New BRZHifi TPA3255 finished 2.1 amplifier - controls don't make sense!?

[Ralferator]

I found this new amplifier on Aliexpress:

https://de.aliexpress.com/item/1005...earchweb0_0,searchweb201602_,searchweb201603_

What i like about it, is that it has 3 channels with one for a subwoofer. So if it had a frequency control for the Subwoofer, it would be ideal for me. But: Like it is the tone controls don't make sense to me. Do you guys have an idea how they are supposed to work?

It says for the tone controls:

No 1. High-Voice control for L/F-Channel - what is that supposed to be? L/F = low frequency? Doesn't make sense because of
No 3. Tone control for Subwoofer Output - ok - this could be a control for the low-pass filter of the Subwoofer then, but where is the volume-control for the Subwoofer then?
No 2. Low-Voice control for L/F-Channel

Could it be that the L/F-Channel is not the subwoofer-Channel then but the normal stereo channels? But what is No. 3 (tone control for Subwoofer Output) supposed to be then? Volume or control for the low-pass filter? Since they write that the subwoofer channel goes up to 200 hz (nothing about -db point though) this amp doesn't make sense without a controlable low-pass filter. But no control for the subwoofer volume also doesn't make sense.

Also - isn't that power supply way to small to power a pair of TPA3255 chips? By the looks it seems to be the same as the power supply in their 2.o TPA3255 amp.

Do you guys have an idea of how it works? Is it just a complete faulty desing?

 

[anon2k2]

I wonder if those are typos and the controls are L/R rather than L/F

 

[Nebbermind]

I wonder if those are typos and the controls are L/R rather than L/F

My guess too.

Tone controls are for L/R channels.
Sub control probably to change cutoff between 20~200hz.
Vol = master Vol control for all spkr connections

 

[Ralferator]

My guess too.

Tone controls are for L/R channels.
Sub control probably to change cutoff between 20~200hz.
Vol = master Vol control for all spkr connections

Still would be missing the Sub volume control

 

[andreasmaaan]

None of the chips they mention in the diagrams have inbuilt filters, so if there are adjustable filters, it's with components that are not listed in the diagram, i.e. I don't think you'll get a definitive answer as to what they mean by "voice control" and "tone control" without finding out from them or someone who has tested the unit.

 

[Panelhead]

Do not know what controls 1&2 do. But 3 most likely adjusts the corner frequency for the sub out. If a volume control this would need to be adjusted every time the volume was changed.
Most if not all active subs have a sensitivity control to allow matching the sub to the stereo speakers. Speakers and sub should track together if volume control works for all three.

 

[Ralferator]

Do not know what controls 1&2 do. But 3 most likely adjusts the corner frequency for the sub out. If a volume control this would need to be adjusted every time the volume was changed.
Most if not all active subs have a sensitivity control to allow matching the sub to the stereo speakers. Speakers and sub should track together if volume control works for all three.

But there is a powered output for the subwoofer. That's why it's made to connect a passive subwoofer. But then the Sub volume control is missing

 

[Panelhead]

Well in that case, there is no telling. If the labeling for the tone controls is incorrect, they also may not function correctly.
Active subs are just more appealing. Most have freq, sensitivity, phase, and even high pass outputs.

 

[tomtoo]

Reading in the glass sphere.

 

[renaudrenaud]

I use TPA3255 with great pleasure in the form of Texas Instruments EVM board (use 2 in mono and balanced).

I've read a lot of negative evaluations on the low cost copies from Ali (error in the schematic, wrong values etc...).

A friend of mine bought a TPA3255 from 3eAudio, less expansive than the Texas and he seems happy with it.

 

[tomtoo]

I use TPA3255 with great pleasure in the form of Texas Instruments EVM board (use 2 in mono and balanced).

I've read a lot of negative evaluations on the low cost copies from Ali (error in the schematic, wrong values etc...).

A friend of mine bought a TPA3255 from 3eAudio, less expansive than the Texas and he seems happy with it.

Iam sure the tpa3255 is a good chip. The problem is always the implementation. That can go from nice to real sh...t.

 

[renaudrenaud]

Iam sure the tpa3255 is a good chip. The problem is always the implementation. That can go from nice to real sh...t.

I had the chance to grab 2 cards with 50% rebate so it cost me 150$ for the 2 in 2017. At the moment I switched on the first card, I never went back to another amp.

I am sure Purify or other brands / technology are better, but I do not feel the need to spend any more penny in another solution. Just listen to music and enjoy.

 

[tomtoo]

I had the chance to grab 2 cards with 50% rebate so it cost me 150$ for the 2 in 2017. At the moment I switched on the first card, I never went back to another amp.

I am sure Purify or other brands / technology are better, but I do not feel the need to spend any more penny in another solution. Just listen to music and enjoy.

Why you should? Even the tpa3116 works well if the implementation is done well.:

 

[renaudrenaud]

Why you should? Even the tpa3116 works well if the implementation is done well.:

I agree, but TPA3255 sounds better (at least this is what I belive).

Beginning in 2012, I bought a lot of TPA3116 to compare them. Even a Suptronics X400 to slot it on the Raspberry Pi (working fine).

But the Elac DBR62 are power hungry and the TPA3255 is able to give them what they want.

 

[tomtoo]

I agree, but TPA3255 sounds better (at least this is what I belive).

Beginning in 2012, I bought a lot of TPA3116 to compare them. Even a Suptronics X400 to slot it on the Raspberry Pi (working fine).

But the Elac DBR62 are power hungry and the TPA3255 is able to give them what they want.

I dont know than we should compare a well implemented 3116 with a 3255 at 10W. Dont know if there is a difference? Sure is the 3255 has more power.

 

[lithoc]

I have this amplifier and I like it a lot .Let me explain the knobs

Treble - treble for stereo channel only (turn all the way to anticlockwise wise until click to turn off tone, much preferred )
Low - bass for the stereo channel

Bass is for subwoofer volume only

Volume for overall volume

There's design issued with this amplifier.

- power supply and amplifier board is connected via a very tiny wire. So whenever the amp being push hard . The amplifier will shutdown. It must be replace

- power supply is rated around 300w.
This amp have 2 x TPA3255 which means the power supply should be around 1000w

- tone control for stereo should be removed for simplicity sake

 

[Ralferator]

I have this amplifier and I like it a lot .Let me explain the knobs

Treble - treble for stereo channel only (turn all the way to anticlockwise wise until click to turn off tone, much preferred )
Low - bass for the stereo channel

Bass is for subwoofer volume only

Volume for overall volume

There's design issued with this amplifier.

- power supply and amplifier board is connected via a very tiny wire. So whenever the amp being push hard . The amplifier will shutdown. It must be replace

- power supply is rated around 300w.
This amp have 2 x TPA3255 which means the power supply should be around 1000w

- tone control for stereo should be removed for simplicity sake

So there is no Subwoofer low pass. That's bad if you want to integrate a passive Subwoofer

 

[raindance]

So there is no Subwoofer low pass. That's bad if you want to integrate a passive Subwoofer

Why? Most subwoofers have that. It's the high pass piece that's missing.

 

[Ralferator]

Why? Most subwoofers have that. It's the high pass piece that's missing.

In fact there are not many passive Subwoofers that i know of that have a low pass filter. If i would buy such an amp i would want to use it with a subwoofer driver built in a box. I wouldn't want to spend a lot of money for a passive low pass. The high pass filter is also missing. For me this amp doesn't make sense at all.

 

[lithoc]

So there is no Subwoofer low pass. That's bad if you want to integrate a passive Subwoofer

There's a 200hz low pass for the subwoofer