just a quick notice if you want to use my parts list, there is one discontinued part:
Manufacturer NXP USA INC (VA)
Description IC AMP AUDIO 80MW STER AB 8SOIC
Manufacturer Part Number TDA1308T/N2,115
Digi-Key Part Number 568-11063-1-ND
Status End Of Life
Last Time Buy Date 06/30/2019

there are 75 and 107mW substitutes available:

http://www.digikey.com/classic/ObsoletePart.a … =568-11063-1-ND

does a higher one affect quality and better go with the 75mW ? i'll update my sheet

There may not have been much activity in this thread, but that doesn't mean that all work has stopped. Progress has been somewhat slower than it could be, but at least there is some movement.

I looked into the amplifier situation, and since Phreeze reminded us that one part in the TDA1308 line was being discontinued, the rest of them have also become non-stocking items, or soon will be. There are a number of other ICs that are pin-compatible and are still stocked items at Digi-Key (for now) but they are not necessarily drop-in replacements; we may need to adjust some of the values of the nearby passive components to make them work correctly for our application.

I have also found a problem with the instrument ROMs that causes playback to be of inferior quality (or just outright incorrect). I am investigating the source of the problem, and have a few theories, but haven't found the exact cause yet. Once it's fixed, I'll have to re-generate all of the test banks and start testing again.

The last bit of news for now is that I'm looking into the cost of production of our own PCB brackets. The drawing has been submitted to the engineering department at the manufacturer, so we should know soon enough if this is an idea worth pursuing, or would be so expensive as to be infeasible. So far, we're looking at 0.81mm-thick steel with nickel finish and stamped audio jack labels.

For the headphone output you could use a high current output opamp such as 4580 if/when another revision of the card gets made. On my own custom sound card I went with opamp + transistors based output buffer to get ability to drive even speakers adequately while having much superior sound quality compared to most ready made chips (THD being under 0.01%, noise floor that's at measurement limits etc.). Drawback is higher component count and greater real estate requirements.
You can also just stick 22...100 ohm range resistors on the output of opamp which will also work but damping factor will suffer and low freq response with headphones will be all over. Paralleling opamps is also an option.

I'll work on a better solution when I have more time, but to allow further testing, I implemented a somewhat kludgy fix for the software, and generated a new ROM. With that particular problem fixed, playback is improved and more correct. So now, it's time for much more testing, to make sure there aren't more of these obscure problems.

If there is anyone to whom I have provided ROM images or modules for testing who wants a corrected version, please feel free to contact me.

I just received the quote from the manufacturer, and it is about as bad as I suspected it might be. That is to say that, without question, I can't afford to even give any further consideration to a production run of brackets. I don't want to discuss the numbers publicly, but let's say that the price is close to, or higher than, the cost of the bulk purchase of InterWave chips that got this project started. I am open to suggestions or discussion, but I don't think we'll be ordering a run any time soon.

3d printing 😉 almost anywhere in the world, you can let them print in the city or order a print online for less than 5 buckazoids. At least the card is fixed more than without a bracket 😉

Phreeze wrote:

3d printing 😉 almost anywhere in the world, you can let them print in the city or order a print online for less than 5 buckazoids. At least the card is fixed more than without a bracket 😉

The problem is that that doesn't actually turn out to be much less expensive than getting a batch made; I just don't have the discretionary income necessary to put into such a bulk order, then hope that nearly everyone will buy at least one bracket per card when the production run arrives.

Also, since we would be talking about a plastic bracket at the prices you mention for 3D printing, I worry about it getting brittle over time, in the warm environment of a PC. If cracks develop while it is powered on and the card moves, the results may be unfortunate.

Any plastic bracket looks unprofessional and spoils the whole design of the card, for me it's a total no go. I suggest some sort of crowd funding for the normal metal bracket production batch.

i don't look at the back of my pcs...i can't even, i have 8 in a row and 4 in a row xD

Phreeze wrote:

i don't look at the back of my pcs...i can't even, i have 8 in a row and 4 in a row xD

It's not just a question of appearance. As mentioned, I worry about the structural stability of such a bracket. Also, some cards have been known to depend on the bracket's conductivity for a connection to ground; there's no elegant way to do that with plastic.

