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#1
Hey guys. Here a small battery powered amp I just built. I always wanting a little amp to carry around, so I built one. Runs off a 9v battery or 9v power supply. Its built in a head form, can power any kind of cab, from a small speaker to a 4x12. Also has a headphone jack.

I was amazed at how good this thing sounded once together. Sounds very nice. The cleans are on par with my tube amps, and the overdrive reminds me of a Big Muff.

Here are some pics.

Components


Board wired up


Faceplate for the controls


Enclosure


Faceplate wired up


Faceplate pops on and off for battery changes




I know the wiring is a mess. I'll be cleaning it up later.
Here is a link to a Youtube video with a sound clip - http://www.youtube.com/watch?v=is9zF9vIUuE
Last edited by Matt420740 at Sep 15, 2010,
#2
Ok. I'm fairly impressed. I really didn't think it was going to sound all that good, but it does. I'm almost ashamed to admit that, because I'm a pure tube man. Don't tell anyone. Ok?
#4
I like the Mouser catalog in the background of the one shot. I almost live at that place. lol

Any chance you can post the schematic for that amp? Or, do you have a link to it? I'd like to build one of these to goof around with.
#6
Quote by KG6_Steven
I'm almost ashamed to admit that, because I'm a pure tube man. Don't tell anyone. Ok?


I've got a tube amp build in my sig


Quote by KG6_Steven
I like the Mouser catalog in the background of the one shot. I almost live at that place. lol

Any chance you can post the schematic for that amp? Or, do you have a link to it? I'd like to build one of these to goof around with.


Its based on this - http://runoffgroove.com/littlegem.html
Just a few changes to tweak the tone, and the addition of a speaker out and headphone out.
#7
yeah a wiring diagram would be awesome!!!! i just finished my electronics classes and i'd love to build something like that. What kind of IC did you use. I'm familiar with building an OP AMP circuit, i think i saw that in there. it sounds amazing, that would be really really cool to build! PLEASE PLEASE put up a diagram/parts list! i have one question for you. why didn't you use perf board? seems like you did it on the cheap, which is pretty awesome. rock on man! do you think there's a way to get more gain out of it? if so, and you find out that would be cool.
#8
Dude, seriously that's pretty freakin awesome. It sounded a ton better than I expected, keep it up.
#9
what resistor did you use for the LED and what was the power values etc for the led? what are the pot resistance values, i looked on the website for the LGmk II and it doesn't give any info about the LED and the pots that i can see. what would you suggest to get some really good gain? what op amp should i use, it says in the print that i should use a lm386 but i've seen some 741's used on other prints. i went hereprint lgmkII any suggestions?
#10
I am amazed by the sound of these little amps myself. I have built a few and they are very impressive. Do you hear a fizzle if you let the note die out from distorted to clean?
Last edited by dacole at Sep 15, 2010,
#12
Quote by Grassyknolls
what resistor did you use for the LED and what was the power values etc for the led? what are the pot resistance values, i looked on the website for the LGmk II and it doesn't give any info about the LED and the pots that i can see. what would you suggest to get some really good gain? what op amp should i use, it says in the print that i should use a lm386 but i've seen some 741's used on other prints. i went hereprint lgmkII any suggestions?


I just used a 5mm Ultraviolet LED I had laying around. Any color should work. 1K resistor will be fine for the LED. I used a LM386-N. You'll need a 5K pot, and a 25-Ohm Rheostat. I didn't use a pre-made board just to save a little money. I've found that on simple, small, low voltage circuits like this, hot-gluing the components to some sturdy cardboard seems to work fine for me. If it were a more complex circuit I would have used a board.
Last edited by Matt420740 at Sep 15, 2010,
#13
A 741 is an op-amp. I don't think you'll get anywhere near .5 watt from one. The LM-386 is an actual amplifier IC. As for the LED and it's dropping resistor. It really all depends on which LED you choose, what voltage it requires to bias on and what the supply voltage is.
#14


Oh my God that is the greatest thing I've ever seen in my entire life. I wonder how the guys who invented the Marshal MG feel when they see a homemade half watt single channel box sound better than their "famous" amp.

I'm amazed that little thing can power a 4x12 with that kind of volume with no OT and only using a 9 volt battery.

Kudos to you sir, now you just need to stain it a cool color and poly it so it wont get dinged up.
#15
i also saw in your build that you replaced one of the caps with a ceramic disc capacitor. which pin did you come off of? and what was the value on there. i have the schematic for the ruby amp and instead of a 25 ohm rheostat, it says i can use a 10k for the volume and a 1 k for the gain. i like the sound yours got so i'm trying to find a way to mod the ruby. anyways, back to the ceraminc disc cap, the caps in the ruby plan are 100uf, 47n, 100n, and 220uf. i was looking at the print and your picture, i can't really make out where the disc goes in the print. print looks like you can out of pin 7. would the pots you suggest work with this set up? i don't know if you've ever looked at the ruby or not but it seems pretty versitle. or should i just make the little gem instead. i know i'm asking a lot out of this tiny thing but i like the sound you got. i have an electro harmonix lp-1 so i guess if the gain isn't what i want i can boost it with that. i'll post pics on it when i get it going, waiting on school to die down a bit and then i'll work on it. i plan on making a 2024 aluminum box for it at school and lifting the board off with some rubber feet and making a clip to hold the battery. or using some RTV to coat the bottom of the board. what would it take to make an 18 volt mod?
#16
The ceramic disk is the .047uf cap. The link in my second post is the schematic and board layout I went by. I used the pots called for in that schematic, but you can sub a 100 Ohm pot for the Rheostat if you can find one. If not Radioshack has the rheostat for $3.99. Play around with the value of the 220uf cap to tweak the tone.

