Class d pedalboard amp project

[Miyagi_83]

Good day, everyone.
I bought this class-D power amplifier module (pic attached). It came in the mail yesterday and I'm pretty excited to try it out. I was going to use it as a pedalboard amp due to its compact size. Before that happens, however, I'm going to test it to see how it performs.
The spec sheets I found online say it's capable of delivering 60W into 4 ohms at 10% THD. Personally, I take that with a pinch of salt, or even a handful perhaps, because, first of all, it doesn't employ a genuine TI TPA3118. The original chip has 32 pins, whereas this one has only 28, so some people online suggest it might be a relabeled (mislabeled?) TPA3110. No problem for me, though, as long as it behaves well.
I'm going to fan cool it because putting a heatsink on it looks tricky here. Correct me if I'm wrong, anyone.

I have questions, obviously.
I'm going to power it with a laptop charger / PSU capable of providing 20V, 3.25A. Good idea? Bad idea? Acceptable? I'm going to test it with an 8-ohm load.

Thanks for any help.
M.

[saturated]

Nice 

What are the black "001" or "100" things

[Miyagi_83]

What are the black "001" or "100" things

They look like inductors to me.

[Tassieviking]

They are inductors.
That amp will fit into a 125A stompbox with a small fan at the end, at least my one did and I used a 100 watt mono amp with a heatsink.
I got a small 5V fan from Tayda and a L7805 regulator to run the fan and that worked great.
I kept blowing up laptop power supplies on mine, but I used it to test stompboxes and I cranked the volume right up when I hooked up a bass guitar so I made it work hard until it did so no more.

One day I will get a better power supply and resurrect it again.

Good luck with it.

[Miyagi_83]

Thank you, sir

That amp will fit into a 125A stompbox

Do you mean a 1590A enclosure? (Search results for 125A spit out a tube amp output transformer)
In any case (pun intended ), the 1590A is awesomely small, which is exactly what I need on my pedalboard 

I cranked the volume right up when I hooked up a bass guitar so I made it work hard until it did so no more.

I understand that you pushed your power amp into clipping. How did that sound? Or did you use some sort of input signal clipping?

[g1]

I cranked the volume right up when I hooked up a bass guitar so I made it work hard until it did so no more.

I understand that you pushed your power amp into clipping. How did that sound? Or did you use some sort of input signal clipping?

I took that to mean he worked it hard until it died. 

[Miyagi_83]

I took that to mean he worked it hard until it died. 

I thought he meant that he'd abused the heck out of the power amp so the PSUs died and, consequently, the amp

[J M Fahey]

It will work, with a 20V supply you´ll get some 20W into 8 ohms, not bad at all.

Remember output is balanced, so no output terminal is grounded, use a plastic jack.

It´s a common beginner´s mistake to use a metallic guitar speaker jack, screwed on chassis.

[Miyagi_83]

Remember output is balanced, so no output terminal is grounded, use a plastic jack.

Thanks for the heads up, Mr. Fahey.

Fortunately, I don't have any of those metal ones on hand, so I wasn't going to use them anyway

Peace. I'll keep you people posted.

[Tassieviking]

Thank you, sir

That amp will fit into a 125A stompbox

Do you mean a 1590A enclosure? (Search results for 125A spit out a tube amp output transformer)
In any case (pun intended ), the 1590A is awesomely small, which is exactly what I need on my pedalboard 

I cranked the volume right up when I hooked up a bass guitar so I made it work hard until it did so no more.

I understand that you pushed your power amp into clipping. How did that sound? Or did you use some sort of input signal clipping?

I meant to say 125B box, I have been looking at a lot of tube amp transformers lately so I can make a small tube amp in a pedal format so the 125A transformer must have been on my mind.
I think I overloaded the power supply with my pedal, I was using a HP laptop supply rated at 120 watts but I was playing loud testing a Bass speaker I had built.
I used a mono TPA3116D2 board with a heatsink on it and 2 top mounted insulated jacks for in and out sockets.
Power was a GX12 2 pin socket, I made leads with alligator clips so I could use it on a car battery if I wanted to.
A small 5V fan that ran of a L7805 regulator was sitting at the opposite end from the jacks.

https://www.taydaelectronics.com/hardware/enclosures/1590b-style-1.html
https://www.taydaelectronics.com/hardware/6-35mm-1-4-plugs-jacks/6-35mm-1-4-stereo-insulated-socket-jack-solder-lug.html
https://www.taydaelectronics.com/dc-brushless-fan-5vdc-1-2-inch.html
https://www.taydaelectronics.com/lm7805-l7805-7805-voltage-regulator-ic-5v-1-5a.html
https://www.taydaelectronics.com/connectors-sockets/2-pins-male-circular-connector-gx12.html

[Miyagi_83]

Ok, I launched this thing today. It works, so I guess I'm happy
I didn't have the opportunity to play it super loud, though, because I live in an apartment, but next weekend I'm planning on visiting my good buddy in the countryside You can guess the rest
Hopefully, I'll manage to put it in an enclosure by that time because, obviously, it picks up noise from the air.
As for the power supply, it didn't even get slightly warm, but I suppose that's due to my being rather lenient with the amplifier.
To be continued...
M.

[Miyagi_83]

Speaking of the enclosure for this thingy, of the fan, to be more specific, is it better when a fan moves the air from the inside out or the other way round?

[Tassieviking]

When I mounted a fan in my pedal amp I had the fan blowing into the pedal, I did not make any other ventilation holes so I placed a spring-washer between the back lid and the box on the screws to make a small gap all the way around.

Since there is no heatsink on the module it might be a chip that dissipates the heat through the bottom of the chip, look at the back of the PCB and see what is under the 3118 IC.
Some PCB's have a lot of vias (small holes) in the PCB to transfer the heat to the bottom of the PCB to act like a heatsink, the back of the PCB becomes the heatsink in that case.
 Make sure you mount the board with enough space under the board for airflow to get through since this might be the side that dissipates the heat from the amp.

[Miyagi_83]

look at the back of the PCB and see what is under the 3118 IC.

A warranty sticker
I'll scrape it off tomorrow and see what's underneath.
From what I've read about this particular module, it uses the underside of the PCB as a heatsink.

I did not make any other ventilation holes so I placed a spring-washer between the back lid and the box on the screws to make a small gap all the way around.

This sounds like a splendid idea! I might give it a try.
What I'm also thinking about is getting a small fan, like super small, 25x25 mm, and make the air flow horizontally. I'll need to do some research on this.

[g1]

It should make no difference whether the fan is set to suck or blow.  Air flow should be equal either way.
If you are using a dust filter, the common way is with the fan sucking, and the dust filter at the fan.  This collects the dust at the outside, where it is visible and easier to clean.  Usually it's just a piece of loose weave foam material, maybe some velcro strips on the chassis to stick the foam to.