I have this transformer - how to find out the windings

I have got a load of Calrec/Lundahl 5606 transformers
I now announce me total ignorance in trying to figure out what each pin does and what are the windings.
Lundahl say they don't have the datasheets because they were a custom for Calrec
They are chunky (like the 5402s) - I boguth them from a guy who works at Calrec
And have I think (from memory - I am not at home now)... 6 or 8 pins on one side and 5 or 7 pins on the other (ie one less pin on one side - and it's not in the middle - the pins line up each from side to side apart from one near the middle)

I do know that they were used for...
"in the module i pulled this from the transformer was stepping the output onf an ne5532 opamp down to 600 ohms.i'll look for further info"

Ok - I have a multimeter and persistance - what do I do

Draw a transformer schematic on piece of blank paper.
Pic a pri and a sec, does not have to match any diagrams.
Asign pin numbers to the pri and sec, do not have to have phase correct.
Measure DCR for all windings. If the same, it is a 1:1.
If different, put the high readings on the pri side of your schematic and change pin numbers.
Put in a signal into the pri. Measure pri and sec voltages and divide to get approx turns ratio.

You have inductance meter?
Signal generator and scope?

I really don't know if it's already asked (sorry), but it would fit into the topic:
Is it possible to demagnetize a core again, and how do i find out if it happens to be magnetized if i bought it used? (as some sellers on ebay might not know about the influence of DMM measurements on audio xfmrs regarding kubi's post)?

Kind regards

Martin

Smallbut:
check the secnd to last post (PRR) on this thread
http://www.groupdiy.com/index.php?topic=9373&highlight=dcr+transformer+xformer
for a little info on demagging. There's probably more info elsewhere on the board, but that's the bit I knew how to find.

Tom[/url]

really, do not get too paranoid. In my experience, modern DMM can´t magnetize mic transformers cores in a way that you will notice any performance effect. Really. And those lundahls looks even bigger than most mic transformers.

I´ve already passed 48v phantom throught the windings of a peerless K241D for almost an hour, uninterruptedly, and no, I could not hear or measure a difference in the frequency responce or overall sound. And I have another one to compare it to.

So, don´t pannic. Just use your MODERN ohmmeter on the windings, and you won´t get enought current to magnetize the cores.

Magnetizing can surely be done, but it´s generally much harder to do than I thought. On one of the sowter papers, he wrotes about magnetizing cores, and the nickel cores are considered not that easy to magnetize, comparing to other materials.

All and all, if it´s really magnetized, it should also be really easy to demagnetize using a signal generator and osciloscope.

jeez, where get the 241?
Pultec MB?
Lucky dog!
:grin:

OLD PULTEC RIAA PREAMPS... :green: now converted to MB1s.

Yep, thanks for the answers!
:grin: :thumb:

Okay he we go
Lundahl 5606 - custom wound for Calrec

Pins

1...............6
2...............7
.................8
3...............9
4...............10
5................11

Resistance
1 and 2 = 11R3
4 and 5 = 11R7

6 and 7 = 5R
6 and 8 = 11R1
7 and 8 = 6R6

9 and 10 = 5R
10 and 11 = 6R5
9 and 12 = 11R4

Inductance (I can;t read my own writing!!!)
1 and 2 = 138mH
3 and 4 = 240pf (I know its capacitance but thats what the meter said...)
4 and 5 = 138.5mH

5 and 11 = 178pf (I know its capacitance but thats what the meter said...)

6 and 7 = 46mH
6 and 8 = 153mH (not sure I wrote this down right)

Please guys...
Oh and after this I have another one (an old Marinaire)

> 3 and 4 = 240pf (I know its capacitance but thats what the meter said...)

Well, since 3 and 4 are "not connected", we would expect only capacitive coupling, and 200 pFd is a good guess.

The inductances look low. Tell us about this meter!!! Common meters do OK with air-core, do not do well with big audio iron. Maybe we can discount its confusion, maybe we have to ignore it.

