Help pick the best transistor.

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chinoy

chinoy

Member
Joined 2022
#1
Im working on a DIY Amp Module.
The creator has given me this list of options.
Im sure for some of the wizards here with decades of exp they could look at it and go this or that.
But to somebody like me just starting out its taken a few days just to download all the data sheets and read them.
After that I dont even know what I need to be looking for in the datasheet to compare which is better.

Any help or guidance in helping me pic the right one would be appreciated.
If you cant cherry pic an option from the list then what parameters are critical in the data sheet. For me to look for.
Also if you have used any and have found it to work well that would be ok also.
 
#3
What is "best"?
With that many semiconductors I would suggest that interactions between them may be more important than individual specifications.

Also, very important!
"Best" might be what you can buy from a local, reliable supplier.
Rather than chasing specifications and buying expensive fakes on an auction site!
 
#5
RJM1 said:
Did you forget to attach the schematic?
Click to expand...
No I thought long and hard about it. And considered it safer not to attach the schematic. May **** off the person who sold me the board.
May **** of somebody here. May get accused of trying to promote somebody too many risks. If you think seeing the schematic will help you answer better sure I can send you the link in a PM.
 
#6
WhiteDragon said:
mje 350/340 and tip41/42 can be removed instantly. not even options


2N5401/5551

2SC/KSC/2690/3503
2SA/KSA/1381

MJE15028/29

NJW0281G/0203G
Click to expand...
Im so happy I made this post. the board did come with TIP ICs. Thank you so much.
Somebody asked what is best ?.
Well best as in transistors that have built their reputation over the years. As working well, sounding good and being reliable.
I knew this was a budget board and had planed on refreshing the parts with the board anyway.
You can ask me whats the best piston to run in a banshee. LOL and I could give you 5 options in order of price vs power, price vs performance, price vs reliability. You could ask me what the best ECU to run on a given configuration. So in that way whats best in the audio world from the list.
 
#8
Car / engine analogy's can work.

Tip 41/42
would give you a working engine.
like a very average factory piston.

Far as performance.
with transistors in very generalized manner
your looking for good gain and transition frequency.
Then a circuit that supports that function

usual goals are power / low distortion
with a amplifier.

So the actual block or engine you start with.
Or actual electronic circuit. Needs to
have a design that even supports performance upgrades.

Or in another very generalized manner.
A already built performance engine,
come right out of the crate needing no
upgrades. It already has the parts
and design to actually support performance.

I would assume a kit that ships with tip41/42
doesn't have much expectations.
It works and runs.
 
#10
WhiteDragon said:
Car / engine analogy's can work.

Tip 41/42
would give you a working engine.
like a very average factory piston.

Far as performance.
with transistors in very generalized manner
your looking for good gain and transition frequency.
Then a circuit that supports that function

usual goals are power / low distortion
with a amplifier.

So the actual block or engine you start with.
Or actual electronic circuit. Needs to
have a design that even supports performance upgrades.

Or in another very generalized manner.
A already built performance engine,
come right out of the crate needing no
upgrades. It already has the parts
and design to actually support performance.

I would assume a kit that ships with tip41/42
doesn't have much expectations.
It works and runs.
Click to expand...
So kind of you.
Yes your spot on it starts and runs.
I spend my life tuning stuff. Not just Engines So thought why not audio.
Believe just about anything in life can be tuned.
I have sent RJM and you both the links. If you feel its not breaking any board etiquette feel free to share them. Im new here and lack the confidence to do it.
 
#13
chinoy said:
Im working on a DIY Amp Module.
The creator has given me this list of options.
Im sure for some of the wizards here with decades of exp they could look at it and go this or that.
But to somebody like me just starting out its taken a few days just to download all the data sheets and read them.
After that I dont even know what I need to be looking for in the datasheet to compare which is better.

Any help or guidance in helping me pic the right one would be appreciated.
If you cant cherry pic an option from the list then what parameters are critical in the data sheet. For me to look for.
Also if you have used any and have found it to work well that would be ok also.
Click to expand...

The suggestions would depend on a circuit diagram; without it - the suggestions given would have very little merit, unfortunately.
 
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#15
One can make pretty good assumptions as to the duties of each transistor in that list. Some types can be ruled out if the alternates listed are available. 5401 makes a better input transistor, assuming it’s up to the voltage (If it’s not, it is NOT a beginner project). A1220 or A1381 make a better VAS - although which one is subject of much debate and the technical reasons for going one way or the other are way over this guy’s pay grade. Vbe multiplier is simply a matter of convenience, although higher gain tends to be better. Once you start using isolated case TO126’s it’s hard to go back to anything else. No TIPs in driver or output unless you are specifically designing for them and understand what you’re going to get (Less performance than anything else). As far as which driver and output pair - larger outputs are better and smaller drivers are, up to the point where you stress either one. The higher your supply voltage and the more 8-ohm-load-equivalents you drive in parallel the more output pairs and the bigger the drivers you need. All of this is just speculation based on what is usually done and not a guarantee of success. The absolute optimum would require study of exactly whats going on in the circuit. But using transistors intended for their duty in a conventional, properly designed circuit usually results in a working, listenable amplifier. With this type of amplifier, there really isn’t that much new under the sun.
 
#18
SHORT answer: the designer gave you that list bacause THEY ARE EQUIVALENT, meaning IN THAT CIRCUIT ALL WORK THE SAME.
Capisce?

Pick ANY in each line, period.

I know, I know, LOTS of people get EXTREMELY ANXIOUS when asked to decide ANYTHING on their own.
 
#19
I wouldn’t say ”all equivalent”, as there are a few “bad” choices in the bunch.

TIP35C are good in low voltage high current use, like 2 ohm capable car amps running off +/-25, maybe +/-30 volts. Current gain at 25 A is higher than the others, but SOA at typical hi-fi amp voltage is poorer. They are a a poor choice for a typical hi-fi amp built out of a 30-0-30 transformer. C5200’s will hold up better. Hell, TIP142 holds up better on +/40 volts. At one time TIP35 we’re dirt cheap, but not anymore.

TIP41 are fine as outputs in 10 watt amps. I have used them as high power drivers - when using an EF3 output stage, and when the point of the exercise was using “all cheap generic transistors”. But using them to drive C5200’s (or worse, expensive Sanken LAPTs) in an EF2 is just plain dumb and for some reason people like the idea. In a typical circuit, I would use any other drivers. The only thing worse you could do is use it for the VAS. It’s been tried, and sounds like garbage. I guess if the implementation were bad enough you might not be able to tell, but in most you would.
 
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