Hello, I apologize if I'm posting in the wrong place. I built a PTP 2watt/channel SET amp ( Steve Deckert's zen1, or SE84) with tube rectification (5Ug4). I have a Minitorii so I would like to use the zen as a headphone amp, however it produces an unpleasant hum, even after drastic improvement through increased C2 capacitance (110uf). The part where I am lost is the resistance that I assume i have to add in series with my headphones. I have tried various resistors in series (headphone out is tapped from speaker posts). 100 ohm -still too much hum, 330 ohm and certain input tubes - I can live with the level of hum. My headphones (AKG k712pro [IMGDEAD]https://flic.kr/p/FBLZPu[/IMGDEAD]) have a sensitivity of 105 dB SPL/V
Max. Input Power 200 mW
Rated Impedance 62 Ohms.
Does this sound feasible? Am I doing something wrong? Can I add resistance? Am I frying the amp?
So far sound and headroom are excellent.
Thank you very much for taking the time.
Radu Christian
pics date from before I installed the headphone jack
[IMGDEAD]https://flic.kr/p/nQS8KX[/IMGDEAD]
[IMGDEAD]https://www.flickr.com/photos/[email protected]/14316270855/in/dateposted-public/[/IMGDEAD]
Max. Input Power 200 mW
Rated Impedance 62 Ohms.
Does this sound feasible? Am I doing something wrong? Can I add resistance? Am I frying the amp?
So far sound and headroom are excellent.
Thank you very much for taking the time.
Radu Christian
pics date from before I installed the headphone jack
[IMGDEAD]https://flic.kr/p/nQS8KX[/IMGDEAD]
[IMGDEAD]https://www.flickr.com/photos/[email protected]/14316270855/in/dateposted-public/[/IMGDEAD]