Help me navigate the world of diy audio kits with respect to guitar amps!

December 10, 2010 5:37 PM

I finally figured out the perfect gift to get the boyfriend but am having trouble finding what I want. Help me navigate the world of diy audio kits with respect to guitar amps!

He's into guitars and the mechanical side of DIY projects, so I'd like to get something that we can spend time together assembling and testing. Then once that's complete, Boyfriendivasian can hopefully design his own enclosure in his CAD program of choice and get it made.

I'm looking for a guitar amplifier with some assembly required--PCB and components only, no enclosures necessary. Looking to spend less than $100 and would prefer to not ghettorig my own setup in order to etch a PCB or work with a perf board. Given a schematic or assembly document, I'm comfortable with ordering parts from Digikey if the components aren't included in the kit. My electrical engineering degree should have me pretty prepared but electronics isn't my forte. I've heard that tube amps are difficult and dangerous due to the high voltage involved--is this true (will we potentially die if we take on this endeavor)? Should I look at solid-state instead?

I've taken a look at this previous question but did not find something that met my criteria.

posted by joydivasian to sports, hobbies, & recreation (6 answers total)

From a quick search it looks like the part of choice for a DIY solid-state guitar amp is the LM3886. These guys' on-line store is closed starting sundown Fridays so I can't tell you how much the pre-made PCB is. There's a lot of discussion about this sort of things at Solid-State Guitar, too.

In general I think a tube amp is a bad idea for a first project. In a solid-state amp, small errors (like a solder bridge) tend to have small consequences; in a tube amp you're much more likely to have a blown-out capacitor or big sparking. I've had about a half-dozen undergrads (mostly musicians learning how to build electronics) work on tube amps over the years; the project usually ends when I hear a loud SNAP from across the lab, followed by a stool falling backwards as the student jumps backwards and starts swearing. It's also likely that the tube amp will be more expensive, because tubes and sockets can be a pain to source.

One other thing to think about is expectations. A guitar amp is made out of two stages that are both difficult to do well: a high-gain, low noise amp for the pickup, and a clean, high-power audio amp for the speaker. Getting good sound of of something like this can be pretty fidgety, and no doubt there are a bunch of black-magic tricks that Peavey et al. have figured out over the years -- it's a lot easier to build a great amp when you get to practice a couple hundred thousand times.
posted by range at 7:59 PM on December 10, 2010

I built a small amp over the past two years using a Ruby amp. It's not very powerful, but hard to screw up. It's also small enough to run on a 9-volt, so the enclosure gets to be a big part of the fun.

In my case, I took a ruby and a digital delay, ran them both off a regulated wall wart and built them into a scratch-built Hello, Kitty cabinet.

Don't be scared by the two years - if I were single and without kids, that would've been more like a month of weekends.
posted by plinth at 3:32 AM on December 11, 2010

If you do go the tube amp route, then I think this CeriaTone kit is nearly the cheapest option there is. But the company, for whatever strange reason, doesn't give full directions for assembly. That said, solid-state amps are useful in their own right. Have you thought about a pedal kit?
posted by tmcw at 8:28 AM on December 11, 2010

The Firefly is a cool basic tube amp. I'm not sure how much the finished amp costs to build, but the kit used to sell for under a $100 (it didn't include all of the pieces though). The kits are no longer available but the PCBs are available here.
posted by drezdn at 10:53 AM on December 11, 2010

Range knows what's up. Yes, you could actually die from a tube amp project- really even off-the-shelf, working properly tube amps contain lethal voltages EVEN AFTER UNPLUGGED FOR SOME TIME.
posted by tremspeed at 9:40 PM on December 13, 2010

Hi all, I know this is belated but I just wanted to say thanks for the advice! I decided to wait for the anniversary rather than Christmas, and ended up with this kit. I'll make sure to follow all safety precautions and err on the safe side while working.
posted by joydivasian at 8:23 AM on April 19, 2011