[sdiy] Transistor help

[René Schmitz]

Hi Kevin and all,

Kevin Lightner wrote:
> However, transistor matching, in my opinion, is blown out of proportion.
> I'm not sure most people can hear a filter and say it sounds like the 
> transistors are unmatched or whatever. I've also built Moog filters with 
> completely unmatched transistors, even from different makers and they 
> sounded great.

I agree.

This has been debated a couple of times here. Check the archives for that.

> It's funny about all the rumors out there in regards to matching too.
> For example, there's a rumor that only the early RA and Musonics Minis 
> used matched transistors in their ladders.

This seems to be based on the schematics, which indicate matched devices 
only on the earlier schematics. (The later schematic only showed a 
circled M for the differential pair, and not the ladder itself.)

> I have 11 (count 'em!) Minis in and they ALL have a colored dot on their 
> transistors, which the other same numbered transistors don't have. The 
> reason, often overlooked, about the very early Minis is that their 
> electrolytic caps are older and of different values when new anyways.
> 400uf, instead of the later 470. 80uf instead of 100uf and so on.
> Their carbon resistors are often *way* off too.
> I often measure the 820 ohm resistors at 1K-1.2K.

Interesting. I presume these are from different "eras"?

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159