No opinion. I treat these "opportunities" as a roll-the-dice proposition and evaluate my options using Expected Value calculations from EE probability class. When expected cost < expected value and also I'm in a good mood, I buy. Or else I don't buy. Other people are of course free to make their own judgements.
I might have caused some confusion, I was asking what you thought about what I wrote
here about hfe ranking for these Fairchild ksc1845/ksa992 transistors:
http://www.diyaudio.com/forums/part...rade-no-longer-available-nla.html#post4950901
Do you think they might have gone to a new way of ranking hfe for ksc1845/ksa992?
E and FB class are nearly the same.
here about hfe ranking for these Fairchild ksc1845/ksa992 transistors:
http://www.diyaudio.com/forums/part...rade-no-longer-available-nla.html#post4950901
Do you think they might have gone to a new way of ranking hfe for ksc1845/ksa992?
E and FB class are nearly the same.
For a low power amplifier, the drivers don't need much in terms of power handling. My vote would be for BC550/60 or the humble 2n2222/2907. Both have great noise figure and are fairly fast. I say it depends on the frequency requirement. Quad 2's have Ft of 250MHz and the BC's have Ft of about 300MHz.
BC550/560 have a Vceo of 45Vce
They would not normally be used as drivers on any power amplifier with supply rails higher than +-22Vdc. That severely limits the output capabilities of the power amplifier.
The maximum Ic of the BC550/560 is 100mA.
That too, as the maximum base current into the output devices, severely limits the output capabilities of the power amplifier.
They would make suitable drivers for a headphone amplifier driving >=100ohms headphone from 15Vdc supply rails.
They would not normally be used as drivers on any power amplifier with supply rails higher than +-22Vdc. That severely limits the output capabilities of the power amplifier.
The maximum Ic of the BC550/560 is 100mA.
That too, as the maximum base current into the output devices, severely limits the output capabilities of the power amplifier.
They would make suitable drivers for a headphone amplifier driving >=100ohms headphone from 15Vdc supply rails.
Not normally used as drivers, but according to the question:
BC550/60 will be fine for the 10V, but not >100mA. 2N2222 will be fine for both. It depends on the requirement. They will also be driving FETs, so I wouldn't know why they would need > 100mA Ic.
They are not widely available in Australia, where can they be purchased?
Thank you, it is nice to find someone who actually reads the prior posts.
The IXYS power FETs have quite a substantial capacitance so they require quite a bit of pull-down current.
But FETs were only one possibility, the drive current of a few paralleled power BJTs also adds up rather fast.
Best wishes
David
Ok, makes sense.
If they're easily available (they should be - they are here), then what about
2SA2016/2SC5569?
If they're easily available (they should be - they are here), then what about
2SA2016/2SC5569?
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