I don't know any electronics or amp engineering, but I've been after an all discrete portable headphone amp, having tried a number of different opamps but never been totally satisfied with any of them. There's very little interest in this kind of amp in the DIY-world, so I've done some tweaking. I think I like bipolars better than JFETs, so I merged the front end of Hiragas le Classe A with the output stage of JISBOS by steinchen/amb. I've only built one channel. It's actually playing music, seems fairly stable, not much offset drift, very low noise. I'd prefer a low supply so I can use AAA's (9-12V) and have the amp class A biased. An alternative is class AB biasing and use 2x9V batteries. The different transistors is because I had matched pairs of BC327/337/549/559. I guess it would be nicer to use only BC550/560 and BD139/140. Some of the resistor values are are taken from the original circuits, some found by trial and error and some just randomly choosen.
I'm not clever enough to simulate circuits, so I don't know if there are major errors.
Can this be made into a good sounding amp? Can you help me with it? I would like to make it with an active ground channel, so this channel should be unity gain. Could it be made unity gain stable?
Please help me make this become a functional and hopefully good sounding amp!
[IMGDEAD]http://img407.imageshack.us/img407/5382/bisbos9vv2ss4.png[/IMGDEAD]
I'm not clever enough to simulate circuits, so I don't know if there are major errors.
Can this be made into a good sounding amp? Can you help me with it? I would like to make it with an active ground channel, so this channel should be unity gain. Could it be made unity gain stable?
Please help me make this become a functional and hopefully good sounding amp!
[IMGDEAD]http://img407.imageshack.us/img407/5382/bisbos9vv2ss4.png[/IMGDEAD]