It really seems like you should be able to design the PCB to allow reuse of brackets from inexpensive Sound Blaster 16's or similar.

the Goat wrote:

It really seems like you should be able to design the PCB to allow reuse of brackets from inexpensive Sound Blaster 16's or similar.

This has been discussed before. That is quite a busy area of the card, and moving or re-ordering the jacks won't be much fun. The answer was no. Furthermore, I find the idea of butchering a working card just for its bracket rather wasteful. I also don't have such a donor card, and would have to find and buy one, then have it shipped, etc., then hope it actually fits. It's definitely not the ideal solution.

i don't really get the idea of crowdfunding. You said, the costs per bracket are about in the region of the interweave chip. How will crowdfunding solve that problem? As not enough argus cards will be produced, not enough brackets can be ordered, thus the price per bracket will be the same. In crowdfunding, people want to get sth in return 😀 and a bracket without a card is uncool 😉

Perhaps we can determine which other cards use the same bracket (i have one, must recheck what card it was), but still the degree of need and interest wil be low

What's wrong with just making your own? How many cards are you guys planning to get? Just scavenge a free blank bracket from any parts machine and drill/file out a few holes in the appropriate spots. We're talking, what, 30 minutes of work?

Considering ~400 (???) of these cards are going to be produced in total, and not everyone's going to want to pay someone extra for a bracket, I can't imagine it would be economical to do a production run.

For those of you who really can't do it yourself, I'm sure there's someone at a local makerspace who'd be happy to help.

xjas wrote:

Considering ~400 (???) of these cards are going to be produced in total, and not everyone's going to want to pay someone extra for a bracket, I can't imagine it would be economical to do a production run.

Your post makes a number of valid points. Personally, I would have liked to be able to opt for a production run of brackets, simply because doing without it feels like we're not finishing the job. We also didn't really know how much it would cost to do a run before now. Even with the numbers as they are, if everyone building a card wanted one per card, we would likely still be able to justify it and come to some sort of arrangement. However, given the apparent indifference toward well-made, professional brackets, an order of such a large number of brackets is very likely not reasonable, especially given the high cost of entry.

So, for the sake of my own perfectionism, I will continue looking for a less expensive source of brackets. If I find one, I will likely just order a few for myself. Failing that, I will just pick up a few blanks and try my hand at making a couple for my own purposes.

What about getting a quote from a machine shop to cut the needed holes in blank brackets?

With a lathe it really should only take about 5-10 minutes per bracket to make.

Not sure it would be worth it to do that except regionally though.

Edit: deleting a whole post of negative wet-blankety kiboshing. In the end, I'm not the one who's done any work pricing out how much it would actually cost to get these made. If you can do it for $2-3 per card with no extra shipping costs, I'm in full support. But to me that sounds impossible for such a small run, and a really miserable use of your time getting it done. If it ends up being $10 per card, I'd far rather spare the effort & just make my own for free.

Economies of scale suck for community-driven hobby hardware, but that's just something we have to live with.

Unless I can find a significantly less expensive means of production, I already consider the matter closed. With the apparent lack of interest, it just isn't worth the effort.

Nonetheless, taking the everyone-for-himself approach doesn't actually result in any savings, unless you already own a bracket that fits or have blanks to spare. Even ordering blanks from China needs shipping. Blanks from Digi-Key still have to be shipped, and are over $4 (CDN) each, before shipping and taxes. Nobody is likely to get it exactly right on the first try, so you'll invariably waste a few. The machine-shop approach isn't likely to come in at under $5 per copy, either, especially if you already had to buy the blanks. Furthermore, some shops would likely consider such a thing an utter waste of their time, given what they'd be able to charge. Also, none of these methods give you stamped or etched jack labels.

Even at U.S. manufacturing prices, it starts to make sense as the numbers increase, but I get the message.

what about simply making a drill template ?

So anyone can print it and tape it onto a blank bracklet and drill the holes himself at home.

This is cheap, easy todo and blank bracklets are found for free on old cases..

The problem is the gameport connector, you'll not be making one with just a drill. I haven't found any brackets with the connector hole in a suitable place either where you can then just drill the holes for audio connectors.