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soundNERD 17th December 2004 01:00 AM

My latest subwoofer - a bridge opa549 built onto a piece of plexiglass
What do you guys think?

I plan on giving this to my dad for christmas.

I know the speaker is trash, but it works pretty well, or at least much better than expected.

The amp is a bridged OPA549 design powered by a 175W transformer (I know, a little too small, but it's all I had). Page 2 shows pictues of the amp. It's built onto a piece of plexiglass.

Sorry if it's slow loading, because until I find a new website host, I have to host it myself. So, my server is an old 233mhz p1 pc, and my internet connection is a 1.5MB down/350k up DSL connection, so it's not the best for web hosting.

Stocker 17th December 2004 03:28 AM

I think you could decorate the amplifier side of the box a bit. Trim the PCBs to have pretty edges, paint them, paint the inside box, use a nice pattern or design... otherwise, not too shabby!

HIPCHECK 17th December 2004 08:51 AM

opa54* sub amp Q?
would really like to see the layout you have, and component values. do you have a pcb file for this amp?

i am building a car gainclone for my midbass speakers, (parts express buyout 7inch in aperiodic enclosure)

i have a working smps that has 31 volt rails after rectification, and would like to regulate them down to 27-30v and add some caps to stiffen up the psu(car smps are week from what i have read)

im looking at lm-338 for regs, unless anybody thinks the lm-317 can be used for psu (only 1A but this is for midbass duty, with extra caps, and an already regulated smps it might work out with lm-317?)

pretty neat plexi cover to show your handy work !!!

soundNERD 17th December 2004 08:00 PM

Thanks for the comments.

I'll be posting this project on my website soon, so I'll also post the eagle files. When it's up, I'll let you know.

I guess I could decorate it more, but don't know if I will. You don't see it too much. I think the thing I want to do the most is add an LED light to it so the edges glow. OR, I was just thinking, I have a leftover set of 2 PC blacklights. All I'd have to do is build a 7912 regulator to run 12V into it. That would look pretty neat. But they could break with the rattling????

I forgot to mention, the box may be stained later on, but I am not sure when. Does anybody know where to get true black stain? I can't find it anywhere I look, and would prefer black stain over any other color. I may also add a nice grille to it.

Finally, those of you who looked at my pictures with a broadband connection, would you mind telling me how good the speed was? Hopefully it was acceptable!

Thanks again for all the comments,

Stocker 17th December 2004 09:39 PM

Speed was ok.

thomas997 17th December 2004 09:48 PM

Cant get your site to work yet :(

soundNERD 17th December 2004 10:04 PM


About not getting the site to work, for some reason my server decided to restarrt a few minutes ago.

Should be back up now

soundNERD 22nd December 2004 08:04 PM

Nobody has any more comments?

I would really like to hear them!

ingrast 22nd December 2004 08:40 PM


Originally posted by soundNERD
Nobody has any more comments?

I would really like to hear them!

May be it's of no consequence in this case, but noticed you attached the back cover with 4 corner screws.

If you really hammer it down (just over 40 - 50 W RMS), you will probably have serious venting air currents all along the borders or, if there is recessed bracing, noticeable rattling. Should like to hear from you.


soundNERD 22nd December 2004 08:50 PM

I actually have 10 screws, 3 across the top and bottom, and 4 down each side.

Plus, no air gets there because there is a board dividing the amp from the speaker and the wire going to the speaker is sealed so no air leaks with hot glue.

I was actually quite suprised when I first listened to it that there was absolutely no noticeable rattling unless you has your ear up to the amp. But either way, the speaker is much louder and you never notice it.

I misunderstood your post. You were talking about the back piece of wood. But the same reason applies. Either way, I think I'll add a couple more screws to it.

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