Yup.  I have prototype boards, but the only difference really is that mine are just a basic PCB and the production boards will be colored and labeled etc.

So do I    I spent countless hours reading chipamp threads on diystompboxes a few months ago before I built my amp.

First - Have a good power supply circuit and a big enough/proper voltage transformer
Second - Big heatsink, there is no such thing as too large of a heatsink

Proper heatsink size for two LM1875 chips, or one LM3886:


Overkill(which isn't a bad thing though):

Ah, RDV got you in here 

First off, welcome to the board RG!  Secondly, those are all great ideas!  I'd like to see our preamp(s) use those features.  How would you protect your inputs from stuff like that?

Now hosted on ssg server.

How much is ample?  Like...47,000uF caps? or are we talking 1500uF caps?  I'm ok with either.

Thats what my lm3886 uses, two 10,000uF 50v caps.

Huge caps are fine with me!  haha, I love the way they look anyway.  I like the looks of this circuit.  If you build it and like it, I'd like to hear about it.  I think if we just changed the tone stack to a marshall style one I would be all set to use it for my lm3886 amp.  From my research, it seems the lm3886 circuit wants around +/-25v input.

I'm not sure what chip you'd want to use for a 5w application...I definetly wouldn't use a TDA2003, I've already posted about how I didn't like that too much.  What type of power source are you going to power this thing with?  That should help narrow down possible chips.  Maybe even a lm1875, it goes as low as 16v (+8/-8), you could do +/-9v with a couple 9v batteries.  Doing that would give you about 4watts of power, should be fine.  To get 5w it looks like you'd need around +/-10v. 

As far as heatsinking goes, in an application like that, an 8" piece of this should do it:


Probably less than that would suffice, but its better to have more than less.  You can get that from alltronics.com for about $2

This sounds like something that could work with a lm3886.

I'm really looking to build a decent preamp so that my lm3886 can be a stand alone amp...

I'd love to go more simple actually.  The simpler the better.  At least to start with.  What I want to see is treble, mid and bass control.  No need for distortion or reverb to start with.  I know for my amp I'd be fine having it as a "clean" amp, then I can just throw pedals in front of it and have as much distortion as I want.  I normally find that I don't like the built in distortions on amps that much anyway, with the exception of a few higher end amps.

Well, I never email him really.  And when I do it takes FOREVER to get one back.  I talk to him on aim.