LL2742: Lundahl Choke

The LL2742 is a 2 coils choke for tube amplifier anode supply. The choke is available with different core air-gap, which results in different inductance and DC current capability. LL2742 can be used in choke input and cap input applications. The coil is wound using our standard high internal isolation technique with isolation foil between each copper layer. The core is an audio C-core of our own production.

The LL2742 is available in 6 versions.

• 4H, 500mA, wired in parallel
• 6H, 350mA, wired in parallel
• 10H, 200mA, wired in parallel
• 17H, 250mA, wired in series - 1 pieces in stock, silicon core
• 24H, 175mA, wired in series
• 42H, 100mA, wired in series

• Please refer to the datasheet on how to wire the chokes, be it in series or parallel. Please note that Lundahl only labels the chokes with the series value. To clarify a choke labelled (in bold):

  LL2742 17H (250mA) has a value of 4H (200mA) when wired in parallel
  LL2742 24H (175mA) has a value of 6H (350mA) when wired in parallel
  LL2742 42H (100mA) has a value of 10H (500mA) when wired in parallel

(N.B. Adjusting the airgap adjusts the DC current and inductance. This is done at the Lundahl factory.)

There are further 2 versions depending on what C-core material you require.

• Silicon-iron
• Amorphous-iron (AM)

Dimensions - 95mm x 75mm x 50mm

PRICE (1 off)
start at £97.16 +vat +p&p

Non-Stock Item - Please allow 4-6 weeks for dispatch. However, we do have 3 x 17H, 250mA, silicon core in stock