Working out math for the wrong answer

[pucho812]

On of the local knuckleheads  wired up  some we111c transformers in a box to run across his mix bus.  He insists that they are 1:4, 150:600. Looking at the data sheet can wire them 1:1/600:600 or 150:600 which would be one to two.  He insists 150 x 4 = 600 so it’s a 1:4. What the hell?

 

[JohnRoberts]

with transformers impedance is the turns ratio squared, perhaps that is a source of some confusion.

JR 

 

[pucho812]

with transformers impedance is the turns ratio squared, perhaps that is a source of some confusion.

JR

Maybe. 

 

[john12ax7]

They could always just measure it themselves.  Any DAW can create a signal and then measure the return signal.

 

[pucho812]

They could always just measure it themselves.  Any DAW can create a signal and then measure the return signal.

They did and I t got the 6dB when wired as a step up and insisted it was 1:4

 

[JohnRoberts]

They did at got the 6dB when wired as a step up and insisted it was 1:4

+6dB "voltage" is 2x voltage or 4x power.... 

Transformers do not increase or decrease power so all deliver 0dB (ignoring losses).

JR

 

[john12ax7]

They did at got the 6dB when wired as a step up and insisted it was 1:4

If they won't accept that 6dB is 2x voltage then I'm not sure what more you can do.

 

[JohnRoberts]

Decibels were originally created to represent power ratios.  They kind of don't make sense for describing transformer turns ratios since power in= power out (more or less).

A 1:2 turns ratio to preserve constant power means that the 2x voltage will only deliver 1/2 the current to maintain constant power.  As I shared already for effective impedance 2x voltage translates to 4x impedance to maintain constant power.

Sooooo a 150/600 ohm transformer would be 1:2 voltage ratio.....

Confused yet, I am... ;D

JR

 

[abbey road d enfer]

On of the local knuckleheads  wired up  some we111c transformers in a box to run across his mix bus.  He insists that they are 1:4, 150:600. Looking at the data sheet can wire them 1:1/600:600 or 150:600 which would be one to two.  He insists 150 x 4 = 600 so it’s a 1:4. What the hell?

Transformer ratio is generally quoted as the turns ratio, same as voltage ratio. Impedance ratio is (N2/N1)².
In the case of a 150:600 ohm xfmr, the ratio N2/N1 is square root of Z2/Z1
Your chap is wrong.

 

[pucho812]

Transformer ratio is generally quoted as the turns ratio, same as voltage ratio. Impedance ratio is (N2/N1)².
In the case of a 150:600 ohm xfmr, the ratio N2/N1 is square root of Z2/Z1
Your chap is wrong.

I agree. I even showed him the math and the rest but nope.  As jr pointed out double of voltage, so 1 volt in and output would be 2 volts at half the current.
I wouldn’t care except he made two cardinal sins.
1. He tried to take credit  for a session at the studio that he was never at. Well known session with a well known artist with lots of photos and tried to tell us he was there. He wasn’t.
2. He writes gear reviews in well circulated audio magazine

 

[abbey road d enfer]

1. He tried to take credit  for a session at the studio that he was never at. Well known session with a well known artist with lots of photos and tried to tell us he was there. He wasn’t.

He could argue he was giving distant mental support...Nothing stops mythomaniacs.

2. He writes gear reviews in well circulated audio magazine

Well circulated doesn't mean credible anymore.
"Those who can, do; those who can't, teach write"

 

[moamps]

Transformer ratio is generally quoted as the turns ratio, same as voltage ratio. Impedance ratio is (N2/N1)².
In the case of a 150:600 ohm xfmr, the ratio N2/N1 is square root of Z2/Z1

Impedance ratio is Zp/Zs or (Np/Ns)2.

 

[abbey road d enfer]

Impedance ratio is Zp/Zs or (Np/Ns)2.

Isn't it the same as"Impedance ratio is (N2/N1)²."

 

[ruffrecords]

Flatter him. Tell him he is right. Then tell him you have a special sharpie. All he needs do is run it round the edge of all the vintage CDs/SACDs he has in his collection and it will instantly create a 3D sound stage with added clarity of every instrument. etc etc As a special favour to him he can have it for only $1000.

Cheers

Ian

 

[moamps]

Isn't it the same as"Impedance ratio is (N2/N1)²."

No. It's not mathematically correct. After you, the impedance ratio of 150:600 transformer is 4:1, not 1:4 which is correct.

 

[moamps]

Flatter him. Tell him he is right. The tell him you have a special sharpie. All he needs do is run it round the edge of all the vintage CDs/SACDs he has in his collection and it will instantly create a 3D sound stage with added clarity of every instrument. etc etc As a special favour to him he can have it for only $1000.

You forgot green pen.

 

[ruffrecords]

You forgot green pen.

It used to be green but that was the early version that works only on regular CDs. The new mauve one also works on SACDs.

Cheers

Ian