The Boominator - another stab at the ultimate party machine

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#5,925
horst303 said:
Not even close, its at least 3 times stronger, but the main benefit is that it is a lot more impact resistant, if you tap two panels with a hammer that have been glued together with PVA than they will come apart, not with this stuff, it dries hard but still behaves like rubber.
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PVA is polyvinyl acetate, PL is a polyurethane glue, as is gorilla glue, as is expanding foam from a can, they differ (from my observation) only by how much moisture they can can absorb and hence how big their bubbles are, which has a direct bearing on their strength, which stands to reason since glue is sticky and air isn't.
PL is the brand name by Loctite, maybe your PL is something else?
There are a lot of manufacturers all over the world, but what you should look out for when searching for it, is that it cures with moisture and that it expands to some degree and I've only ever seen it in cartridges for a caulking gun.
 
#5,927
aterren said:
Wow, lots of comments about glue today. Compatibility with materials is critical.

Saying epoxy is a bit like saying food. There are a lot of variations with varying qualities. Commonly available epoxy will be fine on bare ply wood. It holds up well and can have some modest gap filling properties too (e.g. the west systems stuff). It doesn't stick to polyester resins well, or at all. That's why it isn't good for the phenolic coated ply.

As for PL. I've used a lot of PL400 gluing ply to floor joists. It is amazing and I considered it for my builds but I am concerned it is too thick for the dado joints. They only have 0.01" (0.24mm) clearance in width and half again as much in depth. I'd really prefer to avoid a situation were the glue can't flow and I can't get the parts fully seated. Is there a thinner version?

As for Gorilla glue, this is the second time I've used it. It is just as awful as I remember. Just crap to work with, but I did some test glue ups and I'm confident it is strong enough, especially with the dados.

I suppose a bead of PL to the joint corners to add additional strength.
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Okay let me backtrack here a little, for gluing tight fitting dados, the runny polyurethane like gorilla will likely work better than the thicker polyurethane.
In fact I made a corner shelf recently that that featured dados like this
VTk7ER6.png

they were so tight that I was simply pushing the glue away, my solution was to make the channel wider, so that's 6mm ply with a 8mm cut, and it is amazingly solid.
 
#5,929
Saturnus said:
You can parallel the output channels. It won't give you more output power but at least energy is not wasted on a dummy load.

As mentioned by others the TPA3116 will not work on a "24V" battery. It has a hard voltage limit at 26V built in. Above that and the chip simply shuts down. If you have a dc-dc converter it will work on 24V though. Just note that it is generally regarded that the optimum supply voltage is no higher than 21V.
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Thanks for your reaction. Should have read the datasheet more closely. I just want some extra power when connected to the grid. The battery I have is 12.6V. Is it possible to use this amp in combination with a 19V PSU? Or is it better to go with the maxamp and a 12V PSU?
 
#5,931
If you go to the 3116 thread here on diy audio you will find a ton of posts on power supplies

Bit "yes" you can use the 19v. I have run mine with 12,18.5,and 24 v laptop bricks with n issues.

Actually, I did have it cut in and out on loud passages with the 24v so no I wonder if perhaps it was a bit too hit and perhaps exceeding the chips hard limit as noted above.

I like the versatility of the 3116 boards for this reason.

But honestly, I haven't noticed much difference between my 18.5 v5 amp laptop supply and the 24v 5 amp supply.

Most users on the other thread said the 21v was the best.
 
#5,932
Saturnus said:
You can parallel the output channels. It won't give you more output power but at least energy is not wasted on a dummy load.

As mentioned by others the TPA3116 will not work on a "24V" battery. It has a hard voltage limit at 26V built in. Above that and the chip simply shuts down. If you have a dc-dc converter it will work on 24V though. Just note that it is generally regarded that the optimum supply voltage is no higher than 21V.
Click to expand...

I read in the datasheet that there is an option to run this chip in mono/PBTL and get 1x100w but that it required some more than parallelling the outputs.

See below:

7.4.1 Mono Mode (PBTL)
The TPA31xxD2 family can be connected in MONO mode enabling up to 100W output power. This is done by:
• Connect INPL and INNL directly to Ground (without capacitors) this sets the device in Mono mode during
power up.
• Connect OUTPR and OUTNR together for the positive speaker terminal and OUTNL and OUTPL together for
the negative pin.
• Analog input signal is applied to INPR and INNR.
 
#5,933
PBTL mode and paralleling is similar but not the same. They should not be confused with each other as that could potentially destroy the chip.

Paralleling you just feed the same input to both channels and connect the output poles together + to + and - to -.

PBTL mode requires that the PCB is specially made to be able make use of this mode. The left channel input (or right channel, can't remember) is disabled and output is paralleled by connecting + and - on right channel as positive, and + and - on left channel as negative (or vice versa, can't be bothered to check).

I think all of this has been discussed ad nauseam in the TPA3116 thread.
 
#5,934
Saturnus said:
Random tip. An easy way to secure the battery is to mark it up and then outline that with a couple of large headed phillips round pan type screws. It only needs to be on one of the compartment walls as the battery is so snuggly fit that it doesn't need more than that to hold it.
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This reminds me, how have people been securing things inside the electronics compartment, e.g. the amp enclosure or smaller LiFePO4 batteries? I've been mulling over it but haven't come up with any particularly great ideas.
 
#5,936
croowley said:
"The sound is weak from one channel."
Check if there is a 12V voltage offset on one output. In that case, an output
transistor is probably damaged and the chip needs to be replaced."

How do i check this?
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I must have missed the original post on this but before doing anything else I would check the signal cables and connections, this involves trying different signal cables and source. Then do the same for speaker and power cables. 9 out of 10 times that is problem. (If not 99 times out of a 100).

If it's not a cable or connection problem would be nice to know what is exactly is meant by "weak".
 
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#5,937
Saturnus said:
I must have missed the original post on this but before doing anything else I would check the signal cables and connections, this involves trying different signal cables and source. Then do the same for speaker and power cables. 9 out of 10 times that is problem. (If not 99 times out of a 100).

If it's not a cable or connection problem would be nice to know what is exactly is meant by "weak".
Click to expand...

It means VERY low sound volume, Can barely be heard.
Btw, i don't have the 3.5mm jack on the amp6. What holes is for ground, left and right? Just to make sure i connected the cable the right way.
 
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