Psu Lm3886

Mayday · 31st March 2007, 02:04 PM

I'm going to build a "boombox" for my brothers doughter, using two LM3886, two fullrange elements, and a volumepot in the same box.
I'll be using a pair of RCA inlets, and a 3,5mm jack for her mp3 player.
This won't need a whole lot of power, my question is, is a 150VA 2x15V~ a big enough transformer?

AndrewT · 31st March 2007, 02:26 PM

Hi,
150VA can support upto 100W of output.

15Vac will give about 20 to 22Vdc.
This results in about 15W to 20W into 8ohms or about 25W to 35W into 4ohms.
Seems like plenty of noise for an MP3 player.

It will sound a lot louder than those advertised as 1000W of pmpo power.

Have a look at that other thread on hum in a two channel chipamp. He has a solution that works.

Mayday · 31st March 2007, 02:41 PM

Thanks for the answer!
I've gotten rid of my hum simply by going dual-mono all the way incl trafos.

Mayday · 31st March 2007, 03:02 PM

BTW, just hit me, I will be using a single trafo for the two LM3886 in the boombox, but only one psu-board, so I should be fine right? When it comes to hum that is.

ppcblaster · 31st March 2007, 04:22 PM

AVEL Y236652 250VA 25V+25V TOROIDAL TRANSFORMER

this would give me 35Vcc, Please give me your opinions and

advise to power a BrianGT stereo kit.

Mayday · 31st March 2007, 04:36 PM

If it's a stereo kit, just hook the secondarys with a dot in the datasheet to the underlined AC on the psu card, and the others to the not underlined AC on PSU, just remember to keep them paired.
One pair of secondarys goes to underlined AC1 and AC1, the other pari goes to underlined AC2 and AC2.

Did I make any sence?

AndrewT · 31st March 2007, 04:44 PM

Quote:

Originally posted by AndrewT
Have a look at that other thread on hum in a two channel chipamp. He has a solution that works.

Quote:

Originally posted by Mayday
I've gotten rid of my hum simply by going dual-mono all the way incl trafos.

My memory is like a sieve, I could have checked to find that it was you who found the silence.

Mayday · 31st March 2007, 04:46 PM

That's like me, memory like a goldfish...one lap around the bowl, and "hey! what's this?"

ppcblaster · 31st March 2007, 04:48 PM

I need to order a tranformer

Is the AVEL Y236652 250VA 25V+25V TOROIDAL a good choice?

Thank You

Mayday · 31st March 2007, 04:48 PM

BTW, I think someone else said it first, about dual trafos i meen.

31st March 2007, 02:04 PM	#1
Mayday diyAudio Member Join Date: Mar 2004 Location: Sweden	Psu Lm3886 I'm going to build a "boombox" for my brothers doughter, using two LM3886, two fullrange elements, and a volumepot in the same box. I'll be using a pair of RCA inlets, and a 3,5mm jack for her mp3 player. This won't need a whole lot of power, my question is, is a 150VA 2x15V~ a big enough transformer?

31st March 2007, 02:26 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, 150VA can support upto 100W of output. 15Vac will give about 20 to 22Vdc. This results in about 15W to 20W into 8ohms or about 25W to 35W into 4ohms. Seems like plenty of noise for an MP3 player. It will sound a lot louder than those advertised as 1000W of pmpo power. Have a look at that other thread on hum in a two channel chipamp. He has a solution that works. __________________ regards Andrew T.

31st March 2007, 04:22 PM	#5
ppcblaster diyAudio Member Join Date: Jul 2006	AVEL TOROIDAL TRANSFORMER AVEL Y236652 250VA 25V+25V TOROIDAL TRANSFORMER this would give me 35Vcc, Please give me your opinions and advise to power a BrianGT stereo kit.

31st March 2007, 04:48 PM	#9
ppcblaster diyAudio Member Join Date: Jul 2006	Sorry, I want advice on the power requirements I need to order a tranformer Is the AVEL Y236652 250VA 25V+25V TOROIDAL a good choice? Thank You

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31st March 2007, 02:41 PM	#3
Mayday diyAudio Member Join Date: Mar 2004 Location: Sweden	Thanks for the answer! I've gotten rid of my hum simply by going dual-mono all the way incl trafos.

31st March 2007, 03:02 PM	#4
Mayday diyAudio Member Join Date: Mar 2004 Location: Sweden	BTW, just hit me, I will be using a single trafo for the two LM3886 in the boombox, but only one psu-board, so I should be fine right? When it comes to hum that is.

31st March 2007, 04:36 PM	#6
Mayday diyAudio Member Join Date: Mar 2004 Location: Sweden	If it's a stereo kit, just hook the secondarys with a dot in the datasheet to the underlined AC on the psu card, and the others to the not underlined AC on PSU, just remember to keep them paired. One pair of secondarys goes to underlined AC1 and AC1, the other pari goes to underlined AC2 and AC2. Did I make any sence?

31st March 2007, 04:46 PM	#8
Mayday diyAudio Member Join Date: Mar 2004 Location: Sweden	That's like me, memory like a goldfish...one lap around the bowl, and "hey! what's this?"

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