I built 511B in wood. Excellent result, wood horn is warm and sweet. Far better than other altec metal horns.
Audio system:
Klipschorn
Altec 511B in wood as midhorn
tweeter modified using EV DH3
audio amps:
1.2 W SE DHT amp using RCA 10 output tubes, 71A driver and preamp using RCA tube 26
1.5 W SE DHT integrated with RCA tube 26 and tube 45 as output tube
1.5 W SE integrated with 12AX7 (tube rolling with Telefunken, mullard and bugle boy amperex) and tube 45 switcable to 2A3 as output tube
CD Player
24 bits vacuum tube CDP op amp modified using discrete parts
Turntable
Pioneer with tube phono-pream