SissySIT

[Zen Mod]

N power JFet testing

voltage source of some 20-25Vdc , capable of delivering at least 3A (you can borrow positive rail of your existing Papamp, if you have one ) ...... goal Iq is 2A

what the heck , you can use 19V power brick ,either from your ACA or your laptop

plain 9V battery for gate voltage (connected to gnd of above , to be negative)

10K pot or trimpot for setting that gate voltage

1K gate resistor

some kind of heatsink , best to have 8-12cm fan cooling it all the time of test ...... just to prevent temp. build up ..... you can use main rail for it , just reg it down to fan voltage .....or use 24V fan

ampermeter (one DMM)

gate voltage meter (second DMM)

have all that ?

if yes, I'll draw schm

for THF51-S , body is drain ( no need for isolation for test , just keep heatsink electrically from other voltage potentials , other than + rail), fat protruding pin is source,while thin protruding pin is gate



again , any power N channel JFet , having ebough cojones , and having gate voltage in range of -1 to -3V6 is adequate for SissySIT circuit

if you sort your P channel mosfets , and use those with highish gate voltage (for -19 to -25V and Iq 1A8 to 2A) , in area of -4V5 , JFet can have even -4V gate voltage for intended conditions
have more questions , shoot

 

[chromenuts]

voltage source of some 20-25Vdc , capable of delivering at least 3A (you can borrow positive rail of your existing Papamp, if you have one ) ...... goal Iq is 2A

what the heck , you can use 19V power brick ,either from your ACA or your laptop

plain 9V battery for gate voltage (sonnested to gnd of above , to be negative)

10K pot or trimpot for setting that gate voltage

1K gate resistor

some kind of heatsink , best to have 8-12cm fan cooling it all the time of test ...... just to prevent temp. build up ..... you can use main rail for it , just reg it down to fan voltage .....or use 24V fan

ampermeter (one DMM)

gate voltage meter (second DMM)

have all that ?

if yes, I'll draw schm

Check...(and waits for slow boat from Asia while wondering what “sonnested” means...perhaps it’s from ZM dictionary like trampolinea?)

 

[Zen Mod]

corrected sonnested ........ to connected

 

[chromenuts]

Google knew what you meant even if a gringo like myself didn’t...thanks for the diagram...will tuck it away for when the big bugs arrive

 

[Nelson Pass]

Are these still being manufactured? There seems to be several sellers on eBay...don't want to miss out.

They are NOS with no replacements on the horizon. I bought some from
Tomoaki, and he is a reliable supplier.

 

[Zen Mod]

look what Santa ....

bummer is that I got just 25pcs of ACS (Hall) chips

ookup at Digikey side

will have 75 more in bloody 3 weeks from now .....

anyway , pcbs in no less than 7 days , so train is slowly , but surely rolling



so , besides plenty of tiny parts , these are most important newcomers ... 1K of 2SK2145BL and 250 of Elna Silmisc II 22u/25V

 

[JPS64]

If someone want to etch own PCB?!


JP

 

[chromenuts]

Oh we are spoiled aren’t we?...thanks JPS that is the perfect solution to my paranoid OCD in my head saying “is this right?...am I doing it right?”

 

[Zen Mod]

tnx JPS

that's easily done even with exacto knife and metal ruler

edit- batery switch is big no-no ........... better to pull battery out when not using entire shebang , than forgetting to engage switch to on , while having THF energized

 

[EUVL]

7mA per case , 12V6 , less than 90mW

So you need the 27R degen to linearise ?


Patrick

 

[schultzsch]

Which model of the cinemag transformers is compatible with the sissysit boards?

 

[Zen Mod]

Xformers for SissySIT

Which model of the cinemag transformers is compatible with the sissysit boards?

#60 , Babelfish M25 , AKA M2 on steroids , AKA M2-XA25 bstrd

2. practically 4 options for signal autoformer (pinouts for all present on pcb):

-Edcor PC series 600:15K (same one as in original M2) , thus having gain of 6V/V

-Edcor PC series 600:600 , thus having gain of 4V/V (edit - only for this one it'll be needed few exacto cuts of traces and few tiny wire bridges soldering ;same physical layout of pins as previous one , but different electrical connection needed ..... very hard to accommodate without too much complication )

- Jensen JT-123-FLCPH (same one as in F6) , thus having gain of 4V/V

-Cinemag CMOQ-4LPC (same one as in SIT-3) , thus having gain of 4V/V

for Edcor , you have Don Audio locally

didn't checked for Jensen

for Cinemags , found some in Europe (probably also Don Audio) but no type needed in stock

contact Cinemag directly , it'll be around 50+30$, for pair at your doors

 

[Russellc]

They are NOS with no replacements on the horizon. I bought some from
Tomoaki, and he is a reliable supplier.

Should I request any certain specs, or are they good to go whatever ships? Much thanks for the response.

Russellc

 

[Zen Mod]

well , Moi not exactly being Pa ......... but I wrote few times that I believe any THF51-S you get , will be happy in SissySIT circ

 

[schultzsch]

I recently sold some ll1684 600:600 trafos and I suspect they could have worked here... so sad

 

[Zen Mod]

oh yes , clasical repeater , 4 times 150 Ohms

it'll fit like a glove

hoverer , doesn't matter how high Lundahl is rated , don't be so sure that Lundahl could be any better sound-wise than , say, Cinemag

I didn't tried , but from previous experience , sometimes ancient iron was superior to Lundahls (same type , same circuit) .......

so - who knows why is that good ...... that you sold them

 

[Kris0603]

This project really sucked me in, Tokins are on the way, i'll measure them and if i'm lucky they'll drop right in.

Just how hot do these things run, could i get by with a 3U Dissipante chassis from Hifi-2000 you reckon?

 

[Zen Mod]

even if you decide to open the window (Sweden one , in a middle of winter) , while your cojones go freeze off , 3HE is not going to cut it

at least not in summer time

be a man ! go for 5U/400

 

[chromenuts]

I have a bunch of raw HeatsinkUSA units that are 12”X7”X1”. Their description on the site says:

Quality extruded aluminum heatsink
Alloy: 6063-T6
Width is 12.000"
Fin Height is 1"
Base Height is .300"
Weight is approximately .60 lbs per inch
C/W/3": approximately .85

Think they’ll cut it with this project?

 

[Zen Mod]

one per side , two per case - perfect for monoblock