2sk77b

[generg]

Many thanks to obj who did the THF-51s models!



"I measured my four thf-51s (manually) and used MRs xls solver method in gnumeric to
make models for each of them. This is the first transistors I've measured and made
models for but I get a feeling that each thf-51s is unique part.
I got these from watanabetomoaki asking for low voltage part (20v-60v) .

.SUBCKT thf51-1x0063 D G S ; Drain Gate Source
+ PARAMS: MU=43.571 X=1.494 K=1.339 N=0.902 VCT=0.831 RG=5MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 5000P
CGD G D 5000P
CDS G S 0P
.ENDS thf51-1x0063


.SUBCKT thf51-1x0066 D G S ; Drain Gate Source
+ PARAMS: MU=41.136 X=1.853 K=0.755 N=0.878 VCT=1.212 RG=5MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 5000P
CGD G D 5000P
CDS G S 0P
.ENDS thf51-1x0066

.SUBCKT thf51-1x0067 D G S ; Drain Gate Source
+ PARAMS: MU=46.667 X=1.271 K=1.507 N=1.046 VCT=0.634 RG=5MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 5000P
CGD G D 5000P
CDS G S 0P
.ENDS thf51-1x0067

.SUBCKT thf51-1x0069 D G S ; Drain Gate Source
+ PARAMS: MU=56.181 X=1.412 K=2.257 N=0.609 VCT=0.525 RG=5MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 5000P
CGD G D 5000P
CDS G S 0P
.ENDS thf51-1x0069

https://www.diyaudio.com/forums/pass-labs/314822-greedy-boy-defisit-papas-koans-63.html#post5510688

 

[Zen Mod]

 

[generg]

I replaced the SK77 by some THF-51s models and readjusted buffer current to 20mA and OS bias to 3A.
All the different THF-51 models show in the circuit double and more distortion as the SK77b.

 

[Nelson Pass]

I replaced the SK77 by some THF-51s models and readjusted buffer current to 20mA and OS bias to 3A.
All the different THF-51 models show in the circuit double and more distortion as the SK77b.

Then the models are accurate.

 

[Berny]

We are advised to buy 'them' while they are still availble, I would like to follow that advise for my next amp Should I give priority to the THF51, the 2SK180 or 2SK182?

 

[generg]

Then the models are accurate.

Oh, thank you!

 

[Ben Mah]

Thank you, generg, for the models. I'll give them a try.

 

[generg]

All thanks to member obh!!

:--))

 

[pinholer]

Thank yous to obh and generg for providing the models.

 

[Michael Rothacher]

Someone was paying attention in class! A great compliment.

 

[Zen Mod]

oh yeah!!

it is written in sim , but clumsy ZM forgot to say Kudos! to Mr. MR



I made my 2SK77B model using graphs originating from AnthonyA file , with modeling software on AudioMaker | DIY Audio Projects & More

Mr. MR is Mr. Miyagi for things like that ....

 

[Michael Rothacher]

You’re too kind. The fact they’re starting to get some use is my reward!

 

[generg]

I used Michaels SK180 model to simulate it in ZMs circuit.

I would say half of the distortion of the THF-51, but also half the gain.

Of course the SK180 also vary widely in their specs......

 

[Michael Rothacher]

I wrote to Jan Didden, and he has kindly allowed me to share the original article from Linear Audio Vol. 6 for those who haven't seen it.

Here's the link: Concise SIT Model | AudioMaker

Thanks, Jan

 

[R-K Rønningstad]

Michael is genius!

 

[Zen Mod]

 

[Nelson Pass]

Michael is a genius.

 

[Zen Mod]

Did I said ........ 2SK77 graph is Spooky!

 

[obh]

Michael is a great teacher

 

[toto34]

It was me again!
In mounting 2 SK77 B 50 Watt VFET Amplifier , the 22 Ohm grid resistor remains the same with a THF-51S?