EUVL, in regards to matching 2SK1530s/2SJ201s, what’s preferred/best value match, precision match or P-N match?
All the NN, PP, NP have to be matched at least inside each channel, better to match the two channels too.
That is 8 matched mosfets.( see post 14)
That is 8 matched mosfets.( see post 14)
Wow and wow again this is going to look good.
Made up with pool finalizing details.
Also for the Inesperienced side of things I am here volunterring for same work,
maybe an inesperienced person can find snags that otherwise you more experienced my fly over as taken for granted.
If I may have the schematic I could get started.
Yes, no, maybe ?
Al
Made up with pool finalizing details.
Also for the Inesperienced side of things I am here volunterring for same work,
maybe an inesperienced person can find snags that otherwise you more experienced my fly over as taken for granted.
If I may have the schematic I could get started.
Yes, no, maybe ?
Al
Here is one shematic.
See also F5 thread for details.
You can also keep the 10 ohms Jfet sourse resistors as in regular F5, cut the junction between J74 sources and feed back junction, insert a 4 ohms resistor. In that case you keep the standard feedback resistors of 50 ohms.( 2 x // 100 ohms.)
Do not forget to match all jfets and Mosfets source resistors
Correct me if wrong, Patrick.
See also F5 thread for details.
You can also keep the 10 ohms Jfet sourse resistors as in regular F5, cut the junction between J74 sources and feed back junction, insert a 4 ohms resistor. In that case you keep the standard feedback resistors of 50 ohms.( 2 x // 100 ohms.)
Do not forget to match all jfets and Mosfets source resistors
Correct me if wrong, Patrick.
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I suggest you search into the F5 thread by Euvl (Patrick) name.
This is informative too.
This is informative too.
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You wait until I am done with Variac for the layout, then I will contact Bksabath & AR2 for their part of the work.
In the meantime, someone can start a GB thread for the PCB so that Variac can have some quantity estimates.
Also I need someone from Germany to volunteer to organise a GB and to match the MOSFET source resistors.
Please post here if you are willing, and I shall contact you when we are ready to GB the source resistors.
Patrick
In the meantime, someone can start a GB thread for the PCB so that Variac can have some quantity estimates.
Also I need someone from Germany to volunteer to organise a GB and to match the MOSFET source resistors.
Please post here if you are willing, and I shall contact you when we are ready to GB the source resistors.
Patrick
What source resistors are you using?
Panasonic, Vishay/Dale.
I have a very good Fluke meter which can measure resistance accurately down to very low levels, but I am not in Germany.
Panasonic, Vishay/Dale.
I have a very good Fluke meter which can measure resistance accurately down to very low levels, but I am not in Germany.
Please note :
The request is for a volunteer to record names, addresses, & quantities, collect payments, order the resistors (or I order one time and send to you), match according to my prescribed method, and then distribute them by post.
Quite an undertaking; and I really do not have time this year !!
Hopefully, someone is willing to help out,
Patrick
The request is for a volunteer to record names, addresses, & quantities, collect payments, order the resistors (or I order one time and send to you), match according to my prescribed method, and then distribute them by post.
Quite an undertaking; and I really do not have time this year !!
Hopefully, someone is willing to help out,
Patrick
Futaba MPC74 bulk metal film for audio (non magnetic).
The source is German.
If I buy and ship to you, it adds to the costs (shipment & money transfer).
But still a solution in the worst case.
No use matching with multimeter for 0R22.
Just take my word.
Patrick
The source is German.
If I buy and ship to you, it adds to the costs (shipment & money transfer).
But still a solution in the worst case.
No use matching with multimeter for 0R22.
Just take my word.
Patrick
I will take your word, but you might be underestimating how good my meter is.
You can zero out the resistance of the leads etc.
You can zero out the resistance of the leads etc.
The contact resistance alone between probe and resistor leads will cause more error than you want.
Patrick
Patrick
contact resistance can be zeroed out also.
I have found I get less than 0.1% error between several readings on the same resistor.
Edit: I will confirm what error I get. It has been a while since I have done it, and my memory is not that good. Anyway, I am not arguing with you here I have confidence that your method will be better.
I have found I get less than 0.1% error between several readings on the same resistor.
Edit: I will confirm what error I get. It has been a while since I have done it, and my memory is not that good. Anyway, I am not arguing with you here I have confidence that your method will be better.
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0.1% for 0R22 ?
You must have very steady hands.
Wonder if it is still that steady after say 200 resistors ??
🙂
Patrick
PS still need a good multimeter, but not for measuring resistance.
You must have very steady hands.
Wonder if it is still that steady after say 200 resistors ??
🙂
Patrick
PS still need a good multimeter, but not for measuring resistance.
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The leads have strong Aligator clips. I don't need to use my hands.
I feel like you are trying to challenge me here to a contest, I am almost falling for it 😀
Edit: Or are you suggesting oppening and closing alligator clips 200 times is not as easy a task as one might think.
"Wax on, Wax off" Karate Kid
Actually, if I take 10 readings per resistor, it will end up being 4000 times (two aligator clips per resistor).😱
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EUVL sez that you measure voltage , not resistance
simple CCS is needed , nothing fancy shmansy
absolute value isn't important , just relative , as always when grouping is goal
simple CCS is needed , nothing fancy shmansy
absolute value isn't important , just relative , as always when grouping is goal
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