2SB1236 and 2SD1857 transistors- where?

[ken]

Hello...

I have a dead Fender Stage 160 on my bench that needs 2SB1236 and 2SD 1857 power amp driver transistors. Fender is 'backordered' on these, at least for a month and maybe two.

I can't find these in Mouser, Digikey or Allied at all.

Anyone know where I can find these so I can get this POS off my bench?

Thank you,
Ken

[Enzo]

When it comes to Asian transistor numbers, Digi has a few, Allied has none, and I don't recall Mouser having any, but MCM is a good place to find them, though, in stock, at 61 and 54 cents apiece.

www.mcminone.com

Are those TO220? If you have the 2SC3298/2SA1306 pair in stock, they would work nicely. Can't tell from the drawing or parts list. I suspect they are smaller packages?

[ken]

No, but I wish they were. They aren't normal TO220 shaped but a small rectangle with all three leads coming out one of the long sides.

I wish FMIC stocked more of their parts.

Thank you,
Ken

[Enzo]

Is there a little half round divot in the top? I think I know the shape you mean. Looks likek they sit in a hole on the heat sink, so they have to fit the space. Well, a buck gets the pair of them from MCM.

A lot of OEMs I work with tell you to get the generic parts in the general market. Like the TIP142/147 outputs, I stock them because not only Fender uses them, but also Crate, and they also go into Valvestate Marshalls in place of those BVD whatevers.

[amptech]

Hi ken,
about your transistor problem, you can use any matched pair in the o/p stage and tip41c/ tip42c in the driver stage and 2n5551/2n5401 for replacement long tail pair.
cheers for now amptech

[Enzo]

That is not correct AMptech, these are darlingtons, and using a plain old bipolar will not work. Also, one would have to watch out for voltage, current, and dissipation ratings. The transistors he is looking for are not drivers. There is no long tailed pair, the output is driven by an op amp, 4560.