Maybe this will help -


The layout above uses the stereo input jack as a power switch. I used a mono jack instead and used a mini-toggle for the power switch.
Last edited by Matt420740 at Sep 16, 2010,
#17
I didn't expect it to sound very good either, but it did. Nice diagram too.
***Guitars***
Epiphone Les Paul Custom AP (w/ 2 Seymour Duncans)
Jackson Dx10D Dinky (w/ DiMarzio PAF Bridge)
Epihpone Hummingbird

***Amps***
Marshall JCM 2000 DSL 100 (Voodoo Modified)
Custom 4x12 Halfstack (w/ Veteran 30's)
#18
Wow, that sounds really nice, much better than I was expecting.
#19
awesome dude, i went to class today, and my electronics teacher looked over my plan... i'm using a toggle, but i'm going to stick to the plan. by playing around with the 220uf cap what exactly do you mean. i'm going to go with the perf board, and use an ip socket for the 386, but i'm going to make an aluminum face plate for mine with the led. your plan looks like mine. i went on mouser and found pretty much everything i need. i'll post pics when i get it done, should be in a week or so. thanks for your help!
#20
is this as easy to do as it looks? also what is the ohm rating of the amp?
no sir away a papaya war is on
#22
Quote by the_perdestrian
is this as easy to do as it looks?


If you know how to solder, have a bit of electronics experience than yes this design is very easy.

For someone with no experience at all, something simple like this would be a good place to start.


Quote by the_perdestrian
also what is the ohm rating of the amp?


8 ohm. But it works fine with a 4 or 16 ohm load as well. Your not going to fry anything in this little sucker by mismatching a bit
#23
thats perfect, I have a 8 ohm 4x10 bass cab that I was planning on using for it.

but yeah I have some soldering experiance and have been wanting to build an super simple amp like this for a while.
no sir away a papaya war is on
#25
I made the Ruby version of this amp a little while ago, with a couple slight tweaks recently. (I'm using a master output volume and just connected the two connections where a volume would have gone in the circuit. Also messing around with an experimental "bass cut" switch, which adds a 100uf capacitor in series to the 220uf, cutting the capacitance and making it sound a bit less boomy.)

Awesome small amp, really.

One thing that I discovered is that speaker(s) you run the amp through matters waaaaaaaay more then I expected. I used a tiny 3" 0.5 watt speaker originally. Super trebly horrid just about MG-class sound. Then I used a bit better speaker, and it sounded loads better.

And I think now that the reason solid state amps are so well-known as being bad sounding is because SS amps are usually budget amps. Meaning they use cheapo components, the speaker being no different.

I'd be willing to bet if you were to run an MG through a good speaker cabinet, it'd sound good.

Anyways, cool little amp build. Sounds pretty good.

#26
Quote by SlayingDragons

And I think now that the reason solid state amps are so well-known as being bad sounding is because SS amps are usually budget amps. Meaning they use cheapo components, the speaker being no different.


Yep! I can get a pretty nice tone with a Squier SP-10 run into a Celestion Super 8. Best part, both were free!!
#27
I just put together another one of these today. This one is in a tin box enclosure. Pretty much the same circuit as the first amp, powered by a 9V battery. Switch and LED in front, Gain and Volume on top, and an input and output jack on the sides.



#29
Here is the newest version. Same enclosure as the black one, except the control knobs have been moved to the front. I'll have a few of these for sale shortly if anyone is interested.

#30
im interested. it would be nice to have one to look at when I try and build one. how much?
no sir away a papaya war is on
#31
Wow that sounds awesome. I might build one of these soon. Do you know of any ways to get more gain out of that?
#33
Quote by Nianri6
Wow that sounds awesome. I might build one of these soon. Do you know of any ways to get more gain out of that?


Distortion pedal? IMO, harder distortion than what he's doing with a 386 doesn't sound that great.


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RBY CYOA
#34
Quote by MonkeyLink07
Distortion pedal? IMO, harder distortion than what he's doing with a 386 doesn't sound that great.


Ok, thanks. My Boss Metal Zone doesn't have the tone i want, and i really like the distortion he's getting out of that amp. Just a thought, could i possibly use that as a preamp? Like i said, I don't like the tone of the boss pedal, and my amp doesn't have the distortion I would like it to.
#35
Can someone explain to me what the 5KL or 1M5 or 3k9 means next to the resistors on the actual schematics from runoffgroove.com?

I would assume that 5k or 1M or 3k is the value of the resistor but what does the the letter or number afterward mean? Is it code for something else? Thanks.
#36
the 5kL stands for a 5kΩ Linear pot, the 1M5 is put there instead of 1.5MΩ with the letter instead of the decimal, standing for 1,500,000Ω the same with the 3k9, it being 3.9kΩ, 3,900Ω.


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RBY CYOA
#38
Quote by rapfohl09
Can someone explain to me what the 5KL or 1M5 or 3k9 means next to the resistors on the actual schematics from runoffgroove.com?

I would assume that 5k or 1M or 3k is the value of the resistor but what does the the letter or number afterward mean? Is it code for something else? Thanks.
They are prefixes that mean mega (a million) and kilo (a thousand). Here's a list of them prefixes: http://en.wikipedia.org/wiki/SI_prefix

With resistors you'll probly only use M and k, but with caps much smaller values are usual.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
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Rackmount Tube Amp Project <<< Updates!
#39
You should make a tutorial on how make one of these, for noobz like me

I wanna learn how to make stuff like this...
Guitars:
Schecter Omen Extreme FR w/ SD Blackouts AHB-2
Epi LP 100
Epi LP Special II


Amps:
Randall RG100 Head
carvin x100b head
Carvin x100b 412
Fender FM412 Cab
#40
I got all my components tonight, enough for 2 amps. I figured I would just post in here instead of having another thread that is for the same exact thing.
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