beyerdynamic))))

i don't have anything, i just felt like starting a thread.

CJ, is this you getting me excited about the ribbon transformer thread?

Looking forward to it.

Yes, I have here a tr/bv350027900

the pri is a dead short, but has 750 micro henries

need four wire fluke to get real dcr, better just to count turns and measure wire dia. :green:

i have new micrometer that has extra digits now!!!

weird, but wire varies, no matter what gauge, inch by inch, foot by foot, mile by mile.

sec resistance is
yel-grn-13.3 ohms
grn-blu 15.3 ohms

wow, 10.42 henries sec inductance.


thats 1:13,893 incuctance ratio

=

1:117 turns!!!

:shock:

Yes, I have here a tr/bv350027900

the pri is a dead short, but has 750 micro henries

need four wire fluke to get real dcr, better just to count turns and measure wire dia. :green:

i have new micrometer that has extra digits now!!!

weird, but wire varies, no matter what gauge, inch by inch, foot by foot, mile by mile.

sec resistance is
yel-grn-13.3 ohms
grn-blu 15.3 ohms

wow, 10.42 henries sec inductance.


thats 1:13,893 incuctance ratio

=

1:117 turns!!!

:shock:

Those were BK readinds, the Sencore, which is notoriously lower, but more accurate down below, says

194 micro henries pri ind and 2104 sec milli henries
=
1:10,845 imp ratio = 1:104 turns,

lets go with the BK for total inductance and the Sencore for leakage:

front to back leakage: 5.2 micro henries
back to front: 11 milli henries

sweep test next...wow!

this thing is flat from 1 hz to 400 k hertz.

I ran it backwards with 10 mv coming out the front---touchdown colts!--and 200 mv in.

this does not add up to more than a 1:20 ratio, so in this special transformer, the impedance ratio does not match the tunrns ratio.
this is because of the unusually low pri rtesistance/inductance and coil struture, having a tight couplin of the pri tio the core and the sponge secondary reaching out to the window boundry.

I will see if this generator will drive it front to back...
and do a bh curve

crap, almost a run back by the pats..

..

Interesting. According to the beyer number system, it ought to be 1:27.

I recently got a M560 off ebay. That's a slightly weird ribbon headset mic indented for singing drummers. The tiny transformer in it looks kinda weird. The primary is the outside coil and the turns run in a kind of knot across each other and cover only about half of the bobbin. I was tempted to correct that, but maybe that's just a very ingeneous design I don't understand. :?

crazyt flat for a 1:27.
This ought to be interesting.

[quote author="Rossi"]
I recently got a M560 off ebay. [/quote]

Rossi, do you remember the one which I modded into a new body with a Sowter transformer? That was fun.

I heard that the little Beyer transformers were wound toroidally... ?

Perhaps Marik may comment - he seems to have a good understanding of ribbons and their transformers.


Roddy

Yeah I remember the ribbon element, but I don't think I've seen the whole new mic. I recently connected a chinese ribbon transformer to the Beyer element, but the output was low and there wasn't much bass response. I thought the low cut was done in the transformer (which might have explained the weird primary winding). But it looks like the ribbon motor itself has little bass response. A few days after I bought my M560, there was another one on ebay. I had a mind to buy it and build a nice stereo ribbon. But given the limited bass response, I gave up. Did you take apart the ribbon motor assembly?

I think the beyer ribbon transformers are pretty good. My M160 and M500 sure are lower noise than my chinese ribbons. But the ribbon clamps may also play an important part in noise performance. I wish they'd build a nice large geometry vocalist ribbon mic. They sure know more about ribbon mic technology than pretty much anyone else.

Here it is:

http://www.groupdiy.com/index.php?topic=8440

I still need to take the motor to bits. I'm not sure why there is a lack of bass as it is - in fig. 8 mode it should be fairly flat.

I'm a big fan of the Beyers. They did make what I believe to be a large-geometry ribbon (as far as I know) which was hand made. It looked like the M320 ( http://www.ronharter.com/documents/BeyerM320.pdf ) which was a vocalist ribbon but was larger and better quality. I stupidly didn't buy one for cheap when I could have.

Here it is: http://users.swing.be/beckerp/musee/beyer.pdf

See below:

I have this thing apart.
Waiting for pics to uplaod.
Real tiny core, pri on the oiutside, hold on....

the latest victim..



BH curve, low level, so into the noise floor a bit:



Even though the overall size is small to begin with, there was another can inside the can!
Clever use of two cans to get max shielding with min space.
No wonder people say these are quiet.
The signal from a ribbon motor is probably the lowest level that gets amplified in a studio, so in order to keep the s/n good, you need all that mu metal. I just went at it like a can of sardines.



This is looking at it from the top, with the top can pulled off, and the second, inner can exposed. There was just a small dollop of epoxy like compound that loosened up with the heat gun.

http://vacuumbrain.com/The_Lab/TA/Beyer/Ribbon_Transformer/beyer_ribbon_c.jpg

They say keep it small for max bandwidth, I guess they were not kidding.
This is definatrly the smallest xfmr I have "worked" on.



