what transistor to use??????

[prorms]

iam looking for good transistor in the 1st steps of the poweramp
65v max discert transistors iam not sure what ones to try out
thier all circle in red

[Jan Dupont]

Not the best in the world, but allways gives a good result;
MPSA42 and MPSA92

[lineup]

Originally posted by seanmacss
iam looking for good transistor in the 1st steps of the poweramp
65v max discert transistors iam not sure what ones to try out
thier all circle in red

BC546B and BC556B would be my choice.
65 Volt, 0.500 Watt.
(or BC546C/BC556C higher gain, which is to prefer if you can find C-variants)
They are as good as almost any other small signal.
And you can find them everywhere, in case you need to do service of amplifier in future.

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There are some other commonly used in audio amps,
that can take more than 65 Volt.

2N5401 (PNP) + 2N5551 (NPN) 160 Volt, 0.625Watt
are very often used HIFI higher power amps = higher voltage
They are also very easy to find and to buy.

http://www.onsemi.com/pub/Collateral/2N5401-D.PDF
http://www.onsemi.com/pub/Collateral/2N5550-D.PDF

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My absolute favourites, if you can find them is:
Toshiba low-noise pair.
They can take 120 volt, but they are a bit lower power ( 0.300 watt )
So, we can not put too much current into them at higher voltages.
But if used at max 0.5-2.0 mA (=100-150 milliWatt) they are very good!

2SC2240 (NPN) and 2SA970 (PNP) 120 Volt, 0.300 Watt
They have got very high gain and low noise!
Both things are good for small signal audio.
Can take a bit of searching to find a supplier that still have them in stock.
They may be out of production now.


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Small Signal Lab
for low noise audio

[prorms]

thanks ill check them out right away

[mikeks]

Zetex 796A/696B/1056A

[Leolabs]

I think the 2N5401 and 2N5551 will run the show quite well.

[lineup]

Originally posted by seanmacss
thanks ill check them out right away

Originally posted by Leolabs
I think the 2N5401 and 2N5551 will run the show quite well.

What you need to be a bit careful with
is to have a look into datasheet of transistors you will use
and check out PIN CONFIGURATION.
It might not be always the same, and you will have to bend, twist and adjust those 3 pins a little
to really get transistor's B, C and E in the right places.

If not, you may not get things working.
You may even, if really unlucky, damage something else in amplifier.

If you use BCxxx to replace BCxxx, it will most often work.
But there is no guarantee for it.
Best to make sure.
This was one reason for my choice of BC546, besides they are easy to find everywhere, at least here in Europe.


I see now, you are from Nebraska in USA
so 2N5401 + 2N5551 may be a more natural choice.
I think they are American standard transistors.
This makes the PIN Configuration check out necessary!

I dont know much about these, but MPSA42 and MPSA92, as of ACD choice
may be to find over there.
I am sure they would work just good!



You may have some experience from these things, different transistor pins,
but I tell this anyway
.. maybe some other person reading this will benefit from this important knowledge.


lineup
Europe