Anyone have this LM3886 board or schematic?

[auriga2001in]

Hi,
I have a couple of these boards and was wondering if anyone has experience with them?
It would be great if you can share the schematic so I can understand and debug.


LM3886 Dynamic Feedback amplifier board (MFB) +30-35V | eBay

 

[soongsc]

Hi,

I have a couple of these boards and was wondering if anyone has experience with them?

It would be great if you can share the schematic so I can understand and debug.





LM3886 Dynamic Feedback amplifier board (MFB) +30-35V | eBay

Dynamic feedback?

 

[TallTexan]

Kind of hard to read, but this Ebay listing: LM3886+NE5532 DC Servo Mounted 2x68W Current Dynamic Feedback Amplifier Board has a schematic

 

[tomchr]

Neat. I've seen the same topology in solid state guitar amps as part of the "tube sound" emulation circuitry.

Whether the eBay implementation works well is anybody's best guess. For $15 you're not out much if it doesn't work all that well. Just run it on a current limited supply and use a signal generator and resistive load the first time you fire it up.

Tom

 

[auriga2001in]

So, it's a variable impedance circuit by including the speaker impedance in the NFB loop. And, 2 op amps for nulling dc offset.
The sound seems ordinary and comparable to the stock XY board equivalent.

 

[AndrewT]

if you do not know how to assemble components or cannot read the pinpoint on the pcb board, we suggest you google more information before you buy.

And they promise not to to give the Builder any customer support !

 

[scottjoplin]

Kind of hard to read, but this Ebay listing: LM3886+NE5532 DC Servo Mounted 2x68W Current Dynamic Feedback Amplifier Board has a schematic

How do you know it's the same?

 

[Johnny2Bad]

Is this the same principle as discussed in this thread: ?

Joe Rasmussen "Trans-Amp" - 40 Watt Transconductance "Current Amplifier"

 

[auriga2001in]

Yes, the same concept. Here's an alternative board that works fine in my setup:
https://www.aliexpress.com/item/pcb-board-only-3886-hifi-board-power-amplifier-board-mono-3886-amp-single-lm3886-68w-amplifier/32398654954.html

 

[simon2a3]

Yes, the same concept. Here's an alternative board that works fine in my setup:
https://www.aliexpress.com/item/pcb-board-only-3886-hifi-board-power-amplifier-board-mono-3886-amp-single-lm3886-68w-amplifier/32398654954.html

How do you rate the sound? I'm new to chip amps - valves are my thing. Is this a reasonable place to start, or is the sound compromised? Thanks.

 

[AndrewT]

The sound quality depends on how you build it.
A bad build, or a bad board (=bad build), is likely to give a bad sound.

 

[auriga2001in]

How do you rate the sound? I'm new to chip amps - valves are my thing. Is this a reasonable place to start, or is the sound compromised? Thanks.

I use this board to power the woofers in my bi-amped setup (crossed at 234 Hz). I like the sound and the transients are good when compared with the stock LM3886 boards.
I have not tested this board with a 3-way speaker though.

 

[Elias Zacharopoulos]

Hi all
There is a thread here
http://www.diyaudio.com/forums/atta...00-lm3886-schematics-pcb-apex-supergc-sch-png
(but much better in my oppinion)
that reminds me strongly this thing. (Use pls "Search" function)
Elias

 

[simon2a3]

The sound quality depends on how you build it.
A bad build, or a bad board (=bad build), is likely to give a bad sound.

Thanks Andrew, point taken.

 

[simon2a3]

I use this board to power the woofers in my bi-amped setup (crossed at 234 Hz). I like the sound and the transients are good when compared with the stock LM3886 boards.
I have not tested this board with a 3-way speaker though.

Thanks for the context, sounds interesting.