[a1m80t]

If it’s any comfort, from experience, I discover just about all computer test labs (even the big name companies) put the caseless computers/motherboards directly on foam + cardboard box or some wood plank for testing. I would probably enclosed the power supply in some cheap plastic enclosure though as mains and paper doesn’t really mix all that well

On the other hand, as a noobie on metal work, it took me a whopping 10 minutes to cut all the holes of my m3 and power supply on a two Hammond enclosure. As long as you are not trying to cut squares, it’s really simple. If you have a drill press, it’s like cutting butter. The hardest part is measuring it out, but I find it easier to draw everything on the computer.

 

[noveltone]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif Well if this is just for a class what you could do is get a single sheet of aluminum or plastic or wood, get the stand offs you need for your boards. Then drill and tap the sheet for the standoffs (this is really easy and only requires a hand drill and a single tap). I would make some effort to protect the mains and transformer wiring from stray fingers and then it should be fairly safe. All the other wiring is low voltage, so is not dangerous.

You know, that reminds me of an idea from Nelson Pass' FET Cyclotron amp. See this link: http://www.passdiy.com/pdf/Build%20T...Circlotron.pdf

Edit: see this link regarding the construction specifically: http://www.passdiy.com/pdf/Amazing%2...nstruction.pdf

Go to woodcraft.com and order a custom half-blind dovetailed "drawer," for less than $50. This goes below a metal plate, to which all the electronics are affixed, as m1abrams mentions. This could be mostly below the plate, just having connectors and knobs above it, if you wish. I am chewing on this idea for one of Pass F3 amps. Anyway, give it a look!

Collin

 

[Aman]

OK guys, I've decided to go ahead and buy two enclosures and machine them myself.

I was thinking about getting two of these: DIY Enclosures LLC - Products - DIY-0908 Chassis

I am having trouble figuring out, however, if the boards will be too big for this enclosure. I'm building the 3-channel active ground design, with separate chassis' for the power supply and the amp itself. Will two of these do the trick?

Thanks!

 

[n_maher]

Quote:

Originally Posted by Aman /img/forum/go_quote.gif I am having trouble figuring out, however, if the boards will be too big for this enclosure. I'm building the 3-channel active ground design, with separate chassis' for the power supply and the amp itself. Will two of these do the trick? Thanks!

No offense, but if you're going to have any hope of doing this yourself you should really try to figure these types of things out. You have all the information you need (hint: the size of the pcbs, the size of the enclosure). Get out some graph paper and get to work.

Translation - if you post a schematic layout for comment I'll give you some feedback, but I'm not going to do the work for you.

 

[Aman]

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif No offense, but if you're going to have any hope of doing this yourself you should really try to figure these types of things out. You have all the information you need (hint: the size of the pcbs, the size of the enclosure). Get out some graph paper and get to work. Translation - if you post a schematic layout for comment I'll give you some feedback, but I'm not going to do the work for you.

It's a 3x7 inch board, and there's 3 of them.

Quote:

Glass epoxy 3"x7" printed circuit board, double-layer with plated-through holes, silkscreen and solder mask. Heavy duty 2oz. copper layers provide lower trace impedance. The layout of all parts and traces have been carefully considered for maximum performance. The amplification circuitry are logically grouped in the center portion of the board for short trace lengths. The long and slender shape of the board was designed to achieve a short distance between input and output -- approximately 2" (5cm) between the input JFETs' gates and the output terminal.

The reason I was unsure was because I know some kits are rather particular with wiring and board layout, and I was unsure if any potentially good layout or wiring scheme could be achieved by just barely meeting the physical space requirements of the amp's components themselves, as these enclosures would allow.

This is my intended wiring layout:

Thanks again for all of the help!

 

[Omega]

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif No offense, but if you're going to have any hope of doing this yourself you should really try to figure these types of things out. You have all the information you need (hint: the size of the pcbs, the size of the enclosure). Get out some graph paper and get to work. Translation - if you post a schematic layout for comment I'll give you some feedback, but I'm not going to do the work for you.

Relying on the generosity of the DIY community to help you with a class project seems a bit disingenuous. Would you be comfortable with your professor grading your project, having read all the Head-fi thread and PM's, and AMB's website? If so, power to you! (I'm sure other Head-fi'ers have tried the same thing while being less obvious about it).

As someone who teaches these types of engineering classes (and enjoys Head-fi), I can say that I would be far more impressed by an ugly "from scratch" point-to-point CMoy and paper napkin chicken-scratch schematics coming from a student who could explain, in detail, the design motivation behind every component and topology. That is real engineering, soldering together pre-made circuits and components is an assembly job.

