/MJ21193-D-108487.pdf ALWAYS CHECK AGAINST YOUR STATS.
    Step by step instructions:

    1. Choose a transistor of the same polarity: The first major selection criterion is whether the transistor is PNP or NPN.
    2. Select a replacement transistor of the same material: Most transistors are either silicon or germanium. As bias voltages and other features are different it is necessary to select a replacement transistor with the same material.
    3. Select the same functional type of transistor: Transistors are normally given an indication of their application in the datasheets. The replacement should have the same application if possible.
    4. Choose a replacement with the same package: Choosing a replacement transistor with the same package and pin-out will mean that many of the characteristics including power capability are the same. Ensuring with pin-out is the same (most but not all transistors have their leads in order - EBC) will save many problems with fitting.
    5. Select a replacement transistor with the same breakdown voltage: Ensure that figures for VCEO and VCBO etc are at least as high as the original transistor. Voltage at least or higher
    6. Check it can take the current: Ensure that the replacement transistor can pass the required current - it should have an ICmax greater than or equal to the original transistor.
    7. Collector Current is Greater than or equal to
    8. Select a transistor with a similar Hfe: It is necessary to ensure that the current gain of the replacement transistor is about the same as the original. Current gain values normally vary widely even for transistors of the same type so some variation will be acceptable.
    9. Similar dc current gain
    10. Select a replacement transistor with equivalent Ft: It is necessary to ensure that the replacement transistor will be able to operate at the relevant frequencies, so a similar or slightly higher Ft is advisable. Don't go for a transistor with a much higher Ft as this may increase the risk of oscillation.
    11. . Don't go for a transistor with a much higher transition frequency, NOT ALWAYS A NECESSARY FACTOR.
    12. Choose a transistor with a similar power dissipation : It is necessary to ensure that the replacement transistor can handle the power that it will dissipate within the circuit. Choosing a replacement transistor with a similar can style will often mean that both transistors have a similar power dissipation.
    13. similar power dissipation in collector can be more
    14. Check for any special features: While ensuring the features above are selected, there may be some additional features that need to be considered. These are normally required when transistors are used in specialist applications.
     
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  12. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

    Messages:
    1,887
    Location:
    Victoria, Australia
    The OP is after a source for the KSA1220 (to-126) not a to-3 package power transistor. But yes those MJ21193g's and MJ21194g's are very good devices.
     
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  13. dave404

    dave404 New Member

    Messages:
    34
    Location:
    Whiteford, MD
    Craig
    Thanks for the information and this is REALLY good information for finding replacement components that are not in production anymore. However, oldsansui441 is correct, these will not work without SIGNIFICANT modification to the existing power amp board. I really do need the TO-126 package. As luck would have it there is a member close to me that has a few and we are getting together for a beer today!
    Thanks for the help and it will come in handy one day.
    Cheers
     
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  14. avionic

    avionic " Black Knights " F-15 Eagle Keeper Subscriber

    Messages:
    46,489
    Location:
    Fort Dodge, Iowa
    MJ21194G
     
  15. craig elder

    craig elder New Member

    Messages:
    16
  16. sssboa

    sssboa Well-Known Member

    Messages:
    785
    Popular KSC1845 out of stock on digi :eek2:Where is the world coming to?
     

     

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  17. avionic

    avionic " Black Knights " F-15 Eagle Keeper Subscriber

    Messages:
    46,489
    Location:
    Fort Dodge, Iowa
    Mouser only has 68,000 left. Better get what you need pronto!:biggrin:
     
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  18. fernarias

    fernarias Super Member

    Messages:
    1,117
    Location:
    Merced, CA
    The economy is heating up even more and suppliers and manufacturers are having trouble forecasting new demand. Silicon wafers are also still scarce. Also, since we've had stock outs for a while now, many here buy more than they need (I included) when shopping so imagine if you're running a business that relies on devices that stock out. These businesses are also going to buy more than they need.
    Just in time was stupid for US manufacturers since warehouse space is cheap compared to europe and especially countries like japan where warehouse space is still very expensive (since everyone wants to live in tokyo).
     
  19. EastPoint

    EastPoint Factory Code No. 4200 Subscriber

    Messages:
    4,818
    Location:
    Milwaukee, WI
    Mouser and DigiKey run out of parts all the time. It boggles the mind.
     
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  20. Watthour

    Watthour Electron Rancher - JS3600

    As LesE indicated, if the KSA1220AY goes EOL, the TTA004B and TTC004B might be worth a look, since they seem to completely cover the operating range of the 1220 with higher current and wattage, and only about 12% lower gain, and a slightly lower Ft.
     

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