LL1689: Lundahl Line Output Transformer

LL1689 is a line output transformer for tube amplifiers. The transformer is available with different core air gap for PP or SE drives. The transformer primaries are wound with a special low-capacitance winding technique to achieve the best high-frequency performance. The transformer has a unique high flux, low distortion audio C-core of Lundahl's production. The LL1689PP is assembled with a small core air gap to allow for some DC current unbalance. For the S.E. versions of the LL1689, the core air gap is chosen such that the denoted DC current (18mA for a LL1689/18mA) generates a no signal core flux density of 0.9 Tesla when used with all primaries in series. This leaves a flux density swing of 0.7 T for the signal.

The LL1689 is available in 2 versions to suit the circuit topology. (The air-gap is adjusted during manufacture to suit)

• Push-pull
• 18mA Single-ended

(N.B. The purpose of the airgap is to accept the DC current of the output valve without saturating the core, leaving enough headroom for the sound signal)

There are further 3 versions depending on what C-core material you require.

• Silicon-iron (STANDARD)
• Amorphous-iron (AM)
• Nanocrystalline (NC)

Also, there is an option to have a Faraday Sheild fitted to your transformer to reduce the noise floor.

• Without a Faraday Sheild
• With a Faraday Shield (S)

And a further 2 options depending on what wire you require.

• Copper
• Silver (Ag)

Turns ratio

• 9 + 9 : 1 + 1 + 1 + 1

Overall size including pins - 73mm x 61mm x 53mm

STARTING PRICE (1 off)
£103.03 +vat +p&p

Non-Stock Item - Please allow 4-6 weeks for dispatch

For more information, please refer to the datasheet below.