Roly

langevin am16 trays
« on: May 24, 2005, 03:10:24 AM »
Hi folks
 I found 2 trays for my am16s. (thanks to advice from this forum)They have wax (I think) on the bottom.
 Is it there for isolation?
 Should I leave it there?
 thanks
 Roly
 PS........I was given the am 16s.......how's that for luck?
 cheers


CJ

langevin am16 trays
« Reply #1 on: May 24, 2005, 03:19:57 AM »
What color is the wax?
(please don't say light brown)
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #2 on: May 25, 2005, 06:07:44 PM »
Hi
 It's sort of an opaque (sp?) pale yellow.......I suppose you could call it very light brown.
 Should I be concerned?
 thanks for your help
 Roly

CJ

langevin am16 trays
« Reply #3 on: May 25, 2005, 06:16:37 PM »
It's transformer wax from an over-heated AM-16 output transformer that was sitting above the tray. Did your free AM-16's used to be sitting in these trays, or were the trays scrapped from other units?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #4 on: May 25, 2005, 07:52:08 PM »
Hi
 The trays are from a seperate source.
 The AM16s are very clean, no rust.
 Different question........The input transformers (the smaller ones at the connector end) are different...one is aTF-425-C, the other a TF-425-B. The C has rounded edges, the B has square edges. Also the connector pins on the C one are longer.
 So.........am I out of luck for a matched pair?
 Thanks for your help
 Roly

CJ

langevin am16 trays
« Reply #5 on: May 25, 2005, 10:28:05 PM »
Cool. Your units probably aren't cooked.

Are you reading the p/n off the paper label on the side of the x-former, or from the black ink stamped p/n on the bottom of the x-former?

Do you see 1987 stamped in ink?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #6 on: May 26, 2005, 12:24:22 AM »
Hi
 I see 1987 on the transformer with the paper label TF-245-B the other one has Langevin TF-425-C in ink and on the paper label.
 What would cook the ones that lost the wax?
 cheers
 Roly

CJ

langevin am16 trays
« Reply #7 on: May 26, 2005, 02:00:57 AM »
You mean TF 245-C, not TF-425-C.

It's anybody's guess on the cooked 16's.

Let me check these two versions on the scope. Will report tomorrow.

cj
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #8 on: May 26, 2005, 03:08:35 AM »
Hi CJ
 It's TF 425 C and B. I'm a tad dislexic so I checked again.
 You must live in transformer heaven.
 cheers
 Roly

langevin am16 trays
« Reply #9 on: May 26, 2005, 02:07:54 PM »
Actually if you're a transformer it's probably transformer hell. :green:


Roly

langevin am16 trays
« Reply #10 on: May 26, 2005, 02:30:52 PM »
Gad!!!!......Not transformer abuse!!!!! :cry:  :cry:  :cry:

soundguy

langevin am16 trays
« Reply #11 on: May 26, 2005, 03:01:09 PM »
roly-

one thing to consider, my am16's get really hot, if they werent in a good ventilated box and left on for weeks on end I could easily see wax heating up and leaking, that wouldnt come as the biggest shock in the world.  Could be a million other things too, but in normal operation, those things generate some heat for sure.

dave

chips are good with dip...

CJ

langevin am16 trays
« Reply #12 on: May 26, 2005, 04:15:37 PM »
Especially if strapped.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #13 on: May 26, 2005, 10:36:55 PM »
Hi Soundguy and CJ
 Thanks for your intrest.
 By straped do you mean to get the extra gain?
 cheers
 Roly

CJ

langevin am16 trays
« Reply #14 on: May 26, 2005, 10:50:24 PM »
Yes.

OK, the lams are different.
The coils are the same, but electrical testing (as opposed to opening up another 425) have shown that the older TF-425-A, which may or may not have a different paint job (light lavender as opposed to light blue/gray) , will be less lossy at the low end.

cj
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #15 on: May 27, 2005, 12:17:14 AM »
Hi CJ
 Mine are B and C..... I will check with the kind person who gave them to me and see if he has matched pairs that I could trade for.
 Is the A issue one the best?
 cheers
 Roly
 thank you for taking the time to help.. :grin:  :grin:

CJ

langevin am16 trays
« Reply #16 on: May 27, 2005, 01:16:25 AM »
What color are the inputs?
I have not done a listening test to compare the difference.

Maybe I will pull a lam from the early unit, but I have to be careful not to break any wires. I really do not want to do this, but I am curious myself as to the lam material.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

CJ

langevin am16 trays
« Reply #17 on: May 27, 2005, 02:10:16 AM »
Here is the magnetizing current scope shot. It shows the waveform of the current entering the input transformer as it first reaches saturation. Input signal is a 20 hz square wave.
The first shot is the older Langevin TF-425-A. The second is the TF-425-B:

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16in_sq_20hzoldmag.jpg

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16_in_20sqmag.jpg

Here is a comparrison of the B-H curves. Sine wave at 10 hz. 425-A is first, 425-B is second:

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16in_sine_10hzold.jpg

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16_in_10sine.jpg

The wider the curve, the more core loss.

Here is the B-H with a 20 hz sq wave.  A is first, B is second:

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16in_sq_20hzold.jpg

http://vacuumbrain.com/The_Lab/TA/Langevin/Input_Iron/am16_in_20sq.jpg

I'm no Einstein, but if those lams are the same, my name is Eric Clapton.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Roly

langevin am16 trays
« Reply #18 on: May 27, 2005, 02:32:36 AM »
Well........better not call you Eric.
 Both are the same color of grey.
 cheers
 Roly

CJ

langevin am16 trays
« Reply #19 on: May 27, 2005, 11:55:35 PM »
I couldn't handle it. I broke down under the pressure. I hacked into a perfectly good early vintage Langevin AM-16 input transformer, the third one I have sacraficed in the name of science. What is wrong with me?!

I had to find out if my lam tests were a bunch of baloney as usual, or if they actually meant anything. So, I put the 425-A on the mill and opened her up like a can of sardines.

The transformer in question:

http://vacuumbrain.com/The_Lab/TA/Langevin/Lams/lam_1.jpg

The back plate where the first incision was made:

http://vacuumbrain.com/The_Lab/TA/Langevin/Lams/lam_2.jpg

The goal is to take one lam out for a sample without screwing up the transformer. Not an easy thing to do as there are some 0.0020 inch thick magnet wire splices at the bottom of the core where we will be operating.
One false move with the screwdriver, and snappy gator, kiss you x-former goodbye.

Whats weird is that if the x-former says 425-A on the paper label, it says 425-B on the stamped label.
 
If it says 425-B on the paper label, it says 425-C on the stamped label.

Thank you Langevin for the ambigous part numbers.

Milled the end plate:



First lid off:

http://vacuumbrain.com/The_Lab/TA/Langevin/Lams/lam_4.jpg

The copper lies in between the two mu cans for extra shielding. The copper resists electrical fields, while the mu metal resists magnetic fields.
This is the top of the inner mu can. That black goo is pure Afghan hash oil, smuggled inside transformers during the Russian occupation. And man, is it good!



Pried the mu lid off with the help of a big soldering iron, which was needed to break loose a couple of tack welds. Viola. pay dirt!

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


 

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