BC109B vs NTE123A vs 2N2222

[lowvolt]

I'm attempting to learn more about transistors as they apply to these little guitar pedal circuits that some of us play around with.

I have a few dozen NTE123As, and was looking up what they cross over to, and found a number of answers.  The most prominent desgins mentioned are the BC109B and the 2N2222 (both of which I also have).

As far as (perhaps) fuzz circuits or other guitar pedal type circuits go, are these three transistors the ~same~ in enough regard to actually think of them as interchangeable?

Thank you! 

One step at a time, one new thing each day. 

[Pyr0]

I don't know about the NTE123A, but I have a load of 2N2222A's with hfe's in the low hundreds, anything from 120 to 230, I also have a bunch of BC109B's, but they tend to have hfe's of around 220 up to 320, so I would not consider them equivalent. But it will depend on what citcuit you are putting them into. If you have a DMM with built in transistor tester you could always test them and see what gain range they are in.
I would say that the 2N2222 would be more like a BC109A.

[lowvolt]

I don't know about the NTE123A, but I have a load of 2N2222A's with hfe's in the low hundreds, anything from 120 to 230, I also have a bunch of BC109B's, but they tend to have hfe's of around 220 up to 320, so I would not consider them equivalent. But it will depend on what citcuit you are putting them into. If you have a DMM with built in transistor tester you could always test them and see what gain range they are in.
I would say that the 2N2222 would be more like a BC109A.

Ok, so just trying to follow along here ....

1.) The BC109A has a lower HFE rating than the BC109B, and that is sortof per-normal, do I have that correct?

2.) And which is higher gain ... a numerically higher HFE reading or numerically lower HFE reading?

3.) Is it fair to say that most of the NPN Si transistors by and large ~sound~ the same but just have different gain?

4.)  In most amplifier circuits (at least these little tinkertoy circuits that these pedals are made with) are SE __ AGH >> MY KEYBOARD IS FREAKING OUT AGAIN __ DANG IT >>> THE SHIFT KEY GETS STUCK >>> I"LL BE BACK >>>

[lowvolt]

Ok. continuing with item 4

4.) ... are these transistors actually in the audio path or are they more used as control?

I'll hit up You Tube for some of the transistor tutorials soon, right now I'm just trying to get a basic knowledge foundation going on.

Thanks for the help ...

[Electron Tornado]

You can download the datasheets for those transistors for free from here: http://alldatasheet.com/  and compare the specs. I don't think you'll have a problem using those transistors interchangeably, but someone smarter than me might be able to go into more detail. If your DMM doesn't have a feature to measure gain, then there's an article here that will help: http://www.geofex.com/Article_Folders/ffselect.htm

If you've got a breadboard, build a booster or a fuzz and try them all out.

Have fun!

[Pyr0]

I don't know about the NTE123A, but I have a load of 2N2222A's with hfe's in the low hundreds, anything from 120 to 230, I also have a bunch of BC109B's, but they tend to have hfe's of around 220 up to 320, so I would not consider them equivalent. But it will depend on what citcuit you are putting them into. If you have a DMM with built in transistor tester you could always test them and see what gain range they are in.
I would say that the 2N2222 would be more like a BC109A.

Ok, so just trying to follow along here ....

1.) The BC109A has a lower HFE rating than the BC109B, and that is sortof per-normal, do I have that correct?
Yes

2.) And which is higher gain ... a numerically higher HFE reading or numerically lower HFE reading?
a numerically higher H_fe reading is higher gain

3.) Is it fair to say that most of the NPN Si transistors by and large ~sound~ the same but just have different gain?
It depends on what circuit they are in, transistors can have a lot of different features like collector capacitance, noise level and frequency cutoff, so there will be slight differences, but in most cases I wouldn't worry about it, as the tolerance of other components like capacitors will have a much more pronounced effect in pedals.

4.)  In most amplifier circuits (at least these little tinkertoy circuits that these pedals are made with) are SE __ AGH >> MY KEYBOARD IS FREAKING OUT AGAIN __ DANG IT >>> THE SHIFT KEY GETS STUCK >>> I"LL BE BACK >>>

[lowvolt]

Uh ... Pyr0 did I miss something there ^^^ ?

Oh wait .... now I see it .. your answers are inside the quote.