Version 2 Info

Based around a LM386 amplifier (in my case a JRC 386), the idea was to make it for a guitarist colleague, and also for myself maybe.
2010-11-29_08.18.10.jpg

... continued from Smokey amp vI
20101103: worked on the amp tonight on a breadboard. Well, I understood a few more points, by testing and looking at other schemas of smokey-amp like (in the link section):

The final cap between output and speaker controls the tone. By changing the value your amp will sound different.
Some people use a pull-down resistor (1 M ohm) between input%20 and ground ... don't really hear a difference
Using a tiny ferrite on the input doesn't improve the sound much, but if not present there is no sound at all or extremely hashed sound on the breadboard version... wtf?
A pot on the gain is not necessary, really, it's like the volumn on the guitar itself
A 10 ohm and cap to ground the output pin makes no sound any more on the speaker (but some people have that)
On the breadboard version, no much background noise : why ?
Sound is really distorted, specially the low tone strings. Playing hard rock/metal is cool with it, playing a ballad or folk is so-so (bass end up so loud and sustained that if completely hides the high tone strings). "Nothing else matters" doesn't sound so good.
The "small cap" (22pF) between the input%20 and input- pin is not a killer ... but on the version 1 (not breadboard) it doesn't have that much of bad impact if not really positive. I think I hear less the radio since I put the little cap which can understand since it must eat-away small variations, aka. that faint radio in the back.

20101104: again spent some time playing with the breadboard version, got a few more interresting conclusion

VERY IMPORTANT : a big fat cap between the power rails make the sound much better. Indeed, the amp must generate a lot of variations on the power supply and it distorts the sound and make it sensitive to the ambient magnetic noise.
IMPORTANT : add a pot for the gain, or at least a little resistor since at maximum level the noise is too low. But just lower it a little, and the sound becomes much much better.
Adding a cap between guitar input and input%20 (like a 47uF) make the sound a bit cleaner but I would say with a little less "detail" (sorry, I'm not good at music neither). However sound is more clean. Maybe there is a tradeoff here?
A cap between output and ground is not necessary (no big difference). And if you put a resistor, mind that a single 10ohm baby will get burning in a few seconds... make it serial with a cap if you want. Maybe it worth being tried?

Anyway, thanks to all this, I'll make a version 2 this weekend. Hope result will be nice ^^
20101108: made version 2 on Friday evening. No cap on the input, but a ferrite. Is it a crime or something great (or just useless) ? Dunno. Put also a BIG FAT cap (470 uF) on the power rail and that's a killer : barely no more noise and sound is much more clean. Also important. this one has a gain control pot (10k, too big but I have nothing smaller currently) which is very good : full power you still have noise, but if you just lower it a bit, then bye bye noise and enjoy a clear sound that is plenty sufficient for playing at home on the sofa. Schema coming soon...
20101110: found some guy's comment on blueguitar.org. I copy the guy's comment on a separate page to keep it. Thanks for sharing, that will be most useful I guess.
20101118: well I tried many tricks, tried to implement many alternate Smokey amp like the Smokey Tone Amp of BeavisAudio, variations found on internet ... same : I've got lots of noise. A pot on the gain and a big cap between power rails make things better but no miracle here, I've still got lots of distortion and a background noise. Impossible to get a clear and clean noise.
20101128: it's not because sound is not perfect (hum hum ... far from it in fact) that I should not use it and case it into something. As you can see on the right hand picture, I cased it in a metal "hot lemon tea" can. The plug is in the top cap, and the speaker at the bottom. I tried to fix the speaker with nut and bolts, but to fix the nut to the speaker I soldered it but it didn't stay in place once a little force is applied. Maybe with an arc soldering tool I could, but nothing like that at home, so I will replace it with steel wires, should do the trick.
Only interresting stuff is that now - from power goes to the middle section of the 6.3 mm plug and goes back from the top (not the tip, the other side). Benefit ? Well, no need for a switch, if nothing is plugged in, the circuit is open and battery unused. Got the idea by seing a real SmokeyAmp once.
... continues on Smokey amp vIII

Schema

Version 2, with gain pot and tone control (useless)
2010-11-29_08.18.40.jpg

Version 2, case into a metal can of hot lemon drink.


