M³ Project Announcement - Page 26

I was also going to recommend those, beware they present the measures: [Width x Length x Height]

Depending on the final card size and the internals size of the GX187 which measures externally: WxLxH(124x170x80)(4.9"x6.7"x3.15")

It might be a good choice, that is ofcourse if the powersupply is external.

Let's say that we have 3 channels all running at 80mA quiescent, with a 36V power supply. This roughly translates into 9W of total power dissipation. I'll do some experiments, but you could probably calculate how much heat there would be in a totally-enclosed case... My guess is that it's going to be uncomfortable.

Akku and kasra, the audiokit.it GX187 looks nice, but just a bit too small for the current pcb size.

While Lansing will do custom work, I wonder how much it would add to the cost in small-ish quantities? I have a feeling that to the Lansing people, anything less than thousands would be considered "small". Personally I am not too enamored by the looks or the standard color on the Micropak line. It would be fine for an industrial gizmo, but it's missing that "high end audio" aura.

I do like to set up some kind of group buy for enclosures if we could nail down a vendor and style, but it will be unreasonable to make everyone dremel their cases for ventilation or go topless.

I have initiated a conversation with Larry at LaroccoAudio, and he is open to the idea of making custom M³ cases. As many of you know, his cases are gorgeous (see the examples on Laroccoaudio.net). We haven't drilled down any specifics or costs yet, but if it turns out to be feasible, then that's a possibility.

Of course, a custom Par Metals 20-series enclosure is still something I am looking at. I will be talking to them within a few days about this.

I believe that the board is currently exactly 5"x7" so it would have to be squeezed a bit to fit in that case.

There is already lots of case options popping up, so it is time to decide what is important.

I guess there will be lots of different cases used for the board so I don't think it would be right to optimize for a specific case unless lots of people will go for that case. We are already talking about wented vs closed cases, with or without PSU, tall to take 2" heatsinks or low for 1" heatsinks. The PSU could be compact or large and could be placed close to the board or further away.
With these options alone we have 20 good cases even if they are custom made for this board (4 without PSU and 16 with PSU).

Seeing all these options I think we need to make the choise really simple:
1. No changes on board (go to production ASAP).
2. Decide on one specific case that we optimize for, preferably one that is available both in US and Europe and that is really close to fit the board anyway.
3. Custom made case that will fit the board perfectly with custom made fron panel. Just one version will be made for simplicity. For shipping reasons this will probably be economically interesting for US only.

If you don't go for a custom made case with custome made front panel you will need to drill holes for the pots in the front panel, so the step of drilling holes for PCB standoffs should not be a problem. Drilling 2 or 6 holes should not make much difference.

Personally I am leaning towards an oversized case where I can fit the PSU in the same box.

Well, my Sun 911 has served me so well for so long, I'm considering this solution:

http://home.swbell.net/pabbi/case1.jpg

This case (fancied up with a $4 can of vinyl dye) is 9.25"(w), 10"(l) and 5"(h). One possible configuration:

http://home.swbell.net/pabbi/case6.jpg

The board is mounted horizontally, and the STEPS vertically in the former P/s cage (with some of the existing teflon shielding, supplemented by some of Tangents also). I am certainly open to suggestions about attaching the STEPS, given the recent tales of woe about shorting (and toasting) the LM317. Or, the STEPS can be mounted horizontally, higher, with some metal shielding underneath (with little or no cage modification):

http://home.swbell.net/pabbi/case7.jpg

In addition to the high heat tolerance plastic case, it is also internally metal shielded, yet vented to the gills, even with the fan removed.

http://home.swbell.net/pabbi/case4.jpg

http://home.swbell.net/pabbi/case2.jpg
http://home.swbell.net/pabbi/case3a.jpg
http://home.swbell.net/pabbi/case5.jpg

Just a thought...

Pabbi, that's cute. Try to keep the power transformer as far away from the amp as you could.

For those of you looking to build the M³ with the PSU in the same case as the amp, you can use the off-the-shelf Par Metal 20-series case in the 12"W x 8"D x 2"H size. This allows you to put the PSU board on the left side (as viewed from the front panel), a good distance away from the main board. You could even order the case with an internal divider plate, for a bit of extra shielding.

If the board width is slightly increased to be accommodated in the Lansing cases with removable tops, I am willing to initially produce some quantity (maybe 100-ish?) of laser-cut acrylic (clear or black) slide-in panels that will have proper ventilation and supply them to either whoever's going to distribute the boards (Tangent?) or distribute them myself.

Or we can do a group buy on nicer ventilated FPE panels as well. But I feel that for a large number of us the Lansing option will be a very cost effective, easy, compact, and decent-looking way to house the M3.

Here's a pic of my PPA built in a series 20 case with a STEPS PSU as amb described. I used a 16" wide case so that it matched with standard sized components.

http://forum.av123.com/photopost/dat...Small_-med.JPG

I will be distributing the M³ boards when it goes to production. I am also entertaining the idea of offering some other related parts like tangent does for his amps, for example the AD8610 opamps pre-mounted on Browndog adapters, the Alps blue velvet pots, and maybe the heat sinks, JFETs and MOSFETs too. This might helps builders reduce the number of vendors to order from, and help some non-USA builders who might have difficulty locating some of the parts.

Whether I offer these extra parts depend on the level of interest. I am not looking to make a profit on these. Just enough to cover my expenses, effort, and shipping; as a service to the community. Let me know if you think this is a good idea, and what parts you would like me to offer along with the blank boards.

some of the jfets/mosfets are diffcult to get in Europe, same with tle2426clp. Alps pot is not necessary, since it's easy to get (at least in Germany) and due to its size expensive in transatlantic shipping. OrangeDrop and BC416 caps could be taken into consideration, too.

It's a big advantage if you can put the components in an envelope and declare it as a gift with minor value (<< $60), saves very much shipping cost and customs duty

It is not looking too bad here, RS seem to have everything on the schematic!

amb: A very good idea

Jfets, AD8610!, (MOSfets) perhaps heatsinks, I now have 1.5"ones and perhaps they might be enough..

Is there an official M³ page? Like http://elvencraft.com/ppav2?

It would be great if you could sell the hard to get parts so all the other stuff can be found locally.
Could you add TLE2426 and the trimpots to that list.

I am sure I could get the heatsinks and alps blue locally, but probably at twice the cost.

Could you put together a parts list with Digikey numbers, preferably with the componets you might sell marked.

Pabbi1, that Sun 911 case looks great for an amp!
But I do like when things fit together, so BradJudy idea with a full-width stereo case looks like a more convenient way to go.

My take is that it sound be similar to what Tangent has done. It's useful for you to sell items that are not readily available via Digikey/Mouser/Newark. I haven't tried shopping for the MMM parts yet, so I'm not sure what availability is like, but the Alps and the 8610 on Browndogs are a good start.