Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: egrubbs on October 07, 2006, 07:37:18 AM

Title: Little Gem
Post by: egrubbs on October 07, 2006, 07:37:18 AM
Hey -- I'm looking to build one of these, but I know nothing about absolutely anything related to electronics.

Is there anyone who's willing to walk me through the steps needed to make one of these?

Thanks a lot!
Title: Re: Little Gem
Post by: joecool85 on October 07, 2006, 07:58:04 AM
Sure.  First, do you know how to solder?  Make sure you have a decent soldering gun, then gather all the components needed to make the little gem.  If you have a problem reading the schematic, feel free to ask us what stuff means.  We'll start with that, and we can answer questions as you go along.
Title: Re: Little Gem
Post by: egrubbs on October 07, 2006, 04:20:46 PM
I know how to solder, but my only experience so far has been soldering connections to 1/4" jacks for some electric instruments I've made.

I have a general idea about what this requires:

Four capacitors, one resistor, a 386 chip, two 1/4" jack (I want to make a head instead of a combo), a 9v adapter input, two regular pots and a 25 ohm pot, and a chassis.

The problem is, I'm not really sure what all the capacitors and resistors mean.  I went to some sites that sell parts and searched for the names on the schematic and I got a few too many results than I'd be happy with trying on my own.

There's a 0.01, 100, 220, and 0.047 capacitor, correct?  And what kind of resistor?  Do I just use a 1/2 watt resistor, because that is the wattage of the amp?

I'm going by these two images:

(http://www.runoffgroove.com/littlegem-perf.png)

(http://www.runoffgroove.com/littlegem.png)

I could easily do this if I could see a close up picture of someone who has completed it in real life.  It's kind of difficult for me to put things on paper into real life, but seeing something in a picture or real life is really easy to put together.

This site: http://firebottle.com/ampage/homebrew.cgi?cat=ga&sb=&so=hl&page=1094792242apK8sNh has some kind of close pictures, but not enough to make me really understand what wires go where.
Title: Re: Little Gem
Post by: idle_chatterbox on October 08, 2006, 12:30:35 AM
Egrubbs, you actually COULD make a mock-up of the amp if you put a wire everywhere you see a plain line on the schematic, and soldered everywhere the wires meet. (On some schems where wires cross but are not connected, this is identified. But as I look at it, there are none of those on this schem.)

So in a way, the schematic is a picture of sorts. It's just that once you've determined that the circuit works (and that everything's connected right, etc), you usually want to reorient the various components so that you avoid things like hum or oscillation. At that point, a photo can be helpful. Heck, when I'm just seeing if a schem works I sometimes just use color coded jumper wires with alligator clips and rig it up exactly like it looks in the schematic. Just remember to connect all the grounds, since that "wire" is usually not shown in a schematic.

There's also an aesthetic dimension. Especially among those who are really skilled (not me), there is sometimes an attempt to make the finished product look better by, say, having all resistors in one corner, and having all the semi-cons in another.

Some people are also skilled at arranging the components so that the whole schmeer will fit into the enclosure (not a trivial detail).

But there too, that's what you do once you're ready to rock. When you're just fitting everything up to see if you like the sound, or if a parts substitution will work, you can use the schem diagram as a "picture" of the finished product. Good luck  :tu:
Title: Re: Little Gem
Post by: Stompin_Tom on October 09, 2006, 10:17:29 AM
Hey egrubbs,

I usually use small bear (http://www.smallbearelec.com/home.html) for stompbox parts. He might be a little more expensive (sometimes not), but he specializes in stompbox parts. That way there's less chance you'll order the wrong thing. (I'd say the ruby qualifies as a stompbox of sorts). So I'd order resistors from this list, http://www.smallbearelec.com/Categories.bok?category=Resistors

and caps from this list, http://www.smallbearelec.com/Categories.bok?category=Capacitors%2C+Low+Voltage+Poly+Film

He's got jacks, enclosures, battery clips, etc., too.

The first pic you posted is the perf board layout... so it's more-or-less a pic of the circuit board if you use perf. Put the components where it shows and connect the wires where the lines are. Make sense?

Someone might have posted some pics of their guts over at the diystompboxes.com site... you could do a search...