Yessir, it does!

"Doesn't a SMPS throw a lot of RF into the surrounding environment?"

A regulated SMPS emits a nasty mix of frequencies that are constantly modulated over a very wide range. They're simply not suitable for this use.

I would only use a switcher for a DHT filament if the supply was A) a single frequency oscillator and B) tuned well above the audio spectrum. I did that in each of my 211 monos by modifying a 12V "60W Electronic Transformer" to operate at roughly 80kHz. It was a long process, but the end result works extremely well and meets the goal of producing no audible hum.

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Follow Ups Full Thread

Topic - Anyone use 5V switching power supply for 300b filament? - Iczerman 13:29:37 03/27/24 (17)

I used 12 V SPS for heaters in many projects and they were generally fine with only one exception. - cellailuca 09:38:16 03/30/24 (0)

RE: Anyone use 5V switching power supply for 300b filament? - zacster 19:04:57 03/29/24 (0)

RE: Anyone use 5V switching power supply for 300b filament? - Chip647 06:31:21 03/28/24 (14)

RE: Anyone use 5V switching power supply for 300b filament? - Tre' 14:40:51 03/28/24 (13)

I put the SMPS in a external shielded box. No noise at all. (nt) - Chip647 12:03:45 03/29/24 (8)

Yes, that would work. Shielding. (nt) - Tre' 15:34:19 03/29/24 (7)

Well, no... - Triode_Kingdom 17:17:58 03/29/24 (6)

Most of the crud is well above 20kHz (nt) - Chip647 13:09:37 03/30/24 (3)

But not all, and even the energy above 20kHz is too close - Triode_Kingdom 18:24:38 03/30/24 (2)

Like anything, there are tradeoffs - Chip647 09:53:51 03/31/24 (1)

RE: Like anything, there are tradeoffs - Stephen R 01:24:01 04/07/24 (0)

RE: Well, no... - Tre' 07:56:17 03/30/24 (1)

Agree (nt) - Triode_Kingdom 18:25:15 03/30/24 (0)

my wife's 2004 cell phone near my stereo rig in the basement did that at considerable volume /nt - Story 15:44:23 03/28/24 (0)

Yessir, it does! - Triode_Kingdom 15:23:53 03/28/24 (2)

Easier but no cigar - andy evans 09:28:12 03/29/24 (1)

My Solution - Triode_Kingdom 10:04:26 03/29/24 (0)

Follow Ups

Yessir, it does! - Triode_Kingdom 15:23:53 03/28/24 (2)

Easier but no cigar - andy evans 09:28:12 03/29/24 (1)

My Solution - Triode_Kingdom 10:04:26 03/29/24 (0)

Yessir, it does!

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