Trusonic

[JB Elle]

Do you know anything about the following Trusonic drivers:

15" E 52L woofers
E 15 horns

They are mounted in plain, painted wood cabinets. They look like field coil woofers. I would appreciate any help you could give me

[pelly3s]

i cant tell you anything about it but i can tell you that i want that horn lol. i have one already and i want another and you cant get parts anywhere for them

[Steve Schell]

I crave 'em! JB Elle, from your post it sounds like you have a pair of these systems. They are a rare find and would be very desirable on the vintage audio market.

They are Bob Stephens' copycat version of the Lansing Iconic. They are definitely field coil systems, as were most of the Lansings. Yours is the first Stephens field coil system that I've seen (outside of catalogs) that duplicates the Iconic format exactly, right down to the eight cell horn. I have seen similar systems with four and ten cell horns; Stephens made quite a variety of multicellulars.

My guess is that these were built in the mid 1940s. His earliest products were finished in black crinkle paint, your horn postdates that period. Your labels appear to be the ones that say "Stephens Manufacturing Co. Los Angeles, Calif." His first location was on National Boulevard in L.A., and he moved to larger quarters in Culver City in 1947. As far as I know no field coil speakers were produced after the move.

One thing I'll mention is that it is absolutely essential that the field coils are powered before you feed any audio signal to these speakers. Field coil speakers do not have a permanent magnetic field, but depend on DC current to energize the magnet assembliy. Without it, all energy fed to the voice coils is converted to heat, and they can burn out in a heartbeat. The unit with the tubes in the cabinet bottom is the field supply, which feeds the current to the field coils. The field coils in a Lansing Iconic are wired in series, but I don't know what arrangement Stephens used. Another caution is that these systems were probably rated for about 30 watts of input power. They are highly efficient and will play loudly on little input power, but I would resist the temptation to really blast them, despite their clean output. Those high frequency diaphragms are irreplaceable these days.

Are you in southern CA? I would love to see these speakers in person.

[JB Elle]

Thanks for your reply as information on these speakers is really hard to find. I found them at an estate sale just about a mile from my house (I live in Washington state). The woman running the sale said they were from a "roller rink". That must have been true as there were piles of old "strap on" roller skates in boxes all around. I bought them at the end of the sale and honestly believe that if I hadn't they would have been thrown away(?!?) No one expressed any interest in them.

I haven't hooked them up yet as they are so big they are in my storage shed. It's possible they don't work. I'll let you know how they sound when I try them out. Thanks again for your help.

[pelly3s]

If you dont mind me asking, how much did you pay for them.

[Steve Schell]

JB Elle, I am so glad that you were there to save these very special speakers from destruction! The reason that systems like these are so scarce these days is that most of them have been thrown away over the years. For years field coil drivers were considered to be ancient junk and they were thrown away by the thousands. They must not have listened to them first, as they offer sound quality that is difficult to equal in a permanent magnet driver.

Speakers in roller rinks are usually flown up high, which would explain their remarkably good condition. You may have the nicest pair of these systems still in existence. My fond hope is that you keep them intact and resist any urge to part them out. Many speakers are worth the most in pieces these days, but you have some real rarities that will likely retain their greatest value intact. How much are they worth? Hard to say, as I am more familiar with the Lansing stuff. Lansing Iconics have sold for $10,000 or more each in Japan in recent years.

I have only seen one other example of a similar Stephens system in such good condition, in a home museum collection. It used permanent magnet drivers, and had a very unusual 12 cell (2 by 6) multicellular horn. I once had a pair of Stephens utility enclosures like yours, but they looked like they had been dragged behind a car.

When you fire them up, make very sure that the field voltage is making it to the field coils. Sorry to overemphasize this, but I once fried the diaphragm on a Stephens high frequency unit like yours. The field connection was bad, and without thinking I cranked the amp to try and get more output. I heard a faint "pfft" and the coil was gone.