no porn , no glory ...... especially if you have two of them now
M25 pcb:s populated this case and PSU before, I moved them aside to try SissySit, so it’s basicaly looking about the same
but I’ll add photo when I get casing build back together.
After cooking for ~1 hour, SIT gate to MOSFET gate
Left – 1V39
Right – 1V31
Is the bias voltage critical? The last time I left them ~174+mV but when I checked it was around 160mV on the left and didn't bother to check on the right. I guess it is not completely cooked yet.
Left – 1V39
Right – 1V31
Is the bias voltage critical? The last time I left them ~174+mV but when I checked it was around 160mV on the left and didn't bother to check on the right. I guess it is not completely cooked yet.
Last edited:
difference between 174mV and 160mV is nothing to worry about
point is to set it as close is possible to 0mV when it's completely cooked
anyway , I need to shrink all pictures I made during process and post them with following explanations ..... most probably tonight
1V3 is nice situation ....... tricky one is my own SissySIT , I deliberately chose combo resulting in 750mV of voltage window for opto
oh boy ....
point is to set it as close is possible to 0mV when it's completely cooked
anyway , I need to shrink all pictures I made during process and post them with following explanations ..... most probably tonight
1V3 is nice situation ....... tricky one is my own SissySIT , I deliberately chose combo resulting in 750mV of voltage window for opto
oh boy ....
174mV is not the DC offset but the voltage across the 0R1 for the Iq.
difference between 174mV and 160mV is nothing to worry about
point is to set it as close is possible to 0mV when it's completely cooked
anyway , I need to shrink all pictures I made during process and post them with following explanations ..... most probably tonight
1V3 is nice situation ....... tricky one is my own SissySIT , I deliberately chose combo resulting in 750mV of voltage window for opto
oh boy ....
my SissySit is waiting also with open hood. I don’t dare to try this mod without proper instructions.
SissySIT is much much more robust than you might imagine.
Don't try this at home but there is a rumour that you can accidentally disconnect the V- rail while the amp is running because you are dumb and clumsy and trying to connect a clamp meter around a wire that is too short and although it makes an awful sound, neither the speaker nor the amp suffers any long term illness ... at least that's how the rumour goes ... I can't tell you if this is true for you or not but I heard it from someone I know is dumb and clumsy enough to do it.
Don't try this at home but there is a rumour that you can accidentally disconnect the V- rail while the amp is running because you are dumb and clumsy and trying to connect a clamp meter around a wire that is too short and although it makes an awful sound, neither the speaker nor the amp suffers any long term illness ... at least that's how the rumour goes ... I can't tell you if this is true for you or not but I heard it from someone I know is dumb and clumsy enough to do it.
all pics taken , just need to obtain half day time to finally cook my Sissy , to call it done and post everything
due to (other) life , didn't had half day time entire week ....... even if I did some work on Singing Bush itsybitsies (ready to go on heatsink) , did some actual and some electronic mist work on Babelfish XA25 , did pleeenty of electronic mist work on Babelfish F7
didn't planed that last one , but it happened .....
and yeah, those are tough buggers
didn't made any substantial mistake ( ZM is Chicken) , but I had a hunch
due to (other) life , didn't had half day time entire week ....... even if I did some work on Singing Bush itsybitsies (ready to go on heatsink) , did some actual and some electronic mist work on Babelfish XA25 , did pleeenty of electronic mist work on Babelfish F7
didn't planed that last one , but it happened .....
