[Stephonovich]

Yesterday, we went dumpster diving, (great sport! Once found a case full of printer cartridges that I promptly sold on eBay for $20!) and found an AOL CD in someone's thrown away (but perfectly good) duffel bag. It was fancy, however. It came in a metal case.

Dimensions are:

14x12.5x1 cm (HxWxD)

I'm wondering, could one fit an amp in there? Any type, (CMoy, META...) just a headphone amp. Now, large caps are obviously out of the question. I'm not sure of the names (haven't done much DIY...), but there are two types in a CMoy; the large, cylindrical type, and the smaller, rectangular type. The type that could be bent flush with the board after soldering.

And finally, the jacks. I don't believe I've ever seen a jack small enough for this. That would prove a problem. Although I suppose you could always run leads out and have a small
box with jacks somewhere... Who knows; AOL may finally prove useful for something other than frisbees!


(-:Stephonovich

 

[was ist los?]

i have one. I thought of that the first tim i found it, but you'll have to compromise on size of parts and probably no pot. You'll need AAA batteries or exteranl power source. Just my guesses.

 

[ProFingerSk8er]

gumstick batteries from minidisc recorders/players will fit in there nicely

 

[was ist los?]

You'll need 8 just to get 9.6v of voltage! At $20 a pair for Sanyo/GP gumsticks that $80. Though you could use an AD823 and use less.

 

[Stephonovich]

An external battery pack wouldn't be an issue. I was actually thinking of a META42 (or PPL...) in this, and having a wall wart, thereby just needing a jack. As for a pot, well, I suppose if it were run out of say, a DVD player (963SA comes to mind...), I could use the volume control on that.

Mainly, it's just an interesting idea.

(-:Stephonovich

 

[Squalish]

I have a Fossil Wallet Gift Tin that is the perfect size for an amp, it's exactly the same horizontal formfactor as the AOL coaster case, but about 1" tall. I will probably be building something into it this summer.

Considering that people can fit amps into a 9V battery case, it shouldn't be hard to do an amp in this, but you will always need to consider height, when choosing caps and every offboard part.

 

[Stephonovich]

1" tall, eh? Ought to work. I still think I'm going to do some research into this, though. If it could be done, it would just be übercool... A stackable amp!

(-:Stephonovich

 

[fiddler]

And you can mount a pot vertically so it sticks out of the lid, maybe. I have a very similar shaped tin. I think it came with stamps, or something. Hmmm an ultra-thin amp... might be interesting.

 

[Stephonovich]

Quote:

And you can mount a pot vertically so it sticks out of the lid, maybe.

But the entire point is to make it stackable. At least for me. I think it'd just be so cool to be able to slide it into a pile or something and have it sitting there. But I'm weird that way...

(-:Stephonovich

 

[bralack42]

Do they make pots that small? I found a jack that would vertically fit into the space: Mouser # 161-3504, though I don't really know if it would work. I'd be very interested in seeing this be done.

 

[RacerX]

I applaud your audacity, sir!

 

[Stephonovich]

You mean Audacity ?

I guess not

Anyway, about the jacks... Those are .5 centimeters deep... that would work... [thinks to self] I suppose I could abandon my Hammond case I have that I was going to build my CMoy in... I would also have to order some new caps... Are there any alternatives to C1/C2 in the power supply that would fit in this? (I'm fairly certain C1/C2 for the amp would fit when bent flush with the board)

(-:Stephonovich

 

[tangent]

There are 5 and 7mm high electrolytics out there, made for computer use. They're low ESR and low voltage models, mostly, which seems to fit right in with this amp.

I like the idea of using the AD823 for this, as you can get away with as little as 3V power with many headphones. Remember, though, that your batteries have to start at a higher value for this to work, because they drop in voltage as they get used up. Starting from 5 to 8V would probably work beautifully. If you started at 6V, you could use the 6.3V caps that are commonly available, and thus get a fair bit of rail capacitance.

So, four 1.2V rechargeable gumstick batteries, then? That's 4.8V nominal, up to about 6V when the batteries are fully charged, and 3.6V when they're mostly used up.

For the jacks, you might consider using the ends from a headphone extension cord. You should have enough space inside that case that you can poke the cords through padded holes in the sides of the case, and attach a bead to the cables such that you can't pull them all the way out of the hole or strain the solder joints, but you can stuff the cables back inside the case when you're not using it. It's too much to expect a spring-loaded coiling mechanism, but we can dream, right?

 

[Stephonovich]

I'm thinking I may be building two amps... This CMoy in this tin, and save my OPA627's for a META.

The caps sound good, Tangent. As does your idea for the jacks. Ratshack sells extension cables for pretty cheap.

Where can you buy Analog Devices chips? I see they have a samples program, like TI, but I don't want to be leeching off everyone...

Analog's website sells the chips, I see. But if possible, I'd like to buy everything from one supplier, so's to consolidate shipping.

Geez, those gumsticks are expensive! About $30 a pop! That's $120 just for the batteries. NiMH AAA's are looking better...

(-:Stephonovich

 

[tangent]

Quote:

Where can you buy Analog Devices chips?

Newark for most Analog chips, including the AD823.

Quote:

Analog's website sells the chips, I see.

Yes, but they ship from the Phillippines and Malaysia, so shipping is a $12 minimum. It only makes sense to order direct from Analog if you're getting large quantities, or you can't find the chip anywhere else.

Quote:

Geez, those gumsticks are expensive! About $30 a pop! That's $120 just for the batteries. NiMH AAA's are looking better...

Yes, but will AAA's fit into your case? They're 1cm in diameter "naked", and more like 1.25cm in a battery holder. Do you have that kind of space?