Opening new thread , to make things easier to follow and comment .
Everything started with collective brainstorming in Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans thread , and resulting prototype posted in #618 , Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans
Tnx to all Greedy Boyz involved ........
as I wrote , SissySIT ( in fist time called SUFI-SIT , but then I realized that too much seriousness is ..... too serious 🙂 ) is practically THF51-S Tokin SIT nested in Babelfish M25 circuit (even pcb) , with necessary change in some parts values .
so , schm and last/final pcb iteration are these :
(observe that I finally decided to match my pcbs to DiyAudio UMS ...... taking in account Jason's and 6L6's stance - better keeping things less complicated , than asking for few more taps in existing UMS..... so , besides SissySIT being Sissy , ZM is Mighty Sissy , doing things to save Greedy Boyz from some drilling/tapping efforts)
Everything started with collective brainstorming in Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans thread , and resulting prototype posted in #618 , Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans
Tnx to all Greedy Boyz involved ........
as I wrote , SissySIT ( in fist time called SUFI-SIT , but then I realized that too much seriousness is ..... too serious 🙂 ) is practically THF51-S Tokin SIT nested in Babelfish M25 circuit (even pcb) , with necessary change in some parts values .
so , schm and last/final pcb iteration are these :
(observe that I finally decided to match my pcbs to DiyAudio UMS ...... taking in account Jason's and 6L6's stance - better keeping things less complicated , than asking for few more taps in existing UMS..... so , besides SissySIT being Sissy , ZM is Mighty Sissy , doing things to save Greedy Boyz from some drilling/tapping efforts)
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few general notes:
- yes , it is Poor Man's iteration of SIT-3
-yes, same pcb for Babelfish M25 and SissySIT , skipping/adding few parts for each and using few different parts values for each
-yes,you can choose what to use in circuit - Edcor, Jensen , or Cinemag ; see complicated xformer area - footprint/pads included for all 3 of them
now , to keep this post more interested , placed few pics of my dear T-Bed (from previous thread) :
- yes , it is Poor Man's iteration of SIT-3
-yes, same pcb for Babelfish M25 and SissySIT , skipping/adding few parts for each and using few different parts values for each
-yes,you can choose what to use in circuit - Edcor, Jensen , or Cinemag ; see complicated xformer area - footprint/pads included for all 3 of them
now , to keep this post more interested , placed few pics of my dear T-Bed (from previous thread) :
to quote myself , it was little trouble , who could expect that ........ sims aren't so precise regarding biasing network resistor values (few important factors missing in models , most important of them being gate leakage current)
so , had to heavily alter some resistor values - against values predicted by dummy sims made by even dumber operator , but solved it
I'm pretty satisfied , THF51-S not exactly being PapaSIT (read - made for sissy audio purposes) , but real tough welding drek
intended PSU is classic FW format - Donut with 2x18Vac secondaries , usually resulting in some 22V5dc rails (use CRC in filtering bank)
Iq , say between 1A8 and 2A
actual conditions in T-Bed are 25Vdc rails and Iq of 2A
due to damn big THF case , even 0.1mm thick mica is good enough for THF case being just slightly warmer than metal beneath it
so , 1W measurements (EMU1212 , DIY interface box , ARTA) are :
(FW SIT-3 , as reference , having approx. 0.15% 1W/4R and 0.21% 1W/8R)
so , had to heavily alter some resistor values - against values predicted by dummy sims made by even dumber operator , but solved it
I'm pretty satisfied , THF51-S not exactly being PapaSIT (read - made for sissy audio purposes) , but real tough welding drek
intended PSU is classic FW format - Donut with 2x18Vac secondaries , usually resulting in some 22V5dc rails (use CRC in filtering bank)
Iq , say between 1A8 and 2A
actual conditions in T-Bed are 25Vdc rails and Iq of 2A
due to damn big THF case , even 0.1mm thick mica is good enough for THF case being just slightly warmer than metal beneath it
so , 1W measurements (EMU1212 , DIY interface box , ARTA) are :
(FW SIT-3 , as reference , having approx. 0.15% 1W/4R and 0.21% 1W/8R)
Attachments
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FW SIT-3 declared as 18W/8R and 30W /4R
having THD of , say, 2% at 18W/8R and 2.3%/4R
from some reason (excitement , what else) , I forgot to measure at 30W/4R .... so including what I have - 18W/8R and 16.5W/4R ..... was probably shooting for same amount of THD
disclaimer - these mesaurements made with additional 6db autoformer in-between EMU and amp; it's probably adding some THD of it's own , but who cares
edit: Tea- will answer that later , with more info
having THD of , say, 2% at 18W/8R and 2.3%/4R
from some reason (excitement , what else) , I forgot to measure at 30W/4R .... so including what I have - 18W/8R and 16.5W/4R ..... was probably shooting for same amount of THD
disclaimer - these mesaurements made with additional 6db autoformer in-between EMU and amp; it's probably adding some THD of it's own , but who cares
edit: Tea- will answer that later , with more info
Attachments
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you can see from my measurements vs. SIT-3 data - difference between PapaSIT and THF51-S nature ........ SIT-3 is characteristically having lesser THD on 4R load , while THF is having lesser on lesser (8R) load ; as I see it - result of PapaSIT being developed for lower rails voltage/higher current (pretty much FW form factor/audio usage) , while Tokin Biggie being ... what it is - shaker table/industrial workhorse
final graphs, Freq. response at 4 and 8R load , 1W
final graphs, Freq. response at 4 and 8R load , 1W
Attachments
now, Tea asked for comparison with little jewel (little just in physical size , not in sound ) DEFiSIT ....... for my ears , and for my regular sets of second ears .... same magic is there ; speed , details , authority .....
