Posted by Wayne Parham on November 30, 2003 at 15:31:05

In Reply to: Re: 3Pi and wooden Smith horns ? posted by kupfer_m on November 30, 2003 at 06:43:44:

The Delta 12LF used in the Theater Series three π really needs "motor braking" - electrical damping - so some SET amps aren't up for the task. But you might try it with your amp, because some work just fine. Amplifiers based on the 300B tube are pretty strong.

Don't modify the dimensions of the box or the port - If you want another loudspeaker, I'll send plans for another speaker. The Thermionic Series three π and the Theater Series four π both work well on amps with low damping factors, such as low-power SET amps.

As for mounting the HF horn on top, I suggest that you move the midwoofer up so that the distance between it and the tweeter are the same as called for in the original design. It's also important to maintain the same front-to-back spacing as well.