OT impedance
Moderators: pompeiisneaks, Colossal
OT impedance
in have a couple of telefunken SE trannies, the secondry is near as dammit 4 ohms the primary around 600 ohms yet from the documentation the primary shoud be 1.2k, does this sound as if the traffo is U/S
Re: OT impedance
Just how did you determine 600:4 as the impedance ratio?
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Re: OT impedance
are you sure it's not 8ohm at 1.2k?
Re: OT impedance
I was,nt aware i had, i was refering to measurements taken with my DMM in comparison to the information printed on the traffo, the question being if the traffo manufacturer states a impedance of 1.2k and i am reading 600 ohm is the traffo defectivePhil_S wrote:Just how did you determine 600:4 as the impedance ratio?
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Re: OT impedance
you can't measure it like that.
it's just a ratio.
8:600, 16:1200, and 4:300 are functionally the same transformer.
it's just a ratio.
8:600, 16:1200, and 4:300 are functionally the same transformer.
Re: OT impedance
not to sure i,m following you, correct me if i,m wrong , 4-300 would give 1.2k, is that correct? if so allowing for my DMM not deing my most acurate and slight corrosion i could well be in the ball parkdiagrammatiks wrote:you can't measure it like that.
it's just a ratio.
8:600, 16:1200, and 4:300 are functionally the same transformer.
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Re: OT impedance
sorry you said 4:600 in your original post.
that would be 2:300, 4:600, 8:1200, 16:2400
that would be 2:300, 4:600, 8:1200, 16:2400
Re: OT impedance
Now i am confused how do the readings inter-relate to ratios, sorry if i,m being densediagrammatiks wrote:sorry you said 4:600 in your original post.
that would be 2:300, 4:600, 8:1200, 16:2400
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Re: OT impedance
you have to determine the reading on the primary and then the secondary.
that sets up a ratio between the two windings.
if your primary reads 600ohms and your secondary reads 4 ohms then that's a 600:4 ratio.
That means if you hook up a 4 ohm speaker to the secondary the primary will see 600 ohms.
If you hook up an 8ohm speaker to the secondary the primary will see 1200ohms.
that sets up a ratio between the two windings.
if your primary reads 600ohms and your secondary reads 4 ohms then that's a 600:4 ratio.
That means if you hook up a 4 ohm speaker to the secondary the primary will see 600 ohms.
If you hook up an 8ohm speaker to the secondary the primary will see 1200ohms.
Re: OT impedance
You cannot use a DVM and measure the DC resistance to determine impedance ratio. DC resistance of teh windings tells nothing about impedance, or rather turns ratio. DC measurements can only briefly tell if the trafo is not shorted or burnt. If there are som specs printed on the trafo, or if you have a spec sheet, you have to rely on them.
Re: OT impedance
Are you measuring Ohms? That's not how it's done!jestaudio wrote:I was,nt aware i had, i was refering to measurements taken with my DMM in comparison to the information printed on the traffo, the question being if the traffo manufacturer states a impedance of 1.2k and i am reading 600 ohm is the traffo defectivePhil_S wrote:Just how did you determine 600:4 as the impedance ratio?
You've got to determine the turns ratio based on voltage in/voltage out. Read here: http://www.radioremembered.org/outimp.htm
Use the voltage supplied by a filament winding as your low voltage source.
Re: OT impedance
ok so each time i step up a speaker impedance then the primary impedance goes up as well,diagrammatiks wrote:you have to determine the reading on the primary and then the secondary.
that sets up a ratio between the two windings.
if your primary reads 600ohms and your secondary reads 4 ohms then that's a 600:4 ratio.
That means if you hook up a 4 ohm speaker to the secondary the primary will see 600 ohms.
If you hook up an 8ohm speaker to the secondary the primary will see 1200ohms.
yep i think i have it now, just need to find out if i can use this in a 6v6 champ build im looking at
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Re: OT impedance
yes yes. sorry if that wasn't clear.Aurora wrote:You cannot use a DVM and measure the DC resistance to determine impedance ratio. DC resistance of teh windings tells nothing about impedance, or rather turns ratio. DC measurements can only briefly tell if the trafo is not shorted or burnt. If there are som specs printed on the trafo, or if you have a spec sheet, you have to rely on them.
make sure you use the right measurements to determine the ratios.
Re: OT impedance
just rechecked using my works DVM and got 360-4 which would give me about 1400 which is,nt far off the stated 1.2k on the trafo so i would assume if i load it with 8 or 16 ohm speakers that would give me 2.4 or 4.8diagrammatiks wrote:yes yes. sorry if that wasn't clear.Aurora wrote:You cannot use a DVM and measure the DC resistance to determine impedance ratio. DC resistance of teh windings tells nothing about impedance, or rather turns ratio. DC measurements can only briefly tell if the trafo is not shorted or burnt. If there are som specs printed on the trafo, or if you have a spec sheet, you have to rely on them.
make sure you use the right measurements to determine the ratios.
Re: OT impedance
You still refrain from getiing the point?