LL1688: Lundahl Output Transformer

The LL1688 is an output transformer designed primarily for 845 tube amplifiers. With a primary impedance of 5K5, 9.2K, or 20.5K, and secondary impedances of 4R, 8R, or 16R, depending on how you wire them up. There are options for circuit topology and core material, which you select when you purchase.

 The transformer is 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 primary winding can be tapped for 33% UL connection. The transformers have a special audio C-core of our Lundahl production. The transformers are unpotted, open frame type suitable for mounting inside an amplifier housing

The LL1688 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

• 20K5: 8R or 16R
• 9K2: 4R, 8R or 16R
• 5K5: 4R, 8R or 16R

Overall dimensions including pins - 140mm x 95mm x 95mm

PRICE (1 off)
£191.33 +vat +p&p

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