OT - I Built A Practice Amp!! Now With Pictures And New Beef Flavour!

[phaeton]

Self Aggrandizing Spam, i know!

 

I built a small 1/2W practice amp , using an LM386 OpAmp and some misc capacitors and wires. I've mounted it into a 6qt Rubbermaid storage tub, along with a 4-ohm 6"x9" speaker. You turn it on and off with a $0.54 lightswitch and "switch channels" with another lightswitch. I've taken a few pictures but i haven't developed the film yet. I've got some soundclips though:

 

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As you can see it's no Blackface Fender or Marshall Plexi, but it's got a bad ole trashy rock sound!

 

It's just loud enough to where you have to raise your voice to talk over it, but with a little help from the Tubescreamer, it'll grab some feedback.

 

Sorry for the "look at me! look at me!" thread, but i'm all stoked and wanted to share.

 

This is White Trash Rigging at its finest!

 

w00t!!

[Phait]

Photo

[offramp]

Patience

[Boggs]

No apology needed as far as I'm concerned, phaeton! That thing sounds pretty damned good!! Stick your chest out a little, man... Ya done great!!!

[rog951]

Hey, that sounds pretty good! Now, were the clips recorded with the Tubescreamer on the front end or is that just the "higher-gain" setting of the amp itself? Definitely post a pic when you can!

[Dave The Rave]

Hey Phaeton, take a look at National Semiconductor's "Boomer" chips for your next version. The LM386 is quite long in the tooth now. The boomer chips are more powerful, use less parts and are more efficient too.

 

in the low-power ham radio world (yeh, I'm one....) we used to use the LM386 all the time (still do quite a bit). The newer audio amp chips are taking over these days though.

 

What did you do for a board? Lessee the photos......

 

:DTR

[Lee Knight]

It sounds cool. The way you describe it makes me think you need to build an identical one for stereo! Now THERE'S a stage rig! 2 6x9's side by side...

 

Stereo Rubbermaid combos.

[offramp]

It'd be called the "Phaeton TubTwin".

 

Or maybe "StereoMaid".

[phaeton]

It'd be called the "Phaeton TubTwin".

 

Or maybe "StereoMaid".

 

Does "Fender Twin Reverb" mean 'Twin Speakers'? I always thought it meant 'Twin Channel'. For lack of anything else, i'm calling THIS one the "Anklebiter", but i'm open for suggestion

 

The way you describe it makes me think you need to build an identical one for stereo! Now THERE'S a stage rig! 2 6x9's side by side...

 

Yeah! I could use bread trays and a huge storage tub. The bread tray will be the head, and the huge storage tub will be a 4x...uh.. 6x9 cabinet!

 

FEEL THE BURNNNN!!!

 

Hey Phaeton, take a look at National Semiconductor's "Boomer" chips for your next version

 

Thanks for the pointer! None of my distributors carry it, and (as expected) National wants me to buy 1000 at time... But maybe in a few months jameco will start to carry them.

 

I chose the LM386 because it was cheap and available (i got 8 of them in an IC assortment) and i had the schematic on tap. It was a fun build! I've got the opamp in an IC socket, so in theory i could switch it out with several other types for fun, but i haven't looked into pinouts and stuff of the other opamps i have, yet.

 

My next amp will probably be based on the LM383 (if i can find some) or its awkwardly-packaged replacement, the TDA2002v. That schematic renders an 8W amp and is actually an older Craig Anderton design. I may try to mod it though.

 

For the board i used a radioshack perfboard with copper connections laid out just like one of their small breadboards. I soldered everything to that, all smashed up into one corner because i wanted to leave room for a small preamp later if i chose to add one.

 

I keep thinking about building an amp like these with all the components stuck into IC sockets, which are wired together. That way i can switch out everything and foolaround with stuff.

 

Now, were the clips recorded with the Tubescreamer on the front end or is that just the "higher-gain" setting of the amp itself?

 

These are all without the Tubescreamer. As you can see, there's LOTS of distortion. In fact, a little too much. There are no variable gain or volume controls for the amp, so it relies on the guitar's volume control. Turning down the guitar, it gets quieter, the distortion lessens, but it never really goes away. So it doesn't really do "clean" so well. Kind of a 1-trick pony but that's ok for its intended application. I don't think it was meant to drive a speaker anyways, so w/ headphones that might be different (or deafening).

 

There is the gain switch, and if you want to hear it with the gain set to 20 instead of 200, just listen to the mp3s that start with "20-":

 

http://home.mia.net/~phaeton/Anklebiter/

 

No apology needed as far as I'm concerned, phaeton! That thing sounds pretty damned good!! Stick your chest out a little, man... Ya done great!!!

 

Well, I can't take any credit for the circuit design... Maybe for the cabinet design, but whether that's anything to be proud of or not...

 

About pictures....

 

Much as i hate to say, pics will be slow coming. "slow" as in "weeks", possibly. They won't be very good, either. It's going to be a $4 disposable camera, and I've snapped about 8 pics of this project (after putting it together, unfortunately, not a step-by-step as i would have liked) and i need to find something else to take 19 more pics of. I'd feel kinda silly developing 8 pics with 19 unused

 

I'll make a note of it when i get some uploaded though.

 

It was fun though! I can't wait to build something else

[theblue1]

Rubbermaid makes some great potential speaker enclosures. Back in the 60's I used my allowance to buy a round, kitchen-size trash can, mounted an 8" coax speaker and cut a couple of small ports. It sounded... a little "tubby." But it was light and had carry handles. I actually used it and another one for sound at an anniversery garden party (at a little wedding chaple) my folks asked me to do sound for when I was 13 or 14. For that dress-up event, I inserted a bit of grill cloth over the speakers.

