Hi dear ZM
it's been a while since I'd like to ask you an accurate and simple description of the sissySIT bias circuit. Starting from the objectives highlighted in the DEFISIT and then in the SIT-3.
in short, why that approach to bias?
my question I believe interests many people in this thread
it's been a while since I'd like to ask you an accurate and simple description of the sissySIT bias circuit. Starting from the objectives highlighted in the DEFISIT and then in the SIT-3.
in short, why that approach to bias?
my question I believe interests many people in this thread
well , I can give you short explanation , pointing on some things I already wrote here and there ( in related threads)
or I can give you longer explanation .......
or , as maximally enjoyable variant for you , I can recommend - read first post of this very thread looking for linked related threads .... then read them all
let me know what you prefer ......
🙂
or I can give you longer explanation .......
or , as maximally enjoyable variant for you , I can recommend - read first post of this very thread looking for linked related threads .... then read them all
let me know what you prefer ......
🙂
SissySIT is a special DEFISIT where transistors are paired with Hall chips and opto-couplers .
As i know no single amplifier in the world has Hall current sense chips for a bias sense .
So.... the SIT 3 and DEFISIT may have nothing to do with this topic (except by SIT in the name) ....even sound ... because they say Sissy sound differently from SIT 3. 😀
As i know no single amplifier in the world has Hall current sense chips for a bias sense .
So.... the SIT 3 and DEFISIT may have nothing to do with this topic (except by SIT in the name) ....even sound ... because they say Sissy sound differently from SIT 3. 😀
Still waiting for parts but there don't seem to be many reports on SQ of this (Sissy SIT) amp. Makes me a little nervous.
don't be nervous ...... if you're going to trust me 🙂
it's on par with my DEFiSIT
I have no original SIT-3 , nor my test iteration of same had Papa's Golden Touch , but I'm finding DEFiSIT better sounding ( sweeter , more agile) than (mine) SIT-3 , when driving speakers where 8W is enough
where more is needed , well ..... SissySIT is having 18W 🙂
so , if you take SIT-3 as some kind of goal , this is best thing instead
there are aso several other possibilities , mainly thinking of varying input stage topologies , sans or with overall NFB ...... but I really like this approach with xformer and all
tried driving same OS with ubermambojumbononeTHD FE , but magic is not entirely gone , but of lesser amount for sure
it's on par with my DEFiSIT
I have no original SIT-3 , nor my test iteration of same had Papa's Golden Touch , but I'm finding DEFiSIT better sounding ( sweeter , more agile) than (mine) SIT-3 , when driving speakers where 8W is enough
where more is needed , well ..... SissySIT is having 18W 🙂
so , if you take SIT-3 as some kind of goal , this is best thing instead
there are aso several other possibilities , mainly thinking of varying input stage topologies , sans or with overall NFB ...... but I really like this approach with xformer and all
tried driving same OS with ubermambojumbononeTHD FE , but magic is not entirely gone , but of lesser amount for sure
Hi,
I am making the SissySIT and would like to ask some questions:
1. What is the initial setting value for P2 (OFFSET), zero or max?
2. What is the value of C5? It is marked 10uF in schematic but you gave 22uF in your kit.
3. All zeners are 7V5-9V1 in schematic. What exact value should I use?
Thank you.
I am making the SissySIT and would like to ask some questions:
1. What is the initial setting value for P2 (OFFSET), zero or max?
2. What is the value of C5? It is marked 10uF in schematic but you gave 22uF in your kit.
3. All zeners are 7V5-9V1 in schematic. What exact value should I use?
Thank you.
@SPWONG,
when I remember right ...
1. I would start with the "middle"
2. I asked ZM, answer: "no difference between 10 and 22uF Silmic in sound ..... maybe 22uF is even better"
3. Nelson used all times (hope remember right) 9V1, so i go with 9V1
when I remember right ...
1. I would start with the "middle"
2. I asked ZM, answer: "no difference between 10 and 22uF Silmic in sound ..... maybe 22uF is even better"
3. Nelson used all times (hope remember right) 9V1, so i go with 9V1
1. yup - middle ; not mentioned in tutorial in post # 1 , so - as you got them from factory
2. as Carsten wrote
3. anything between 7V5 -9V1 ; I'm packing 8V2/500mW in kits
2. as Carsten wrote
3. anything between 7V5 -9V1 ; I'm packing 8V2/500mW in kits
Just finished the SissySIT.
It does make music.
The IRFP9140 and THF51-S are really HOT!
Thanks Zen Mod.
It does make music.
The IRFP9140 and THF51-S are really HOT!
Thanks Zen Mod.
Slow progress on my part , I took a little time over the holidays to try and get some of the case work done as this requires the most hours and noise
a few steps along the way
Assembled an AMBLABS e24 to use as a trigger for powering up the transformers
getting it all wired up
and finally completed a little more of the wiring so that I can test the power supplies - discovered that I have plenty of fuses but no spare fuse holder , so now I have a good excuse to continue soldering the boards.
And little Mu hats for the cinemags in case they hum like the M2X
..dB
a few steps along the way
Assembled an AMBLABS e24 to use as a trigger for powering up the transformers
getting it all wired up
and finally completed a little more of the wiring so that I can test the power supplies - discovered that I have plenty of fuses but no spare fuse holder , so now I have a good excuse to continue soldering the boards.
And little Mu hats for the cinemags in case they hum like the M2X
..dB
Looking good B! I'm waiting parts kit also. Meantime trying to make some decision about casework..diy or modushop.
I am using a F4 bought (on here) completed for my Sissy Sit. I am in the process of converting to dual mono. I didn't consider my new psu boards and connector blocks would fail to line up with the holes in the Modushop tray. It's a pain and messy having to drill in between the pre-drilled holes of the base. About time the whole world went metric if you ask me.