my first try at a LM3886 layout, any comments/suggestions?

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filholder

Member
Joined 2005
edjosh23,

Yeah you are probably right mate. However it just not very practicle for my setup and my missus who an interior designer seems to be alergic to visible wires.

I have found a solution anyway. I am building a solid copper shelf in the enclosure which the actual amp board will sit on. This will also act as shielding and the heat sink, its all gonna be a bit tight which makes this, my first audio project, a bit tougher than i had expected but hopefully the end result will look and sound good.


Will post pictures when i have got one channel together

Fil
 
M

mantisory

Member
Joined 2002
Hey guys.
I had posted earlier regarding the 300VA, 30/30 toroidal transformer i had purchased, which apparently is getting near the danger zone for the 3886 after rectification. So I am wondering...I have a Hagtech Bugle that requires 2 9V batteries, but I was thinking that I could somehow 'bleed' power off of the rectified PS to supply it..would this be possible and/or advisable?
The PS that Hagtech offers is +/- 15V at 0 to 100mA...
Thanks,
Mantisory
 
S

SheldonD

Member
Joined 2004
mantisory:

You can't bleed off the voltage but you could use the extra power (300VA is ample) to supply a regulated uing 15 volt regulators to the Bugle. In other words you are sharing the current capability of the transformer ( and diodes) . you cant lower the voltage to the power amp doing this.

the Voltage is still on the high side for your power amp, you might think of regulating it too, using adjustable ones like LM338.
 
BrianGT

BrianGT

Retired diyAudio Moderator
Joined 2002
chipamp.com
mantisory said:
Hey guys.
I had posted earlier regarding the 300VA, 30/30 toroidal transformer i had purchased, which apparently is getting near the danger zone for the 3886 after rectification. So I am wondering...I have a Hagtech Bugle that requires 2 9V batteries, but I was thinking that I could somehow 'bleed' power off of the rectified PS to supply it..would this be possible and/or advisable?
The PS that Hagtech offers is +/- 15V at 0 to 100mA...
Thanks,
Mantisory
Click to expand...

2x30vac should work just fine. After the diode drop, it will be just below the max voltage in the datasheet. However, this is a conservative rating, and you should be fine. I have a friend running a LM3875 gainclone with a 2x35vac transformer, without issues. I don't recommend exceeding 2x30vac, but a 2x30vac should work just fine.

--
Brian
 
BrianGT

BrianGT

Retired diyAudio Moderator
Joined 2002
chipamp.com
mantisory said:
thanks brian,
However, in the end, i suppose i wouldn't mind running my Bugle off the same tranny if i can...just have to figure out how to do it :)
B
Click to expand...

I found a pair of 24vct @ 1A, which would work great for the bugle. Drop me a mail and I can sell one to you for $9 (1/2 of retail). (should be able to ship it for $6 to canada)

PC 24-1000
http://www.belfuse.com/Data/DBObject/1.0-24.pdf

Drop me a mail if interested.

--
Brian
 
M

mantisory

Member
Joined 2002
Sorry if i am such a newbie (I think i need to get back to more reading basic electronics books), but i am not sure exactly how i would really use this..i mean, i guess i could run them in parallel off the mains with the GC, and then regulate it...is this what you are suggesting?
Byron
 
maxw

maxw

Member
Joined 2004
Well I finally got all mine together today and have been waiting to test the high-cap snubber version against the oh-so-last-year regulated version.......long story short, the regulated version seems to have far less controlled bass to me.

Maybe my post regulation wires are too long?
Has any one else directly compared them?
What were your thoughts?
 

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moving_electron

moving_electron

Member
Joined 2004
maxw said:
Well I finally got all mine together today and have been waiting to test the high-cap snubber version against the oh-so-last-year regulated version.......long story short, the regulated version seems to have far less controlled bass to me.

Maybe my post regulation wires are too long?
Has any one else directly compared them?
What were your thoughts?
Click to expand...

I posted a comparison here the other day.

I did not percieve a loose bass problem with the regulated vs. the unregulated high capacitance. I checked it out with some jazz with standing bass as well as load rock. The Green Day drummer gives the toms a pretty good work out on the American Idiot CD and it seemed very tight to me on the regulated. But the mains were crossed over to subs at 90Hz.

My wires from reg board to amp board are no longer than about 5.5 inches ( 14cm ). The regulated is implemented dual mono and has the carlosfm IGC values on Digi01 boards. In the test the unregulated high cap BrianGT 3886 was configured as a single supply to both channels.

If you are crossing to subs and comparing, keep in mind that the two amps you are comparing may have diferent gains and you therefore will have to adjust the sub volume to make the sub output the same for each main amp you are testing.
 
C

carlosfm

Banned
Joined 2003
The snubberized unregulated high cap. PSU (uff!) is the one to go, I've got to this conclusion some time ago (and I posted it).
It is better than the regulated PSU.
I recommend ya'all to update your amps.:usd:

It is also cheaper, much less work to build one, no heatsinks...
What do you guys want more?:p
 
maxw

maxw

Member
Joined 2004
moving_electron said:


I posted a comparison here the other day.

I did not percieve a loose bass problem with the regulated vs. the unregulated high capacitance. I checked it out with some jazz with standing bass as well as load rock. The Green Day drummer gives the toms a pretty good work out on the American Idiot CD and it seemed very tight to me on the regulated. But the mains were crossed over to subs at 90Hz.

My wires from reg board to amp board are no longer than about 5.5 inches ( 14cm ). The regulated is implemented dual mono and has the carlosfm IGC values on Digi01 boards. In the test the unregulated high cap BrianGT 3886 was configured as a single supply to both channels.

If you are crossing to subs and comparing, keep in mind that the two amps you are comparing may have diferent gains and you therefore will have to adjust the sub volume to make the sub output the same for each main amp you are testing.
Click to expand...

Excellent, thanks alot.

carlosfm said:
The snubberized unregulated high cap. PSU (uff!) is the one to go, I've got to this conclusion some time ago
Click to expand...

and thank you for your oppinion....

I am still testing :smash:
 
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