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Rinat

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  1. About using 2sa1413 as a substitution of 2sa1486. Am I wrong that they looks pretty similar? I am waiting them from bdent, they are in TO-251 cases. I've found only one datasheet with this type of case for 1413: 1413 datasheet jp to-251 1413 datasheet en 2sa1486 en
  2. Thanks! I think I can use 2SA1413 everywhere with a proper heatsink. It could dissipate up to 10W with an "infinite heatsink" by datasheet. I can't find what 1486 dissipates more than 10W. But I am going to buy STN9360 and 2SA1156 as well just in case.
  3. I've found that 2SA1413 is the 2SA1486 in a D-PAK TO-252 case. Thanks!! Ok, my new plan: 1) Try to make an adapter for 2sa1413 as the most authentic option. 2) If the first case would not successful for some reasons, I will try STN9360, thank you, JoaMat. Reducing voltage is the last option for me. 🙂 I want to make initially the most authentic T2 and only after that I would make another T2 variations. For example I would like to completely change all CCSs in favour to higher internal options, modern components, etc... 🙂
  4. https://diyaudiocart.com/ON-Semiconductor-Bipolar-Transistors-BJT-16A-250V-200W-NPN Is it a reliable source?
  5. Hi all. I've found that I can't buy 2SA1486 transistors ( Could they be replaced with 2SA1413 ? I don't see any differences between them in datasheets except a lower constant power dissipation: 10W instead of 15W. Maybe I missed something important....
  6. I know about fakes and try to buy all silicon from trusted sources - forum members, bdent etc. Anyway, thanks for the advice! I also would test all the transistors before use them, and not only test for breakdown voltage, but build curves, measure capacitance, etc. I would not allow my NOS transistors to burn 🙂 Why don't I build modern version of T2? Because I already have many rare components and I believe that I could find necessary components or replace them with something similar.
  7. Hi. I am searching for 2SA1468 and 2SK246-GR There are only 5 pcs on the bdent ( Could I replace them in the original T2 scheme (I already have PCBs) without lowering sound quality ? 2SA1468 -> 2SA1968 | 2SA1413 ? Or maybe just someone knows where could I buy them ? Or what device should I destroy to get them ? No, really - I don't afraid used, but original transistors 🙂 I just a little desperate to find at least a little reliable source of these transistors 😞 Thanks!
  8. Does it mean that if I would raise loudness level so much so that amplitude of output current would be more than 3A(or 6A in balanced configuration - with 2 boards per channel), then It would work in AB? Ok, It means that I do'nt need to buy x*3 number of transistors. Thanks 🙂
  9. Thank you very much! About the bass filter - I think I'll add it to the feedback, just need to calculate conditions of stability properly. Just a two questions(sorry if they are stupid): 1. How much transistors I need to purchase ?) I mean if they should be matched with each other ? For example: I need to get 4*9 2SA1943 (for balanced configuration). But how should I match them for such a parallel connection? And how much should I buy them ? Asking just because they are not cheap 🙂 and as a fan of tubes I have no experience with matching transistors. 2. The uberamp2 works in class A or AB ?
  10. Hello! I am going to try to build the Uber amplifier for Raal Sr1a. But Kevin said that What should be changed in the scheme to drive 0.2 ohm load better? Is it the last version ? Thanks in advance. uberamp2.pdf
  11. Hi all. Maybe a stupid question, sorry, but what about using Maida 21ct voltage regulators for the power supply ? It look like it have a nice PSRR, noise (20uV at 400v) and impedance. It could be confugured for voltages up to 525v and it could be used for negative voltages too (with a separate wind). What are the disadvantages of this regulator in comparison with original from Kevin ? I am asking, because I already have 6 boards 🙂 Thanks in advance !
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