Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans

[Zen Mod]

few more , with 6db autoformer inline , so somewhat higher THD;

however , who cares for numbers , I'm interested in general trend here

 

[kbergsson]

And it sounded good while welding train tracks? 🙂

 

[Zen Mod]

'nuff for today

will hear it tomorrow , in stereo .... needing other channel for that 🙂

 

[obh]

my 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

 

[Zen Mod]

tnx.

maybe will try with them , but ....... this is show time , past sims

🙂

 

[Zen Mod]

addendum;

Iq set to 1A85 , rails ( in T-Bed) close to 25Vdc

while IRFP9240 gate is sitting at some -4V1 , THF51-S gate is sitting on -3V45

so , optocoupler is there to fill 0V55

contrary to all sims , there is no turn-on , nor turn-off thump

🙂

 

[flocchini]

addendum;

Iq set to 1A85 , rails ( in T-Bed) close to 25Vdc

while IRFP9240 gate is sitting at some -4V1 , THF51-S gate is sitting on -3V45

so , optocoupler is there to fill 0V55

contrary to all sims , there is no turn-on , nor turn-off thump

🙂

It keeps getting more and more interesting 😉
Will have to test my THF51-S when I am home 😀

 

[Zen Mod]

should I call it SUFI-SIT , or better - SISSY-SIT ?

 

[flocchini]

THeF51-SIT

 

[Dennis Hui]

Me like SissySit. ������

 

[Chul]

Mighty ZM, I see you are having fun but it is not easy for me to follow you now.. 🙁

What was the current through the THF51 and FET gate?

 

[Zen Mod]

it'll be clearer to you , hopefully tomorrow when I (hopefully) finish the other channel and post exact schematic

in principle , schematic is same as Babelfish M25 , with few changes in resistor values , few (protection) diodes missing , one added , one resistor less etc.

didn't measure gate leakage currents ....... maybe I will , but if build of other channel goes without troubles , most probably not ......

 

[Soundhappy]

should I call it ....or better - SISSY-SIT ?

Oh no sissy ! WAKOO-SIT MOD25 😀

Frank Zappa - Joe's Garage

 

[Zen Mod]

looking at graphs in SIT-3 user manual , and comparing them with THD values I got for SissySIT , I'm observing few things :

-funny , due to nature of PapaSIT , THD in 4R load is lower than THD in 8R load , while this is not the case with THF

-also funny - regarding THD , SissySIT is on par with SIT-3

few things more , to think of :

-should I measure THD spectra ( and whatnot) of ZM's DEFiSIT specimen , and what conclusions , dumb as I am , I can get from that ;
-should I try THF51-S in SEF amp cradle , so SIT being slightly tamed with some source resistance ...... I'm not scared of work involved , but grumpy of necessary critical listening later , to decide which one is better ......... hate critical listening ......... I like normal -greenaroundmyhead music enjoyment ......

 

[Chul]

-should I try THF51-S in SEF amp cradle , so SIT being slightly tamed with some source resistance ...... I'm not scared of work involved , but grumpy of necessary critical listening later , to decide which one is better ......... hate critical listening ......... I like normal -greenaroundmyhead music enjoyment ......

If I may say what I felt from 2SK82 experience, in a subjective term(what else?😀), the sound without Source R was like a sharper knife.

The difference with and without Souce R was also similar to the bass frequency of ported and sealed speaker enclosure. When an amp becomes more flat, on assumption, then the uneven character of a speaker is revealed. The rather strange size and shape of my Altec Valencia is revealed, I imagine.

On other posts Nelson said;
"I personally find the undegenerated output more interesting sonically."

It was not 'better' but 'interesting' and I feel similar. Please keep going, many are following you.....😉😉😉

 

[lhquam]

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) .

The capacitances shown in your models are very high which will require a lot of drive to the gate.

 

[obh]

thf-51s capacitance

Got values from soundhappy
http://www.diyaudio.com/forums/pass-labs/269379-live-lab-hangout-1-1-posted-6.html#post4234184 post #51 5000pf

I've not yet measured capacitance of thf-51s. Did not managed to
do that before I had to clean the lab (when daughter arrived back from university for summer holiday and relaimed her room 🙂. But it is on
todo list (together with temp drift, and double check RG). Any link you can
share how to measure ciss, crss, coss?

 

[Soundhappy]

All " wild horses " 300 to 1K watt´s Tokin SIT's or hockey pucks IXYS mosfets input junction capacitance is high
, amplifier input needs buffer with 25 Ohm impedance output if not high frequency response roll off very quickly.
Cinemag, Jensen or Edcor transformers frequency response have his limits as well
Mr Pass talk about this solution presented similar 2SK77B Digital-Domain SIT, video starting 00:20:37
BAF Presenter Nelson Pass

 

[Soundhappy]

looking at graphs in SIT-3.... hate critical listening ......... I like normal -greenaroundmyhead music enjoyment ......

Frank Zappa - Fillmore East, june 1971 on Vimeo

Must try Pumpkin music test tracks 😀 Kind regards

 

[Zen Mod]

made second channel

now cooking on bench

listening after lunch