Be populating the board tis week(even if I have gotten most of the parts a few weeks back). Pics be up this week or next. Just ordered the casing(went with Par-Metal in the end). Opamps inside be 4627 and 4898 for the other.

I have a Mini 3 and I think its fantastic except for its limited drive capability, clips into low sensitivity phones and too much noise for sensitive IEMs. Its very nice though. The first thing I noticed was how nice the bass sounded, pretty fast too.

As I said in shoutbox, PM me if you want a Mouser BOM for the M3(if you bought the rest of parts from AMB) and Sigma 11.

Also on sb is that my stuff from parts connex(wire, dmm, knobs, switches) have not arrived, its been 4 weeks via small packet, should I be worried? I should have stuck with priority, I was so stupid.

I have a Mini 3 and I think its fantastic except for its limited drive capability, clips into low sensitivity phones and too much noise for sensitive IEMs. Its very nice though. The first thing I noticed was how nice the bass sounded, pretty fast too.

Try this:
remove U4, connect pin6 of U4 with a piece of wire directly to pin1 of U3 and increase both C5s to 2200uF(16V).

Alas this will be too big for the enclosure perhaps, but will increase power output in low impedance headphones, will do nothing for headphone impedances above 120 Ohm though.

Here's some pictures from my latest build, the CKKIII.

http://www.amb.org/audio/ck2/

Why'd I pick this one? In short, because I didn't want to spend $500+ on all the parts necessary to build a B22. I also like the idea of a regulated power supply, discrete JFET inputs, and no global feedback design. Having something that could fit in a fairly small chassis with it's own power transformer was also a must for me. Made the whole order a few months back and it's been sitting around for a while before I could finish the chassis. I ordered the majority of the parts from Digikey (PM me if you want my own BOM) and that came out to $140 (with shipping and tax). PCBs, pot, and a handful of transistors from AMB was another ~$50. Neutrik and RCA jacks from PartsExpress put the total cost a bit over $200.

(Zoom out)

This is a nice looking chassis. Hammond makes 'em well.





Papa's drill press, but this is my first time trying to cut metal


Made these little cutouts with the Front Panel Express software. They turned out to be very helpful.



As you can see, I botched the IEC cutout pretty bad. All the cuts were done with the drill press, but that one had to be done with a Rotozip and a special bit. Something about my table/clamps wasn't stable, so I lost control and blew it. It's not as bad as it looks, but it's still noticeable even with the module installed. Also notice how the backplate cuts aren't nearly as clean. I have no idea what happened there.


V regs on their heatsinks



Hats off to AMB for having such a high quality PCB. A real joy to work on.



Heatsinks on the output pairs. Ti says they're optional, but I can't imagine running this amp without them.



Again, this is a good looking amp.



Here's the front plate. The shaft sticks out a bit, but if I had a larger knob it probably wouldn't be a biggie. I frickin' love the locking Neutrik connector though. Super solid and makes going back to other connectors painful.



I'm guessing this chassis was meant for running wires down the side panels. It works really well. Also, is my mains wiring considered dangerous? It was the only way to get it to the switch. I should find a way to heatshrink it or something I guess.



The rest of my wiring is pretty good I think. Not as bad as some vintage amps. 18 AWG, solid core copper used all around.



That's an HD600 and an A900. I chose the 4x gain configuration. With the CD player's output, I sit around 10ish on the knob. With my laptop, it's around 12ish. I'm measuring around 300mV RMS for fairly loud listening levels on the HD600, which is in line with Tyll's number. I used pink noise and some Tool to gauge it. If you really want to rock out, they can take about 500mV+, which corresponds to about 1-2 oclock. I imagine these require a fair bit more voltage swing for peaks if you listen to dynamic classical music, but my RMS meter can't measure that obviously. Overall, I don't think I'm running out of gain any time soon.





Random notes:

• Output stage is biased at around 30mA as Ti recommends. I can leave my finger on the heatsink for about 5 seconds before I want to pull away. There doesn't seem to be much heat radiating though, and I'm thinking I could push it a lot higher (60mA is the max according to Ti) even with the top panel installed. But on second thought, I don't have any headphones that draw over 30mA, so I don't think this baby is leaving Class A any time soon. Still might tweek in the future too see how much of a difference it makes
• As you can see, I have a second pair of RCAs that are driven directly from the output. I tested this briefly and it drove my Zamp well enough. Maybe a gainless buffer power amp is in the near-future for me?
• I wired the xformer secondaries wrong at first. I only noticed because it started heating up big time. I think if I hadn't shelled out for the fancy pants, heavy duty diodes I would have blown the them
• I measure 18VAC on secondaries. It does drop a little when loaded
• I can't find the clear rubber feet that came with the chassis. Anyone know where I can find some?
• I might be willing to take on some other aesthetic mods. An acrylic top plate would be cool, like on Ti's own build. More than anything else though, I'd like to get the front plate laser engraved with CKK

In terms of sound...well it sounds great to me. It's a clear step up from my Cmoy or laptop output. ZuneHD seems to have poor extension in both directions in comparison. HD600 and the A900 are both very listenable on this amp. A900 has very noticeably improved bass control; I'm guessing it's the lower output impedance. But the A900's grain in the treble is much more apparent now, although the HD600 is still very smooth up top. Not veiled though I'm not experienced with high-end stuff so take everything with a grain of salt.

I'm sure most you guys out there have heard this amp before. But if anyone in Orange County wants to check it out, just let me know. Overall, I'm happy with this one and I'll be keep listening for a while. 

(ultrabike: OJ I made some mods to your post - pic/text sizing only. Hope you don't mind. Fantastic work BTW!)

Good pics and nice build OJ!

I've bult a CK2-3 as well, but didn't like the sound at all. compared to the M^3 it's a bit harsh I think?
your build looks great though! should consider an M^3