Transistors - What is A,[GR/BL/Y] suffix?

[blight]

Hi!

I have a damaged Yamaha AX-870 audio amplifier... since the output stage is damaged i guess i have to replace all transistors after the DC-coupling capacitors (i am a noob)...
I have found all the parts at a german shop but in the schematic (**broken link removed** red circles mark parts with visible damage and yellow circles are output stage transistors which i have compared to the ones from the other, working channel and IIRC have shortcuts or other damage) the 2 transistors at the inputs of the output stage have an "A" suffix (i.e. I have found 2SB1186 but the schematic says B1186A[D/E]) - is the A something like low-noise which is more expensive? what does the D/E mean?
For another transistor the schematic says A1015[Y] - should i try to get 2SA1015Y or 2SA1015 now?
Also on some site i have seen 2SA970 GR and 2SA970 BL (the schematic says A970[GR/BL]) but the german shop only has 2SA970 - i guess it would work using the parts without the suffixes but i would like to know what they mean! (especially when some seem to be "explicitly stated" like it says B1186A and not B1186[A]) or are these letters meaningless?
:roll:

Thanks,
blight

 

[Nigel Goodwin]

They are selected gain figures,

2SA970 - 200 min.
2SA970GR - 200/400
2SA970BL - 350/700

I wouldn't expect them to make a great deal of difference, there's still going to be a very high open-loop gain - it might make a very slight difference to the distortion figures, but nothing audible.

 

[blight]

Thanks!
What about the A suffix? Is that low-noise or something else?

 

[Nigel Goodwin]

Thanks!
What about the A suffix? Is that low-noise or something else?

I couldn't find those transistors listed!.