SissySIT

[twitchie]

Yes, daily meditation and yoga are the secrets to becoming more Zen!

My internet level just went up by 10 points! I am an intermediate interneter now!

 

[myleftear]

After yoga comes workout

 

[Robin De Wolf]

I finally started this build (R2) after lots of reading and first building the Sony VFET. Tnx to Papa and ZM!

 

[Zen Mod]

avoid using gargantuan size resistors, where smaller ones are intended

in most cases that means thicker pin wires, which means unnecessary stressing metalisation of pad holes (vias)

I mean - if resistor legs/pins are going easy in, ignore me , but - if you need to persuade them to go in, it's just mess

 

[Robin De Wolf]

Those were the only 100r I had in my stash. I believe you kit did only include 8 pieces of 100r resistors. They got in without any stress on the pads, still some wiggle room left. They are Dale metal film 1%, should be fine for R21 right? (As long as SIT is on shortest leash).

 

[Zen Mod]

for SIT - you can put shortie on board (in place of resistor) and gate resistor on flying lead , near to SIT gate

however - nothing critical - gate resistor for SIT can be anything between 22R and 100R , and for mosfet anything between 100R and 470R

 

[G600]

Hum, do we have to populate the 100r for SIT in pcb AND flying 100r, or only one?
Schematic says both.

 

[Zen Mod]

well, schematic ........ who drew that one?



it really isn't critical - having one (preferably flying), or both or just one on pcb ........ as long SIT is behaving and wires are short, pretty much no difference

one, flying - preference

if you did in any other way, just chill

 

[G600]

Okay.
Won't blame Pa.
I'll remove the pcb ones some day.
I have a very small hum, will tidy the power wires.

 

[Robin De Wolf]

So far so good. I have a question though on the thermal insulation material. Pras provided a thin sheet with the THF51S as shown in attached photos. Is it sufficient to use those?

 

[Zen Mod]

good enough, tried and confirmed
if you ever get Keratherm 86/82 sheet from conrad.de , replace it

 

[Robin De Wolf]

Thanks ZM, comforting will do that when I mod my chassis into VFET format.

 

[Botte]

So far so good. I have a question though on the thermal insulation material. Pras provided a thin sheet with the THF51S as shown in attached photos. Is it sufficient to use those? View attachment 1004250

Don’t forget to remove the sticker from the bottem of the THF 51.

 

[Robin De Wolf]

Well spotted! I still need to do the second one (clean it with rubbing alcohol).

And these need cleaning as well:

 

[Robin De Wolf]

Ok, I will refrain from trying to explain why I like the SissySIT so much but it is definitely the best/most special I have built so far. Oh and the best I have heard for that matter

I was wondering, with future P iterations coming, is it possible to "P" (active FE) my R.2 iron FE?

 

[Zen Mod]

yes, it is

if you cut part of existing pcb, or at least empty it of parts or .......... see:

 

[Robin De Wolf]

Haha oh no that's not happening. I won't touch it. Next one, whichever, will be P

 

[Kris0603]

I'm getting around to building my R1 SissySIT, however my current (Abbas Audio) DACs have hot outputs, around 4.5 Vrms (according to Mr. Abbas, i have not measured them), and i'd rather not throw most of the signal away by attenuation. Unsure of the output impedance of the DACs, i will try to find out (tube buffers on output). I guess i could wire the autoformer differently to lower the gain, very grateful for any suggestions.

 

[Zen Mod]

with these xformers, it's really either 4x gain or 2x gain

2x gain would end with 9Vrms (OK, smidge lower, output not really being 1x, as all followers) , and that's 10W at output

4.5rms , with regular gain of 4x ( smidge less) should end with, say , 17Vrms, which is 36W ...... which Sissy can't reach of course

conclusion - you'll still need to attenuate, no free lunch

good thing in entire calculus is - majority of music (except modern crap) is rarely reaching exact 0db of digital level

 

[ggetzoff]

Choky,

I’ll be interested in R3 when ready…