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"The Wiener" TPA3118 amplifier card

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impuls60

Member
Joined 2011
I wonder if it could have something to do with the mismatch I mentioned.. The temperature settled and didn't get any higher even at max, (I can still touch it).
Cogitech have you found a favourite frequency yet? I guess the amp have to be powered down to use the switches safely? I'm doing swaps now but I'm not seeing huge impacts in heat generation.
Besides that the initial impression is very good! It has none of the problems the other boards have and the hiss is slightly better than my uber modded tpa3116! Have anyone had time to notice any tonality preferences caused by the input caps? I had to increase treble +4db( probably because of filter mismatch with speakers) to make it sound the same as my modded tpa3116.
I was shocked to see how small it was in my hands;) The pictures doesn't give a true impression of the size at all^^.
 
cogitech

cogitech

Member
Joined 2011
Paid Member
@ impulse60

We posted at the same time (see one page back). I don't know if it is my favourite frequency, but 500kHz is working well for me. Cooler than 1000.

I am also running a big mismatch right now. 4ohm board with 8 ohm speakers. I don't think this would cause heat, just a worse high end roll-off (which may be why you need +4dB treble).
 
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cogitech

cogitech

Member
Joined 2011
Paid Member
One thing I should note: My board is anchored to the "chassis" (cookie/biscuit tin) by one copper stand-off (a typical PC motherboard standoff). I have these copper stand-offs installed in all 4 holes, but only one is anchored to the chassis with a screw. (The stand-offs are actually installed backwards, with the male threads screwed directly into the mounting holes of the board - they "self-tapped" into there very snug. Ingenious? I think so.)

So, since the chip is heat-sinking into the ground plane of the board, and the board is anchored to the chassis with copper, there must be at least some heat sinking into the chassis.

I just thought I would mention this in case others have their boards on plastic legs or some other insulating material.
 
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impuls60

Member
Joined 2011
Cogitech, I've running the amp almost flat out now@6ohm for a couple of songs and the chip is still touchable:) So I guess the heat dissipates a lot better at a higher temperatures.
In my car I'm going to run 3.3ohm in my car so that might be another story..
I too am at 500kHz and it sounds really sweet! Next up is 600kHz and I might wonder if the differences will appear in the upper treble??
But now its time for another beer and some more listening!
 
gmarsh

gmarsh

Member
Joined 2004
impuls60 said:
Night and day difference with the psu grounds connected together:) No detectable hum now! Hm, I thought the dac's ground were floating.. obviously not.
I've also noticed that the chip runs a lot hotter than my modded 3116 chips. At moderate volume it gets almost painfully to touch. As test setup Im running 24V and 87db 6ohm speakers with a 4ohm amp output filter. Not the best way to test this amp but my car setup isn't ready yet.
So is the best way to solder a copper heatsink to the tin blob underneath or glue/paste a heatsink on top? It could problably survive without the heatsink for a short while, but I don't want to take any chances with it since it's already a bit underpowered for my setup.
Gmarsh, do you think the chip could handle a soldering temp of 320C for 3 seconds If I solder a copper sheet to it?
Click to expand...
Silicon can handle a much higher temperature than your finger can, and the TPA has thermal protection. I wouldn't worry about it, unless the amp starts cutting out.
 
cogitech

cogitech

Member
Joined 2011
Paid Member
impuls60 said:
Cogitech, I've running the amp almost flat out now@6ohm for a couple of songs and the chip is still touchable:) So I guess the heat dissipates a lot better at a higher temperatures.
In my car I'm going to run 3.3ohm in my car so that might be another story..
I too am at 500kHz and it sounds really sweet! Next up is 600kHz and I might wonder if the differences will appear in the upper treble??
But now its time for another beer and some more listening!
Click to expand...

Enjoy!

(I don't think the sw.freq. will change the sound much, but you never know. The main point of it is to avoid interfering with your favourite AM radio station. :D
 
gmarsh

gmarsh

Member
Joined 2004
As for configuration: the AMx switches can be changed on the fly with the amp powered up. Just remember that not all AMx settings are valid, if you're changing from one frequency to another make sure the "intermediate" settings when you're throwing switches are valid.

The GAIN/SLV ones can be changed on the fly technically, but you have to power off/on the amp (or mute/unmute it with the connector on the terminal block) for the new gain setting to take effect.
 
cogitech

cogitech

Member
Joined 2011
Paid Member
gmarsh said:
As for configuration: the AMx switches can be changed on the fly with the amp powered up. Just remember that not all AMx settings are valid, if you're changing from one frequency to another make sure the "intermediate" settings when you're throwing switches are valid.

The GAIN/SLV ones can be changed on the fly technically, but you have to power off/on the amp (or mute/unmute it with the connector on the terminal block) for the new gain setting to take effect.
Click to expand...

I thought I read in the datasheet that the gain setting is registered at boot time and cannot be changed on the fly. Maybe that was for a different IC. Been reading a lot of datasheets these days. But I guess that's basically what you just said. I just assumed the amp has to be powered off before changing them. :D
 
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gmarsh

gmarsh

Member
Joined 2004
I should point out - the bottom copper layer is the "heatsink" on this amp. If you've laid the card directly on an insulating surface, you're basically blocking this heatsink. This will probably make the card run hot.

Putting it on standoffs (a half inch or so is great) provides air convection underneath the card which will keep it cool. Mounting it with the PCB vertical is really good, though probably not necessary.

If you're mounting it to a flat metal case, a thermal pad works great for pulling heat out of it. This is the one I throw in with the thermal/mounting kits:

H48-6G-20-20-4-1A t-Global Technology | 1168-1677-ND | DigiKey

I also throw in 4 of these standoffs (they're 3mm, put a washer underneath them for ~3.5mm):

R30-6200314 Harwin Inc | 952-2365-ND | DigiKey
 
gmarsh

gmarsh

Member
Joined 2004
reo said:
Yea i hear ya i use optis. also, I did try that number 6 trigger to give me 20db and my speakers are not able to handle that so back to all switches to off position. thanks for yor help
Click to expand...

Looking at the card with the "WIENER" text right side up, the 6 position DIP switch is the one to set it up.

OFF is to the left, ON is to the right. Switches are labeled 1 through 6 top to bottom.

For 20dB gain:
OFF (150+)
OFF (75+)
OFF (30+)
OFF (150-)
OFF (75-)
ON (30-) - this switch will be on unless you're in slave mode.

For 26dB gain (I ship the boards this way)
ON
OFF
OFF
OFF
OFF
ON

32dB gain:
OFF
ON
OFF
OFF
OFF
ON

36dB gain:
ON
ON
OFF
OFF
OFF
ON
 
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