I've just downloaded the latest Kicad and started messing around in the schematic editor. I've noticed that when you place tube symbols, the filament connections aren't shown, even when you place both halves of a given tube. Is there any way to fix this so it shows up in the schematic?
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Suggestions, anyone? I can lay this project out freehand in Orcad, but would prefer being able to do it properly using Kicad.
It depends on the symbol, but isn't there a separate section (part, unit, or whatever the correct term was) of the symbol with the filament connections?
It could be because it's almost universal that filament connections are implied, not shown. My understanding is that this is to keep the schematic clean, and because the connections are AC direct from the transformer. They are shown in truncated form in the PS heater string, often with the symbol for the tube filament.
I'll take a closer look at the Kicad library and see if I can find some VT schematic symbols with filament pins. It'll be important, as I intend to run the two (maybe three, if I include a line stage) tubes in the design with filaments in series from a 12V switching adapter with some extra filtering. Some of he rest of the 12V will power a self-designed DC-DC converter to generate the B+. That bit will live in a die cast box with feedthrough caps so it doesn't pollute the neighborhood. What worries me is when I actually go to net out the design. I've used generic schematic symbols for the resistors and caps, and it may ask for footprints.
If I was free-handing the PCB in Orcad Layout, it would be no big deal, as I already have extensive footprint libraries of the parts I like to use.
If I was free-handing the PCB in Orcad Layout, it would be no big deal, as I already have extensive footprint libraries of the parts I like to use.
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A lot of the V7.0.1 valve symbols are multi unit with often a Unit C with the heater terminals, see the ECC88
I did manage to connect the filaments of my valve DAC in both the schematic and the layout, see figures 9 and 13 of https://linearaudio.net/valve-dac-submicron-silicon-meets-submillimetre-vacuum-0 , but I can't remember what symbols I did and didn't edit.
Current version is V7.0 and it is pretty good. I upgrade when a new stable version is available. This machine currently has the last releases for V5.x and V6.x but I will likely remove them soon.
Problem solved - all I had to do was select a dual triode tube symbol, click three times and get all three pieces, including the bit with the filaments. I'm working with the ECC88, as it appears to have the same pinout as the 6JK8 I really have in mind for the project. That's for the RIAA section. For the line amp, I may end up using a 5965, as it has the 12V filament option, and I have a few hanging around.
The stunt I have in mind is described here:
https://www.diyaudio.com/community/threads/folded-cascode-riaa-tube-preamp.396784/#post-7293118
The line amp would use feedback cells similar to those described here:
https://www.diyaudio.com/community/threads/hybrid-riaa-line-amp.339676/page-3
The schematic showing the gain cells is in post 51.
The stunt I have in mind is described here:
https://www.diyaudio.com/community/threads/folded-cascode-riaa-tube-preamp.396784/#post-7293118
The line amp would use feedback cells similar to those described here:
https://www.diyaudio.com/community/threads/hybrid-riaa-line-amp.339676/page-3
The schematic showing the gain cells is in post 51.
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I will have to look closer to see if the extra bit with the filament pins also includes the connection for the internal shield at pin 9 present on the 6JK8. If not, I'll likely need to edit the last piece to make it so.
There is a footprint associated with the 9-pis tubes in the Kicad symbol library. Does that footprint fit the usual 9-pin noval PCB socket?
Last time I checked it was for the smallest 9 pin sockets commonly available in the EU. Don't work with Belton or amperex clones. I made my own. Compare against a mechanical drawing of the socket you want to use and adjust accordingly.
I don't know, I made my own noval footprint. In fact I can post my footprint and E88CC symbol, but not now, as it is 1:11 AM here.