Replacement transistors in Leach Superamp. Help needed!

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AudioAmpFanat

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Joined 2009
#1
Hi Guys!
I am new here 🙂

I am building leach Super Amplifier the PCB's are allready done, but there is a problem - i can't buy the 2N3439/2N3440 and 2N5415/2N5415 transistor pairs in my country. Can someone suggest replacement transistor pairs for these transistors in Leach Supeamp original design?

P.S. sorry for my english.
 
#7
AudioAmpFanat said:
In my country they are aviable thats why i am asking about them !!!
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If they are orig Hitachi components and no copies from unknown brands and 120/160V are appropriate Uce voltage, you can buy it. If only copies available, I would not buy perhaps there are counterfeits - for more informations please read carefully this:
Counterfeit Transistors
By the way - where is your country? - "Antarctica" is a junk - isn't it?
 
#11
So again (just to be 100% sure 🙂) whitch transistor pairs is for whitch replacement pairs ?

Witch for 2N3439/2N5415

And witch for 2N5416/2N3440
 

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#12
2N3439 and 3N3440 are for practical purposes, the same. MJE340 will sub in S-Leach or similar amps. Different package, but it will *work*. MJE350 will sub for 2N5415 or 2N5416 in these circuits.

Most of the high gain Jap-type predriver transistors can be made to work, but since performance of these tend to be higher the circuit may need to be adjusted. For very low Cob types, the Miller caps may need to be increased to make it as stable as it is with the older obsolete types. The MJE's are just universally available, and not too "hot". Collector current ratings on the MJE's are lower than the TO-5's but even a 1/2 amp part is well within rating here. I wouldn't be surprised if Ic wasn't package or bond wire limited anyway.
 
#14
AudioAmpFanat said:
OK since im able to get MJE340/MJE350 transistors here in my country i think i will use them, but exacly whitch capacitors need to be incrased (whitch number in schematics)?
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some amplifier specialists claim, better to avoid these types of audio applications - read in this case this one:
http://www.diyaudio.com/forums/soli...0-bd159-gbp-transit-frequency-ft-unknown.html
http://www.diyaudio.com/forums/solid-state/3853-bf469-470-471-472-vs-mje340-350-better.html
http://www.diyaudio.com/forums/soli...ver-stages-high-power-amplifier-overview.html
 
#18
AudioAmpFanat said:
So then what about 2SD669/2SB649 transistors can i use them?

P.S. i dont need no "hi - end" parts i am building this amplifier mostly for PA applications!
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Then you can use MJE340/350, at best from "ON" or "ST"

I would buy from Farnell in your country; from their you get also some the mentioned types at start of this thread from me:
Bipolar Transistors (BJT) Single | Farnell LT
additional you can ask there:
Sveiki atvykę į RS Online

not the cheapest suppliers, but always good quality

here another URL regarded replacement parts for HV Video BJT's
Cozy Room HTML template
 
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