I have been messing around with tube audio, Ham and Shortwave equipment for well over 50 years. After retirement 18 years ago I dedicated most of my time to collecting, testing, repairing, restoring and building tube audio equipment as well as acquiring piece-by-piece a collection of very rare A.D. Audio equipment designed and built by Andre Dumortier during the 50's and 60's in Belgium. In Europe, Andre Dumortier was known as the "Saul Marantz" of Europe. His amplifier, preamplifiers and tuners were very well designed electronically and physically, his amplifiers are very McIntosh in appearance with black, potted transformers and nickel-plated chassis. All of his amplifiers (that I know of) used 7189 (6BQ5/EL84) as output tubes and designed for use with efficient speakers. He also incorporated a very unique and nice variable expanded on his preamplifiers and integrated amplifiers. More information can be found on my website if you search "Dumortier".