Multiple windings output transformer connections possibilities
- Thread starter ln76d
- Start date
Help Support GroupDIY Audio Forum:
For 1:2 only one way primaries in parallel, secondaries in series, connect together as follows
1-3
2-4
6-7
8-9
then input is 1 and 2. Output is 5 y 10.
For 1:1 there are two ways depending on the impedance level. Parallel primaries and parallel secondaries (0.5 secondaries in series) for low impedance. For high impedance, usually recomended, all series. Connect as follows:
2-3
6-7
8-9
then input is 1 and 4, output is 5 and 10.
I won't tell you where to connect the shielding, you need to connect it to a low impedance reference point, usually chasis but may be less noisy to connect it to some other ground. YMMV with this.
JS
1-3
2-4
6-7
8-9
then input is 1 and 2. Output is 5 y 10.
For 1:1 there are two ways depending on the impedance level. Parallel primaries and parallel secondaries (0.5 secondaries in series) for low impedance. For high impedance, usually recomended, all series. Connect as follows:
2-3
6-7
8-9
then input is 1 and 4, output is 5 and 10.
I won't tell you where to connect the shielding, you need to connect it to a low impedance reference point, usually chasis but may be less noisy to connect it to some other ground. YMMV with this.
JS
what circuit?
what kind of a transformer? how big is the core? what is the DCR on the winds?
what kind of a transformer? how big is the core? what is the DCR on the winds?
I never read the word "higher"...
For tube output you usually are looking for very high impedance on the pri. This transformer may or may not be enough, you'll see noticeable low end drop if it's not enough. Also notice that some tube outputs have DC across the secondary and this transformer is probably not prepared handle it.
42x42x15x6?? In what multiverse are you living dude! I usually guess the bigger core that could fit inside the box, but might not even be an EI core in which case you just have to guess. If you do know the type of core you could make a better guess.
JS
For tube output you usually are looking for very high impedance on the pri. This transformer may or may not be enough, you'll see noticeable low end drop if it's not enough. Also notice that some tube outputs have DC across the secondary and this transformer is probably not prepared handle it.
42x42x15x6?? In what multiverse are you living dude! I usually guess the bigger core that could fit inside the box, but might not even be an EI core in which case you just have to guess. If you do know the type of core you could make a better guess.
JS
joaquins said:
Why "this transformer is probably not prepared handle it" ?
In standard connection there shouldn't be DC across secondary but i want to connect it to small voltage node at cathode.
joaquins said:
Dude
It's EI core, i don't now why but i assumed that it would be obvious it's EI. Overall dimensions of it are 42X42X15mm.
Sorry, i have sometimes problem with terminology in english, like in case of transformer specific parts.
I can't only determine center column size (hope you understnd what am writing about
) As also i'm sick and have fever
Maybe drawing would be better for dimensions?
Attachments
AndreasSchwarz
Active member
Hello,
it is a M42 Core, in the picture on the left.
http://www.jogis-roehrenbude.de/Trafoblech-1.jpg
Regards Andreas
it is a M42 Core, in the picture on the left.
http://www.jogis-roehrenbude.de/Trafoblech-1.jpg
Regards Andreas
> Is there an option to do it?
Peel all the wire off. Put on new wire.
3.5:1 and 4:1 are the same for about any practical purpose. We generally do not know plate impedance within 20%, and we never know true load impedance.
Peel all the wire off. Put on new wire.
3.5:1 and 4:1 are the same for about any practical purpose. We generally do not know plate impedance within 20%, and we never know true load impedance.
Thank you Paul as always
Between 3.5:1 and 4:1 there's not much difference it's obvious, but your connection schematic show 3.5:0.5.
Isn't 3.5:0.5 equal to 7:1 in ratio aspect?
Or did you skip the part of rewire it to 3.5:1?
No there's no option to rewind it
Not my pair of shoes. If transformer wouldn't fit this project, then i will use it elswhere
Between 3.5:1 and 4:1 there's not much difference it's obvious, but your connection schematic show 3.5:0.5.
Isn't 3.5:0.5 equal to 7:1 in ratio aspect?
Or did you skip the part of rewire it to 3.5:1?
No there's no option to rewind it
Not my pair of shoes. If transformer wouldn't fit this project, then i will use it elswhere
> I can't simulate paralell connections in most cases i have error.
Put 1 Ohm or so in series with each winding.
