3E Audio 260-2-29A : TPA3255 / HA3588 CoilCraft / PFFB Fully differential.

[xschop]

From Jeff's store. Brand is CNLINKO

 

[gsusay]

From other reference/drawing I found that XLR pin #1 is ground, #2 is POS signal and #3 is NEG signal. Did you have issue with your XLR connections (judging from your pic)? Thank you

Hi, I think wiring is all right. I've checking other builds and the wiring is the same. Check the amp reviewed here that 3e audio sent. I've seen in audiophonics another one connected the same way. I've playing music the whole morning and it's sounds awesome . There's a click when the dac switches on but it's not an amp's issue it happens in the sub amp too. It is a dac thing. I connect the ground to the chasis as you can see in my pic.
I'm very happy with this amp . It's sounds flawless.
Thanks

 

[rusnak666]

This is my wiring...

 

[xschop]

This is my wiring...View attachment 414171

Are your panel mounted XLR connectors male or female?

 

[rusnak666]

Are your panel mounted XLR connectors male or female?

Female, see picture...

 

[xschop]

Ok, good to know, as that is how Neutriks are wired. How is yours sounding and what power supply?

 

[rusnak666]

Ok, good to know, as that is how Neutriks are wired. How is yours sounding and what power supply?

I use it with mornsun LOF550-20B48, I temporarily replaced my hypex ncore nc502mp with it in my living room and I don't hear any difference, speakers are canton vento 896.2, subwoofer svs pb1000 and dac sabaj a20d 2020

 

[DaN0]

I just finished a 6ch build and fired it up last night. Everything seems to be working correctly, but I noticed I'm getting a decent amount of "singing" from the boards themselves while testing with an 8R dummy load. Anything above 700Hz comes out of the amp modules (I haven't narrowed down which component is causing the issue, but it happens on all 6 channels). It doesn't appear to be the power supply as the sound moves when I switch channels. It's a much higher level of singing than I've ever experienced before on an amp build, does anyone else's exhibit the same behavior?

 

[3eaudio]

@DaN0
can you try only power one board to see whether has same noise?

i am also confuse that 8R dummy load? how this connect to the amp and what equipment you use for the noise capture? did you connect to speaker?

 

[DaN0]

I just tried with only one board powered and it demonstrates the same behavior.

Regarding the dummy load, I'm using an ARCOL 8ohm 150W power resistor attached to a speakon plug. The amp makes the same noise regardless of what is connected (dummy load, real speaker, or nothing connected at all).

I'll message you a link to a video of the noise happening (while I change the frequency of the sine wave).

 

[antcollinet]

I'll message you a link to a video of the noise happening (while I change the frequency of the sine wave).

Can you do that with / without a load connected.

 

[DaN0]

There's no change in the behavior with or without any load connected (real speaker, dummy load, nothing plugged into the speakon jack)

 

[antcollinet]

There's no change in the behavior with or without any load connected (real speaker, dummy load, nothing plugged into the speakon jack)

Something else worth trying - disconnect all but one board from the PSU to eliminate any effects from components on another board.

 

[jlx]

It is a known issue in the industry that OCCASIONALLY a power supply does not get along with a particular class D module. For example I know of a top end Meanwell supply that hummed when connected to a Starkrimson amp module. It happens...Try a different psu

 

[olieb]

The amp makes the same noise regardless of what is connected (dummy load, real speaker, or nothing connected at all).

So it is not output related. It seems not to come from the PSU.
After you checked connecting only one module as @antcollinet proposed.
Does it change with frequency? Does it change with input level? Singing in idle?

 

[3eaudio]

@DaN0
i would suggest try this

1. unplug input 2 signal cable to verify one amp board
2. if the noise gone,then it is noise coupling from SMPS in experience
3. if the noise still there, just power one board in your enclosure means un-power other 2 boards
4. if the noise still there, take off SMPS and one amp board, place to some insulated material like a desktop, repeat test

btw,what is this? resister?

 

[CamRector]

By singing do you mean “hiss”?
What sensitivity are your speakers?
I made a 4 channel 3e that powers my high sensitive (112db@1m) compression drivers.
I have to stick my ear in the horn to hear any hiss.
I still wish we could lower the gain on these modules.

 

[Wolf11Man]

If you power more than one TDA3255 from one single power supply, there will be noise resulting from the slightly different switching frequency of the single amps.
Texas Instruments tells you to make one amp the master supplying it's switching frequency to the following slave amps.
Any decend amp module should supply contact to the corresponding pins. Maybe 3eAudio read and understood the data sheet and implemented this maste/ slave option. It is really not that complicated.
If not it is simple a question of how much the amps differ in frequency, some may make audible noise, others not. The power supply also has some influence on the audibility of this problem.
Even if you don't hear these frequency problem, it still may degrade the sound quality. So ask 3eAudio how to make the master/ slave connection with their product.
Here is a link to the TI information: https://www.ti.com/lit/an/slaa787/slaa787.pdf

I don't think it is wise to ignore such information from the manufacturer of a chip amp if you design amp modules.

 

[CamRector]

If you power more than one TDA3255 from one single power supply, there will be noise resulting from the slightly different switching frequency of the single amps.
Texas Instruments tells you to make one amp the master supplying it's switching frequency to the following slave amps.
Any decend amp module should supply contact to the corresponding pins. Maybe 3eAudio read and understood the data sheet and implemented this maste/ slave option. It is really not that complicated.
If not it is simple a question of how much the amps differ in frequency, some may make audible noise, others not. The power supply also has some influence on the audibility of this problem.
Even if you don't hear these frequency problem, it still may degrade the sound quality. So ask 3eAudio how to make the master/ slave connection with their product.
Here is a link to the TI information: https://www.ti.com/lit/an/slaa787/slaa787.pdf

I don't think it is wise to ignore such information from the manufacturer of a chip amp if you design amp modules.

They didn’t miss it at all.
I am just unsure how to implement the master/slave option and didn’t know what effect it would have.
I’m using a 51v 1200w micro audio powersupply to driver these boards (went big to possibly add more in the future)

 

[Wolf11Man]

Is there no description in the 3e manual? It is quite simple and only needs some bridge/ jumper changed and a two wire connection between the boards.

How exactly it is done for 3 modules is on page 2 and 3 of the linked manual. With pictures and all!