Both lm3886 boards connect to the one supply . that is the factory setup and its works. however, I cannot drive the amps with any of my lab supplies. They all connect the same . One supply - 2 boards

 

So what is "neg"?

A picture would help.

The factory power supply is a standard DC output supply, 26v DC + - & ground
ebay link ......

.http://www.ebay.com/itm/320721441729?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

Test that PM amplifier with another capable PSU.

Have you current limited your PSU? What is the setting?

yes I have set the current to 2amps ,,3amps ,6amps 10amps and no go. I would like to think DC is DC. but not in this case.

I have tries 4 different PSUs and the same result
hp6267b
lambda 345a
Kepco JQE 36-15
HP 6289a

 

I took a current reading on the pos terminal in series with the factory power supply. only 70ma draw . so it isn't drawing that much current.
so its not the amp rating of the lab power supplies thats causing the problem. It must be impedance related or something.

 

The HP 6267B is a single lab supply. From the pictures in your ebay link, it is quite clear that the LM3886 module needs +26 V, ground and -26 v.
Your lab supply is only supplying + 26 V.
I don't know how to explain it clearer.

 

The HP 6267B is a single lab supply. From the pictures in your ebay link, it is quite clear that the LM3886 module needs +26 V, ground and -26 v.
Your lab supply is only supplying + 26 V.
I don't know how to explain it clearer.

I get it ! finally . So the solution is to use " 2 lab power supplies" and jumper them accordingly to output +26 and -26 . I guess that is the reason for dual power supplies.

thanks I will try that !

 

Look at the pretty pictures in the post #22 link. The amplifier boards have three power input pins, V+, GND, V-. The power supply board has three power output pins, +V, GND, -V. As mentioned in posts #4 and #6 (!!!), a single output power supply will not operate these amplifier boards. All four of the power supplies listed in post #16 are single output supplies. One at a time, none of them will work. The supply in the link is a single device, but it is a dual supply. It has two power outputs, not one. The amplifier boards need two power inputs, not one. That is why they work with the intended supply. That is why they do not work with a single lab supply. Another 25 posts will not change this.

ak

 

I get it ! finally . So the solution is to use " 2 lab power supplies" and jumper them accordingly to output +26 and -26 . I guess that is the reason for dual power supplies.

YES! At last!
Just make certain that the outputs from the lab supplies are truly floating (they usually are, but earth connections can make trouble).

 

Look at the pretty pictures in the post #22 link. The amplifier boards have three power input pins, V+, GND, V-. The power supply board has three power output pins, +V, GND, -V. As mentioned in posts #4 and #6 (!!!), a single output power supply will not operate these amplifier boards. All four of the power supplies listed in post #16 are single output supplies. One at a time, none of them will work. The supply in the link is a single device, but it is a dual supply. It has two power outputs, not one. The amplifier boards need two power inputs, not one. That is why they work with the intended supply. That is why they do not work with a single lab supply. Another 25 posts will not change this.

ak

ya ya ya ! well anyhow I got it to work with two discrete lab power supplies thanks to Benta. Thank you Benta for being patient .
all I had to do is jumper the output terminals on each supply to output the required +26 and -26 and now the universe is in order and perfect !

 

YES! At last!
Just make certain that the outputs from the lab supplies are truly floating (they usually are, but earth connections can make trouble).

right now i am earth grounded and it sounds great , however, I will take your advise and try floating them.

 

If it works, don't bother. Your supplies are floating (as they should).
At least you've learned something about dual supplies.

Benta.

 

absolutely ... this is the way I learn by experimenting , I just couldn't let go of this one . Some things like this will drive me crazy until resolved .
now I have a good reason to buy another psu to add to the collection . Thank you Benta