N power JFet testing
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
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
Attachments
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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?)
Attachments
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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.
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
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
Attachments
7mA per case , 12V6 , less than 90mW
So you need the 27R degen to linearise ?
Patrick
Xformers for SissySIT
#60 , Babelfish M25 , AKA M2 on steroids , AKA M2-XA25 bstrd
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$, for pair at your doors
Which model of the cinemag transformers is compatible with the sissysit boards?
#60 , Babelfish M25 , AKA M2 on steroids , AKA M2-XA25 bstrd
2. practically 4 options for signal autoformer (pinouts for all present on pcb):
-Edcor PC series 600:15K (same one as in original M2) , thus having gain of 6V/V
-Edcor PC series 600:600 , thus having gain of 4V/V (edit - only for this one it'll be needed few exacto cuts of traces and few tiny wire bridges soldering ;same physical layout of pins as previous one , but different electrical connection needed ..... very hard to accommodate without too much complication )
- Jensen JT-123-FLCPH (same one as in F6) , thus having gain of 4V/V
-Cinemag CMOQ-4LPC (same one as in SIT-3) , thus having gain of 4V/V
for Edcor , you have Don Audio locally
didn't checked for Jensen
for Cinemags , found some in Europe (probably also Don Audio) but no type needed in stock
contact Cinemag directly , it'll be around 50+30$, for pair at your doors
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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
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
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
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?
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?
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