</cranky diatribe>

 

[Aman]

Quote:

Originally Posted by Omega /img/forum/go_quote.gif Relying on the generosity of the DIY community to help you with a class project seems a bit disingenuous. Would you be comfortable with your professor grading your project, having read all the Head-fi thread and PM's, and AMB's website? If so, power to you! (I'm sure other Head-fi'ers have tried the same thing while being less obvious about it). As someone who teaches these types of engineering classes (and enjoys Head-fi), I can say that I would be far more impressed by an ugly "from scratch" point-to-point CMoy and paper napkin chicken-scratch schematics coming from a student who could explain, in detail, the design motivation behind every component and topology. That is real engineering, soldering together pre-made circuits and components is an assembly job. </cranky diatribe>

I completely understand your position.

The project is intended to be a kit, and I'm encouraged to receive outside help. Again, this is for non-majors and it is just something I'm taking to get a better understanding of audio hardware, and it's definitely helping in that respect! I've already had to do circuit analysis projects with similar end-goals in mind as the ones that you listed off above.

But now I just want to get that good grade and be on with it, and have a sexy headphone amp as well.

 

[oneplustwo]

Aman,

I would leave a little more room in there if I were you. The enclosure you specify says the interior space is 9x8. That would mean the holes you drill for the standoffs would have to be perfect in order for you to squeeze them in. That also means that the enclosure itself would have to be manufactured to at least the indicated measurement which, could be the case, but risky in my mind. Also, don't forget, you need to leave room for the volume knob, headphone jacks, input jacks, and power jack. To be comfortable, I would recommend finding something at least 10" wide by 9" deep. You can get away with something smaller for the power supply enclosure, but I kind of like the aesthetic of 2 identical boxes.

 

[johnwmclean]

You could get them in, you need to double up on one pair of holes for two boards with standoffs. You have around 23.5mm left across one side, for volume pot, connectors, IEC socket and jacks. You could utilise the side of the B22 board that has the lower profile components for your volume pot, as a thought. See attached.

 

[n_maher]

Quote:

Originally Posted by Aman /img/forum/go_quote.gif It's a 3x7 inch board, and there's 3 of them.

I don't understand why you're telling me this. I'm more than aware of the size of a beta22 pcb. And you still haven't told me how you plan to fit 9" of pcb in a 9" case. Me, I'd be uncomfortable with that lack of a margin for error, even if you stack some of the boards as suggested. You really need to put more thought into this and put pen to paper. I'm all for encouraging new DIYers but I'm also a big fan of encouraging the Y part of that equation. We're not here to hold your hand, but we'll certainly lend a hand if you stumble along the way.

 

[oneplustwo]

Aman,

In the spirit of learning, you might consider just mounting everything on a piece of MDF or something like that at first. Then you can play with your layout a bit and figure out exactly what you need before committing big bucks to a real enclosure. Or, as I mentioned previously, you can go cheap with a cookie tin and try it out. Worst case, it doesn't work and you ate a bunch of cookies. But it would be a cheap way to learn your way into what you need and get some basic case working experience under your belt. Just to give you my own example...

I had originally bought two cookie tins. One for the amp and one for the power supply. I ended up squeezing everything into the amp tin but turned the orientation of all the components 90 degrees from my original plan to make everything fit. Once I got everything done and started listening, I got the dreaded transformer hum. So I remounted the transformer outside the tin, in yet another tin and that got rid of 99% of the hum. Along the way, I learned a ton and didn't spend hardly any money. Now that I have a better idea of what I'm up against, I'm thinking about spending some bucks on real enclosures.

Just an idea... take it or leave it.

 

[scytheavatar]

If you are doing this for an entry-level electrical engineering class, I have a suggestion for you: make something else. Perhaps the Mini3, and you can buy the panels so that you don't have to drill them. The Beta22 is a very poor choice for a beginner, and the odds of you getting a working setup at the end of the day is not very high. It wouldn't be pleasant if you spend weeks fixing up the Beta22 only to get a piece of junk in the end.

 

[Gatsu]

Aman,
I hate to say this (and I may be wrong of course) but I think you may have bitten off more than you can chew.
The Beta22 and Sigma22 are in no way beginner "kits". Myself, I've been DIYing electronics stuff for more than 20 years and recently started building my own Beta22 based off Naamanf's monster build. I can say without a doubt that this is the biggest project I've done to date (certainly the most expensive)
Like many others above me I would also recommend that you work on something smaller and less complicated first and then learn from your mistakes on that.

Just a thought...

 

[a1m80t]

well, the guy already bought the betta 22 and sigma 22 so its too late. But in my opinion, its a bit risky to spend $85 on a case that doesn't really fit all that well. You might consider an old compaq or dell computer case

 

[Gatsu]

Oh I'm not suggesting that he give up on the Beta22. Merely that he should try a smaller project first. Then once hes done that possibly go back to the Beta and see how he goes.

So far the Beta has been a great learning experience, and I haven't even started building the amps yet
I've had to learn how to program microprocessors as well as designing my own PCBs so far...