DIY ESS AMT Tower Trans-line


2008-02-20 3:55 am
I have been working on a replica of the AMT Tower, The drivers I am using is the "great Heil" and an Audax HT240z. The Audax is a 93 db 4ohm woofer listed as a 10 inch, in all actuality it is more like a 9 inch. This woofer is very fast and is an excellent match with the Heil, althought still had to use a autotransformer to pad the Heil 10+db. The crossover is also DIY using all poly and foil caps T2A Autoformer and copper foil inductors, configuration is Linkowitz-Riley 2nd order @ 2500Hz. The outcome is one of the most amazing speakers I have ever heard. The Heil produces details that are mind blowing , the woofer transline configuration produces low bass, there is really no need for a sub, the midrange is very smooth never overdone, I really cant say enough about this fine speaker.

Another great combination for the Heil AMT is the Audio Nirvana10 or 12 inch, I installed the super 10 in an O/E pair of AMT Towers crossed at 5k. In comparison the Nirvana has bolder mid range but suffers in the Bass arena, where to Audax shines.

I have noticed alot of complaints about the Heil Shout, initially I thought the Heil was a little harsh on some songs and flawless on others. What I found is the Heil is as/or nearly as revealing as Horns and really love being driven by tubes. I dont have my Tube amps yet, but I picked up and amazing low buck DIY tube pre-amp on ebay Called the Mini Spice. This fun to build kit pre-amp comes in many configurations, bare boards, stuffed boards and sometimes plug and play. I reccomend the stuffed boards to keep it simple, then add you own favorite parts. I used the Goldpoint Mini-v attenuator and a Greyhill switch. The great thing about this pre is that it uses 3 12ax7's 1/2 tube is used per side this makes it possible to roll any 12a family tubes throughout the preamp to change sound and gain.