Langevin 5116b out trafos to CJ ?? (warning : lots of pics)

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rafafredd

Well-known member
Joined
Jun 3, 2004
Messages
2,409
Location
Rio, Brazil
For reference, this is the original schem:

langevin5116b.gif


There´s a studio near my house that has 12 channels of Langevin 5116b moded mic preamps. The guy found all the amps in an old radio station, all burned, in the corner, and get it for free. Strangely all the output transformers were open winding. So, he had a tech to mod it to use with the outputs transformerless. So it worked great for those ten years, but now it starts to get noisy, and then he came to me and asked if I could do something for him about those preamps. I got three channels, the ones that were most noisy, and I had a look at the mods that this tech did for him. He substituted the output tube for a 12AU7 and is running the output stage single ended. He gets the signal from the lower plate and together he did a feedback directly to the input transformer primary :?: very strange mod, if you wanna know what I think. I really do not like the concept, but I must say that the studio these things came from did great recordings on the last 10 years with those moded Langevin preamps, and the studio owner insists on using JUST these tube preamps in the recording he does, despite he having other types of preamps, including Pultecs, Ampex, and UA. He likes tubes. So, t still sounds great, but I must admit I hate the concept of the mods, and I´m sure it will sund even better with the original circuit in place again.

So, I got one of the four channels racks, with three channels of tube pres in there and bring it home. I do like the recordings that was done with the moded pres as it stands, but I would really like to have those things wired back as originals. Here is a pic of the actual unit:

DSC03881.jpg


DSC03882.jpg


DSC03883.jpg


DSC03884.jpg


Here you can see two of the output transformers. I´m sending one for CJ (if he wants to rack it open... I really think it would be very interesting to see those western PP out trafos from the inside) and the other to Bran Sowter - I´ve wrote to him about it, and I´m waiting for hime to get back to me, but I think he might be interested in dissecting it and having a recreation of this one in his PRO VINTAGE section). Hopefully Brian will make a copy, of for those of us that are curious about what goes on inside it, hopefully CJ can do his magic with this one also.

Here is a pic of the dead ones:

DSC03886.jpg


And here you see the output trafos side by side with an UTC LS series. The Langevin trafos are really small as you can see:

DSC03887.jpg


As you see, it´s not a question thread, just kind of an anouncement, as I know other people were also interested in this one sometime ago. But feel free to add anything in here.
 
Cool!
Looking forward to that classic iron.
If I fix it, you can have it back.
Then if you want to send one input, I can test it without destroying it, and we will have the whole set.
But no pressure, just an idea.
Thanks Raf!

Maybe John Hall has the blueprints. No luck getting a hold of him.
I think Doc Hoyer might have the info on those Langevins.......Raf, hold on to that output for a day if you have not shipped it yet. I may be able to get the winding data,
cj
 
Here's some Lawn-juh-van transformer data that might be of interest.

Right-click and "save as"

2MB PDF

I scored some very nice NOS Chicago 20Kp-p:600/150 output transformers a while ago. I have these set aside to build 5116Bs if I ever come across suitable input transformers.
 
Hey Raff I have a bunch of reichenbach 20k -600 outputs that are spec for 26db if you capacitively coupled them. Wil

Wilebee
 
WOW! This board looks just like the ones I have here now.

I know that there are at least two other types of 5116Bs ou there. A point to point and another PCB from Langevin. The ones I have and the ones that´s on Ebay listings are in fact ELECTRODYNE mic preamps, but it uses Langevin (WE) iron and it´s also the exactly the same circuit as the other 5116Bs...

CJ, no I have not shipped the iron yet. Please, PM your adress and I´ll do so.
 
I have been wanting a pair of these mic pre's for some time. They were recommended to me by Fred Cameron who was definitely a man who knew tube circuits. He designed, cloned and refurbished many pieces of tube gear but was probably best known for his microphones and mic mods.
Since the 5116b topology isn't that vastly different from most tube pre's of that vintage, I always imagined that the mojo was in the Langevin transformers. It's funny that 5116b's came up on prodigy since I mentioned to Steve at Bloo about a week ago that it would be cool to clone these.
CJ-----how many 5116's does your friend have? I am looking for 2.
 
The 5116B (and its equivalents) is a great amp. It can be used as a preamp, booster or line amp (up to +24dBM, I believe). You can build a whole mixer with just that one type of amp. I wish I had scored some years ago when old tube stuff was still cheap; they're priced way too high for me now.
 
Moonshot, you can call the number on this site for info on the Langevins.

Treat the guy nice because he is very cool and knows just about every oldschool audio engineer that is still alive.

cj

http://home.earthlink.net/~rogerr7/autran.htm
 

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