[Blue Strat]

Phaeton,

 

Try changing that 10uF cap between pins 1 & 8 to 1uF when you get the chance. It should give you more of an overdriven tone instead of the fuzz tone.

[phaeton]

Try changing that 10uF cap between pins 1 & 8 to 1uF when you get the chance. It should give you more of an overdriven tone instead of the fuzz tone.

 

How come?

 

-and-

 

Sorry to everyone that i started my own self-pendangaring thread over here instead of keeping it in the confines of Bluestrat's DIY thread in the Guitar Forum

[Phait]

Phaeton - I have a digicam to sell you.

 

 

I'd get one, they're real convenient.

[Blue Strat]

Originally posted by phaeton:

Try changing that 10uF cap between pins 1 & 8 to 1uF when you get the chance. It should give you more of an overdriven tone instead of the fuzz tone.

 

How come?

It doesn't overdrive the bass. It's like the lower frequencies are set at the gain of 20 and the higher frequencies get the full gain of 200.

 

Another thing I've noticed is that different batteries give the amp different tones. I'm not sure why that it, unless it's a voltage, current, or internal resistance issue.

 

You can also replace the switch with a 10k linear taper pot for a gain control.

[mtlwannabe]

That's stinkin awesome. I bet people would buy those as novelty gifts on eBay, I would! As long as it says "aint skeered" to amplify the white trashiness. j/k

[mixposure]

Any word on a pic?

[phaeton]

Bluestrat...

 

Does your lil Smokey amp sound anything like this one? Or have you modded it more to taste?

 

They're very similar, schematicwise...

 

In the meantime, you can stuff yours into a rubbermaid tub too... until you can build an MDF box for it

[Blue Strat]

I think your 386 practice amp sounds better than mine. Could be the recording (going through a mic) or it could be the speaker as well as the differences in the circuit. My Smokey is pretty close to the schematic, but I used different value caps (a 10uF and a 4.7uF). The 10k gain pot works, but I still can't get a clean tone out of it without turning the guitar's volume down.

[henrysb3]

The latest issue of Guitar Player or EQ (can't remember which) has an amp called the Pyp Bomb. It uses a PVC sewer pipe "tee" as the enclosure. Looks like a cool idea. If you used a Little Smokey circuit in it, you could play Smokey on the (brown) Water .

 

(riff) Dah Dah Deh, Dah Dah Dee Deh...

 

Henry

[Blue Strat]

Originally posted by henrysb3:

The latest issue of Guitar Player or EQ (can't remember which) has an amp called the Pyp Bomb. It uses a PVC sewer pipe "tee" as the enclosure. Looks like a cool idea.

I use a 4" PVC drain cap for my enclosures. Here's a picture of the enclosure (from the bottom) with a CD for scale. The board is 1.75" square.

 

http://img.photobucket.com/albums/v253/bluestrat28056/fuzz_guts.jpg

 

This one is a Fuzz Face clone.

[Boggs]

Here's a link to a couple of pics of mine... http://www.musicplayer.com/cgi-bin/ultimatebb.cgi?/ubb/get_topic/f/19/t/011717.html

 

I put it in the wrong forum. Sorry guys...

[phaeton]

Ok, since Boggs is jumping off a bridge, i will too-

 

http://home.mia.net/~phaeton/Anklebiter/amp_front.jpg

 

and

http://home.mia.net/~phaeton/Anklebiter/upend.jpg

 

I have other pictures but they came out even more horrible than i expected them to...

 

Anyways... sorry these are so big n ugly. Be sure to check out Boggs' nicer-looking amp head in the above URL.

 

I'll try to resize these a lil smaller this evening.

[Jessica T]

This has been really awesome to see your DIY project come to life and have a neat sound! One thing I must ask; why use a linear taper pot for gain like blue strat says? Why not use a pot where the resistance is logrhythmic so that the gain continuum sounds even to our ears? Also, what type of capacitors are you using? Any electrolytics? Those can get leaky and mess up your signal. You might consider using polystyrenes or polypropylene ones in the parts of the circuit that directly pass the audio signal. Also, how are you powering this thing?

[theblue1]

Originally posted by phaeton:

http://home.mia.net/~phaeton/Anklebiter/amp_front.jpg

 

It has kind of an iMac look to it, somehow.

 

[deanmass]

iTub

[Jeff Klopmeyer]

iLike it.

 

- Jeff

[phaeton]

t has kind of an iMac look to it, somehow.

 

*groann*

 

 

You see...

 

My amp doesn't look like an iMac...

 

The reality is...

 

Apple computers look like cheap Rubbermaid

 

Or maybe i don't know what i'm talking about, so i'll STFU

 

iLike it.

 

Actually, i think it works out really good with the speaker facing upwards like that. It gives the perception of it being louder than what it is (although it's still louder than you'd expect 1/2W to be), but it also makes it easy to hang a mic off the end of the computer desk by its cord and "grille it".

 

You know, bust out some legos and make an apparatus that can swing the mic over the speaker like a pendulum..... Instant mechanical tremolo!

[Phait]

That is the weirdest damn amp I've ever seen. But kinda cool.

[Boggs]

That is VERY cool and sounds amazingly good, Phaeton! You built the combo and I built the head version...

[the stranger]

Killer thread, guys.