Scryer ... or how F8 met Mighty SissySIT

Spacing on sink to accommodate Sissy (42)....

PF-ZM-Scryer_02.jpg
PF-ZM-Scryer_01.jpg
 
  • Like
Reactions: 2 users
Some progress... lots of tapping—and some more vent holes for his Mighty-ness.

I may have to flip a coin to see if I fill these chassis with Sissy (42) or Scryer first!

Oh, and ZM—just confirming that the drain connection is from the case of the SIT—the ring connection on the SIT needs to be under the isolator bushing....?

PF-ZM-Scryer_03.jpg
 
yes, 1A5 initially

when both Iq and DC Offset are in ballpark, fine tune both in temp equilibrium ( not that it matter much, but procedure yadayada)

1A6 to 1A8, whatever makes you happy

1A6*0R11=176mV

ZM—aren't the critters here 0R22 (R139-142)? So, 352mV @1A6?
OR what don't I (yet) understand..? :oops:

Oh, and 2X working PSUs ready to go... still have to make some fronts...but they fired right up no issues.
(Nice residual blue glow there with no place to go!)

Almost ran into trouble there on the back wall with the DC blocker in the way of SissySIT (later) boards (Scryer won the coin toss).

PF-ZM-SissySITvsScryer_01.jpg
 
  • Like
Reactions: 6 users
See? I KNEW it? I did think about that...but alas, my maths? and my abilities to "see parallel" in schematic form (they ARE in fact IN PARALLEL)? Oh man. That's why we (I) have you. I love being the one to ask the most inane question....was just discussing this topic with @ItsAllInMyHead .... maybe someone will be inspired.
 
Last edited:
  • Like
Reactions: 1 user
See? I KNEW it? I did think about that...but alas, my maths? and my abilities to "see parallel" in schematic form (they ARE in fact IN PARALLEL)? Oh man. That's why we (I) have you. I love being the one to ask the most inane question....was just discussing this topic with @ItsAllInMyHead .... maybe someone will be inspired.
Maths is for weaklingzezzez and continental boyz :rofl:

Could you tell us a little bit more abput your DC blocker(z)?
 
  • Like
Reactions: 1 users
Speaks protection. He's a member here—and makes a lovely Ferrari of a PSU—which would have saved some space in these tidy cases. Price doubled since the last I picked up some of the DC blocker boards. I'd love an actual DIY solution... but these are close—and compact. Not entirely sure what would blow in my Xovers since all the up front caps are film (probably more I don't know yet), but the protection circuits have tested themselves...most recently in J2 Bableness....
 
  • Like
Reactions: 1 users
Cooking... Left mono....
0.185V with twiddler maxed at bottom rose slowly from 0.174V when it was cold... so that's about 1A68ish...
Shift resistor change? Something I read along the way someplace... or am I good ZM?
Offset is pretty stable...comes up a bit as it cooks. The whole shebang feels really stable I have to say.
(lid isn't finished... will be not so grained in the end... couldn't wait!)

Oh, and ZM, these aren't the SITs from my Sissy 1.0 build... these are Prasi, marked 3.09V and 3.07V...

PF-ZM-Scryer_04.jpg

PF-ZM-Scryer_05-bias-left.jpg
 
  • Like
Reactions: 1 users
Official Court Jester
Joined 2003
Paid Member
two things dictating do you need more juice:

-temp of heatsinks (55C at top, unassisted in summer time)
-mosfet dissipation - if Keratherm or Alumina Oxide, good for 45W

whatever you hit first, stop

I'm lazy to get back and search what rails you have, but you know the math for mosfet diss.

going zzzzzz

yup, if you go for more juice, backup with Iq, increase level shift resistor to 150R, readjust Iq and Offset

small slide of Iq and offset is normal, from cold to hot, but if you take numbers, you'll see that percentage is small

my goal wasn't to push any of these to absolute stability, but to have Iq and offset stable enough both in temperature domain and in domain of sliding rails ( mains fluctuation)

when having CCS with LT3092, stability is sliiiightly better, but I had so many obstacles to obtain those in quantity, inevitably resulting in minor compromise

prepare for next level in your Magical Mystery Tour ......... foot-tapping is to commence!
 
  • Like
Reactions: 1 users