heater wiring

[tenderland]

I am using a seperate powersuply for a 2a3 design. I would like to use an octal din to connect them. I am concerned about the
wiring from the heater supplies. Is it a bad idea to run the heater wiring in the same cable as the other B+ lines ?
any sugestions ?

 

[Sherman]

I'm no expert but I would think the chance of inducing hum would be much greater if the heater wires were in the same cable as the B+. I would run them separately. If that isn't possible then maybe twisting the AC wires together and shielding the DC would be enough.

 

[tenderland]

hum , hum

That sounds practical .I saw a picture in the photo galery and he used just one cable to teh socket. I gues you would have to prototype and test different methods . I assume you need a load on the power supply when testing . What would be a good way to just fire up the powersupply only ?

 

[Sherman]

Re: hum , hum

... he used just one cable to teh socket. I gues you would have to prototype and test different methods . I assume you need a load on the power supply when testing ...

If all you want to do is see if the heater AC is junking up the B+ you could just put a power resistor on each to load them a bit then put a scope on the B+ to see if you have any interference. I don't think you'd have to match the load exactly to your real-life set up.

 

[tenderland]

load

After reviewing the power suply section of the print it looks like ther is a voltage divider loading it . On the B+ line ther is a 220 k in series with 68k to ground. I think that should be ok , yes ?

 

[Sherman]

Re: load

After reviewing the power suply section of the print it looks like ther is a voltage divider loading it . On the B+ line ther is a 220 k in series with 68k to ground. I think that should be ok , yes ?

Depends on the wattage but yes I think it should be OK. Report back on your results. I would be very interested in how it works out.

 

[tenderland]

heater

I recieved the iron today , tubes on the way , detailed report in about 2 weeks