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Topics - mydementia

#1
This one's on clearance at PartsExpress...
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=129-075&ctab=14#Tabs
Will it work?
Looks like it has a pair of secondaries 16-0-16 rated at 0.5A on each side... I can't tell how much current the LM3886 'wants' from the data sheet... I see plots with supply voltage vs current - these currents are all in the 60mA range... then I see the 7A min in the table at the beginning...

Thanks in advance!!
Mike
#2
Amplifier Discussion / Finally finished my LM3886
June 22, 2007, 03:32:11 PM
Hi guys.
Just wanted to send out a special thanks for all your help in getting my LM3886 chipamp going.  I spent this morning assembling/wiring it.  Worked great the first time I turned it on!!  I wired the level pot backwards (no biggie) but everything else was just fine.  Very neutral clean tone - really shows the speaker/cab/guitar 'sound'.  I was a little surprised that there wasn't more output volume available - but I didn't mess with the I/O resistors... just added the level pot (not like there's not enough volume...).  I'm sure it would be louder running into 4-ohms instead of my 8-ohm Swamp Thang...
I put together a little webpage documenting my components for future newbie builder reference.  Have a look.

http://www.freewebs.com/mydementia/LM3886/myLM3886amp.htm

Thanks again!!
Mike
#3
Hi Guys.
I've been highly distracted with all the new stompboxes over on Aron's forum, but am finally getting back to this project.  I soldered up my chipamp.com boards last night - what a joy!  I bought the mono kit from Brian a couple months ago... very professional looking. 

So...
1) I bought this transformer from PartsExpress following this forum (and Brian at chipamp.com) recommendations:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=122-615
I'm still not satisfied with my enclosure - but really want to put this beast together.  I want to build it up on a wood block just to get it all working... so my question here is about grounding... Am I creating my 'star' grounding from the 'ground' pole of my AC Jack? 

2) The 10000uF caps on the power board scare me... Do I need to treat them as high-voltage power caps (using a 5W, 10ohm resistor to the positive lead with the other end clipped to ground) - or are they more innocent than I think?  I just don't want to get dead... ;)  Other 'drainage' techniques appreciated...

Thanks for looking.
Mike
#4
Hi guys.
I'm tired of hauling my tube amp to my buddy's house for practice so I'm going to finish my other speaker cab and build an LM3886 amp (got the chip with my last Futurlec order...) to leave there (that way, I can bring my pedal-du-juor or my SansampGT2 for a preamp). 
I started digging around for a transformer and wonder if this one will work:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=129-035

Also, regarding heat sinks... how big does it REALLY need to be?  The two in JoeCool's pictures (sticky thread in this forum) are HUGE!!!

Thanks for looking.
Mike