Live Lab Hangout #1.1 Posted

[dady]

SoundHappy
😱😱😱😱😱😱😱

 

[PSz.]

In the absence of Sea Ranch secrets here are the circuits swimming around my head these days. Gathering parts and planning layouts...

That SEPP circuit is straight from a Tokin app note.
The other circuit was lifted from a DeLite thread and lightly modified. I like the bias portion, just need to wire it so that a scratchy or open pot wont cook the SIT.

 

[Michael Rothacher]

Kewl stuff 🙂

Sort of a "SIT F6" kind of thing there. Does the app note provide any interesting insight?

Check out Gerd's little bias arrangement too.

 

[PSz.]

Gerd's little bias arrangement

Ah yes, that is another favorite. I found a nice page on back bias:
What is Back-Biasing?

Edit:
App note doesn't really have any new info. It just presents that circuit as is, but it shouldn't be too hard to fill in the blanks.

 

[Michael Rothacher]

I think it's very cool how old craft goes and comes around again. It's true of many things in art and engineering. Most of our problems were solved in the 1930's and 40's

I shudder to think how much time I've spent re-inventing the wheel, but sometimes that's the pleasure.

 

[Soundhappy]

SoundHappy
😱😱😱😱😱😱😱

?

 

[Michael Rothacher]

40pf at 30V. Send me some.

 

[Soundhappy]

Its just for inspiring Diyers about sit amps topologys.
I don't have any but maybe we find together
So many secrets with Tokins to explore
Best regards 🙂

SIT OTL No.1

 

[PSz.]

Sign me up for those parts too.
Soundhappy, that amp is pretty cool looking. I think it could be cleaned up a bit.

 

[Soundhappy]

@ PSz.

 

[Michael Rothacher]

Now, that's funny 🙂

 

[jama]

Hello all. I have build lamp amp using 2sk182. Results are very exciting... Power supply are two PS in parallel and 30V, one 500W 150V bulb and 8 ohm resistor.

 

[jama]

Power supply and polarization voltage

 

[jama]

Red trace is input signal from generator. Blue trace is output to 8 ohm load

 

[jama]

From other freq I did spectrum using scope tools. One image is input and the second one output. Second and third harmonics...

 

[jama]

And output to 20Khz square signal

 

[jama]

Next step: changing voltage in PS and polarization to get greater power output....

 

[Soundhappy]

Hello all. I have build lamp amp using 2sk182. Results are very exciting...

Very interesting 2SK182ES on lab bench work .
Congratulation and please send us more results
about sweet spot and findings.
Thanks Jama. Kindly regards
🙂

 

[kasey197]

From other freq I did spectrum using scope tools. One image is input and the second one output. Second and third harmonics...

Very cool jama - what was the output voltage when the reading was made ? (Rms/pk-pk?)

Also see if you can measure the output impedance of your amp ...

 

[jama]

Sorry, I had in bad state my Rload. With 7ohm load in good conditions, power output low to 4 Watt into 8 ohm (see photo). I have calculate Zout to 4.2 ohm.
I want to increase voltage of PS to try get greater power output.