maybe I can say that SissySIT is somewhat Berserked DEFiSIT , and note that all comparisons are made between properly made DEFiSIT (dual mono and whatnot, with Cinemags on input) , while SIssySIT is still "just" T-Bed iteration - with crappy PSU common for both channels , ubercrappy powerwiring and Edcors on input
as illustration , set of measurements of my dear DEFiSIT ......
maybe I can say that SissySIT is somewhat Berserked DEFiSIT , and note that all comparisons are made between properly made DEFiSIT (dual mono and whatnot, with Cinemags on input) , while SIssySIT is still "just" T-Bed iteration - with crappy PSU common for both channels , ubercrappy powerwiring and Edcors on input
as illustration , set of measurements of my dear DEFiSIT ......
few general remarks (more):
-every combination of THF51-S and P channel mosfet (say IRFP9240 or IRFP9140) , having difference of Ugs** to make at least 350mV window to squeeze opto bjt in , is proper candidate pair for usage in SissySIT .
** measured at 22-25Vdc rail and 1A8 to 2A Iq ; typically -3V5 for THF and 4V1 for IRFP9xxx, resulting in 600mV window
-without source resistors , paralleling of IRFP mosfets is harder task , so - use Keratherm for (that one) mosfet .
-power on thump is , even if there , practically benign ; power off thump even lesser
-as always with Papa-inspired amps, all settings finished in temp equilibrium ; be a Sissy , use multiturn trimpots ...... leave one turn trimpots to braver and more worthy ones 🙂
- for more comparison , of 42 and everything, download http://www.firstwatt.com/pdf/prod_sit3_man.pdf and readreadread , looklooklook , thinkthinkthink
that's it for now ..... must do some work on that schematic in first post, and include few missing (Z) diodes
-every combination of THF51-S and P channel mosfet (say IRFP9240 or IRFP9140) , having difference of Ugs** to make at least 350mV window to squeeze opto bjt in , is proper candidate pair for usage in SissySIT .
** measured at 22-25Vdc rail and 1A8 to 2A Iq ; typically -3V5 for THF and 4V1 for IRFP9xxx, resulting in 600mV window
-without source resistors , paralleling of IRFP mosfets is harder task , so - use Keratherm for (that one) mosfet .
-power on thump is , even if there , practically benign ; power off thump even lesser
-as always with Papa-inspired amps, all settings finished in temp equilibrium ; be a Sissy , use multiturn trimpots ...... leave one turn trimpots to braver and more worthy ones 🙂
- for more comparison , of 42 and everything, download http://www.firstwatt.com/pdf/prod_sit3_man.pdf and readreadread , looklooklook , thinkthinkthink
that's it for now ..... must do some work on that schematic in first post, and include few missing (Z) diodes
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Nice Monger sissie speaker��
The harmonic decay of the Sit3 is incredible .
Is it ok for 2sk82 too?
The harmonic decay of the Sit3 is incredible .
Is it ok for 2sk82 too?
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looking at I/U graphs with gate voltages , hardly to expect specimens having gate voltage lesser than -4V , to mate with P channel mosfet
rail up to 20, Iq up to 1A .....
so , pretty much - no
😀 😀 Mighty 400 watt´s SITokin are just sissy for Big Greedy Boyz 😀 😀 😀 
🙂
Interesting amplifier project thanks Zen Mod !
🙂Interesting amplifier project thanks Zen Mod !