Your Favorite Signal, Driver & Power Transistor used in your Amp and Why?

[John Biles]

Hello Everyone,
If this Question has been asked before can you please let me know where the link is.
My question is with all the Amplifiers that have been built by Members on this forum, you all must have a favorite Signal, Driver Power transistor that you continue to use because it's reliable, gives for your Amplifier the best sound.
There must also be some disappointing Transistors out there as well, that you wouldn't used again.

I would like to know so that i can test these transistors in my design.

[tlf9999]

Signal: 2n5401/5551 - have plenty of them. realiable and get the job done just fine.
Driver: 15030/31 - have plenty of them. reliable and get the job done just fine. I also use to220 MOSFETs ocassionally.
Power: usually some power MOSFETs. today's favorite is FQA19N20.

[John Biles]

Thanks tlf9999,
I will download the datasheets on those ones and check their specs, Thanks

[edl]

Signal:
-bc546/556 (bc212/182): cheap, realiable. good for max. 60V rails
-2n4401/5551: higher Uceo

Medium:
-bd139/140: cheap, realiable. good for max. 40V rails
-mje340/350: very high Uceo

Driver:
-bd239c/240c - bd241c/242c - bd243c/244c: these are old, "slow" devices, but they are so cheap, and do the job well with lower (max. 40-50V) rails.
-mje15030/15031: one of the best drivers

Power:
-2sc5200/2sa1943: good price, fast, easy to mount
-mj15003/15004: very hard to kill, greeat SOA. for rails up to +/70V.
-mj15022/mj15023 - mj15024-mj15025: they are excellent for high power amps, for high rails (+/-100V)
-mj15015/mj15016: I'm using two pairs for 200W PA amps. cheap devices.
-bd911/912 - bd249c/250c: good old devices for little amps.

Be careful, there are a lot of fake power transistors in the shops!

[John Biles]

Thankyou edl,
This is the type of info I am looking for, thankyou for taking the time to supply this info.
I will be downloading the datasheets on all the transistors you have listed, Thankyou Again!

[MikeB]

Additionaly for smallsignal i like mpsa18 in the inputstage.
For Powerbjt i also like the mjl3281/1302/21193/21194/21195/21196.
With the rest i go conform with edl.

[Mr Evil]

Signal:
BC550C/BC560C - Low noise, high gain, quite fast.
2SK389/2SJ109 - Dual JFETs, low noise.

Driver/medium power:
D44H/D45H - Fast and high gain, you won't see many better than this.

Power:
Exicon MOSFETs - I stay away from those horrible BJT things!

[bocka]

My question is with all the Amplifiers that have been built by Members on this forum, you all must have a favorite Signal, Driver Power transistor that you continue to use because it's reliable, gives for your Amplifier the best sound.

This is mainly a quastion of your topology not only of the devices used. You can make a good as well as a mediocre amp with all the devices listed above. A transistor must fit your design criteria first. After choosing your favored device you should change parts and listen if they sound better. It's impossible to say that transistor A sounds better than transistor B or vice versa.

The only statement that can be given is that device A or can handle your desired output power, voltage, speed... or not. Or that the ß is sufficiant, has a low/high input/reverse/output capacitance and so on.

Yes, I've also prefered devices, because I've a lot of them.

Small signal

2SK389/2SJ109
ZTX450/ZTX550
2N5401/2N5551

Medium Power

MJE15034 / MJE15035
2SA1930/2SC5171

Power

MJL1302/MJL3281
2SA1943/2SC5200

A lot of devices for enough permutations. Maybe you can do something uncommon like using MJL1302 and 2SC5200 in your output stage?