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Confirming transistor subs,,,

Am I correct in assuming 2N3055 is too slow(fT) for replacing the original 2SC244 in this receiver? Seems fine in all other values,, and much closer than 2N5038 in it now,,,
TIA
 

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I agree,,, however I asked because some of the values in subs aren't as important as others, and I dont have that much experience with SS stuff... For example KSC1815 is supposed to be a good replacement for obsolete 2SC536 but 536 Frequency is 115MHz,, KSC1815 is 80MHz, as are other 1815 specs I've looked at...
Just dont know what to believe, there isn't much support here... Guess it depends where in the ckt its used,,, so trial and error for now!!!!
 
I'm still struggling with subs,,, I keep reading that KSC1815 and KSC1845 are subs for 2sc458,,, but the data sheets don't agree... 458 has Ic=100mA,, 1845 has 50,,, 458 has 115MHz,, 1815 only has 80...
Seems a 2n3904 has covered in all values, but I haven't seen it mentioned... Also saw sub for 2SC536 is KSC1815,, but that falls short in frequency also... It looks like 2n3904 can cover this one also... I dont see 3904 recommended as subs for Sansui's,,, is it only because of pinouts, rather than a problem with the transistor?? It's pretty easy to just insulate and move a pin to use a very common and dirt cheap transistor, unless i'm missing something major...
Thanks for any input...
 
I've had to use subs with different pin outs. Either having to install them backwards from the original, or having to cross a leg.
 
Yep,, exactly,,, I've done that on all the subs I've used so far,,, maybe that's the reason the subs I'm choosing aren't being used more here? But the values are closer than some asian subs that have pins matching...
 
The particular kind of old transitor "2SC458LG" tended to became noisy. These were easily identified because they had an odd encapsulation type not like the TO-92 case. These should be replaced if found in your unit. The modern 2SC458 may fail like any other transistor, but it is no special like the 2SC458LG.
One could use KSC1815 for them. Another alternative is KSC945CG. Depending on where you are located you may be able to find toshiba 2SC2458GR or 2SC2458, (a 50 cent part with the same die as the 2SC1815). Another option may be the KEC KTC3198 which is identical to the 2SC1815. Rohm has been manufacturing the 2SC458 until recently (and it is unlikely that they have the failure mode of the old 2SC245LG), and you may be able to find these. Most people in this forum try to preserve the pin-out of the original part when replacing. This is why you will not see a 2NXXXX part replaing a 2SCXXXX, unless there is no alternative available. Nothing wrong with the 2N3904, except that it tends to have lower gain than the japanese types you are trying to replace.
 
Thanks for the reply,,, I have KSC1815 and KSC1845 coming from Digi this week,,, I'll use one of them for replacing 2SC536 preamp transistors... I didn't get a lot of replies here, and looked at data sheets and some subs were not at least equal to the original parts,,, in some values.. 3904s were equal or better than the ones they replaced... Pinouts are an easy work around for me
Look at my post #24...
 
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