Hi all, I've posted some images of this amp in the DIY project gallery. I've finally sorted out the niggles I was having with it, and finalised the wiring and whatnot, So I thought it deserved its own thread.
It's powered off a 19v switch-mode laptop PSU, and that is dropped down to 10 volts with a linear regulator. The result is near silent operation, at any gain Ive felt the desire to use. Its currently set at 4x, which makes 2/3rds of the volume adjuster usable with my HD465s.
I've experimented with a few op amps in here, namely 2132, 2134, 4556, 4560 and 6558. It seems stable with all but the 6558 (which was only tried because I found them in a headphone amp in some commercial gear, I'm not sure what it requires to be stable.
The board I used is the Cmoy RA1 from Fred's Amps, running a resistive divider and 0.1uF decoupling on the V+ and V- This was responsible for helping the sound with more tricky amps a great deal. Even though I've played around with different chips, the 2132 has ended up being my choice in the long run since it sounds smoother, cleaner, and over all, seems to distort a lot less than anything else, in every situation I've tried it in. I don't intend to be using this as my primary amp for long, but I think it'll be a useful tool for hearing the differences between op-amps.
Well, I'll offload some pictures now, Any questions, feel free to ask!
details of the board and inside, notice the caps on the bottom side to fit them easier
some of the amps I tested, plus the linear regulator
This pic, plus a few above, aren't exactly the final piece, eg. volume knob, and a few other details
Finally, check out what just arrived in the mail today...
I have most of the semis on the way from element14, I still haven't made up my mind on the main channel op maps though... Has anyone tried opa 2132 or 2134 with the O2? I'm thinking it could be worth a try since I already have one spare and love how they both sound. We shall see.
Thanks for reading this far anyway!