Filaments DC or AC?

[kodabmx]

I use these: MINI DC-AC Inverter 12V To 18V220V/380V 500W Boost Step UP Power Module New Hot | eBay
For a power amp...DC-DC 8-32V to +-45V-390V Step-up ZVS High Voltage Capacitor Module Charge Board | eBay
For a simple line stage or negative bias supply. DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay

And this for a preamp or medium power application. They all work flawlessly and have no measurable noise at the plates of the tubes. I use HER208 diode for lower power, and UF5408 for the power amps. I even use a Delon voltage doubler on the medium powered one to get 420V for a driver stage...

 

[gabdx]

They are AC output, I am confused.

 

[popilin]

I am confused.

I knew it since post#28, no offence, just kidding.

 

[kodabmx]

That's why I also said which diodes I use. BTW 2 of the three I posted have DC output built in.

 

[kodabmx]

Also the formatting got screwed on that post. Sorry about that.
The 500W has only AC output, and I use UF5408 as a bridge.

 

[NuClear235]

I ordered
DC-DC 8~32V to 45~390V High Voltage Boost Converter ZVS Step-up Booster Module 890270282639 | eBay

So I hope will be ok for my tube headphone amp. (Clone of Little Dot 2).
It needs 175V AC or 230 DC.
I have transformer with 16V AC out. What a pitty is not on this booster integrated rectifier and filter... I have to insert more module.
Next I will add DC filament stabilizer.

I use these: MINI DC-AC Inverter 12V To 18V220V/380V 500W Boost Step UP Power Module New Hot | eBay
For a power amp...DC-DC 8-32V to +-45V-390V Step-up ZVS High Voltage Capacitor Module Charge Board | eBay
For a simple line stage or negative bias supply. DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay

And this for a preamp or medium power application. They all work flawlessly and have no measurable noise at the plates of the tubes. I use HER208 diode for lower power, and UF5408 for the power amps. I even use a Delon voltage doubler on the medium powered one to get 420V for a driver stage...

 

[trobbins]

A full-bridge of UF4007 or similar smd will give you 230VDC with 12VDC in, when using the 0-220V output winding.

I'd recommend using a commercial AC/DC smps power supply plug-pack with regulated 12VDC output to provide power for heaters and to the step-up module, then you have a regulated B+ as well, and no need for any AC wiring/safety concerns.

 

[santitrucco]

AC or DC filament 300B tube?

Hi friends, I have a new ask?
AC or DC filament 300B tube?
Why?

 

[6A3sUMMER]

IMHO,

If you like 100Hz/120Hz intermodulation tones on each music note or music tone, then use AC filaments on the 300B.
And even with no signal applied and AC filaments on the 300B, you are not likely to get hum down to less than 500 or 1000uV (0.5 to 1 mV).

DC is more trouble to implement, but does not have the above problems.

Read all 189 posts of this thread, and see if you believe my conclusions.

 

[merlin el mago]

Hi friends, I have a new ask?
AC or DC filament 300B tube?
Why?

General consensus is DC for DHT heaters.