A round nylon bobbin is used. Same thing with SM 57 xfmr.
Pri wire on outsde, 9 or 10 turns, will find out shortly:


Got the micro workin, so more exact wire sizes from here on out!
This is your first, precicion, DIY xfmr hack job, ribbon primqary wire gauge:




I just figured out that the reason the pri is wound last is because the wire is so thick that the bend radius would make it impossible to wind
around the inside of the core without taking up too much space, which would also mean more leakage, since there would be more air in the winding.
Also, this core material is probably hi mu something, even though it looks like grained silicon from the outside. If you wrap that big wire around the core too tightly, you can alter the magnetic properties of the core material due to mechanical pressure. I was reading about this on the Magnetics web site, which has a lot of good info in their online library.
They even have to watrch the epoxy that is used to encapsulate some of the powdered cores. If the tempeture coef. is wrong, the strain will decrease inductance. Ask Svart what this does to a tuned switcher.

Wow, excellent work CJ! :thumb: :thumb: :thumb:
Lots of good info and some inspiration for my DIY ribbon transformer experiments (once I get the time to continue).

So it is just one primary winding and one secondary, no windings in parallel or in series? Have you measure the real DCR of the primay yet?

[quote author="rodabod"]Here it is:
http://www.groupdiy.com/index.php?topic=8440
[/quote]

Cool mic, I like your design! Maybe it is the thick gauze in front of the actual ribbon (or whatever is below the gauze) that causes the bass loss.

[quote author="rodabod"]
I'm a big fan of the Beyers. They did make what I believe to be a large-geometry ribbon (as far as I know) which was hand made. It looked like the M320 ( http://www.ronharter.com/documents/BeyerM320.pdf ) which was a vocalist ribbon but was larger and better quality. I stupidly didn't buy one for cheap when I could have.

Here it is: http://users.swing.be/beckerp/musee/beyer.pdf

[/quote]

Thanks for those links! Great material!
I think I read somewhere that the M320 has a ribbon motor pretty much like the "modern" beyers. It is not much older, either. There was a pristine looking M320 on ebay about a month ago, but the price got pretty high, so I didn't buy it. I wonder if the M360 has a bigger ribbon motor; it is somewhat bigger on the outside and it has higher sensitivity. On the other hand it could be related to the M500. The french description says it has a presence peak. The M500 motor is slightly bigger than the M160 motor.

By the way: I was told that there were early beyer ribbons before. But I've never seen one, not even pictures. Supposedly they had an RCA-77-type look.

I picked up an old CBC commentator unit off ebay and disassembled it. The mic pre/compressor units have teeney weeney beyers in them.

When I trace out the circuit, I will try to disable the compressor section or make it switchable.

Click the pictures to make them bigger





William

Primary: 10 Turns - 0.077 Ohms

Luckily we had an old 8042A with the 4 wire. The newer Flukes we have feature a dual display function, but no 4 wire.

Anyway, thats pretty low dcr.
This core lookes to be about 8 lams of high Ni, darn camera bateries went out, have to go shopping.

Jedes transvestite ist unterschiedlich. Dieses ist keine Ausnahme. Die Laminierungen wurden schlossen oder löteten oder stempelten aus auf Stück hochwertigem Nickel heraus geschweißt. Der Lack bildete es schwierig zu zergliedern. Ich mußte die Laminierungen auseinander schneiden. Die Spule Leitung ist ungefähr 0.004 Zoll im Durchmesser.

:razz:

:thumb: I see little Beyer taught you some German :green:

[Translation for non German readers: Every transvestite is different. This one's no exception. The laminations were closed or stamped out of a solid piece of high grade nickel. The laquer made it difficult to disassemble. I had to cut the laminations apart. The coil wire is about 0.004 inches in diameter.]

Yet another excellent hackjob, CJ! :sam: :sam: :sam:

Thanks, but I still do not know how this thing was built.
I am thinking that they stamped a one piece lam, only with no gap like the Ollire Iron.
Then they would have to fashiona bobbin around the center leg of the core, then spin the wire on somehow, like a torroid. The wire would be on a shuttle, pre curt length, which would not be much, in this case, as the mean turn lenght is very small.

I thought I remember Gus talking about spinning a oil on a core without lacing up any lams.

I did not see any signs of soldering or welding, as that would probbly ruin any anneal.This nickel alloy was very tough, I had to squeeze with all my might just to get thru one lam. And the lam legs are less than an 1/8 inch thick!

The core measures 11 mm by 16 mm, outside dims, 8 lams per stack.

[quote author="Rossi"]Translation: Every transvestite is different. [/quote]

Freudian slip, or intentional assertion?

Either way, thanks for looking under another tranny's skirt CJ! :green: