Because the winding has a DC resistance of 5 ohms and with a 16 ohm load this would result in about 1/4 of the voltage output lost as heat in the winding.
With a 45 ohm load only 1/10 (10%) is lost as heat and more power will be delivered to the load.
But I don't understand were there would be 6db of gain comes from considering that you can only run a maximum of 2/3 the ACrms voltage to use its fully designed bandwidth of 300Hz to 3400Hz, if your amplifier is designed to only feed a 1200ohm impedance at 200mW.
To get the full 200mW you must limit your lowest frequency to 465Hz!!
jer 🙂
With a 45 ohm load only 1/10 (10%) is lost as heat and more power will be delivered to the load.
But I don't understand were there would be 6db of gain comes from considering that you can only run a maximum of 2/3 the ACrms voltage to use its fully designed bandwidth of 300Hz to 3400Hz, if your amplifier is designed to only feed a 1200ohm impedance at 200mW.
To get the full 200mW you must limit your lowest frequency to 465Hz!!
jer 🙂
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If you search hard enough you may find another manufacture or supplier that has the exact transformer you need, or have one custom made.
Or even modify the one you have, IF you can get it apart and the the secondary winding is on the top as it should be.
This would be very difficult to do with such a small transformer.
jer 🙂
Or even modify the one you have, IF you can get it apart and the the secondary winding is on the top as it should be.
This would be very difficult to do with such a small transformer.
jer 🙂
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You have not stated what you are using as a driver as this may not be any kind of issue to worry about, except for the sake of theory.
jer 🙂
jer 🙂
The driver is Unknown to me. The current TM003 to 8 ohm 0.8W circuitry is working i know that and i simply need to replace the speaker with 45 ohm and 0.3 W speaker. But make sure to find the correct Audio transformer for it.
I am going to bujy the transfoermers today for test.
I am buying 42TM026 should i also buy few others?
I am leaning toward the ones having ratios closer to 5:1 like TM004, TM017, TM118, TM010....
I beleive one of them should be a good one?
I am buying 42TM026 should i also buy few others?
I am leaning toward the ones having ratios closer to 5:1 like TM004, TM017, TM118, TM010....
I beleive one of them should be a good one?
Stick with the ones that have a low secondary DC resistance to minimize any losses to the load.
There are only a few in that list.
The IMHO 026 is the only one that seems suitable for you application.
jer 🙂
There are only a few in that list.
The IMHO 026 is the only one that seems suitable for you application.
jer 🙂
The 004 will have a even higher frequency of core saturation point than the 026 model, as indicated by its lower designed input (primary) impedance.
Probably in the 600Hz to 700Hz range.
I am curious to know your results. 😉
jer 🙂
Probably in the 600Hz to 700Hz range.
I am curious to know your results. 😉
jer 🙂
Items Backordered
I just found out that these items are on backorder on mouser and the lead time is 17 weeks. I cant wait that long. I am hoping to find smthg else on other websites like digikey.
BAD LUCK
I just found out that these items are on backorder on mouser and the lead time is 17 weeks. I cant wait that long. I am hoping to find smthg else on other websites like digikey.
BAD LUCK
I am running out of luck... i could not find any other website which sells the xicon 42tm026 transformer.
I looked in digikey and their way of filtering the transformers is confusing me. Can someone give me an idea on what should i filter out while buying a suitable transfomer from digikey? what should i look for on the options?
Thanks in advance
I looked in digikey and their way of filtering the transformers is confusing me. Can someone give me an idea on what should i filter out while buying a suitable transfomer from digikey? what should i look for on the options?
Thanks in advance
Digikey only has two transformers that meet your impedance requirements and are only rated at 50mw.
They are also very expensive at nearly $20 for each one!!!
Invalid Request
More information is needed about your application in order to help advise you the best that we can.
There are many other cheaper and more efficient ways to drive a 45 ohm speaker than by using a transformer that has a limited bandwidth.
FWIW
jer 🙂
They are also very expensive at nearly $20 for each one!!!
Invalid Request
More information is needed about your application in order to help advise you the best that we can.
There are many other cheaper and more efficient ways to drive a 45 ohm speaker than by using a transformer that has a limited bandwidth.
FWIW
jer 🙂
Hi,
Like I said, you probably don't need a new transformer
for a simple low fii application as long as the 45 ohm
driver goes loud enough to be useful, it probably will.
The extra 6dB level comes from the the extra voltage
swing of the output given by reducing the turns ratio.
With no real idea of the capabilities of the circuit
driving the transformer a lot of this is handwaving.
