Transistor matching

After the carrier block has finished, it's time to match the transistors.

I have built a simple curve tracer from Elektor Electronics (Feb. 2009).

More info about this Transistor Curve Tracer,

http://www.elektor-electronics.co.uk/magazines/2009/february/transistor-curve-tracer.810360.lynkx


And this is mine.




A sample screenshot of a typical 2SJ49 mosfet,

It looks like this.......

Have the TO3 transistor mounted on the carrier block and it fits very well.




More tests to follow.

Good job, boys!

Congratulations!

http://www.abf-online.org/results/ayg09-res.htm#BOTeam2







:-)

Making a new poweramp

I'm in the process of making a new solid state power amp that uses the old but good "Lateral" mosfet by Hitachi. Since they are in To3 package, mounting them onto the heatsink will need some work. I have decided to make a "carrier block". The output transistors will all sitting on the carrier block and then the block will be mounted on the heatsink.

Machining of the carrier block by a small CNC:




This is a test version which will hold two TO3 transistor. The milled block look like this:




We will need a flat surface to ensure good thermal contact with the heatsink, some touch up is then required.




Not too bad I think. :-)

Don't do this at home .........

Bulk metal foil resistor is very expensive but gained a lot of good words in audio application.

I thought you might have heard that there is a new type called the "Naked" foil. A lot of people claim that it has a very noticeable improvement over the traditional style, encapsulated type.

In order to see what's inside under the epoxy coat, I have cracked one and let's take a peep. :-P





After taking off the "black" coat, there is another coat covering the metal foil. It's obvious that it is used to protect the delicate metal foil.
So, you might ask, what's under the brown coat then?
Here it is,





Yes, the expensive metal foil resistor is now completely vanished. We can see the foil which is bonded to the brown coating.

OK, here is the real "Naked" foil resistor,





Sexy? I don't think so. :-P

How does it sound when comparing to the usual type?

It does show some merits, a little bit more open and relaxed but the difference is subtle.

Emerson, Lake & Palmer

"Welcome back my friends to the show that never ends,
I'm so glad you could attend
come inside, come inside......"

I think this is from a live around 1974,



is this from the same concert? :-)