Schematics

Audiophile (reproduction) oriented:

• The Audio Design Guide by Andrea Ciuffoli contains a large number of audiophile project using our transformers
• L0rdGwen has published an extensive building description for his ”Aegis DIY Tube Headphone Amplifier” at the DIYAudio.com community.  On head-fi.org additional material is published ”here”
• Laszlo Csaszar suggests a SRPP (Shunt Regulated Push Pull) topology for a DAC using E88CC tubes and Lundahl LL1678. 
• Jac Music collection of schematics using Lundahl transformers . (Jac Music is our German distributor of audiophile transformers)
• Old-fasioned 30W Push-Pull amplifier. A very comprehensive building instruction by Claus Byrith. This amplifier uses LL1663/PP transformers.
• Easy-to-build SE amplifier Yet a very comprehensive building instruction by Claus Byrith. This amplifier uses EL34 tubes and LL1664/80mA transformers.
• Schematics by Aqua Blue is now collected in a separate list.
• Lynn Olsen push pull amplifiers Amity and Aurora and preamplifier Raven (Lynn Olsen web site is at http://www.nutshellhifi.com)
• The Revenge KR842VHD SE Amplifier using LL1623/90mA, LL1648 and LL1638. (This PDF document requires Acrobate Reader 4.0 or later to load cleanly) Reprinted, with permission, from audioXpress , Issue 12, 2001, p.p. 44–49, of audioXpress magazine. © Copyright 2001 by Audio Amateur Corporation. P.O. Box 876, Peterborough, NH 03458, USA. All rights reserved.
• The ARMADA SET amplifier project.
• Alexander Kitic SE amplifier with the impressive 813 beam tetrode tubes and Lundahl LL1688 output transformers.
• Claus W. Boening Discrete Solid State Moving Coil Phono Stage with LL1933 

• Claus W. Boening Single Ended Hybrid Power Amplifier with LL1693/230mA

Studio (recording) oriented:

• Bo Hansén phantom powered active DI with LL1538 (scroll down on page).

Video transformer oriented:

• How to build a video isolator from Tomi Engdahl´s blog ePanorama.net.