T1s at the load CCS for reaching 15mA in place when combined with the main reg.
I'm sorry I don't understand, what's T1s? The power transformer of PSUDII simulation?
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Could be R8-9 56K in place of 58K be the cause of issue?
Sorry in place 68K
Given that you find proper sized HV cap and high PIV bridge that fit well I am afraid of narrow space between adjacent copper lanes at places. Although the bottom side pictures are blown out and I can't say for sure. HV needs safe distances not to arc over.
Thanks! I will do some trimming if it’s too close.
J309 is T1-T3 (#6194)
I tested again without SSHV2 the CCS load and now can't reach 15mA, reach the same as with SSHV2.
If I use 2SK170 in place of J309 as used for my 26 preamp, could I reach the 15mA? If yes what Idss have I to choose?
When you first confirmed 15mA maybe it was in a hotter ambient. If you have 2SK170V >15mA they should reach. Probably some J112 or J113 can do it too. Its the JFET that produces the current in that active load CCS you are trying for. M1 IXTP D-Mosfet is just a cascode to protect the JFET from HV. You don't need to match the JFETs because you have trimmers to regulate their IDSS. But they must be able to reach beyond your target ceiling. Measure them for IDSS in few Volts VDS, as much as the VDS they see now in that circuit. Measure that across the J309s before you pull them.
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