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Did not use this in the end, used the TSE circuit for the DHT heater.
Decided to change the DC regulator used to provide heater power to the 45's (DHTs) to a Coleman reg.
Info on the reg
Rod was very helpful in answering question, and ships quickly.
You do need to figure some stuff out, but he has a well written installation guide. Main thing is you need to generate raw DC power at a fairly high current. But, depending on the tube, he has recommendations for the parts you need to get. He also has a pwb to help with this part, but I opted to only buy his reg board, and hand wire the raw supply.
First thing is to pick a transformer
For a 45, he recommends a Hammond 6.3V 5A PN 266L12
but I found a this on ebay, for a slightly better price and it meets all the specs:
Hobart Electronics® 12.6VCT@2.85A or 6.3V@5.70A -- Pri:115V Transformer
I ran simulations with PSUD2 to make sure I'd get the right voltage.
Parts
I'm using version 7 of the Coleman Reg. When I ordered, I asked for a kit to support both 45 and 46/47 tubes, 46/47 has a higher heater currant.
45 needs a R1 of 0.68 ohm. For 46, you add R2 of 3.6 ohm
I bought two caddocks, MP930-0.33-1% for R1, and a 3.9 ohm 7W, AC07000003908JAC00 for R2
For one of the .22uf cap, the one right next to the transistor that has to be 5mm off the board, I used a wima mkp instead of the one provided. It barely fits, but it does help push the resistor against the transistor lol.
Using two MBR1045G schottky diodes in full wave rectifier (section 2.19 of the AN-DHT-V7-2 guide.
C1 (per the figure in Sec 2.19) are two PN B41231A7109M000 (10000uf, 35v, 4.7A ripple) in parallel, so can handle a ton of ripple)
C2 is a ECO-S1EP183CA 18000UF 20% 25V SNAP