lm3886 builds

[scaesic]

anyone done one for a practice amp?

im looking for a poweramp project for a practice amp, i want something easy but super clean to be driven by the amz mosfet boost.

is this what im looking for?

i dont mind spending a little more dollar for something thats going to be voiced better for guitar/less distortion.

[Meanderthal]

 Yes(not me though), and quite recently too.

Details here

(Input lm3886, you will be richly rewarded)

[petemoore]

  Doesn't matter as much to me which amp as which speaker.
 I was jammin' on my tube amp with my PB, echo, phase, dist, comp, boost, octave.
 I decided to try my new [I have an old one, as in one week], LM3886tf build on the PB effects/Guitar.
 Works great.
 period.
 Of course the two 12'' greenbacks being a big part of the sound.
 Impressive, very very good in general and for an SS unit, of course *different than tube, great little amp ! I thought for some reason a chip-amp would be 'slouchy' in some respect..but, reading the specs and stuff...not at all!
 Yupp, sounds great, does stuff the Tubes don't....
 1/2 OT I just pulled it off of PA amp duty, I've got 2 new 50wRMS titanium, ferro cooled Compression Drivers [and horns] coming Monday'...building up the PA action !!! I was going through all my old half baked, toasted, coils literally falling out of the HF drivers...lol...all six of them [1 used to be 'beefy']...and did what I did last time for PA...double up on the HF driverz, I like my high end clean, reliable, and with 'reserve power handling'...that should do it.
 The amp itself is like an 'addendum' to the power supply [the transformer equates to 'expensive or free', I used the free ones], I burnt some 1n4003 diodes, and opted for the Huge Rectifier diodes, they're holding!
 Other than that, the heat sink...I wayyy overkilled on the first one, this amp though has a 4x4''x 1'' HS, and I haven't really warmed it up yet.
 I've seen/played/tested/heard about lotsa amps, this one is super low noise, and quite the responsive little beast. Power's up 2x12''ers, will Crank 1x12''.

[tcobretti]

Check here:

http://generalguitargadgets.com/index.php?option=content&task=view&id=185&Itemid=210

and

http://www.ssguitar.com/

[grapefruit]

I've seen several commercial guitar amps that use the LM3886 and they sound about as good as any other SS design for the same money. The main differences are in the preamp and speakers for SS guitar amps.

Cheers,
Stew.

[R.G.]

Pete speaks the truth.

There's little reason to try to build a discrete power amp or find a better low distortion amp in the 20W to 50W category with the availability of the LM3886. It's cheap - used ones can be had for $1.99, new ones are under $6.00 - and it's good, as the hifi clone people make "Gainclones" and speak of them in the loving tones usually reserved for tweako solid-silver/polypropylene/teflon/oxygen-free stuff. A good power transistor costs $1.50-$3.00 each, and you need a pair, so the LM3886 costs about the same as just the output transistors in a discrete design.

And it's rugged, relatively. It self protects thermally and against short circuits and abusive loads. The only simple way to kill it is to put too much power supply voltage into it.

As Pete notes - it's the POWER SUPPLY that matters. You want a power transformer of 42 - 48 Vac center tapped or less. Any more is tempting the voltage gods to kill your chip. You want perhaps 2A current. You want filter caps of at least 3000uF, preferably 4700uF/50V. You want a 10A or better bridge rectifier. The power amplifier is just a wart on the power supply.

[scaesic]

ok, this is to replace a commercial tda2030 based amp which i really dont like. i know what pete is saying about the speakers, im gonna upgrade to eminence delta demons at the same time.

originally i was going to keep the ps and replace the power amp, whats the difference between the lm3886 and the tda 2030 in terms of sound? is what im planning completely pointless? i didint want to toy with the power supply because im always a bit scared to mess in that area.

iv read geos power supply basics for effects, any other good resources on ss amp power supplies?

[petemoore]

lm3886 and the tda 2030 in terms of sound?
  They are both from very similar breeding pools. I haven't tried an 2030, I guess it's bark is very similar to the an LM's, given the same stimulus and scenario. according to The data sheets and build reports..and these can probably tell this comparison in better detail and accuracy.
    is what im planning completely pointless? i didint want to toy with the power supply because im always a bit scared to mess in that area.
  I don't recommend toying with potentially lethal voltages, 'always a little bit scared' is a good thing to recognize...[even now, so am I], this fear is for well founded reasons.
  Crate Power Block..used to be 79 bux, perhaps you can cajole a new one for that somewhere or find a good used one.