One LM1875 would be all you would need, I recommended it because depending on what he can find for a horn driver, he won't get enough volume out of the LM386 setup.  HOWEVER, I would definetly recommend trying the Ruby first.  Just find a good driver.  Also, for stompbox use a Ruby is better because as syndromet said, you can run it on 9v, no bipolar PSU to deal with and whatnot.

The ruby uses two lm386 chips to bring 1watt of power total.  With the proper horn driver it *could* be loud enough.  I would recommend a more powerful chip though, maybe something along the lines of a lm1875 (depending on voltage applied it can be up to 30watts RMS, or as low as 14 or something.)

21-0-21 is going to be a little closer than I would want to be on the max voltage of 60v.  21 + 21 = 42 x 1.4 = 58.8v DC.  If your line voltage was just a little high, it could easily put you over 60v DC.  While it probably does work fine in *most* circumstances, I would hate to say to anyone that it is totally ok to use it.

A little high voltage, not not high enough VA ratings.  21+21v is really the max you could run, so it *should* work. 

Ideally for a dual LM1875 setup you should have 18-20v secondaries and between 100-150VA rating.

Well, its about twice the VA rating you need for a dual LM1875 setup, but it should work great.  The voltage output is near perfect, so I'd go with it.  But if you can find one the same but with maybe...100-150VA that would be fine as well.  Of course, as I always say, it's better to have more than needed.  That's how I build my amps.

For $53 I could have this: http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=122-610 (18+18v toroidal) at my door. 


Shipping included I could get it to you (after it gets to me) in 4-6 weeks for $75 USD total, or in 4-6 days for $85 total.  Not a huge savings and it could potentially take a really long time to get it since it would have to get to me first and then get shipped again.

No links teemuk, he attatched pics.

Looks good btw.

The LM3886 kits from Brian come with resistors and spots on the PCBs for bleeding the caps.  Assuming he put the kit together properly, it's a pretty safe kit.

You did raise a good point about current as opposed to voltage on those caps though.

Star grounding works excellently.  As far as the 10k uF caps, they could hurt you, but you don't have to worry about draining them.  The boards are set up with a resistor connecting the two pins of the caps so that when there is no electricity flowing they drain themselves.  They drain in about 1 minute or so.  If you are worried, just check the voltage at the caps before doing anything.  Better to be safe than sorry.

First, I would read about Chipamps: http://wiki.ssguitar.com/index.php?title=General_Chipamp_Info

Then, about the LM3886 here: http://wiki.ssguitar.com/index.php?title=LM3886

Yeah, that shouldn't be too hard.  60wRMS power output is easy.  The LM3886 has 50wRMS at 8 ohms and 68wRMS at 4 ohms.  So run a 4 ohm speaker (or two 8 ohm speakers) and you'd get the power quivelent.  After that it's just finding the right speakers to make it sound right.

Could you give me a link to this "Power Engine"?  I've never heard of it.  We can help you on building a power amp though.

It all depends on the tone you want.  I personally have found that many ss amps have covered my needs, so I haven't pursued doing a tube setup.  Ideally you should build a ss power amp, then build a ss preamp and a tube preamp, you could swap them out as needed.

Well, I don't have any schematics for you, but a tube preamp would definetly give good tone if done properly.  This has been done on many, many guitar amps with pretty good success.  The sound won't be identical to a tube amp, but definetly similar.  This is due to part of the tube amp's sound comes from the tube poweramp not just the preamp as on SS amps.

Diodes is where it's at for modding distortion.  I haven't done anything with peavey preamps, but I've played a ton with a transistor based overdrive of my own and diodes is where it's at.  If you want a mean metal type distortion/overdrive, try using LEDs.  Different color LEDs react differently (to an extent), I use RED ones.

As far as I know there isn't anything you can do with the gain on this amp, but you can easily add a volume knob by simply putting a potentiometer in line with the input.  I would suggest a 100k audio (log) pot.