and yeah, those are tough buggers
didn't made any substantial mistake ( ZM is Chicken) , but I had a hunch
will post pics etc. tonight
yesterday did final cooking of my own Sissy, while working on Singing Bush
facts:
- original opto iteration is looking nicer ;
-second opto iteration is looking somewhat uglier , when implemented in Ikebana style
-bias stability of original iteration in temperature domain is completely fine if gates of output critters are behaving nicely
- bias stability in general is not matter of Ugs difference between SIT and MOS , again just matter of well behaved gates ( having leakage or not)
so , decision which opto arrangement you'll apply at first is completely yours
I already prepared pcb files exclusively with 6N139 ..... in case that there will be further interest in SissySIT
yesterday did final cooking of my own Sissy, while working on Singing Bush
facts:
- original opto iteration is looking nicer ;
-second opto iteration is looking somewhat uglier , when implemented in Ikebana style
-bias stability of original iteration in temperature domain is completely fine if gates of output critters are behaving nicely
- bias stability in general is not matter of Ugs difference between SIT and MOS , again just matter of well behaved gates ( having leakage or not)
so , decision which opto arrangement you'll apply at first is completely yours
I already prepared pcb files exclusively with 6N139 ..... in case that there will be further interest in SissySIT
My experience with 2 SissySIT:
#1 is not modified and sometimes starts with -200mV offset and sometimes -100V offset. Depends on what colour Billie Eilish hair is that day probably. It settles down usually around -20mV offset. I have adjusted it closer to 0mV let it cool sometimes for hours, sometimes for days and next time I run it to stable it's -20mV again. Just likes to be there and it's not wild so I just stopped adjusting it and it's good. I still check offset now and then but do NOT check Iq anymore for good reason
#2 was a wild one. I adjust offset and bias, it swings wildly like trying to drag my kids out of playground when they were small (they are actually very good but good exaggeration). #2 would never settle on anything consistently no matter how many times I heat cycle it and adjust it. I would monitor it and simply lean forward to adjust it and it would jump up to 30-50mV before I even get my hand close to the amp. For days I was trying 4 different meters and probe cables and the damn auto shutoff beeping meters drove me crazy enough to buy a benchtop meter (big bottle of rum would have been cheaper but I don't drink)
SissySIT #2 needed to go visit the Amp Whisperer and came back completely different.
It's sad to see that there is not more interest. To me I could never build a version of DEFiSIT or SIT 3 and Woofertester's investigation makes me even more certain I could not do this because of the V and I curve traces. Move off the sweet spot and you got offset. I know degeneration helps tame this but still ... to much calculating and measuring in my opinion. One day I may try it. I still have 2SJ201 in 2.3-2.6V range and have 2SK182ES in 2.4V range and a 2SK182ES at 4.6V and another one at 4.3V at 24V and 1.8A.
Before SissySIT I have parts in the drawer. With SissySIT I have music thanks to ZM and to Papa
#1 is not modified and sometimes starts with -200mV offset and sometimes -100V offset. Depends on what colour Billie Eilish hair is that day probably. It settles down usually around -20mV offset. I have adjusted it closer to 0mV let it cool sometimes for hours, sometimes for days and next time I run it to stable it's -20mV again. Just likes to be there and it's not wild so I just stopped adjusting it and it's good. I still check offset now and then but do NOT check Iq anymore for good reason
#2 was a wild one. I adjust offset and bias, it swings wildly like trying to drag my kids out of playground when they were small (they are actually very good but good exaggeration). #2 would never settle on anything consistently no matter how many times I heat cycle it and adjust it. I would monitor it and simply lean forward to adjust it and it would jump up to 30-50mV before I even get my hand close to the amp. For days I was trying 4 different meters and probe cables and the damn auto shutoff beeping meters drove me crazy enough to buy a benchtop meter (big bottle of rum would have been cheaper but I don't drink)
SissySIT #2 needed to go visit the Amp Whisperer and came back completely different.
It's sad to see that there is not more interest. To me I could never build a version of DEFiSIT or SIT 3 and Woofertester's investigation makes me even more certain I could not do this because of the V and I curve traces. Move off the sweet spot and you got offset. I know degeneration helps tame this but still ... to much calculating and measuring in my opinion. One day I may try it. I still have 2SJ201 in 2.3-2.6V range and have 2SK182ES in 2.4V range and a 2SK182ES at 4.6V and another one at 4.3V at 24V and 1.8A.
Before SissySIT I have parts in the drawer. With SissySIT I have music thanks to ZM and to Papa