mje15030/1 special?

Dieter,

These MJE15030/31 ON Semi TO220AB transistors are very rugged (150V 4A), and quite fast (30MHz ft). I use them in a 100W kitset amp I sell, and they perform extremely well.

They will handle up to 8A surge, so they make wonderful drivers in PA and pro-audio roles. They are also very good in unprotected hifi amps, since with a 10R base stopper on the output devices, they never blow even when the outputs incinerate.

Toshiba make very good drivers, but the current rating is four times less. They are the 2SC4793 and th 2SA1837, with ft of 100MHz and 70Mhz respectively. They are extended beta devices with nominal around 80, and match ideally to the 2SC5200/2SA1943. They are excellent in any 100W hifi amplifier, and I use them in my 55W AKSA kitset.

A readily available but old (and slowish, 15MHz) driver is the BD911/912 series from Philips. These are an old standby and will handle, I think, around 3A. I would not advise using the MJE340/350, since these are much higher voltage than needed, quite slow at 10MHz, and will only deliver 500mA, which I don't believe it enough for two low beta output devices operating from 50 volt rails.

Cheers,

Hugh R. Dean
www.printedelectronics.com