• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Indignizuma or Podignia?

guptonr

guptonr

Active Member
I haven't been very active on AK for a while, but the bug bit and I started a new project. I was tired of my tiny iPod speaker/dock and decided to make a portable stereo. I started with the Podzuma by Darren Zuma over on the parts express project gallery. However, I wanted something a little different. I settled on making a portable stereo with Zuma's power schematic but changed the amp to the Lepai 2020 and the speakers to integrated Indignias. I'm trying to keep the cabinet dimensions as close to the parts express 0.38 cabs as possible. Some dimensions have changed due to construction needs, but the net vplume has stayed pretty close to 0.38. The drivers, crossove, porting will all be the same as the Indignia. I'm using 3/4 plywood because i don't know what kind of beating MDF can take.
 
Register to hide this ad
For a portable setup the plywood is a better choice than MDF. Durability is not MDF's strong point. Can't wait to see pictures of your project!
 
Here's some pics of the progressing project: first is the first completed crossover and the other is the cabinet. You can see the beginnings of the Indignias. The baffle is not complete yet. The brace in the middle of each speaker is like the one from the PE premade cabinet. The space between the speakers gets the electronics and battery.

1336537638243.jpg


1336538942257.jpg
 
The thing will probably be pretty heavy, but it's not like I'll be toting it around much. Put it in the truck, haul it to the lake, sit back and enjoy.
I'll remember to scale down the pics when I put some new ones up. I'm also doing some some of the common mods to the Lepai amp. There's lots of stuff on it at DIYaudio.com.
 
This is my first "from scratch" project. All I've done before is to recap and re-foam a cople pairs of speakers and clean up a couple of vintage receivers. The Indignia design collaborative is pretty extensive and easy to follow. The seed for the project was "how can I get something portable that sounds anything like the Marantz 2250 paired with the large Advents I have. I didn't want to use a car battery and a wheel barrow so I had to scale down.
 
Cabinet dampening

I have some Owens Corning 703 and 705 rigid fiberglass acoustic panels I'm planning on using for cabinet dampening. It's 2" thick but I was planning on splitting it in half and using 1" thick pieces to dampen the top, bottom, back and sides. Does anyone know if this material works well for this application or will it deaden it too much?
 
The 703 with absorb the sound waves in the cabs, but to dampen them, you might be better off buy cheap stick on floor tiles and gluing them in place with the recommended floor glue. You can cut the stuff easy and it really makes the cabs dead sounding....that is: no ringing or hollow sound when you knock on them..
 
Thanks for the heads up Djnagle. That's what I was afraid of. In the Indignia design thread, some folks used foam "egg crate" mattress foam and another used quilting batting. I'll see what I can get a hold of around here.
 
The point of that bit in the Indignia thread is that it isn't an exact science. You don't really need something specific for this build, just something to eat up the backwave. With the window brace you've got, the boxes should be plenty stiff. If you want to deaden the wood some you can use something as simple as oil based modeling clay (oil based so it doesn't dry out). Stick that on walls that you think are ringing and you'll be fine. Use something porous like egg crate foam to eat up the backwave and you'll be fine.
 
Power Supply Question

I have a question a about the power on my project. I'm using Zuma's power schematic (below) but with the exception of adding a battery shut off switch on the + circuit to the battery. The power supply is rated at 12v 2 amps actual voltage is 13.7. The battery is a 12v 7.2 Ah which puts out 12.6 volts on a full charge. Everything works fine except for one anomaly. With the battery off, the voltage at the amplifier indicates 13.7. When the battery is on, it indicates battery voltage of 12.6, regardless of whether or not the power supply is connected. I thought the higher voltage (13.6) would power the amp with the battery on. Does the higher amperage of the battery overpower the power supply? Or does the voltage drop from the power supply because it is charging the battery until it equals the battery voltage? I'm way beyond my capabilities here.

1337731463702.jpg
 
Finished It!!

I finally got this thing finished. I was able to ops test it for an evening at a lake and it sounds great. I did find some air leaks from the speakers into the electronics compartment so a little rope caulk should clean give the bass just that wee but more punch it needs. The amp, battery, and crossovers are contained in the middle section. The baffles and back panel are removable in case repairs are needed. The thing weighs in around 40 lbs so it's only portable in the strictest since: self contained power, able to be moved around with little damage.

1338176588316.jpg

1338178879387.jpg

1338176606908.jpg
 
Cool! Congratulations.
I love it.
That Lepai amp is pretty amazing and cheap.

Now you need some pneumatic wheels and a hefty handle, and who's better than you?
 
Hey! Way to be innovative! Back in the 90's I did something similar using a solid state amp out of a RCA New Vista console and a couple of 6x9" speakers. :no: Doubt it sounded anywhere near as good as yours, though.

Ray, does that Workmate look familiar? It's a lot cleaner than mine.

guptonr said:
I have a question a about the power on my project. I'm using Zuma's power schematic (below) but with the exception of adding a battery shut off switch on the + circuit to the battery. The power supply is rated at 12v 2 amps actual voltage is 13.7. The battery is a 12v 7.2 Ah which puts out 12.6 volts on a full charge. Everything works fine except for one anomaly. With the battery off, the voltage at the amplifier indicates 13.7. When the battery is on, it indicates battery voltage of 12.6, regardless of whether or not the power supply is connected. I thought the higher voltage (13.6) would power the amp with the battery on. Does the higher amperage of the battery overpower the power supply? Or does the voltage drop from the power supply because it is charging the battery until it equals the battery voltage? I'm way beyond my capabilities here.

1337731463702.jpg
Click to expand...

:scratch2: I'm not sure I can answer any of your questions. The first question I would ask myself, however, is will the T-amp be safe/operate sufficiently on 13.7 volts. If so, and it were me, I'd probably just try the whole thing and see what happens. If I understand your questions and concerns it may, indeed, be a good idea to have a switch to remove the battery from the circuit. Or, use the type of switch that allows either the battery or the T-amp to be in the circuit.

Brian
 
The amp seems to work fine. The manual for the amp says its max is 14 or 14.5v so it may be ok. There's a lot of info at DIYAudio on it but most of it concerns the older version. Ran it all night in several power configurations. I ran it on battery only, power converter only (battery switched off) and power converter charging the battery. I didn't measure it so I don't know what the voltage is under load.

Where would I measure it to get volts to amp under load?
 
You must log in or register to reply here.
Back
Top Bottom