On the evidence in hand, using more guess than fact:

1-2: 150 ohms
4-5: 150 ohms
6,7,8: 150 ohms CT
9,10,11 (or 12?): 150 ohms CT

Any pair of 150 ohm windings could be seriesed for 600 ohms.

The 150ohm could be worked at 600 ohms, but both the inductance and the DCR seem too low to be likely, unless this was only guitar-band application.

This is the only info I have
"in the module i pulled this from the transformer was stepping the output onf an ne5532 opamp down to 600 ohms.i'll look for further info"

The meter is this...
http://www.maplin.co.uk/Module.aspx?ModuleNo=33524&doy=search

Looks like a decent instrument, although I am amused at the specification on capacitance accuracy: 10,000uF, +/- 0.3pF!

EDIT: Ah---I see now there is another spec on accuracy, of 1%. I guess they just should have deleted the "+/- 0.3pF" from the range spec.

I got the meter with its cousin the semi conductor analyser on sepcial offer
spent a lovely afternoon testing the hfes on about 50 transitors for a BA283 (hfe over 600!)
About 10 passed!

> Atlas LCR Passive Component Analyser Automatic test frequency selection (DC, 1kHz, 15kHz, 200kHz)

OK, it's ignorant about good audio iron. L at 1KHz may be much less than L at 20Hz due to skin effect on the iron.

Taking the 140mH number it gives for 11 ohms of DCR, it may really be 1H at low audio frequency. 1H at 20Hz is 120 ohms, which makes sense for DCR=11.

> transformer was stepping the output onf an ne5532 opamp down to 600 ohms

Since a 5532 can drive 600 ohms fine, I'm not sure what this tells us.

Was the corpse a good broadcast or studio board, or a voice system?

I am not sure of the corpse - I know it is Calrec - and I know the guy who sold it to me works for Calrec and sometimes hangs around here..
i will grovel and try and get him to answer

thanks for the help so far...

[quote author="uk03878"]I am not sure of the corpse - I know it is Calrec - and I know the guy who sold it to me works for Calrec and sometimes hangs around here..
i will grovel and try and get him to answer

thanks for the help so far...[/quote]

Why not just drop a note to Per Lundahl?

UK, does this look OK?
I need phasing to place numbers correctly, so if you haver a scope....




That sec will get close to a henry, not a lot of inductance for line level, most folks go with 5 or 10.

Yes, when measuring inductance, you can specify two things to try and keep on the same page with other people,

voltage level
frequency

if you vary either, inductance can change.


you measured capacitive leakage BTW, when you went from 5 to 11.
good deal!
core perm can be level dependent.

[quote author="bradzatitagain"][quote author="uk03878"]I am not sure of the corpse - I know it is Calrec - and I know the guy who sold it to me works for Calrec and sometimes hangs around here..
i will grovel and try and get him to answer

thanks for the help so far...[/quote]

Why not just drop a note to Per Lundahl?[/quote]
I did - they don't have any details as it was custom wound for Calrec only
and they didn;t keep a copy of anything (mmmhhh!!)

[quote author="CJ"]UK, does this look OK?
I need phasing to place numbers correctly, so if you haver a scope....
.[/quote]
Blimey CJ - spot on

I will get my scope out at the weekend and have a bash at putting a signal though (I am in the dark - but am enjoying this)..

thanks

Looks like CJ is spot on in his guess of opamp

Cyril Jones did some testing for me here are the prelim results:

I have posted the transformer to you.

I ran a signal through the transformer found all windings gave a similar output so the ratios are about 1:1:1:1, this with no loads.

2 of the windings would load quite heavily with 200 ohms with excelent square wave, the second 2 exhibited quite severe top loss with a load of 3Kohm, initially I was surprised since all winding had similar dc resistance. Per Lundahl respected contractual obligations and would not reveal the operational conditions. I did not push Per as I have a lot of respect for him and a good relationship and wish to continue that.

I then remembered an old design which used mixed feedback and searched through old Lundahl files and found their LL7401 transformer with a similar winding arrangement.

Now - I have find out that
What the f**k do I do with them?