2SC3329 low noise transistor

[analag]

2SB737, 2SC2547E/2SA1085E www.allicmall.com

 

[bcarso]

Thanks analag---that looks like a useful link.

 

[analag]

Always a pleasure

Analag

 

[kvintus]

What is the advantage of having a compund pair transistor input stage instead of a normal two-transistor solution?

/Anders

 

[clintrubber]

It's more linear. For a topology where the feedback is just 'around the opamp' but not including the discrete input-pair it'll help reducing THD.

 

[kvintus]

Thanks for the reply!

For a topology where the feedback is just 'around the opamp' but not including the discrete input-pair it'll help reducing THD

I can understand that. Makes totally sense.

It's more linear

This is what is stated in the Allison article (ESP project 66) too. What I don't really understand is the expression "linear". What exactly is more linear? Maybe this is a stupid question of a more filosophical nature, but I really want to understand this fully.

Thank you!

/Anders

 

[clintrubber]

W.r.t. linear: less THD, giving a more exact (but amplifier) reproduction of what comes in. That's all obvious of course, so I'm not sure if I understand your question.

It'll depend on the exact mic-pre circuit, but say you have a differential pair (2*BJT), which is voltage in, current out. The load-resistors do a I-to-V-conversion so the total is V-in, V-out. The diff-pair will not do an exact V-to-I over it's whole input-range, so distortion arises. Read up on diff-pairs etc, to get the whole story.

So more specific: an amp can be described by:

V_out = K*V_in

...and you hope 'K' is constant. But mostly it isn't. How 'linear' it is says something about how constant it is. It's in fact the same, linear & constant. Imagine a V_out vs V_in graph. If K was constatnt the graph is a straight line. And then the voltage-relationship is said to be linear.

Sorry for all those words I'm using here to explain; as they say too little time to write a short message.

Regards,

Peter

 

[kvintus]

Thank you for your answer. Sorry if it was a stupid question. I know about differential pairs and those things. What I was asking was about the use of the word linear and how it relates to distortion (non-linear = distorted, right?). But it's all clear to me now, I think. Back to work!

/Anders

 

[clintrubber]

(non-linear = distorted, right?).

Yes.

 

[bcarso]

I hunted for some more precise explanation of linearity, and found some ok class notes as the tenth reference on the first page that comes up when using google with the entry

linearity "linear operators"

It looks like it is from a 2004 course at MIT.

 

[bcarso]

BTW back (sort of) to the thread topic: the three of you who took me up on my free transistors offer should be receiving them soon, as they went out about a week ago now.

 

[Rossi]

Hey Brad, thanks a lot! I got mine today; can't wait to use them. I'm surprised the postage was only 80 cents. I'm sure it would cost 5-10 times as much to send the same envelope from Germany to the US. I just sent a 4 page letter, standard size, to Frankfurt. The postage was 99 Euro cents ($ 1.25). German Post is expensive and not very reliable.

As I said, if the other guys could make up their minds for a group buy, I'd be in. I'm sure I'll be hungry for more of these fine transistors once they're gone.

Anyway, thanks again. That was really nice of you, Brad!

 

[bcarso]

That is cheap postage isn't it? The light weight helps a lot, and also speeds it through customs I understand compared to ponderable parcels.

 

[clintrubber]

Got some goodies from Brad as well recently and indeed, it went very fast from CA --> NL.

 

[Samuel Groner]

Today, I found some transistors in my letter-box as well. That's really great from you, Brad - thanks a lot! And if there's a group order, let me know... (I don't read the Black Market on a regular basis)

Does it happen that someone has a spice model already?

Samuel

 

[kvintus]

And if there's a group order, let me know... (I don't read the Black Market on a regular basis)

Me too!

/Anders

 

[gentlevoice1]

Hi All,

Just briefly resurrecting this thread as I am looking for a source for genuine and reasonably priced 2SC3329GR/BL Toshiba transistors and Hitachi 2SC2545-47 transistors.

Might one of you know where these can be found?

Cheers & thanks for any input 

Jesper

 

[Bill Wilson]

Check out U.T. Source, they are reliable & carry some out of production transistors.

 

[gentlevoice1]

Hi Bill ... thanks for your feedback and suggestion. As it is I already did that and they unfortunately don't have them .. Cheers, Jesper

Check out U.T. Source, they are reliable & carry some out of production transistors.

 

[Sredna]

http://www.futurlec.com/Transistors/2SC3329pr.shtml

They sent me GR.