Nobsound

[Douglas Blake]

Thank you all in the much needed schooling on what brands to buy and which ones to avoid. After troubleshooting the amp, I found out that it was actually a faulty power brick. Douk Audio 150W 24V/6A AC/DC Power Supply Adapter Transformer US/EU/UK/AU Plug | eBay

My experience with both EBay and Douk audio are not good. EBay seems to have a lot of marginal stuff that is likely returns bought as pallet lots. I've had a much better experience with Amazon and often at lower prices.

I suppose I should've been more suspicious when it claimed it is a 'Real' 24V@ 6A power supply. The electrical outlet plug is not grounded, and it is very flimsy. One review left said that it was noisy.
I tested the amp with a car battery which was out the car and played music through it. At the minimal level, there wasn't any interference or whistling.

Mark's comments about setting the chips up as Master/Slave to synchronize the clocks are right on point. You will get a beat tone between the channels on a mono signal if you don't. Sadly many of the dirt cheap versions of this two chip amp don't do that.

Running it on 12 volts isn't a good comparison. At 12vdc you're likely only getting about 5 or 6 watts per channel out of it. It will also be prone to premature clipping which can seriously cloud your results.

Here is a power brick you can trust... Supernight 24v 5a
Something to understand about these little SMPS bricks is that they are not intended to be connected and disconnected frequently. In both the supply and the amp, the large bulk capacitors cause a rather sizeable inrush of current when you first plug them in. This inrush will, over time and repetitions, seriously degrade the lifetime of your supply. Best bet is to hook it all up and leave it that way.

I would like to also replace the capacitors based on everyone's consensus. There are ten 470uf 35 V capacitors. 5 have both leads connected to the positive portion of the circuit board while the other five have the negative lead going to the negative and the other going to the positive etching.

That's weird. Have you confirmed this with a meter? If you are right, it's just a waste of money putting 5 of those caps in there...

I don't know what the purpose is of that is or how to figure out the total capacitance to add in one large capacitor. At first, I thought it would be 4700 uf, but since both leads from the 5 of the capacitors are connected to the positive etch, I'm not sure.

The would give you ~2200uf at 35 volts, which should actually be enough.

If you are wrong and all caps are active, you would have 4700uf at 35 volts which is more than adequate.

It's the 25 volt caps you gotta watch out for.

And Douglas, if after all the capacitor swapping and it all blows up in my face, I'll gladly buy a Senucn amp if you approve! They look really well made and cost the same for what I paid for the Nobsound amp and power supply.

I think you'll probably be happier with the Senucn, but in the end it is strictly your choice.

 

[Douglas Blake]

Many thanks for this overview that is useful for our less experienced members.

No worries! Always glad to help out.

 

[ontariomaximus]

It's not my experience. I looked at quite a range of these amps with a number of different chips and configurations and figured out early on that Douk audio and it's brands aren't the way to go. Just looking at their board photos told me they were not likely to be well designed.

With a proper low ESR cap (or caps) in the bulk supply, inductor feedback should be minimized although it still makes it into the chip itself.

Of late I've narrowed this down to a short list of models that I buy.

For the bare bones I generally go with the senucn amp. It is well designed and nicely assembled for the price... A502 Review

If you want tone controls I mostly order the Linkfor tpa3116d2 Review

If you want bluetooth I order the Proster version (No Review, yet)

I find these to be of adequate quality, after upgrading the caps.

Speaker wise I usually match them up with entry level Fluance or Elac to make "soundbar killer" systems that everyone seems to like well enough.

well after reading your review, I couldn't help but order one of the A502's for cdn$72.99!

 

[FauxFrench]

well after reading your review, I couldn't help but order one of the A502's for cdn$72.99!

I only read "$72.99" (assuming us$). When it is cdn$ and one cdn$ is 0.75 of a us$, I see very little reason to bother with upgrade of a Nobsound or similar. When I buy a "bare-board" amplifier at a very low price, I expect to do some experiments and modifications. When I buy a finished product it is because I mainly expect to use it that way and not having to modify it first.

 

[Douglas Blake]

well after reading your review, I couldn't help but order one of the A502's for cdn$72.99!

I'm not here to sell stuff but that is a pretty good little amp.

You won't need to update the caps and the power supply that comes with it is plenty good enough. Enjoy!

 

[Douglas Blake]

I only read "$72.99" (assuming us$). When it is cdn$ and one cdn$ is 0.75 of a us$, I see very little reason to bother with upgrade of a Nobsound or similar. When I buy a "bare-board" amplifier at a very low price, I expect to do some experiments and modifications. When I buy a finished product it is because I mainly expect to use it that way and not having to modify it first.

It's only $51.99 in US dollars.
I used Canadian links so that you would have access to my reviews. (Amazon propagates US reviews to Canada but not vice versa.)

Here's the US link ... Senucn Audio USA

There's no need to do any upgrading on this amp. The ones I've been getting lately have 50 volt caps and good quality supplies with them.

 

[durkla18]

Looking at post #31: New Breeeze Audio TPA3116 2.0 100W dual chip

I would like to change the capacitors to the correct value and type. I am considering these: C330C105J5R5TA KEMET | Capacitors | DigiKey

And please forgive me, I am having a hard time figuring out how many I need. From chremann's post it says: " Internally generated gate voltage supply. Not to be used as a supply or connected to any component other than a 1 μF X7R ceramic decoupling capacitor and the PLIMIT and GAIN/SLV resistor dividers."

From this I'm presuming I need 6. Is this correct?

 

[ubergeeknz]

Looking at post #31: New Breeeze Audio TPA3116 2.0 100W dual chip

I would like to change the capacitors to the correct value and type. I am considering these: C330C105J5R5TA KEMET | Capacitors | DigiKey

And please forgive me, I am having a hard time figuring out how many I need. From chremann's post it says: " Internally generated gate voltage supply. Not to be used as a supply or connected to any component other than a 1 μF X7R ceramic decoupling capacitor and the PLIMIT and GAIN/SLV resistor dividers."

From this I'm presuming I need 6. Is this correct?

Replace which capacitors?

 

[durkla18]

Hi ubergeeknz, Thanks for responding!
The six 2.2uf capacitors near the heat sink in his picture were the ones that I was going to change. What chermann wrote was confusing to me, I'm probably just overthinking it though.

 

[ubergeeknz]

Hi ubergeeknz,Thanks for responding!

The six 2.2uf capacitors near the heat sink in his picture were the ones that I was going to change. What chermann wrote was confusing to me, I'm probably just overthinking it though.

Ah I see

Yes you could use the part you specified

It should have better performance for hf hash. But it seems the caps are quite far from the pins which isn't ideal.

 

[durkla18]

ubergeeknz,Thanks for that important detail! I used my micrometer and the lead spacing is only 2.1 to 2.2 mm max. That would definitely be a mess. Unfortunately, the closest caps with a lead spacing for 1uf in the X7R spec measure 2.54mm and the minimum quantity is 500.

Would the longer leads cause more noise than the caps that are already on there?

 

[ubergeeknz]

ubergeeknz,Thanks for that important detail! I used my micrometer and the lead spacing is only 2.1 to 2.2 mm max. That would definitely be a mess. Unfortunately, the closest caps with a lead spacing for 1uf in the X7R spec measure 2.54mm and the minimum quantity is 500.



Would the longer leads cause more noise than the caps that are already on there?

I was referring more to the tracks on the PCB. The lead length will be negligible compared to that anyway.