Anyone Use TransistorAmp software program

[geozero]

It seemed like a good program whereby you put in variables such as gain, impedance and transistor type and then it creates a schematic on the fly... but I am noticing that the resistor variables are waaaaay too low.  Since most other sources state to use a high impedance on the input and a low on the output, comparing what the software does seems totally wrong.  I am tempted to build one based on their specs and see what happens.  Anyone use it?  What do you think - any good for stomp boxes?

[MaxPower]

From what I remember it only worked within certain parameters. Exceeding those parameters resulted in getting incorrect answers.  Or maybe it didn't work at all, I no longer recall.

[GibsonGM]

I thought it worked pretty good for what it is....but, all of us should (in time and with practice) be able to quickly set up a BJT as an amplifier in about 3 minutes...so I think of programs like this - which WILL be limited - as learning aids more than something that can do it all for me.

If that were the case, I'd just nab circuit blocks from other designs, like the LPB etc. 

[R.G.]

It seemed like a good program whereby you put in variables such as gain, impedance and transistor type and then it creates a schematic on the fly... but I am noticing that the resistor variables are waaaaay too low.  Since most other sources state to use a high impedance on the input and a low on the output, comparing what the software does seems totally wrong.  I am tempted to build one based on their specs and see what happens.  Anyone use it?  What do you think - any good for stomp boxes?

I am reminded of this quote from Lewis Carrol's "Alice in Wonderland":

"Would you tell me, please, which way I ought to go from here?"
"That depends a good deal on where you want to get to," said the Cat.
"I don't much care where--" said Alice.
"Then it doesn't matter which way you go," said the Cat.
"--so long as I get SOMEWHERE," Alice added as an explanation.
"Oh, you're sure to do that," said the Cat, "if you only walk long enough."
(Alice's Adventures in Wonderland, Chapter 6)

This is often mis-quoted as "If you don't know where you're going, any road will get you there."

The concept of a program that just does something highly complex and technically involved with only a few key-presses and without requiring any understanding of the underlying process turns up a lot here.  It's most often in the context of PCB layout, where people have heard of "auto routers" and envision a program where they just put in the schematic and the program feeds them a beautifully laid-out circuit board.

The programming profession has long referred to this as pressing a DWIW key, the acronym standing for Do What I Want. Generally this is followed by a correction that what was needed was a DWIM key - Do What I MEANT - not what I wanted.

It's possible to auto-generate transistor gain stages, resistor values, and so on, but telling the machine what direction to go so you get a decent result requires knowing enough about the desired result that you might as well just do the Ohm's Law calculations and DIY - Do It Yourself.

Computers are literal idiots. They will happily do the same wrong thing over and over until you figure out how to tell them a better thing to do.

[PRR]

> the resistor variables are waaaaay too low

What is "waaaaay too low"? I can buy 10 Ohm, 0.1 Ohm, even Zero Ohm resistors.

> sources state to use a high impedance on the input and a low on the output

The simple Grounded Emitter amp does not have a low output impedance unless it sucks a lot of current.

Input and output Z on a Grounded Emitter stage tend to be "similar", at least not very different. You get a high input Z with a high hFE device, but that only goes so far. You also get a higher input Z by opting for low voltage gain.

The single-transistor amplifier is a stepping-stone. To get "good" results you usually use transistors in pairs, and direct-coupled for simplicity. If TransistorAmp gives you a leg-up on design thinking, good. If you happen to have a simple chore (not super high voltage gain or large difference in in/out impedances), fine.

> I am tempted to build one based on their specs and see what happens.

If you can afford the buck worth of parts, that would be a fine path.

[R.G.]

If you can afford the buck worth of parts, that would be a fine path.

And a great deal in terms of education received divided by money spent!