NEW Nvarcher TPA3255 Mono Module with Flat Inductors. Measurements inside. $35

[daniboun]

Hi amigos,

I'm sharing a little discovery at a very reasonable price. I found this module particularly interesting, even though it doesn't seem to have a PFFB circuit. The components seem to be of good quality, especially the flat coil inductors. This module reminds me a bit of the 3E AUDIO 480-1-29A.
I don't have any information regarding the op-amps; I imagine they must be soldered under the PCB, but I'll do some research and when I have the information, I'll share it with you.

SPEC:


Report Item
Class D integrated circuit TPA3255
PBTL mode
2 ohms, 480W high power output, Class D low heat generation
Balanced input
Precision low-pass output network
Mono design
Power supply voltage: +18-53.5V
Output power: 150W/8 ohms, 260W/4 ohms, 480W/2 ohms
Size:90*80*20mm,Weight :160g
Undistorted output: 28.21V
Magnification: 11.98 times
Residual noise: 78.7uV
Signal-to-noise ratio: 111.4dB
THD distortion: 0.0028%
THD+N distortion: 0.0053%
Frequency response bandwidth: ±0.035dB

AP actual measurement data test power supply: no-load +46.6V full-load +41.6 with 8-ohm load

 

[MCH]

Thanks for sharing
Ufff that heat sink is tiny, and doesn't seem there is an easy way to attach anything different. Are there pictures from the back side in case?

 

[daniboun]

Thanks for sharing
Ufff that heat sink is tiny, and doesn't seem there is an easy way to attach anything different. Are there pictures from the back side in case?

Just updated the pictures, checkout

 

[berjine]

Interesting thanks

 

[Roland68]

Hi amigos,

I'm sharing a little discovery at a very reasonable price. I found this module particularly interesting, even though it doesn't seem to have a PFFB circuit. The components seem to be of good quality, especially the flat coil inductors. This module reminds me a bit of the 3E AUDIO 480-1-29A.
I don't have any information regarding the op-amps; I imagine they must be soldered under the PCB, but I'll do some research and when I have the information, I'll share it with you.

SPEC:


Report Item
Class D integrated circuit TPA3255
PBTL mode
2 ohms, 480W high power output, Class D low heat generation
Balanced input
Precision low-pass output network
Mono design
Power supply voltage: +18-53.5V
Output power: 150W/8 ohms, 260W/4 ohms, 480W/2 ohms
Size:90*80*20mm,Weight :160g
Undistorted output: 28.21V
Magnification: 11.98 times
Residual noise: 78.7uV
Signal-to-noise ratio: 111.4dB
THD distortion: 0.0028%
THD+N distortion: 0.0053%
Frequency response bandwidth: ±0.035dB

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AP actual measurement data test power supply: no-load +46.6V full-load +41.6 with 8-ohm load


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Are you sure there are any OPamps at all?

 

[Wickers]

I could imagine using it to drive the woofer of an active speaker. But just by looking at it, I wouldn’t dare assume it can handle the rated 480 watts for long. (Not that I ever listen to music at 480 watts anyway.)

 

[daniboun]

Are you sure there are any OPamps at all?

I asked the vendor....waiting for the answer

 

[KL....]

Thank you, @daniboun, with PFFB utilisation, do you mind asking the vendor? Perhaps pre/TPA3255 FB only, maybe post FB or other (local) form as mentioned by @Hayk?

The Coilmx Flat Wire Inductors look very nice....

 

[daniboun]

Thank you, @daniboun, with PFFB utilisation, do you mind asking the vendor? Perhaps pre/TPA3255 FB only, maybe post FB or other (local) form as mentioned by @Hayk?

The Coilmx Flat Wire Inductors look very nice....

View attachment 506436

I did not ask for the PFFB but it is not specified in the spec....will ask )
From the graph , the frequency response is well behaved, albeit with a slight rise at 20 kHz:

Regarding the op-amps, I haven't received an answer, but I wonder if there might be a bypass of the buffer... Unless they're located behind the heatsink.

 

[Roland68]

I did not ask for the PFFB but it is not specified in the spec....will ask )
From the graph , the frequency response is well behaved, albeit with a slight rise at 20 kHz:

Regarding the op-amps, I haven't received an answer, but I wonder if there might be a bypass of the buffer... Unless they're located behind the heatsink.

