Finished my lm3886

[Joecool85]

It's not a wicked looker, but its freakin' loud!

[Connoisseur of Distortion]

holy crap, that much heatsink??? it's massive!!!

[BrianGT]

Looks good!  It is overheatsinked, but it is definately better than having too little   Also allows for adding a lot more modules to it in the future for more power.

Good job!

--
Brian

[Joecool85]

Yeah, I figured I would get the huge heatsink since it was cheap on eBay, and that way I can have like...2-4 chips on there no problem.  It barely gets luke warm right now 

I also used a 250va transformer which is overkill for that too.

[petemoore]

  Hard to tell how big those pliers are..
 Perhaps you could give the amp dimensions so I can get a better idea what size.
 Awesome...loud...that's always nice in case you're wanting headroom... .
 PDCool. Looks like a nice item to have.

[Joecool85]

The enclosure is 12x8x4.  That doesn't include the heatsink.

[Connoisseur of Distortion]

i intend to make one of these soon. my heatsink is much smaller, but probably sufficient. If not, i have a little fan to top it off! 

would an 80 VA transformer be suitable? i expect a resounding "no", but...

[Joecool85]

I'd say its too small.  RDV got away with a 96va, but I personally recommend no smaller than a 160va.  All that will happen though is that you won't get full power, and if you push it hard enough you will overheat the transformer and kill it...but if it's what you got and you don't want to buy one, I'd give it a shot.  How many volts is it?

[Connoisseur of Distortion]

i'll be running the tranny at 30 V, 2+2/3 A. So, post rectification, i'll have +/- 42 V rails. if i understand this data sheet right, that means it'll want to kick out 80 watts? ouch. maybe i should find a new transformer...

[RDV]

Looks good!  It is overheatsinked, but it is definately better than having too little   Also allows for adding a lot more modules to it in the future for more power.

Good job!

--
Brian

It's not really oversinked for a guitar amp, for a stereo amp, yes. I probably pushed him in that direction. If he wants to add another LM3886 though he's set and ready heatsink and transformer-wise.

Regards

RDV

[RDV]

i intend to make one of these soon. my heatsink is much smaller, but probably sufficient. If not, i have a little fan to top it off! 

would an 80 VA transformer be suitable? i expect a resounding "no", but...

I used a 36VCT 56VA tranny at first and it was as loud as a practice amp should ever be. R.G. Keen has said that 1VA per watt will work in most cases. It's not ideal, but you will get sound. It never did heat up that much either, though I didn't try to gig with it or anything.

Oh, and don't skimp on the heatsink if you plan to play guitar through it. Just trying to save you some trouble later. It doesn't have to be as big as Joecool used, but it should bigger than a CPU heatsink(even w/ a fan).

RDV

[RDV]

Good job Joecool!

RDV

[Joecool85]

Thanks RDV, I'm happy with it.

[brad]

Did you use thermal grease between the chip and the heatsink?  I haven't tried it yet, but I figure a heatsink is only as good as the contact between itself and the surface it's supposed to be cooling.

[Joecool85]

Yup.  Silicon stuff from radioshack.