Mu Metal cans and transformer parts

[rlaury]

I'm working on a new product that requires a Lo ratio input transformer. 150 / 600  1:2, with  a 30dB  Mu Metal shield.
for my prototype I'm using a Jensen JT-16-B. It's exactly what I need except the price is $100US. Expensive!
I would like to wind these myself. I have the stuff to build a CNC winder. It shouldn't be that difficult to set up and wind these.  Where is best place to get supplies, lamination's and cans?

Any suggestions appreciated.

RonL

 

[PRR]

For a similar project I noted that Hammond now sells a 150:600 mike transformer for around $70. I do not recall how many dB are in the shell. Yes, this is not far short of Jensen's price, and we know Jensens are excellent.

If you can beat this prices, you may have a few outside sales.

My suspicion is that by the time you tool for Mu shields, you'll be asking for money to cover your investments.

 

[rlaury]

The Hammond stuff looks interesting. I haven't been to their site for years.
Didn't know abut the Mic/line transformers. I'll check it out.

Thanks
RonL

 

[gridcurrent]

Triad A-67j's are usually available on the used market.
Catalog specifications indicate alloy shielding, 40 to 60 dB of hum reduction.
The single hole mounting allowing rotation is especially useful when located near magnetic fields.

 

[Andy Peters]

I'm working on a new product that requires a Lo ratio input transformer. 150 / 600  1:2, with  a 30dB  Mu Metal shield.
for my prototype I'm using a Jensen JT-16-B. It's exactly what I need except the price is $100US. Expensive!

Is that their web-sales onesy-twosy price, or did you call them for a quote for production quantities?

 

[rlaury]

Yep. Thats the onesy twosy price. I'll be getting higher volume quotes this week.

 

[Michael Tibes]

Just in case you were not aware: mu metal might be difficult to work with, afaik it can't be bent or drilled without loosing the mu-effect. So you might have to get hold of ready-made cans if you do the winding yourself. OEP offers cases for their transformers, maybe those could be used?

Michael

 

[Matt Nolan]

Just in case you were not aware: mu metal might be difficult to work with, afaik it can't be bent or drilled without loosing the mu-effect. So you might have to get hold of ready-made cans if you do the winding yourself. OEP offers cases for their transformers, maybe those could be used?

Michael

Or you could look at what it takes to re-anneal the mu-metal. It might be a simple oven.

 

[Bo Deadly]

Is this for PCB mount? Make a footprint for multiple different transformers. For example, I use one PCB footprint for Jensen, API, Cinemag, and OEP parts like this:

This is also what Sound Skulptor does. They have a build document called "MP12 Input Transformer Options" that illustrates very clearly. Having flexibility with an expensive part like this could be important down the line.

The OEP A262A2E and A262CAN can is available on newark.com for less than $25 USD.  I have not tried OEP parts but despite the price I would be surprised if they didn't do the job just fine. If you're trying to get ultra-low noise because you're running it straight into an ADC and going digital, then maybe the JT-16-B gives you a few dB lower noise floor (no idea) or slightly better low frequency distortion. But otherwise, ultra low noise / low distortion is quickly lost in the noise and distortion of downstream circuitry.

If you want your gear to be absolutely top notch, then you're going to have to buy a part that has a proper name (and more important, it has to be expensive) and winding your own isn't going to do that.

 

[JohnRoberts]

Back in the '90s I was sourcing inexpensive mic input transformers from China (for installed sound systems). Back then the vendors we (Peavey) approached didn't even know what mu metal was... It took a while but they figured it out.

I suspect by now decades later, Chinese transformer vendors have figured out mu metal.

If not needing very high volume, there are probably decent quality domestic and/or EU transformer makers cheaper than Jensen (premium transformers). 

JR

 

[gridcurrent]

Where is best place to get supplies, lamination's and cans?

you can get the cans from Hudson.
http://www.hudson-technologies.com/
a vendor for many coil winders including the so called "premium" folks.

 

[rlaury]

Thanks All! I have a Triad A67J on the bench that I plan to take it apart to reverse  engineer it.
I hate to destroy it but I need to find out how it's wound. Anybody done this?

 

[Di_Sousa]

Where is best place to get supplies, lamination's and cans?

Laminations, bobbins and wire you can buy from EDCOR:

http://www.edcorusa.com/parts


Coil Bobins also from Cosmo Corp:

http://www.cosmocorp.com/en/index.cfm?loc=1&


Mu-Metal Cans:

https://www.don-audio.com/radiation-shielding-magnetic-shielding-tafo-hum-trafo-shielding-electro-magnetic-sheets-grain-oriented-electric-sheets-electro-magnetic-foil-shielding-foil-shielding-sheets

http://uk.farnell.com/oep-oxford-electrical-products/a262can/screening-can-transformer/dp/1172345?ost=OEP&selectedCategoryId=&categoryId=700000096003&searchView=table&iscrfnonsku=false

 

[CJ]

do a costing sheet

wire $$
lams $$$$ (high if nickel)
tape $
bobbins $
enclosure $$
lead wires $
varnish or epoxy $
toaster oven for bakeout $
winding machine $$$
solder $
labor $$$
electricity for toaster oven and winding station $

also see that if there is a problem with the transformer, you will have to fork out $$ but Jensen would probably cover their end of the deal

 

[rlaury]

Yep.. It's a thin line between make or buy. If I could make it
better, that's one thing. You would be lucky IF you could do that.

 

[CJ]

also consider your health, burning enamel off magnet wires is toxic, so are solder fumes and varnish fumes,

also eye strain, and a reduction in your free time,

i added tap to the cost sheet, 10 bucks a roll for poly and the same for some good glass/cloth tape,

and shipping tape if you mail them somewhere,

 

[Di_Sousa]

Yep.. It's a thin line between make or buy. If I could make it
better, that's one thing. You would be lucky IF you could do that.

CJ is right in the end might be more expensive to do it yourself than to buy the Jensen part

But hey, you might want to learn, you might have fun doing it. But be sure about one thing you would not do it better than Jensen.