LL1691B: Lundahl Output Transformer

The LL1691B is a dual coil C-core tube amplifier output transformer for a 20K: 8R impedance ratio Based on the LL1691 design. The LL1691B is available in PP and SE versions. The coil is wound using our high internal isolation technique with isolation foil between each individual layer of copper wire. The core is an audio C-core of Lundahl`s production.

The transformers are highly sectioned with harmonically sized sections, which results in a minimum leakage inductance. Combined with a low capacitance coil winding technique, this results in a wide frequency range. The transformers have a special audio C-core of our Lundhal`s production, which is gapped for the desired DC current. This would depend on the current draw of the output valves. The transformers are of an open frame type and are suitable for mounting inside an amplifier housing.

The LL1691B is available in 2 versions. (The air-gap is adjusted during manufacture to suit)

• Push-Pull
• 70mA 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)

The constructor can adjust the following primary and secondary impedances depending on how the winding sections of the transformers are wired together via the exposed solder pins.

Primary impedance: Secondary impedance

• 20K: 8R

Overall dimensions including pins - 148mm x 103mm x 90mm

PRICE (1 off)
£294.37 +vat +p&p

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