I have small fm receiver with headphones output which is working fine on headphones but when I connect it to diy tube amp there is no sound. It seems that it uses that 32 ohm internally as indicator to let the signal out so I guess I should put resistor or two on output to simulate load. I measured the headphones resistance: left to ground 1.5 kohm, right to ground 1.5 kohm, left to right 32 ohms which additionally confused me. Does anyone have experience with this, I could use advice?
Edit: tube amp is fine and headphones work fine.
Edit: tube amp is fine and headphones work fine.
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Hi Vasko,
Firstly it sounds like your headphones may have a broken ground, if they are 32ohms left to right, then they should be 16ohms each side to ground. With no ground all you will hear is the stereo difference signal, which will be low volume and bass light.
Does the amp work with another source input? Confirm the amp is working first with another source.
Firstly it sounds like your headphones may have a broken ground, if they are 32ohms left to right, then they should be 16ohms each side to ground. With no ground all you will hear is the stereo difference signal, which will be low volume and bass light.
Does the amp work with another source input? Confirm the amp is working first with another source.
I have similar problem when I wan to use my Optimus phone to drive an amplifier , I found that adding a 47 ohm in parallel with amp input does the trick.
In fact, it does not even need to be a permanent load, which would make it complicated to use the amp with a regular preamp or other signal sources, so I added a normally open pushbutton to the amp,
it adds the headphone simulator load only when I push it, for 2 or 3 seconds, what it takes to be detected and enabled, after that I lift my finger and it´s out of the circuit.
If I connect a regular preamp, I don´t push the temporary button.
I had to build a permanently loaded earphone to guitar plug cable (I hid the resistor inside the larger guitar plug body) and carry it in my tool box, when I want to test Guitar amps with prerecorded Guitar tracks I carry in my phone.
Hope it helps.
In fact, it does not even need to be a permanent load, which would make it complicated to use the amp with a regular preamp or other signal sources, so I added a normally open pushbutton to the amp,
it adds the headphone simulator load only when I push it, for 2 or 3 seconds, what it takes to be detected and enabled, after that I lift my finger and it´s out of the circuit.
If I connect a regular preamp, I don´t push the temporary button.
I had to build a permanently loaded earphone to guitar plug cable (I hid the resistor inside the larger guitar plug body) and carry it in my tool box, when I want to test Guitar amps with prerecorded Guitar tracks I carry in my phone.
Hope it helps.
This seems to be a standard method used for detecting when headphones are connected,
and applies to Apple hardware as well.
Yes laptops especially need to detect when to switch from headphone to internal speakers and back to allow separate volume settings.
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