In fact, no op-amps are needed with this PBTL configuration, but a balanced connection is required. I would still recommend using an additional buffer, though. Only one dual op-amp is needed for that.

However, looking at the board and reading the description, three questions come to mind.
- The description mentions a "Precision low-pass output network." Does the amplifier not transmit the full frequency range? Or do they only mean the output filter of the power amplifier stage?
- Next to the balanced input are three 2-pin connectors. Unfortunately, the underside is labeled in Chinese. What are these connectors for? Or are they jumpers for the low-pass filter setting? (*)
- On the other side of the heatsink are three solder pads. Two of them are labeled 12V and Ground on the underside. Is this the power supply for an external buffer board? Does this buffer board already exist? What is the third pin for?

You don't need to worry about answering this, of course; it was just something I noticed.

(*) If I've translated correctly, the three connections are labeled as follows (from the inside out):
- Peak clipping/overheating
- Watch the opportunity
- Reset

 

[TurtlePaul]

I am always conflicted in these amps with 89 dB SINAD and no PFFB. Yes, they perfectly implemented the TI PBTL layout (but somehow don’t have an input buffer and maybe not DC blocker caps?) and that noise and distortion will be inaudible but we have so much more now.

 

[daniboun]

In fact, no op-amps are needed with this PBTL configuration, but a balanced connection is required. I would still recommend using an additional buffer, though. Only one dual op-amp is needed for that.

However, looking at the board and reading the description, three questions come to mind.
- The description mentions a "Precision low-pass output network." Does the amplifier not transmit the full frequency range? Or do they only mean the output filter of the power amplifier stage?
- Next to the balanced input are three 2-pin connectors. Unfortunately, the underside is labeled in Chinese. What are these connectors for? Or are they jumpers for the low-pass filter setting? (*)
- On the other side of the heatsink are three solder pads. Two of them are labeled 12V and Ground on the underside. Is this the power supply for an external buffer board? Does this buffer board already exist? What is the third pin for?

You don't need to worry about answering this, of course; it was just something I noticed.

(*) If I've translated correctly, the three connections are labeled as follows (from the inside out):
- Peak clipping/overheating
- Watch the opportunity
- Reset

This is a stand alone module (RTR) : you dont need any extension board. As you can see : as per measurements it covers the full frequency range ) so the Precision low-pass output network is probably a marketing label )

I am pretty sure that the module is sold with some "user manual" , should be nice to get it.

 

[daniboun]

Where can I buy this amplifier?

Sure :

https://fr.aliexpress.com/item/1005009959236571.html

 

[daniboun]

I am always conflicted in these amps with 89 dB SINAD and no PFFB. Yes, they perfectly implemented the TI PBTL layout (but somehow don’t have an input buffer and maybe not DC blocker caps?) and that noise and distortion will be inaudible but we have so much more now.

I completely agree. Let's say I see an opportunity here to build a dual-mono amplifier for under $130. The modules are sold for €35 and don't seem bad, hence this thread.))

 

[MCH]

I completely agree. Let's say I see an opportunity here to build a dual-mono amplifier for under $130. The modules are sold for €35 and don't seem bad, hence this thread.))

Dani, at this point you should be able to order a few PCBs to jlcpcb and build a 5 channel with pffb and everything you want for 100 euros

 

[daniboun]

Dani, at this point you should be able to order a few PCBs to jlcpcb and build a 5 channel with pffb and everything you want for 100 euros

RTR PCBs with all components ?

 

[MCH]

RTR PCBs with all components ?

Hot air gun and magnifying lens

 

[daniboun]

Amigos got the answer

"No OP amps on this module"

 

[Roland68]

Amigos got the answer

"No OP amps on this module"

I figured as much. So, only with a balanced connection and ideally with a buffer.
Of course, it also works with an input board that can convert single-ended to balanced.

 

[daniboun]

I figured as much. So, only with a balanced connection and ideally with a buffer.
Of course, it also works with an input board that can convert single-ended to balanced.

The question we can ask ourselves is: what is the default gain if we attack the module directly?

We could use a buffer of this type if needed: