A
Anonymous
Guest
Does anyone know the true Explorer headphone output impedance?
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A
Anonymous
Guest
I got it.
150 ohms
150 ohms
A
Anonymous
Guest
Happy New Year Goodrat! How did you come up with 150 ohms? And if it is 150 ohms why does Minelab recommend using 32 ohm headphones. Espeically when there are so many good 150 ohm headphones available? Thanks!
HH
Beachcomber
HH
Beachcomber
A
Anonymous
Guest
This is how I calculated.
First I plug in a stereo "Y" adapter to make it easy to measure. I plugged in a stereo plug that is open to I can measure AC RMS voltage.
The Machine was set to a constant tone.
With no headphones, measuring the ac output you are measuring without load so you are effectively measuring before the series resistor in the machine. No current flow so no voltage drop).
Next I plug in phones with a known impedance on the other side of the Y cable and measure again.
From these measurements you can calculate the series resistor on the machine.
Now remember, if they are recommending 32 ohm headphones, one reason is because they are available for home stereo's. But also keep in mind that since the Minelabs use tip and ring without sleeve, when you connect 32 ohm stereo phones, you end up in series and you end up with 64 ohms.
The Koss UR-30 actually have about 100 ohms per side. When connected to a Minelab, you end up with 200 ohm phones!
Many 150 ohm phones are in parallel and the speakers may be 150, but the phones are actually 75 ohms, it depends on what brand you use and how they explain their specs.
Then again, there is the speaker efficiency. How loud they are may not only depend on the impedance.
First I plug in a stereo "Y" adapter to make it easy to measure. I plugged in a stereo plug that is open to I can measure AC RMS voltage.
The Machine was set to a constant tone.
With no headphones, measuring the ac output you are measuring without load so you are effectively measuring before the series resistor in the machine. No current flow so no voltage drop).
Next I plug in phones with a known impedance on the other side of the Y cable and measure again.
From these measurements you can calculate the series resistor on the machine.
Now remember, if they are recommending 32 ohm headphones, one reason is because they are available for home stereo's. But also keep in mind that since the Minelabs use tip and ring without sleeve, when you connect 32 ohm stereo phones, you end up in series and you end up with 64 ohms.
The Koss UR-30 actually have about 100 ohms per side. When connected to a Minelab, you end up with 200 ohm phones!
Many 150 ohm phones are in parallel and the speakers may be 150, but the phones are actually 75 ohms, it depends on what brand you use and how they explain their specs.
Then again, there is the speaker efficiency. How loud they are may not only depend on the impedance.
A
Anonymous
Guest
I have been using the Grey Ghost Headphones on mine for years and I believe they are 150 ohms.
Happy New Year
Beachcomber
Happy New Year
Beachcomber
A
Anonymous
Guest
Would you by any chance have an opinion why my Grey Ghost headphones are so weak with my Explorer and not so with a Sovereign and a GQ SS?
They have 150 ohms transducers. Is it possible that the way they are wired up such that impedance goes up to 300 ohms? Can I rewire the phones up is such a way as to imcrease the SPL.
Thanks, Juan
They have 150 ohms transducers. Is it possible that the way they are wired up such that impedance goes up to 300 ohms? Can I rewire the phones up is such a way as to imcrease the SPL.
Thanks, Juan
A
Anonymous
Guest
I beleive those phones are in parallel, resulting in 75 ohms. If you wired in series you get 300. But either way, the speakers end up with the same voltage accross them.
Try those new phones that came out....now what are they called...? <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="
">
Sorry, I can't say, I'm not a sponser here. <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="">
Try those new phones that came out....now what are they called...? <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="
">Sorry, I can't say, I'm not a sponser here. <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="
">