Are these transistors interchangable?

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I'm building a diy preamp for my diy amp. all component values ilustrated.
transistor_audio_preamp_1.jpg


accidentaly broke off all the legs of one of the BC547 transistors.
https://www.sparkfun.com/datasheets/Components/BC546.pdf

i have one 2SD2375, could i used it?
2SD2375 npn transistor complementary pnp, replacement, pinout, pin configuration, substitute, marking D2375, equivalent, datasheet

emmiter-base voltage 6v for both, collect-base difference of 30v, collect-emmiter difference of 15.

as long as it doesn't completely mess up the signal, and just changes the parameters of the preamp a bit, im fine with that.

Nomimal voltage: 12V

Current consumption: 1.2mA

Voltage gain: 50-55

Maximum input signal level: 150 mV p/p

Maximum output signal level: 8 V p/p

Frequency response: 20 Hz to 200 KHz
 
Transistors with too much input capacitance can filter the highs off a signal. Imagine a 600 pf capacitor parallel with the base of your TR1. Datasheets mostly don't show that, Cib, but you can go some by the size of the case. TO220 is pretty big , TO92 is pretty small. Not even going to look at your bc33725 datasheet, alldata versions of datasheets are pretty stripped down from the real thing. Try datasheetcatalog.com for some full featured datasheets.
emitter base voltage is a very basic measurement, not having much to do with capability for music.
Some indication is given by some transistors Ft spec. I just changed the drivers of my amp from 3 mhz TIP41c/42c to 30 Mhz MJE15028/29 and the highs really cleaned up.
If your signal is mellow guitars and human voice, those signals don't have any highs. So don't worry about it. I was testing with top octave solo piano, and that really shows up a circuit with bad high frequency response. (Peter Nero, Young & Warm & Wonderful dynatrack LP). Speakers were 14 khz capable, as are my ears. Steinway calibrator for what a top octave piano is supposed to sound like is in the next room from the speakers. If you don't have one, go to a concert that has one and listen carefully, particularly to the low & high frequencies. Tough sound source to reproduce.
Fast transistors for front ends don't have to be expensive. I find them occasionally for $.02 to $.08 on closeout at newark (farnell US) when they hit the end of the bin & want rid of them. I'll buy a hundred then, cheaper than the $9 freight on the box usually. BC639/640 BCE were bargains recently, in previous years I've scored MPS8099/8599 with the more usual EBC pinout. If you want the classic 2n5401/5551 or BC546/556 you'll pay more like $.35 each because that is what project sheets require.
 
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I've built the preamp, using BC550C transistors.
Improved the volume quite a bit, maybe to the upper limit of my small speakers. Some cool distortion with the volume all the way up, clean signal with the volume down a little bit.
Will still try your recomended circuit today. Probably will be better.

The thing is, that the original BC547 transistors i had, were from a device, identical to the one i got the C33725 and BC550.
So they probably are.
Or I might just go buy the 547's, i'm not that lazy. maybe a little bit.
 
"The absolute maximum current this transistor can handle is 100 mA. This is the DC current rating. The peak current rating is 200 mA."

Might be a dumb question, but if my power source is 2.5A, all that current doesn't go throught the transistor, right? otherwise my preamp should have fried by now
 
"The absolute maximum current this transistor can handle is 100 mA. This is the DC current rating. The peak current rating is 200 mA."

Might be a dumb question, but if my power source is 2.5A, all that current doesn't go throught the transistor, right? otherwise my preamp should have fried by now

What indianajo said: these transistors just pass a few mA in this circuit.

Your power supply is "X" Volts (guess around 12V since that´s what schematic shows) which is the main parameter.

In that context, 2.5A is a secondary parameter, and it just means it´s 2.5A capable, you can draw up to 2.5A

Actual current drawn by your device is way smaller.
 

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...if my power source is 2.5A, all that current doesn't go throught the transistor, right?...

Look at the plan. There's series resistors on the transistors.

The lowest is 2.7k.

Use math. 12V/2.7k is 0.004,4 Amps. That's if the transistor is a Dead Short. Which is not a useful condition. More likely the transistor is "fair fight" with resistor, so 6V/2.7k or 0.002,2 Amps (2.2mA).

That's not even looking at the 1k which is in series with everything. Even if the rest of the circuit were a dead-short you could not have over 12mA (0.012A) flowing.

Yes, it is very common to have hundred-mA transistors doing few-mA chores.
 
Might be a dumb question, but if my power source is 2.5A, all that current doesn't go throught the transistor, right? otherwise my preamp should have fried by now


Your power source is a voltage source, not a current source, so it presents a fixed voltage to the load. Current it has no control over (except limiting it on overload) - the load will set the current.
 
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