If there is *any* difference in turns, large current will flow in parallel windings.
SPICE default transformer has ZERO ohm windings. It will not even start the computation because "obviously" it can give INFINITE current, which would blow-up the computations. It won't even try.
In real life, turn counts are (often!) very closely matched, and all windings have real resistance. A "100r" winding may be 5 Ohms or so. So adding explicit resistance is legitimate and more realistic. And it solves SPICE's "problem".
However if you just want voltage ratio, there is no need to parallel 0.5 and 0.5 windings. The answer will be the same voltage ratio. (However SPICE may complain about the "un-used" winding; put 1Meg from both ends to ground so it has something to figure.) In real life, if you have identical windings it may usually be a bit better to parallel them for lower total parasitic resistance.
Put 1 Ohm or so in series with each winding.
If there is *any* difference in turns, large current will flow in parallel windings.
SPICE default transformer has ZERO ohm windings. It will not even start the computation because "obviously" it can give INFINITE current, which would blow-up the computations. It won't even try.
In real life, turn counts are (often!) very closely matched, and all windings have real resistance. A "100r" winding may be 5 Ohms or so. So adding explicit resistance is legitimate and more realistic. And it solves SPICE's "problem".
However if you just want voltage ratio, there is no need to parallel 0.5 and 0.5 windings. The answer will be the same voltage ratio. (However SPICE may complain about the "un-used" winding; put 1Meg from both ends to ground so it has something to figure.) In real life, if you have identical windings it may usually be a bit better to parallel them for lower total parasitic resistance.
PRR said:
Yes, it's correct
It's 1:3.
Would be there signifacant difference between this connection for 1:3 and this which i posted?
For 3:1, my connection scheme use primary windings as in original use of this transformer, with yours it use secondary.
PRR said:
It's works, i added winding resistance in virtual model options ;D
First time when i measured transformer with scope i only used primary windings in series and one 0.5 winding on secondary side. It gave me 4:1 ratio but there was low end loss. I will try measure it with two 0.5 in parallel and see is there any change!
3:1 ratio could be little bit to low. Output impedance of microphone would be ca. 360ohm
3.5:1 = ca 260ohm it's much better
4:1 = ca. 200ohm
7:1 = ca. 65ohm
4:1 and 7:1 would be best option if there's no problem with impedance ratio, if i didn't missed anything.
Time to measure
If you AC couple it it's all right, no DC. If you connect directly from the cathode to ground it will have DC current and for that usually gapped transformers are used, to minimize the THD at low freq. Most transformers aren't gapped, as they don't need to handle DC and the gap brings other problems, that's why I said probably this transformer isn't prepared.ln76d said:
I was asking cause you quoted too many dimensions for the transformer...Dude
It's EI core, i don't now why but i assumed that it would be obvious it's EI. Overall dimensions of it are 42X42X15mm.
Sorry, i have sometimes problem with terminology in english, like in case of transformer specific parts.
I can't only determine center column size (hope you understnd what am writing about
As also i'm sick and have fever
Maybe drawing would be better for dimensions?
The center column area is (or should be) twice the area of the side one, in this case I guess the one you measured 6x15mm so the area of the core should be around 180mm^2. Knowing that and the material you have most data about the core, in some cases you may need the average length. The material of the core might be hard to identify.
JS
On a side note - if it's an output transformer (as indicated in first post), don't expect it to work well for very-low details like microphone in- or output. You need mumetal or amorf for this, not sufficient to have the right ratios.
Jakob E.
Jakob E.
joaquins said:
AndreasSchwarz is right, that it's M42 core, so there's a gap
gyraf said:
Yes this one was output tranformer. Am using in microphones reversed input transformers (two types - small core and bigger core) for 6.3:1 ratio, and one output with 10:1 ratio, from the same company. It's DDR Funkwerk Leipzig.
Don't know material, looks the same like in their microphones output transformers (CM7151 etc.), and these which i have installed sounds amazing. I could speculate that material is similar to that which was also used by gefell, but maybe am wrong here. Looks really similar.
Definately it isn't transparent type like lundahl, but also there's no symptoms of sound degradation.
Three types tested are really linear, i measured transformers response as also electronic circuit response.
Still didn't measured wiring 7:1 for this one, probably i will try today.
Btw. as a curio, CM7151 output transformer have exactly same core, but the height is 17mm instead 15mm.
Similar threads
