The 'Thor T-line'

[Erik Mandaville]

There was a thread today that contained a couple of examples of more traditional dynamic driver loudspeakers, and I just wanted to share a really neat design that had been published in 'Audio Express in May of 2002. I came across this the other day when searching for SET and PP tube amp information. By the way, if some of you are even a little bit interested in making your own equipment, you might want to check out this publication. However, it can be very educational audio reading in general -- even if you don't usually build things yourself. Sometimes it can be a bit on the technical side, which can get boring after awhile...but not always.

This speaker was designed by the very well-known Joe D'Appolito, and is a transmission line loudspeaker. I have been interested in T-lines for years, but never ever got around to building one myself. I have never heard such a system with tube amplifiers, or any amplifier for that matter, but in theory this type of system seems that it could be a very good match for tube amplification. It uses very good drivers in the usual D'Appolito array (AKA MTM) and is a good looking speaker.

Just thought I would leave this with you all. It can be found at www.madisound.com. Find the 'Kits' link (Madisound makes a very highly rated kit version of this speaker for about $1500/pr), and locate the 'Thor T-Line.' I don't have the knowledge to include an illustration here, but the Madisound website provides a nice image as well as of course more information. It looks like it could be a great system.

Take care,

Erik

Dean: Your "Original" idea on the Ping-Leo thread made me Thanks for that.

[mobile homeless]

I had a pair of Fried Q4 transmission line speakers in the late 80s and early 90s. It actually had extremely open sound and was involved in one of my favorite systems I ever owned. Of course, it was also in the best listening room I ever had as well. Still, I loved those speakers and the transmission line approach gave them a very open sound, this run with a B&K ST-202/Cary SLA-70, Superphon SP-100 or Cary Audio SLP-70 and Linn LP-12 (a leftover college system). The Bud Fried's speakers were excellent and not too bad a load. You dont see them around too much anymore.

kh

[Deang]

Man, you had a Superphon. Those were supposed to be killer. I really wanted one of those back then -- but could only afford the Thalia.

[Erik Mandaville]

Kelly:

I appreciate your mentioning Fried's designs; and that you have had experience with them is honestly enviable. The T-line seems really to be a kind of cross between a much more common bass reflex and folded horn. Just from what I have read (again, I have never heard one, darn it!)they are evidently efficient, and are able to produce surprisingly low and linear bass response by way of a much smaller driver than would normally be required for the same extension. And they, as you mentioned, apparently have an open and detailed presentation. I think Fried was also interested in using series rather than parallel networks, which is also not very common. I've done some reading on this, and it was laborious and technical to say the least. But there may be some advantage to using series networks. That nice sounding monitor I posted a picture of in our secondary listening area uses such a network. Every time I hear those things I wonder why they aren't in the main system! Their efficiency is just on the low side, and the room upstairs is larger. I first used them with my little ASUSA 4-watter, and they did fine, but only up to a point.

Dean (and Leo too if you happen to read this): I want you to know that what I said about installing tubes ontop of a good solid state amp was not intended as sarcasm. Given the context, it may have come across as such. It is something I have sort of joked about in the past, and would have been my way of dealing with an unexpected (and not necessarily desired!)affinity for transistors. Maybe it was something my dad told me to do -- he always asks why I go to such trouble with tubes, when solid state devices are in his words "...so much more reliable, don't generate damaging heat, have better linearity, etc., etc.) I bring him up because he has a great wealth of electronics knowledge. He even laughs at the fact that I have enjoyed using tube rectifiers over silicon diodes. Whatever. What can I say, I enjoy tubes. I haven't listened to a good SS amp in years, and probably won't for one simple reason: I'm afraid I might really like it!

The 'Audio Express' Thor T-line article was done well, and this speaker has gotten (as far as the extent of my own reading)only the best of praise from those who have heard it. I have used SEAS drivers in the past, and they are built fantastically well. There seems always to be a warning associated with the Thor, though -- something that amounts to, "...be prepared to accept the fact that these speakers will bring out the very best AND worst qualities of whatever system to which they are connected." The cost of about $1,550/pr for a complete kit (cabinets, crossover parts, drivers, cables, internal damping material, and needed hardware)is a great bargain! Sure a little bit of work is involved, but what a fun project it could be!

Moondog report: Most of the parts have been removed, but it is just too hard to work ith a broken, splinted finger. I know for sure that stripping wire (especially slippery Teflon hookup wire)would be next to impossible, so I may have to wait a week or two to begin the rebuilding. If I can't sell them because they are going to look so different inside from probably every other Moondog now howling, I will rewire them for 16 ohms and use them with my Lowthers. Those two always got along with one another quite well.

Again, you all take care!

Erik