Home Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Choke Filters, and the Buzz...

My latest amp project is a 6C45 choke loaded driving a 211, B+ is 800vdc, driving the 211's at 60ma.

Nite View

Thus far I'm very pleased, but am getting a small amount of buzzing from the first choke.

Power supply is 1650vct --> 866jr's --> 6CG3 --> Swinging Choke ---> 15uf oil ---> Smoothing Choke --> 30uf oil. There's a 100K bleeder to keep the power supply in "choke loaded mode".

Both chokes are old stock Thordarson, rated at 350ma, well behind both the DC + Peak AC draw, so shouldn't be anywhere close to saturating.

Digital delay powers the 211's, 6C45's and 866jr's first, then brings up the B+, 6CG3 and 6106 (for driver stage) once the mercury has vaporized.

Ironically the buzz from the swinging choke is louder than the hum from the AC filaments.

Changing the choke would be tough, as the chassis is a tight fit, so I'm looking for other solutions.

I'm toying with either a snubber across the first choke, or a small cap in front of the first choke. I don't really want to up the B+ but have a bit of room (caps are rated at 1000v)

Any idea which (if either) would work best, and how to pick the correct cap value (and appropriate voltage ratings)??




This post is made possible by the generous support of people like you and our sponsors:
  Signature Sound   [ Signature Sound Lounge ]


Topic - Choke Filters, and the Buzz... - Gary Kaufman 13:44:19 02/8/03 (21)


You can not post to an archived thread.