Yes you actually can capacitance and speed is alike not to mention mounting ...1494 combo is more rugged designed to operate in higher voltage and higher power but this is no problem
You might have to play with the bias and the wise thing to do is to replace both working and not working ones from the other ch .
Kind regards
Sakis
You might have to play with the bias and the wise thing to do is to replace both working and not working ones from the other ch .
Kind regards
Sakis
I'm sure you can replace 2SA1184 / 2SC2824 with 2SA1837 / 2SC4793 and
2SA915 / 2SC1940 with BC639 / BC640. The BC's have slightly lower voltage rating, but the amplifier is a 70 W, so I'm guessing an 80 V transistor should do fine. Measure the supply rail-to-rail. My guess would be around 72 V. I'm also of the impression the full supply voltage can never be put across these transistors.
Measure; don't take my word for it.
2SA915 / 2SC1940 with BC639 / BC640. The BC's have slightly lower voltage rating, but the amplifier is a 70 W, so I'm guessing an 80 V transistor should do fine. Measure the supply rail-to-rail. My guess would be around 72 V. I'm also of the impression the full supply voltage can never be put across these transistors.
Measure; don't take my word for it.
Vbe on the BCs is very slightly less than on the 2SA915 / 2SC1940. I would guess they wouldn't be running at more than 5 mA. At 5 mA, the old transistors will have a Vbe about 0.67 V vs the BCs at 0.62 V. I personally don't think it will be cause for concern. I may be wrong, but in my experience, this size difference (up to 10%) is within device tolerance anyway, and no design should be that tight.
Below 5 mA, the difference is even more negligible.
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Maybe i could use 2SA1306/2SC3298 for drivers and 2SA949/2SC2229 for predrivers because this ones i have ...they are a bit more beefy than the originals, but probably will do well...shall i give it a try ? As said here, i will never mix BCs with 2Ss...say japaneese with european transistors...
Thanks
Thanks
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hahahahhaha .... you could but i dont think that 1306-3298 that you have are originals unless you pulled them out of a working amp ...Sorry to say that i have them also original ( the green ones for the PNP ) in the same prize ...each ...
I am not trying to sell here ... but YES i like to brag a bit about my stock ...
Regards
Sakis
I am not trying to sell here ... but YES i like to brag a bit about my stock ...
Regards
Sakis
Well Sakis, i have this board to pull this transistors and use them in my amp, but maybe i can find some new originals still around here in my country...
Attachments
I got this board from a scraped ONKYO Integra, and i going to use this transistors to repair my A-45 , i will replace all transistors in both channels, then i will have a spare pair of the 2SD845/2SB755.
Thanks
I will not buy them i got 20 sets hahahahahahaha
I wish success to your work ....
20 Sets ????? then you must have the biggest stock os this pair in the world !!!so why you dont sell me a pair ? what are you going to do with all those ??? maybe next hollydays i go to greece, meet you in Athens, and convince you to sell me a pair
Those and many more ...now days we repair about 1000 audio devices per year mostly amplifiers
before i got this stock most of the times we had to modify amplifiers similar way like you are trying and go as close is possible but we consumed time and we had to long run and evaluate changes from any aspect like stability oscillations and /or others ...
Now i am offering my customers original replacements at a very expensive cost but they get to keep amplifier very very original in case they like to ...So i make money with this and also i save time since the original you only have to solder them inside measure offset and bias and you are sure and done within minutes ...
I have about 30pcs of 2SK150 another 20 of 2SK34 ( very rare ) and about of 100 pcs from 2SC 1000 or 2sc1313 all of them extremely rear to get in original condition ...
I think in the near feature i am going to have so much fun with those and money also .
I showed the parts in my every day semiconductor supplier here in Greece and the guy actually started to cry !!!!! ( i offered also to sell to him at 10 euro a piece )
before i got this stock most of the times we had to modify amplifiers similar way like you are trying and go as close is possible but we consumed time and we had to long run and evaluate changes from any aspect like stability oscillations and /or others ...
Now i am offering my customers original replacements at a very expensive cost but they get to keep amplifier very very original in case they like to ...So i make money with this and also i save time since the original you only have to solder them inside measure offset and bias and you are sure and done within minutes ...
I have about 30pcs of 2SK150 another 20 of 2SK34 ( very rare ) and about of 100 pcs from 2SC 1000 or 2sc1313 all of them extremely rear to get in original condition ...
I think in the near feature i am going to have so much fun with those and money also .
I showed the parts in my every day semiconductor supplier here in Greece and the guy actually started to cry !!!!! ( i offered also to sell to him at 10 euro a piece )
Well, today i finished the repair of my Onkyo A-45, and maybe it could be usefull for someone with same problem. I replaced the outputs 2SB755/2SD845 for 2SA1301/2SC3280...the drivers 2SA1184/2SC2824 for 2SA1535A/2SC3944A...the pre-drivers 2SA915/2SC1940 for 2SA1123/2SC2631 and replaced the DC servo controller 4558DX for NE5532, and it works perfect, so i am going to do the same in the other channel
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