AMB Laboratories DIY Audio

[linux-works]

some photos taken today after some more proto building:











one of the photos shows a black resistor network with 1 leg 'bent' and skipping over a pin. you may have to do that only if you are trying to use a part with too few pins (internal resistors). you need at least 8 resistors and that pin-1 common bussed pin HAS to be in the square hole (the index hole). but right after the index hole are 1 or 2 'useless' holes that we may have to skip over to find the first real useful bit. this is why one of my r-network chips had to do a little leg spread dance kind of thing

in the other photo that has all yellow r-networks, there's no dancing needed those were properly ordered parts and they fit into the holes just fine. again, note that pin-1 is where it is on this board and you want to see both r-network labels (actually, on all 4 of the networks) if you look at them from this angle.

some photos show stacked modules. more details on that later on.

[pixeljedi]

Looks fantastic! Awesome job.

[Billyk]

Wow!
This stuff is getting soo cool!!
Stunning photos as always too!!!

[amb]

Regarding this photo:



I should point out that pin #2 of the black resistor network should go into the "PWR" pad instead of the "TST0" or "TST1" pads for the power indicator LED to work. Of course, as linux-works mentioned, no worries if you are using the proper 11-pin resistor network (as shown in the two subsequent photos with the yellow resistor networks).

[linux-works]

with the black r-network as shown, you lose the power-led feature, if you can call it that.

the led displays come in 10 segments per chip. we only need 8 of them so we had 2 left over. 1 can be called 'power' and always be on if the board is getting power. that's what 'pwr' (the pad/hole) means. I didn't try to have one of the resistor network pins hit 'pwr'. if you can bend 2 pins over and make this happen, great if not, you won't get an led (top most on each display) that is always-on. in fact, you may not even want this.

if you install the proper parts, no leg bending is needed and you automatically get the top led segment to be 'dc power ok' whether you want it or not

to turn all led's off, just remove the jumper. in some of my boards, this is a yellow jumper.

[DorkVader]

Oh wow.

Of course I'm always impressed with the quality of photos you've put up (I remember, in particular, a bantam (I think) dac in a panavice (or similar), it was at thin point, I decided to browse around for other cool stuff you'd done.) but this is fantastic. I've always been a particular fan of the rainbow cables, having seen too many ugly grey (gray?) IDE ones, normally. It just gives a feeling of happiness when I see them. Secandly, the symmetric nature of the boards appeals to me. Truly, this is a great-looking build, and it's not even cased yet! Also: those look like torx screws holding it together? It's hard to tell from this angle, but hex is perhaps, normally less pointed an the inside.

Though the allure of saving money by not breaking the boards apart appeals to me, the thought of pretty rainbow cables in a plexiglas-topped enclosure wins any day.

'Course, I'm always happy to see updates to this, and I'm always happy to see pretty build pictures (eye candy mmm); it may be that I'm really tired right now, but that's just taken the cake, the meal, and the entire bakery(if you will allow me to expand on the idiom).

I'm going to have to drool over this a little more.

[linux-works]

those are hex screws, for sure. they were cheap and look OK enough so I got a bunch of them. of course I never can find the right hex key to tighten them. I tend to wear out the wrench just below that, in size, a lot

yes, I like the ribbons as well. I bought some length of that at digikey and also some boring grey stuff in case anyone wants that, but the ribbon does add some nice color to the project.

EDIT: it was my browser, firefox. hit control-mousewheel and you zoom both text AND graphics. all my images were scaled and so they were distorted. control-0 brings it back. all fixed.

note that (for me, at least) the images are not coming out as crisp as they normally are. I have not found out why, yet, but the flickr images don't have a resizing issue that I'm seeing on the website, so you may want to view them directly at flickr, for now:

http://www.flickr.com/photos/linux-works/

thanks for the interest!

[DorkVader]

I couldn't tell a difference, but that's primarily because I was using my trinitron monitor, and I usually try to ignore how the horrendous vertical pixel pitch messes with photographs. Changing over to another CRT, they still look good to me. I'm glad to hear digikey sells the rainbow cables (what don't they sell?), I'll be sure to get them when I eventually build mine.

I see that the LEDs on the bottom boars aren't socketed. This is probably because of height restrictions, right? I'm not planning to go balanced for awhile yet, so I'll only need the one, and I'm pretty happy the option to socket is there.

I don't want to ask too many specific questions (because it's not done) but I see there is a square-pad for the LED bargraph, so you don't put in in backwards or whatever, but I can't identify anything on the LED-bit itself distinguishing where the "pin1" (or whatever) is. Is it just which side the label is on (if it's only on one side?)

Anyway, this is very exciting!

[linux-works]

I see that the LEDs on the bottom boars aren't socketed. This is probably because of height restrictions, right? I'm not planning to go balanced for awhile yet, so I'll only need the one, and I'm pretty happy the option to socket is there.

if you use tall stand-offs (like I used) then even sockets will work. I just got tired of using them on the led chips. be sure on the orientation, first; but they are safe after you install them and won't blow or break (there are series R's that protect them).

it also looks more 'even' without those items in sockets

I don't want to ask too many specific questions (because it's not done) but I see there is a square-pad for the LED bargraph, so you don't put in in backwards or whatever, but I can't identify anything on the LED-bit itself distinguishing where the "pin1" (or whatever) is. Is it just which side the label is on (if it's only on one side?)

there's a notch on the side of the chip, running fully up and down the height of the chip. you'll see it when you do the build. it matches up with the silkscreening on the pcb, too.

those displays are in the dollar range and I first remember seeing them in blister packs on the shelves at radio shack. this was 20 or more years ago and its nice to see that mouser/etc still have them in stock and they are still being made.

that single yellow jumper will disable the light show if you ever want to cut down (slightly) on current draw or don't want to see the lights flashing for one reason or another. the flashing is very very quick, though and normally all but the 'pwr' led is off.

[amb]

Here is mine, with the board sections together:

Image

δ1 relay-based attenuator