Put it like this : in normal use for a 200mVA transformer
driving a 300mW driver, both are used well below the
maximum ratings, e.g. in a portable transistor radio.
Buying or salvaging another cheap 8 ohm driver
is far simpler than replacing the transformer.
Why you are using such a transformer in the first
place is still beyond me, except in a valve radio.
rgds, sreten.
Like I said, you probably don't need a new transformer
for a simple low fii application as long as the 45 ohm
driver goes loud enough to be useful, it probably will.
The extra 6dB level comes from the the extra voltage
swing of the output given by reducing the turns ratio.
With no real idea of the capabilities of the circuit
driving the transformer a lot of this is handwaving.
Put it like this : in normal use for a 200mVA transformer
driving a 300mW driver, both are used well below the
maximum ratings, e.g. in a portable transistor radio.
Buying or salvaging another cheap 8 ohm driver
is far simpler than replacing the transformer.
Why you are using such a transformer in the first
place is still beyond me, except in a valve radio.
rgds, sreten.
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I have a PCB on hand. I used multimeter to draw the exact circuit on the scehmatic.
I have attached the schematic.
There is a header connector on it where all the connections are made from the main system. The + gives power to relay.
When Relay is not On the audio is coming to the PCB through P+ and P- and then goes to transformer to speaker.
There is a connection M which controls the transistor. When the M turns the transistor on, the relay gets the ground and causes the relay to make connection at I+ and I-. Hence the audio now comes from I.
It is a PCB used in health care so I bet the P+ and P- is audio from TV or entertainment and then when the caretaker wants to speak it is given higher priority so the relay turns on and the audio only goes through I.
As I said I dont know the circuitry on the main system. But i think its coming from TV when relay is off and then when relay is on then it gets the voice of the person speaking.
I tried the speaker 8 ohm and 45 ohm on my desk with the Tm003 transformer and audio from the computer and my iphone. On both the 8ohm is louder and 45 ohm is very low.
So i was wondering what sort of calculations is needed to make change in trasnformer when speaker is changed. Is there any other website besides digikey and mouser which has transfoermers and how can i narrow it down to what i need?
I have attached the schematic.
There is a header connector on it where all the connections are made from the main system. The + gives power to relay.
When Relay is not On the audio is coming to the PCB through P+ and P- and then goes to transformer to speaker.
There is a connection M which controls the transistor. When the M turns the transistor on, the relay gets the ground and causes the relay to make connection at I+ and I-. Hence the audio now comes from I.
It is a PCB used in health care so I bet the P+ and P- is audio from TV or entertainment and then when the caretaker wants to speak it is given higher priority so the relay turns on and the audio only goes through I.
As I said I dont know the circuitry on the main system. But i think its coming from TV when relay is off and then when relay is on then it gets the voice of the person speaking.
I tried the speaker 8 ohm and 45 ohm on my desk with the Tm003 transformer and audio from the computer and my iphone. On both the 8ohm is louder and 45 ohm is very low.
So i was wondering what sort of calculations is needed to make change in trasnformer when speaker is changed. Is there any other website besides digikey and mouser which has transfoermers and how can i narrow it down to what i need?
Attachments
So why do you need a transformer?
Do the devices have model numbers, if so you might be able to find the data or schematics you need via Google.
I gave you all of the math needed for impedace transformation, and you seemed to understand it back in post 16&17.
There are many Electronic Parts Surplus supply out there that may have the exact part you need but they are getting scarce.
Google and lots of searching would be your best bet.
First you need to figure out exactly what kind, and, what the level is of signal(s) you are dealing with.
One of them may not even be strong enough (have enough power) to be able to drive a speaker in the First place.
jer 🙂
Do the devices have model numbers, if so you might be able to find the data or schematics you need via Google.
I gave you all of the math needed for impedace transformation, and you seemed to understand it back in post 16&17.
There are many Electronic Parts Surplus supply out there that may have the exact part you need but they are getting scarce.
Google and lots of searching would be your best bet.
First you need to figure out exactly what kind, and, what the level is of signal(s) you are dealing with.
One of them may not even be strong enough (have enough power) to be able to drive a speaker in the First place.
jer 🙂
The transfomer is probably there for impedance matching. Using the 45 ohm speaker caused the audio to be really low. Hence for that reason i need transfomer.
I did calculations yes. based on those calculations I tried digikey but the filters to find the transformers seemed not enough to me.
And I know only mouser and digikey to use so was getting confused on where to find more options for transformers
I did calculations yes. based on those calculations I tried digikey but the filters to find the transformers seemed not enough to me.
And I know only mouser and digikey to use so was getting confused on where to find more options for transformers
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