Owen, nice figures for that amp!
I guess that the measurements were done with a low source impedance? It seems as if source impedance is the ‘elephant in the room’ with op-amps, maybe even when configured as a buffer?
If you have the inclination it would be nice to see how the performance stacks up when operated unbalanced, and with 2k5 in series with the positive input (to simulate a 10k pot at the half way point). Also, if the original tests were not carried out with some capacitance in parallel with the load it would be good to add some for a re-test (about 200 pf in parallel with 30R for headphone cable + headphones?).
I mention this humbly, as you have obviously put a lot of time and effort into it, and it is very kind of you to post the circuit and layout.
I guess that the measurements were done with a low source impedance? It seems as if source impedance is the ‘elephant in the room’ with op-amps, maybe even when configured as a buffer?
If you have the inclination it would be nice to see how the performance stacks up when operated unbalanced, and with 2k5 in series with the positive input (to simulate a 10k pot at the half way point). Also, if the original tests were not carried out with some capacitance in parallel with the load it would be good to add some for a re-test (about 200 pf in parallel with 30R for headphone cable + headphones?).
I mention this humbly, as you have obviously put a lot of time and effort into it, and it is very kind of you to post the circuit and layout.
Hi Guys,
It's good to see so much interest in the amp! Looks like there are enough people interested to make a parts kit feasable as well.
Here is what I was thinking for pricing:
Amp and PSU boards - $20 includes shipping anywhere
Boards and SMD parts kit (all IC's plus thin film 0.1% resistors and X7R caps) - $95
The parts kit would include all SMD parts for both the amp and PSU
If everyone can let me know exactly what they're interested in then I can start collecting payments and shipping boards. Please don't ask about partial kits or just amp boards, the only options available are the ones listed above unless absolutely everyone wants a different assortment for the parts kit (eg. No PSU parts).
I'm on vacation right now, so replies might be slow (typing on an iPhone isn't much fun) but I'll be sure to answer everyone's questions when I get back to somewhere with a computer and a keyboard.
Happy holidays to everyone!
Owen
It's good to see so much interest in the amp! Looks like there are enough people interested to make a parts kit feasable as well.
Here is what I was thinking for pricing:
Amp and PSU boards - $20 includes shipping anywhere
Boards and SMD parts kit (all IC's plus thin film 0.1% resistors and X7R caps) - $95
The parts kit would include all SMD parts for both the amp and PSU
If everyone can let me know exactly what they're interested in then I can start collecting payments and shipping boards. Please don't ask about partial kits or just amp boards, the only options available are the ones listed above unless absolutely everyone wants a different assortment for the parts kit (eg. No PSU parts).
I'm on vacation right now, so replies might be slow (typing on an iPhone isn't much fun) but I'll be sure to answer everyone's questions when I get back to somewhere with a computer and a keyboard.
Happy holidays to everyone!
Owen