Quick Navigation All projects Hardware Links Top projects Alan numitron clock Clapclap 2313/1386 SNES Pi Webserver USB Volume/USB toys Smokey amp Laser cutter WordClock ardReveil v3 SNES Arcade cabinet Game boy projects cameleon Home Presence Detector GitHub AlanFromJapan Contact me Who's Alan? Akizukidenshi Elec-lab Rand Nerd Tut EEVblog SpritesMods AvrFreaks Gameboy Dev FLOZz' blog Switch-science Sparkfun Suzusho Datasheet Lib Reddit Elec Ermicro Carnet du maker (fr)	Smokey amp vII Last update: Tue Nov 28 13:28:49 2023 kalshagar - Smokey amp vII Version 2 Info Based around a LM386 amplifier (in my case a JRC 386), the idea was to make it for a guitarist colleague, and also for myself maybe. ... continued from Smokey amp vI 20101103: worked on the amp tonight on a breadboard. Well, I understood a few more points, by testing and looking at other schemas of smokey-amp like (in the link section): The final cap between output and speaker controls the tone. By changing the value your amp will sound different. Some people use a pull-down resistor (1 M ohm) between input%20 and ground ... don't really hear a difference Using a tiny ferrite on the input doesn't improve the sound much, but if not present there is no sound at all or extremely hashed sound on the breadboard version... wtf? A pot on the gain is not necessary, really, it's like the volumn on the guitar itself A 10 ohm and cap to ground the output pin makes no sound any more on the speaker (but some people have that) On the breadboard version, no much background noise : why ? Sound is really distorted, specially the low tone strings. Playing hard rock/metal is cool with it, playing a ballad or folk is so-so (bass end up so loud and sustained that if completely hides the high tone strings). "Nothing else matters" doesn't sound so good. The "small cap" (22pF) between the input%20 and input- pin is not a killer ... but on the version 1 (not breadboard) it doesn't have that much of bad impact if not really positive. I think I hear less the radio since I put the little cap which can understand since it must eat-away small variations, aka. that faint radio in the back. 20101104: again spent some time playing with the breadboard version, got a few more interresting conclusion VERY IMPORTANT : a big fat cap between the power rails make the sound much better. Indeed, the amp must generate a lot of variations on the power supply and it distorts the sound and make it sensitive to the ambient magnetic noise. IMPORTANT : add a pot for the gain, or at least a little resistor since at maximum level the noise is too low. But just lower it a little, and the sound becomes much much better. Adding a cap between guitar input and input%20 (like a 47uF) make the sound a bit cleaner but I would say with a little less "detail" (sorry, I'm not good at music neither). However sound is more clean. Maybe there is a tradeoff here? A cap between output and ground is not necessary (no big difference). And if you put a resistor, mind that a single 10ohm baby will get burning in a few seconds... make it serial with a cap if you want. Maybe it worth being tried? Anyway, thanks to all this, I'll make a version 2 this weekend. Hope result will be nice ^^ 20101108: made version 2 on Friday evening. No cap on the input, but a ferrite. Is it a crime or something great (or just useless) ? Dunno. Put also a BIG FAT cap (470 uF) on the power rail and that's a killer : barely no more noise and sound is much more clean. Also important. this one has a gain control pot (10k, too big but I have nothing smaller currently) which is very good : full power you still have noise, but if you just lower it a bit, then bye bye noise and enjoy a clear sound that is plenty sufficient for playing at home on the sofa. Schema coming soon... 20101110: found some guy's comment on blueguitar.org. I copy the guy's comment on a separate page to keep it. Thanks for sharing, that will be most useful I guess. 20101118: well I tried many tricks, tried to implement many alternate Smokey amp like the Smokey Tone Amp of BeavisAudio, variations found on internet ... same : I've got lots of noise. A pot on the gain and a big cap between power rails make things better but no miracle here, I've still got lots of distortion and a background noise. Impossible to get a clear and clean noise. 20101128: it's not because sound is not perfect (hum hum ... far from it in fact) that I should not use it and case it into something. As you can see on the right hand picture, I cased it in a metal "hot lemon tea" can. The plug is in the top cap, and the speaker at the bottom. I tried to fix the speaker with nut and bolts, but to fix the nut to the speaker I soldered it but it didn't stay in place once a little force is applied. Maybe with an arc soldering tool I could, but nothing like that at home, so I will replace it with steel wires, should do the trick. Only interresting stuff is that now - from power goes to the middle section of the 6.3 mm plug and goes back from the top (not the tip, the other side). Benefit ? Well, no need for a switch, if nothing is plugged in, the circuit is open and battery unused. Got the idea by seing a real SmokeyAmp once. ... continues on Smokey amp vIII Schema Version 2, with gain pot and tone control (useless) Version 2, case into a metal can of hot lemon drink. Links http://www.smokeyamps.com/ http://www.whatsamattyfo.com/index.php/building-a-portable-guitar-amp-the-smokey-amp/ Various music related electronic projects http://www.runoffgroove.com/ A simple re-version of the Smokey amp : the LittleGem http://www.runoffgroove.com/littlegem.html http://forum.hackedgadgets.com/viewtopic.php?t=170 Japan user-made reseller http://item.rakuten.co.jp/takamatsu/632296 Noisy Criket, very good stuff it seems http://www.beavisaudio.com/projects/NoisyCricket/ SolidState Guitar Amp forum http://www.ssguitar.com/ A 25w version, but maybe ideas to take http://www.eleccircuit.com/25w-hi-fi-audio-amplifier-using-ic-lm1875/ Interresting version, much similar to what I did for version 2 http://www.instructables.com/id/Make-a-Sweet-Portable-Guitar-Amp/#step1 One more version, seems this time they sell it so it has to work ! http://www.electronics-lab.com/projects/audio/010/index.html One more, not a guitar amp but can worth looking http://www.tangentsoft.net/audio/cmoy-tutorial/ One more, simple LM386 amp http://tehnikservice.net/2011/02/02/amplifier-with-lm386/ One more, with LM386 http://hackaweek.com/hacks/?p=131 Remove the hiss ? http://www.wentztech.com/radio/Technical/Misc/lm386.html Another version, not exactly the same http://www.amb.org/audio/mini3/
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Smokey amp vII

Version 2 Info

Schema

Links