Live Lab Hangout #1.1 Posted

[PSz.]

Excellent as usual! Thank you.
I have a follow up question for you. Was the inductor version tweaked to a sweet spot or were the operating parameters somewhat arbitrary?
Also, did the package arrive?

PSz.

 

[dady]

Better every time dear friend. Clear like water.

 

[Soundhappy]

Lab Hangout #3 is posted. Have fun

Fabulous Lab Hangout thanks a lot Michael
for all graph preparation and basic Tokin test demonstration & explanation.
So after resistor reception i do and report my values.
Feedback ? I don't care all matter it's kind
who give a chance to transistor take care of emotions , beauty in music
and if posible with frequency linear response and "all ideal"
but in reality amplifier topology design is art choice ,
better option for listeners finding thrills.
Big hat guys like it play the game
....me soldering station
Kindly regards

 

[generg]

Mike you fill with your detailed informations and by the presentation of yourself a gap that was open for a long time.

Many, many thanks for the way you found to reach us better!

And of course it was a hit to hear a "Gerd" spoken in American way.........!

 

[Zen Mod]

yup , another geezer crunching da brain - thinking in plate(anode)-gate(grid)-cathode terms , while talking about drain-gate-source

kids nowadays are happy enough to be taught in vivo about source degeneration and IV lines , while when I was a kid , I had to inhale few kilos of yore book dust and electrocute my self few times , salvaging precious freshly drawn graphs on mm paper from burning

 

[Soundhappy]

yup , another geezer crunching da brain - thinking in plate(anode)-gate(grid)-cathode terms , while talking about drain-gate-source

Yes Zen Mod

ITokin

 

[cwtim01]

Subscribed, and thanks for the great explanations.

I'm reading D.Feucht's book recently and struggled to understand those 2 port networks - but all of a sudden, things become so clear when you explain the concepts of series current feedback.

 

[Michael Rothacher]

My pleasure, thanks for the feedback

 

[Michael Rothacher]

yup , another geezer crunching da brain

Showing my age, am I?

 

[Michael Rothacher]

And of course it was a hit to hear a "Gerd" spoken in American way.........!

I'm sorry for my bad pronunciation of your name. I will endeavor to sound more german next time.

After all, I'm a Rothacher.

 

[Michael Rothacher]

I have a follow up question for you. Was the inductor version tweaked to a sweet spot or were the operating parameters somewhat arbitrary?
Also, did the package arrive?

Yes, well a bench (no listening) "sweet spot" anyway. I chose 42V because that was a convenient value, then I just looked for a spot that gave reasonably low THD with dominant 2nd at low power, and sufficient low-distortion full power.

It's a black art of course, I would hate to give anyone the impression I arrive at this with a slide rule and flow charts and such.

I got the package. Curves made. Will post soon. Thank you!

 

[bogdan_borko]

Very good Michael nice videos. Would you make something more advanced, like measuring ac gate current over sin signal freq. sweep in common source and common drain mode? Square signal freq. sweep could be also very interesting. BTW why only SITs, why not commonly used mosfet (IRFP240) and bjt(2SC5200)? Just an idea. Keep up the good work!

 

[Michael Rothacher]

Does anyone have any "known good" 2SK182ES, or curves for them? I'm thinking the two that I have are bad. Even the high voltage curves are just way out of whack.

I think they should look a lot more like the 2SK180.

I've seen a "bad" 2SK180 that has that same whacked-out character, so I'm wondering...

Soundhappy, what's happening in France?

 

[Michael Rothacher]

Must sleep.

 

[Soundhappy]

Soundhappy, what's happening in France?

Hi Michael

Received 8 ohm 50 watts today and i am ready to test 2SK182ES
this evening just last question :
ground are connected with (-) on lab psu ?
Thanks for answer.
Best regards
Christophe

 

[Michael Rothacher]

Yes. And I tied (-) to safety ground in the video.

The voltage and current are fairly low here, but it never hurts to keep one hand in your pocket.

Must sleep.

Just in case I misunderstood the question: The black terminal (-) is not internally connected to the chassis safety ground which is tied to the green terminal. You'll see in the video, I tied them together for that test.

 

[PSz.]

I've got some 182s that I can send your way. Not yet tested, and somewhat suspect though. At least we would have a few more data points.

 

[Michael Rothacher]

Sure let's try that. I'll curve them for you and send them back. Let me cover your expense (or buy you a pizza).

I think these parts have promise if I could get a few good samples.

And we can't let shappy down.

 

[Soundhappy]

Yes. And I tied (-) to safety ground in the video.

The voltage and current are fairly low here, but it never hurts to keep one hand in your pocket.

Great dear Michael
Yes safety first
Hear sit test photos with 8,2 ohm resistor / 12V / 2A
Best regards
Christophe

 

[PSz.]

I'll send them out first thing tomorrow.
I'm actually more interested in the 180s at this point. I've got a few of them on the way from Japan. Nice ones that have not been abused in a smelter somewhere in China. I'd like to see curves for those.