Can I use another 10R resistor as a dummy for the anode CCS??
RollE2K seems to have good experience with using this anode CCSs after the SSHV2 board....that why I like to try....
I have tried using BottleHead C4s as the anode CCS after the SSHV2 board...with not as good result.....now have gone back to use anode resistors instead after the SSHV2 board with great results.....
RollE2K seems to have good experience with using this anode CCSs after the SSHV2 board....that why I like to try....
I have tried using BottleHead C4s as the anode CCS after the SSHV2 board...with not as good result.....now have gone back to use anode resistors instead after the SSHV2 board with great results.....
The 10R from the schematics is just for measuring CCS current. Myself i always test the CCS with a 12V supply and use a plain resistor instead of a pot when using as anode load. There is a ebay user selling matched DN2540s so you only have to test one, then use same value on next channel.
And the CCS of the SSHV2 doesnt make the tube work with constant current. Plus you get better chqnnel separation if using cascoded DN2540s a load due to approx 120dB psrr.
And the CCS of the SSHV2 doesnt make the tube work with constant current. Plus you get better chqnnel separation if using cascoded DN2540s a load due to approx 120dB psrr.
it depends on what current you are targeting? for approx 20mA i have often landed around 100-120R so a 500R pot plus the 330R resistor would work there, but when you have found your target current you should remove both the pot and the R3 and replace them with the value you measure over them (since they are in parallell).
Here you have the source i have used for matched DN2540's - 2 x Supertex DN2540N5 DN2540 Depletion Mosfet DIY CCS | eBay
Here you have the source i have used for matched DN2540's - 2 x Supertex DN2540N5 DN2540 Depletion Mosfet DIY CCS | eBay
I have ordered three batches of the DN2540s from this seller, and have had flawless service.
Alex
RollE2K....thankyou for your mails....but I guess I am a bit less lucky because when I click the link you included, I get the following error message:
""...This listing (2) has been removed, or this item isn't available...""
I would say I am targeting 12mA to no more than 25mA (say 10-30mA)....trying to find the sweet spot....for VT-25A.....
""...This listing (2) has been removed, or this item isn't available...""
I would say I am targeting 12mA to no more than 25mA (say 10-30mA)....trying to find the sweet spot....for VT-25A.....
- Please check that you've entered the correct item number
- Listings that have ended 90 or more days ago won't be available for viewing.
Try this link then, it should work - 2 x Supertex DN2540N5 DN2540 Depletion Mosfet DIY CCS | eBay
I don't think it's a good idea to use the CCS as filament supply. Perhaps consider a good linear regulator with CRC filtering. I've done this and the performance is outstanding. A regulator such as the LD1086 is solid up to 3A with adequate heatsinking.
Please also consider your maximum heater to cathode voltage for the tube you are using. If the voltage exceeds the tube data sheet specification, you can easily "float" your heater supply at the center tap of a voltage divider, and parallel a 0.1uF cap across the bottom resistor. Feed the divider with raw B+ (before the regulator) and bypass the filament with a 10uf - 33uF cap close to the tube.
Good luck, and please take care around HV!
Probably an LM117/LM317...
You might want to check out Morgan Jones' book. I believe he has a constant current source filament supply using bipolar transistors.