Why no DIY preamp input/mic output irons?

[MicDaddy]

I've a few transformers I'm trying to replicate. Very little on winding preamp inputs or mic output transformers.

Is it lack of core availability, # of turns, dia of wire used?

 

[ruffrecords]

It is a seriously black art.

Cheers

ian

 

[gyraf]

..but by all means: get on with it!!

So much else has been lifted from black art to common knowledge by this forum - this topic could very well be next.

And it sure as he.. would do wonders to general audio quality out in the real world.

Look in the transformers meta: loads of info collected in there.

Jakob E.

 

[MicDaddy]

Ed Anderson seems to have figured it out and CJ has left lots crumbs to pick over.

The obstacle now is finding quantities of materials to start poking holes into ideas.

MagMetals has a catalog of laminates, where do you even start?

LH2023 looks like MagMet DU something something but which? Does anyone (MagMet or otherer) sell in quantities less than what an 18-wheeler can haul?

 

[CJ]

there are some nickel lams on evilbay from Korea, which has a pretty good program in metalurgy at the local college from which springs some pretty good stuff i am told,

what are you guys after?

for input a K-241-D is hard to beat, for a 4:1 tube output a Jensen is extremely hard to beat,

we could probaly wind those,

you do need some refined equipment for winding fine wire, tensioners and wire guides, to name a few,

then there is mechanical, like mu cans and term plates,  and polycrysteline wax is nice to have,

 

[pucho812]

there is a lot of science going on in those tiny and sometimes large cans.  They effect so much. Having worked on a side that has tried to replicate specific transformers in an attempt to cut cost, I can assure you of a few things. The off the shelf ones you get from reputable brands are well worth the money you spend on them.  Secondly any knock off there of may look like the real thing, may smell close to the real thing and may even have the same size, shape and pin out. But that is when the similarities end and the differences come into play.  I'll give you an example not all 1:10 mic input transformers that share the cinemag pin out sound the same but they may look the same.  What's worse is when you have an established product already in the market place, trying different brands of transformers always yields different results and while on paper the less expensive one would be the one to choose,  from a sonic  standpoint it may not be especially with an already established sound/product.

 

[MicDaddy]

CJ, you created a monster I cannot silence.  :-X  winding gear is covered. Might obtain a second winder as I have some "upgrade envy"  as mine is a few years old and there's a nicer one with more tricks. That would force me into purchasing more tensioners and less setup.  I need a long term solution for winding in house a microphone output transformer for a dynamic mic. The winding is simple, I only need to come up with a design using readily available materials.

pucho812, I want to make them in house if possible, as long as they function and do the job and sound ok then that is the goal. Ideally a few mic input to various preamp designs.

 

[CJ]

those Neumann mic transformers had some unique lams in there which used some secret alloy mix, along with a certain annealing process that gave them the mojo properties they are famous for, some people say that the transformer was more important to the sound than the capsule, who knows,

Lundahl makes some good capsule transformers, but you could probably DIY something just as good if you used a C core,

 

[pucho812]

pucho812, I want to make them in house if possible, as long as they function and do the job and sound ok then that is the goal. Ideally a few mic input to various preamp designs.

fair enough, might even get some good ones out of it.  you could go the inexpensive route and talk with the boys over at edcor.

 

[joaquins]

The only reason I haven't at least tried it is the lack of NI lams to start with, I don't think GOSS worth the really hard effort. For OP is quite fine and I've done a few of those.

JS

 

[MicDaddy]

Group buy on laminates?

I had something almost worked out with Moby recreating  some lams; but finances require I focus on all efforts in keeping this product going.

I'll measure up the lam I'm trying to copy, and see if I cannot find an equivalent stamp in the MagMet catalog. Then it's a matter of recreating the bobbin or finding one similar and then just wind and test and try some things.

Got a ton of homework to do.

 

[dirtyhanfri]

I'm finishing building a CNC coil winder, quite funny project I did with a friend, now we're getting into the electronic part, and I started looking for supplies.

Coil formers can be get from china vía eBay or aliexpress easily (what about 3D print them? maybe it's cooler than cost-effective).

For the laminations, I've requested a few quotations two days ago but didn't get response, maybe I asked for so small quantities, but there are at least two or three suppliers in the EU.

Anyway I think I should start with some 600:600 or something easy before getting into mic input transformers.

Assuming I won't wind a Lundahl quality transformer, getting something usable looks like a nice challenge, and there's a lot of info here (CJ's dissections are great) so why not try?

 

[gyraf]

Go for it.

If I was you, I'd try to contact Per Lundahl and ask if it could be possible to buy a bit of their core material.

This might not be possible for several reasons, but he has been very helpful to the DIY-community in the past, so it's worth a shot.

While you're at it, you could as well ask him for advice on getting started - don't push it, but you may as well ask....  ;D

Jakob E.

 

[blankrazor]

Here is a source for c cores  of various sizes and other transformer parts,  they don't have a minimum order either.
http://www.alphacoredirect.com/

 

[dirtyhanfri]

I got response from http://www.abschirmungen.eu/ looks like they're able to sell me small amounts of core...

They have two different Nickel laminations (Including mumetal quality) in various sizes.

Gyraf: As soon as I get the winder to work I will try to get in touch with Per Lundahl, hopefully he will understand I'm not trying to get their business, just winder a few transformers for myself...

 

[MicDaddy]

Good news dirtyhanfri, keep us posted. Please keep us up to speed with ordering quantities and what not.

 

[Moby]

Group buy on laminates?

I had something almost worked out with Moby recreating  some lams; but finances require I focus on all efforts in keeping this product going.

Hey mate I still keep this deal on hold.

 

[mitsos]

I'll measure up the lam I'm trying to copy, and see if I cannot find an equivalent stamp in the MagMet catalog.

Got a ton of homework to do.

I believe the small mic inputs seen around here (2622, Cinemag, Altran, Jensen) all use EE2425 lams.  The slightly larger ones (like the UA610 input) might use an EI375 and will take more signal/bass before distorting. I thought I saw somewhere that the K241 used an EE2627, which is also slightly larger than the EE2425.  One could make a great input trafo with any of these lams, it depends on everything else (winding structure, winding tension, wire size, tape thickness, etc).  In the end, you will likely have to wind a few times, changing things a little bit each time, until you get the results you expected. 

Does anyone know about Jensen's winding methods? 

 

[MicDaddy]

Moby, once my diaphragm project is done and paid for we can move forward.

mitsos, I opened up a Jensen microphone output tonight. It's an oddball one, but I wanted to get a feel for their winding construction.

Here's some pics from that:

I call this quasi-bifilar until someone tells me otherwise.

 

[MicDaddy]

Jensen JT-110K-HPC
EE 1x1
looks like glassine between layers

I murdered the thing opening the mu shield making reversing turns counts impossible.
The can was potted with a clearish too soft for plastic but harder than wax type of a substance. Smelled sweet when heated so I opted for brute force opening vs toxic asphyxiation.  I'm gonna try to melt/heat some of the clear stuff today, outside, and see if it goes gooey, and if so then future openings should be able to go a lot smoother by having a bit more discipline and patience and try boiling in a breast milk bag.