Found this, is it a speaker Xover?
I am not familiar with this type of transformer- they have four leads on each "side", two of which are twisted together. Looking at the circuit I can't positively identify where a ground would be connected. The board as a unit has six leads, all are color coded differently.
Are these caps polystyrene? Is "NPC" a brand name or a type? Would the red tipped ends be for positive polarity?
Is this board is for a stereo hookup, with two identical channels? Or are these in parallel?
I'm just being curious and wanting to learn about components and how to test this circuit for fun.
Thanks,
Keith
I am not familiar with this type of transformer- they have four leads on each "side", two of which are twisted together. Looking at the circuit I can't positively identify where a ground would be connected. The board as a unit has six leads, all are color coded differently.
Are these caps polystyrene? Is "NPC" a brand name or a type? Would the red tipped ends be for positive polarity?
Is this board is for a stereo hookup, with two identical channels? Or are these in parallel?
I'm just being curious and wanting to learn about components and how to test this circuit for fun.
Thanks,
Keith
Hi Keith,
You just need an LCR meter. That will do inductors and capacitors. Get one with selectable test frequencies and displays Q and D. It will do resistance as well most likely.
The inductors are shielded, it is probably for higher frequency use. Yes, polystyrene capacitors. They are heat sensitive and can short if the leads get too hot.
You just need an LCR meter. That will do inductors and capacitors. Get one with selectable test frequencies and displays Q and D. It will do resistance as well most likely.
The inductors are shielded, it is probably for higher frequency use. Yes, polystyrene capacitors. They are heat sensitive and can short if the leads get too hot.
Hmm... with one side of the cap removed I measured the inductor winding parallelled with the 25nF cap to measure 22mF, that calculates out to resonate at just about 6.7Khz. So... maybe it is an xover for a tweeter afterall? Still not sure how the two sides are being used together to form a high pass filter? Can you guess if this is either a circuit for one filter/tweeter, or two? I'm just guessing because I can't seem to figure how the circuit works yet...
Sorry I have no experience with design tools, but I put together a partial drawing in Gimp below. The board has 6 external leads, all color coded differently, marked with green letters. Each coil assembly has eight leads, numbered. Note that two are those actually two leads twisted together, 4 and 5. I have only drawn the left side, since the other side is mirrored.
The four left coil leads (3,4,5,6) are electrically connected internally- evidently a tapped winding or two windings connected. The two leads on the right (1 and 2) are a separate winding. Verified with DVM.
Resistance measured between lead 3 and lead 6 is about 3 ohms, between 3 and 4 is 1.5 ohms, and between 5 and 6 about 1.5 ohms.
Resistance between leads 4 and 5 is about 0.2 ohms, and between 1 and 2 also about 0.2 ohms.
Hope this helps, thanks for your help!
Keith
The four left coil leads (3,4,5,6) are electrically connected internally- evidently a tapped winding or two windings connected. The two leads on the right (1 and 2) are a separate winding. Verified with DVM.
Resistance measured between lead 3 and lead 6 is about 3 ohms, between 3 and 4 is 1.5 ohms, and between 5 and 6 about 1.5 ohms.
Resistance between leads 4 and 5 is about 0.2 ohms, and between 1 and 2 also about 0.2 ohms.
Hope this helps, thanks for your help!
Keith
It appears to be something like this.
If you can manage to disconnect the two twisted wires, you might found out how the inductors are build.
These are potcores, 'turnable' transformers, and are available in various frequency ranges.
The numbers stamped on them indicates the material involved and the frequency range.
Many potcores are application-specific build, and not often bought as on your pictures.
Notice that point 1 is a 'common' for the other potcore too!
Further thought: a balanced - unbalanced signal transformer with filter.
AB / EF are balanced inputs, C / D are unbalanced outputs with that common as a ground.
Used on stage for a bass guitar player with noise suppression?
If you can manage to disconnect the two twisted wires, you might found out how the inductors are build.
These are potcores, 'turnable' transformers, and are available in various frequency ranges.
The numbers stamped on them indicates the material involved and the frequency range.
Many potcores are application-specific build, and not often bought as on your pictures.
Notice that point 1 is a 'common' for the other potcore too!
Further thought: a balanced - unbalanced signal transformer with filter.
AB / EF are balanced inputs, C / D are unbalanced outputs with that common as a ground.
Used on stage for a bass guitar player with noise suppression?
Attachments
Thanks! I'll do some research into potcores, a term I did not know.
I did see that point 1 is common to the two coil assemblies, but curious about there not seeming to be any external lead to that point.
And thanks so much for the attached schematic, I am embarrassed not to have taken the time to learn how to make those...
I'm now out-of-town, and will get back to exploring this next week, particularly looking at your thought about "AB / EF are balanced inputs, C / D are unbalanced outputs with that common as a ground."
So far, I haven't wanted to untwist those leads... hoping to figure this out without the need to... but we'll see.
BTW- this circuit was found at a hamfest estate sale, so there's not really much context to suggest the type of gear it came from.
Keith
I did see that point 1 is common to the two coil assemblies, but curious about there not seeming to be any external lead to that point.
And thanks so much for the attached schematic, I am embarrassed not to have taken the time to learn how to make those...
I'm now out-of-town, and will get back to exploring this next week, particularly looking at your thought about "AB / EF are balanced inputs, C / D are unbalanced outputs with that common as a ground."
So far, I haven't wanted to untwist those leads... hoping to figure this out without the need to... but we'll see.
BTW- this circuit was found at a hamfest estate sale, so there's not really much context to suggest the type of gear it came from.
Keith
Broken, removed, not connected (pin 1 of a balanced XLR input is also ground, but that would change this circuit).
This was done with Tina from TI, registration only, download & use for free. Missing are 'connectors' to draw proper circuits, as simulation is the main function of it.
Those are pretty unknown here, and it can be of any origin indeed.
About my suggestion of a bass guitar: why two channels and guitars have unbalanced outputs already...
It can also be a wheatstone bridge filter with single polarity output, the filter to supress noise from the outside. Lots of those equipment is not audio-related at all, and 6.7kHz is not an odd value in that pro-field.
