Conversation Between foton and cajun

24 Visitor Messages

  1. Hello cajun,
    It looks like P-channel fets becoming rare. oh well, I will go with BJTs. Thanks for the help.
  2. Hello cajun,
    May i ask you for another favour? I have forgotten about one more semiconductor firm. The name is Central Semiconductor Corporation. They do make P and N-channel FETs. I did try to compare their parameters to 2SJ74 and 2SK170, but it is very criptic for me. It looks like they do make them in two package styles: leaded and smaller SOT23F. The latter one is small, but I think I still can solder it with no problems. This is url:
    Would you find a moment to look there?
  3. OK, I am unable to figure out how to attach the file. I can not find on their website the file which thery sent to me either. This is url to their jfets:
    It is strange they only have 4 of them
  4. Thanks a lot !!!!! Let me figure out how to send the PDF file.
    I am unable to attached the file. No attach option available in Private Message or send e-mail screens. The only attached option is on response screen on regular forum. But, I am not able to attach the pdf file anyway. I am getting missing security token message. Strange
  5. foton,
    Hi. Renases was started by Hitachi and Mitsubishi. I would be happy to take a look at the file and look for a 2SJ74 replacement. Send me the file.
  6. Hello, may I ask another question? I have contacted Renesas. I am not sure the origin of the firm, it is an American firm. It looks like they took over production of some semiconductors from Toshiba. Mostly the ones, which were discontinued by the latter one. I asked them about 2SK170 and 2SJ74 jfet transistors. The gentelman whom I talked to said they might have suitable replacement, but they do not make 2SJ74 direct equivalent. He sent me PDF file with products and information about them. Would it be possible for you to check it? I will build Hiraga 20W one with BJT transistors, but I would also like to experiment with Le Monstre, which uses jefets for input transistors. Please let me know you will have time to check for me.
  7. You're welcome. I miss engineering.
  8. Thanks for all your help. I will check what I have at home. I have lots of samples in few junk bins.
  9. MJE180G/MJE170G look like good replacements for the 2SAa634/2SC1096.
  10. I would use the BC547/BC557, to be a little safer, and it looks like mouser has them. The Sankens will work for the output transistors. The MJ11022/MJ11023 or MJ11024/MJ11025 in place of the 2SA634 and 2SC1096 doesn't make sense. They are darlington transistors, and the originals are not. I will look for suitable ones and send another post later.
  11. It looks like the problem is with input transistors. It is being recommended to use the listed ones, which are: 2SA782 and 2SC1775. The are also obsolete and exsiting ones are expensive. Would BC549/BC559 work in this position? I think they are still available. I need to check with Mouser electronics.
  12. All listed transistors here are obsolete. They can be found, but they are expensive. People recommend these replacements as driver/output transistors: MJ11022/23 or MJ11024/25 and MJE15030/31 MJE15032/33. I should have them. Would Sankens work in this curcuit as output transistors?
  13. Sorry for the size of the image. I do not know how to resize it:
  14. Hello cajun,
    I have made a little bit of a mess here. I want to build Hiraga for the past......8 years. This is the last time I have seen the schematic. Really, Hiraga designed two amps: "Le Monstre" which is also known as 8W one, and Hiraga 20W known as Class A. The 8W one has jfet input transistors where 20W one has BJTs. I forgot about 20W one. This is the one which I want to build. I will try to send you schematic through PM. One of the reasons I forgot about it is the website of the guy who posted it is down. But, I was able to find it.
  15. I'm not sure which design you are asking about now. A BJT will not usually work in place of the 2SJ74. Will study.
  16. It looks like there are problems with 2Sj74 JFET transistor. Is out of production. They are available on e-bay, which is not my favourite source. If I remember correctly one of the first Hiraga schematics used BJT transistors at the input. Is it possible to use BJTs and preserve sound quality of this amp?
  17. Yes, they are kind of big. But, they might look very cool:
  18. I have never built an open baffle design. They tend to be large with a low SAF, spousal approval factor. I have read about them and have some understanding of them.
  19. Thanks for the link. That will be my future project. You have mentioned before speaker design. Have you built open baffle ones?
  20. foton,
    I think that the ideal application for the Sanken transistors, with very high voltage rating but not so high current rating, is using them in parallel in a very high power design. When I searched for designs using them, that is mostly what I found. A design that I would guess that you would be interested in, and that they should work well in, is the Hiraga 30W design, The Sanken FETs have enough voltage, current and power for this design, and this design is insensitive to the speed of the output transistors.
  21. Which type of amplifier fast Sanken transistors can be used in?
  22. Yes, BOZ is one of the pre-amps which I want to build. I am recently interested in simplified circuits for audio. Pass designed two more circuits which I want to try based on 2Sk170 jfet. One is BOZ version based on JFET and one is here:
    And here is more info about behavour of BOZ:
  23. Hello cajun,
    Thank you very much for your help.
  24. Hi,
    Maybe we should take our conversation off of the forum. I found a schematic for the Bride of Zen preamp, Is this the one that you want to build? The only transistor in it is the IRF610. This is available.
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