Langevin AM-16 DIY?

[alk509]

Hi folks,

I found an old AM-16 schematic while cleaning my hard drive and having never seen or used one, I wonder, is it worth trying to DIY one of these guys? do they sound good? has anyone tried?

Peace,
Al.

 

[guitarmaker]

I've also collected a bunch of info on these pres. I've heard they're really nice sounding, especially for drums. I see Sowter seels the in/out transformers. Not sure what suitable transistor substitutes would be best. I guess I'm with you, I'd like to know if anyone has done these up and what they thought of them.

Steve

 

[alk509]

[quote author="guitarmaker"]Not sure what suitable transistor substitutes would be best.[/quote]

Oh, yeeeeah... What transistors go in these puppies???

Peace,
Al.

* * * EDIT * * *

OK, I figured it out. From the AM-16 manual at sowter's website:

Q-1-2 (Langevin 1101) may be replaced with 2N929
Q-3,4,5,6, (Langevin 1201 or 1401) may be replaced with 2N2897 or 2N3053). [sic]
Q-7,8 (Langevin 1401) may be replaced with 2N3053.
NOTE: Some early models of the AM 16 used TI-487 instead of Langevin 1401. Replace with TI487 from Texas Instruments). [sic]

The manual goes on to give voltage charts, setup instructions, transformer specs, etc.

Peace,
Al.[/quote]

 

[NewYorkDave]

Never used 'em myself, but my buddy Ytrehalf (who posts here sometimes) owns a couple and says they're the bomb for guitars.

 

[PRR]

If it is the monster I am thinking of: the magic is in the iron, which is very custom stuff. For this amp: if you have the right iron, the transistors don't matter. If you don't have the right iron, it is just a beast.

 

[Flatpicker]

I bet they'll sound different using modern transistors too, but still good. PRR's correct, though - the iron's going to make the biggest difference. I eventually want to build one and see how it sounds, but I'd love for someone to beat me to it. :wink:

Used to, you could find some old ones on evil-bay, but I haven't checked lately.

 

[wilebee]

I have about 500 2n929's for the 1st and second stage of the am 16 if people are interested in building some. I would agree with PRR the magic is in the iron on this one both input and output. a balanced centertapped input transformer and athe same on the output with a tap on the secondary for neg feedback. very cool amps

Wil

Wilebee

 

[rafafredd]

Sowter have the AM16 output iron clone. He also have the input clone, but I guess you could use many options at the input.

Look at sowter.co.uk in the pro-vintage section.

 

[tk@halmi]

Rafa or others,

Do you still have the schemo for this thing someplace? Can you repost?

Thanks,
Tamas

 

[NewYorkDave]

Gerry C. has a webpage:
http://www.geocities.com/ciminosound/langevin-am-16.html

 

[Rob Flinn]

If your someone who worries about capacitors directly in the signal path then this is the one for you!

 

[smilinfu]

The sowter transformer clones for this came up in the old group. but I can't recall who it was that was looking to use them.

 

[soundguy]

I havent used anything for guitars since I got am16's years ago. Whatever that tells you.

Ive been wanting to whip up one wih the sowter transformers to see what the story is. There is a guy in cali making a reissue right now.

dave

 

[alk509]

Any way of varying the gain in this thing?

Peace,
Al.

 

[soundguy]

no...

patch it in to a limiter on the out or build a variable pad for the input, which you are going to need anyway.

dave

 

[CJ]

Awesome preamp. The warmest transistor, or for that matter, tube or transistor amp I have ever heard. Warm, buttery dc saturation sound. Great for guitar, and also for vocals. I gave my transformers to Brian to do the reverse job. I will probably purchase a set next month.

The board is double sided but the traces are huge with lots of clearance, so it would be fairly easy to make one. The circuit is very unique. I showed it to our resident genius here at work and he just shook hus head, saying that it probably took years to design and tweak. I still don't understand it.

I have all the specs on the transformers, save but the number of turns.

I would run it wide open and just use mic placement and mic choice to attenuate.

I tried a Lundahl 7903 at the front, but it just did not have that sound.

I have the original circuit board already in the rack. I took off the side rails and soldered them directly to the chassis using Big Bertha, one of those monster soldering irons that everyone should own.
If you unsolder the transformer leads from that pain in the arse connector, be sure to write everything down as there are a ton of wires both input and output.
cj

 

[rafafredd]

It would be really nice if you could post any info on that output iron, CJ...

 

[CJ]

Raf, I believe you have that post archived also.
I will dig it up.
:guinness:

 

[rafafredd]

I have DC resistance and inductance of the windings.

But I do not have the number of windings and core type info. The guy from Audiolink.com.br thinks about trying to make a replica available. So, more info is better.

 

[CJ]

Unfortunately, that was my first transformer investigation, and I had not graduated to the cutting torch and mill by then, so I have not seen the innerds.

I have seen at least four different types of transistor sets used in those things, so PRR is right. Don't sweat getting the exact ones in the circuit.