I see chokes, filter reactors, swinging chokes, smoothing chokes, and other types. They all look more or less the same, but I'm sure they're intended for different purposes, right?
Which of these can be used in a pi filter for a tube amp power supply? Any tips, tricks, warnings?
Thanks!
Which of these can be used in a pi filter for a tube amp power supply? Any tips, tricks, warnings?
Thanks!
A "simple" smoothing choke is what goes in a PSU's П section filter. Look for adequate current handling capability and low DCR.
The voltage across the choke in a CLC filter is low. So, the max. voltage rating is usually a non-issue. However, a solid hipot rating, to prevent arc over onto the grounded lamination stack, is necessary.
The voltage across the choke in a CLC filter is low. So, the max. voltage rating is usually a non-issue. However, a solid hipot rating, to prevent arc over onto the grounded lamination stack, is necessary.
Thanks! So what is a swinging choke or a filter reactor? All names for the same thing? Interchangeable?
A filter reactor is simply the technical name for a choke. A swinging choke is one that allows it's inductance to vary inversely with load current unlike a linear choke that is more stable. This is accomplished by carefully controlling the gap size. Swinging chokes are used with what is known as a choke input supply where the choke is directly off the rectifier before the first filter capacitor. Swinging chokes will begin to saturate more then a linear choke as it approaches it's "rated current". This action provides a higher voltage output during a heavy load thus offering better regulation.
Interesting. Always assumed swinging chokes were a cheap skate "Dynaco" solution. Are there examples of commercial amps using swinging chokes in choke input supplies? Maybe in guitar amps?
Hello,
Some chokes are better than others! Especially for choke input the differences can be big. Tango from Japan did make chokes especially designed for choke input. Lundahl says their choke can be used for choke input and for use in between two caps ( CLC)
For choke input you will need a transformer with an higher output voltage because the choke will create a big voltage drop and you need to take care of a minimum current flow. If there is no current the voltage will go up much to high. Info can be found using google.
I use choke input for all my gear. If you did not yet buy a transformer better start with choke input right away i would say. Getting another transformer one year later is a waiste of money ,
I did use several Lundahl chokes and they all work very well.
Greetings, eduard
Some chokes are better than others! Especially for choke input the differences can be big. Tango from Japan did make chokes especially designed for choke input. Lundahl says their choke can be used for choke input and for use in between two caps ( CLC)
For choke input you will need a transformer with an higher output voltage because the choke will create a big voltage drop and you need to take care of a minimum current flow. If there is no current the voltage will go up much to high. Info can be found using google.
I use choke input for all my gear. If you did not yet buy a transformer better start with choke input right away i would say. Getting another transformer one year later is a waiste of money ,
I did use several Lundahl chokes and they all work very well.
Greetings, eduard
The only Lundahl products i really like are their chokes. Still, a bit disappointing that the amorphous types buzz like а swarm of locusts when used in a choke input arrangement.
Swinging chokes, when correctly used, are not 'cheapskate' engineering but good engineering. They provided the required result at reasonable cost. They were used when a reasonably stable high voltage was needed but the extra cost and complexity of regulation would not needed. They are less needed nowadays than they were 60 years ago because we have SS rectifiers and big capacitors.
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