Here is a an aikido circuit used as a headphone amp: http://www.tubecad.com/2006/04/27/aikido_high_impedance_headphone_amplifier.png
Problem with the circuit is that volume control is missing. A requirement for a headphone amp.
I'm just wondering if this is the right way of connecting a pot to the circuit above: http://img261.imageshack.us/my.php?image=aikidowithvolumecontrolsn8.png
thank you for the help
Problem with the circuit is that volume control is missing. A requirement for a headphone amp.
I'm just wondering if this is the right way of connecting a pot to the circuit above: http://img261.imageshack.us/my.php?image=aikidowithvolumecontrolsn8.png
thank you for the help
Looks OK to me. 100k (audio taper) should be a fine choice.
I also like the way you're planning to retain the 1Meg resistor R1. This will help prevent nasty noises in case the volume control wiper is not a perfect contact to the track. The only thing you might need to add is a coupling cap at the input, but only if the signal source has any DC bias on it.
I also like the way you're planning to retain the 1Meg resistor R1. This will help prevent nasty noises in case the volume control wiper is not a perfect contact to the track. The only thing you might need to add is a coupling cap at the input, but only if the signal source has any DC bias on it.
Hi,
Original post by jarthel
Since ther is no reply to this question, I will try to contribue my 2 cents worth.
What I will do is to measure the signal's DC voltage across the signal to ground with a multimeter. It's fine if it fall around +/-40mV. (smaller the better.)
But you don't have to worry too much, this DC Voltage is normally very small, and at worst shift the bias of the front stage by a volt or 2, I recon the 2 triodes in your Aikido's front stage will try to balance the effect off by themselfs. and since there is an output coupling cap, this DC signal will not get through to your headphone and ruin it.
I'm still a student in this, so, I hope its the correct.
Cheers
Original post by jarthel
how do I know if the input has DC bias?
Since ther is no reply to this question, I will try to contribue my 2 cents worth.
What I will do is to measure the signal's DC voltage across the signal to ground with a multimeter. It's fine if it fall around +/-40mV. (smaller the better.)
But you don't have to worry too much, this DC Voltage is normally very small, and at worst shift the bias of the front stage by a volt or 2, I recon the 2 triodes in your Aikido's front stage will try to balance the effect off by themselfs. and since there is an output coupling cap, this DC signal will not get through to your headphone and ruin it.
I'm still a student in this, so, I hope its the correct.
Cheers
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