View Full Version : James B. Lansing - Solid State Transducer Energizer - Amplifiers

02-21-2018, 12:39 AM
Hello all,

This is my first post here. I would like to know more about some very early amplifiers made by JBL: the Solid State Transducer Energizer.
The reason for this is question is that I recently got my hands on a JBL SE408SE, in mint condition.

Obiously, I have already done some research myself. If I understand correctly, the amplifiers were used with systems alike the Paragon, Lancer 99... and maybe more?
Also, these amplifiers were fitted with 'stage direct connection differential circuit' (JBL T-circuit). Which has to be some kind of circuitry making the amplifier suited for each model (using EQ, filters,??).
Another thing I find, is that these amplifiers could not only be used in companion with the speakers mentioned earlier, but could also be used INSIDE the speakers. They could be mounted inside the cabinet, making these speakers possibly one of the earliest self-powered speakers ever made?

What I have doubts about, are the model names. I found the following types:

SE408SE (the one I have)

Correct me if I'm wrong, but I understood that the 'S' versions were suited for mounting inside a speaker. So, no cabinet or enclosure. Can someone confirm this?
Also, can someone explain to me what all the differences are between the above amplifiers? Does someone know the specific years each type was made? I believe they are all from 1960s-1970s?
There is quite some info on the internet about the SE408S, but I couldn't find anything about the SE408SE...

Some more pictures:



Last but not least, always a tricky question... can someone give an estimation of the value of these items?
This is what I was able to find, but the prices vary substantially:


Thank you all in advance!

Best regards,


02-21-2018, 03:00 AM

A look inside this site's library section might have led you here:



02-21-2018, 03:36 AM
Thank you for your reply. I have indeed seen that page, but still no information about the SE408SE?

02-23-2018, 05:51 PM
Hi Teun,

You have asked a LOT of questions. I will try to address at least some of them.
The Energizers without an "S" suffix were earlier amps that used germanium transistors, sounded terrible, and were prone to blowing up. And yes, I know, because I have heard them, and repaired them. These are the SE401 and SE408. The transistors are only available surplus, and they frankly aren't worth fixing. It makes me laugh when I see these listed for big bucks on Ebay. I PRAY potential buyers know the difference, I'm guessing the sellers don't, or just don't care.
The "S" amps were excellent amplifiers. They were a complete redesign by Bart Locanthi, using his patented T-circuit (which is the basis for most complementary push-pull amps that followed)
So "S" stands for silicon, which replaced the use of germanium transistors in the earlier amps. It has nothing to do with mounting.
The amp for mounting is the SE408S, The "stand alone" version of the same amp is the SE400S. The only difference between these is the 408S had no "face" or cover as it was designed to mount in JBL cabinets with the back facing out. I have never heard of an SE. I am guessing it was a mis-print or the E just stood for Energizer.
I have personally owned a 400S, a SA600 and I still own a SA660 to this day, and wouldn't sell for any price. They need to be recapped after all these years, but once done, they are very hard to beat sonically. ...and BTW the 600 and 660 never used the "S" suffix but are T-Circuit silicon amps.
There were variable damping cards made, which could plug into the amps. There were several different ones designed to match various JBL systems. In all honesty I have never used them or heard them in a system. All they could do is lower the damping, which might help in an over-damped system, like an LE14A in a very small enclosure, other than that I can see no use for them.



02-25-2018, 11:35 PM
Dear Kev,

Thank you for your answer, this helps me a lot!
Still some research left to be done by me, to find out what the SE408SE really is. When I know more, I will share here ofcourse.

Best regards

09-03-2019, 08:29 AM
Dear Kev,

Thank you for your answer, this helps me a lot!
Still some research left to be done by me, to find out what the SE408SE really is. When I know more, I will share here ofcourse.

Best regards
Not sure if your still looking for information but the 1966 catalog shows some information on the SE model. It appears its identical to the 400SE but is designed for a in cabinet installation. Hope this helps