i'm still learning about all this, so i don't know all the pro's and con's but i was thinkning about an SS combo, for a clean acoustic sound...
also thought that building it myself would be an excellent way to learn.
The main use for this would to plug in my acoustic guitar, but it would also be great if mp3/cd/mic could be plugged in along with the guitar i.e the need for two channels, maybe with phantom power?!?
also thought that building it myself would be an excellent way to learn.
The main use for this would to plug in my acoustic guitar, but it would also be great if mp3/cd/mic could be plugged in along with the guitar i.e the need for two channels, maybe with phantom power?!?
the simplest way would probably be use a LM3886 chipamp with a simple Opamp buffer at the input with a Tone stack and then another Opamp with Gain......you could build a few different preamp curcuits (for low impedance and High impedance Inputs) and add a simple summing curcuit before the power amp stage......
This is simular to how I built my Electric Guitar/Bass amp accept I added several selectable overdrive stages and it is only one channel but it goes from very quiet with no overdrive engaged to super crunchy when the OD is engaged.....
Cheers
This is simular to how I built my Electric Guitar/Bass amp accept I added several selectable overdrive stages and it is only one channel but it goes from very quiet with no overdrive engaged to super crunchy when the OD is engaged.....
Cheers
i'm confident in my soldering ability and ability to piece together
kits and whatnot. but i don't have the knowledge about all of this to figure out what i need to make a good acoustic amp.
is this a hopeless task for me, or are there people out here willing and able to guide me through?
maybe you have some suggestions for pdf's or something to study?
also i was at the chipamp site, which of the kits there would suit me?
oh, and thanks a lot for the replies so far...
kits and whatnot. but i don't have the knowledge about all of this to figure out what i need to make a good acoustic amp.
is this a hopeless task for me, or are there people out here willing and able to guide me through?
maybe you have some suggestions for pdf's or something to study?
also i was at the chipamp site, which of the kits there would suit me?
oh, and thanks a lot for the replies so far...
Build Albert's Bass preamp and add a chipamp or better still a UCD180.
http://www.albertkreuzer.com/start.htm
http://www.albertkreuzer.com/start.htm
A electric guitar/bass amp has to have a high input impedance as most Pickups are high impedance, so the Preamp has to have a high impedance input......
For a PA system or anything with microphones you would need a low impedance input as most mics are low impedance.....
This all mostly has to do with the pre amp used in the amp...the simplest way to go to build a preamp is to use Opamps , Once you know how to use an opamp you can basicly build an amp with just that basic knowlege, well you still ned to know about supply filtering and calculating Gain for inverting and Non-inverting inputs and Phaze and some other stuff but much of that will be covered when learning about opamps.......
If you go to the National web site or the TI web site there are lots of application manuals that explians much of this stuff, pluss there are a lot on line sites that explain a lot of the Basic principals of electronics.......
Good luck
For a PA system or anything with microphones you would need a low impedance input as most mics are low impedance.....
This all mostly has to do with the pre amp used in the amp...the simplest way to go to build a preamp is to use Opamps , Once you know how to use an opamp you can basicly build an amp with just that basic knowlege, well you still ned to know about supply filtering and calculating Gain for inverting and Non-inverting inputs and Phaze and some other stuff but much of that will be covered when learning about opamps.......
If you go to the National web site or the TI web site there are lots of application manuals that explians much of this stuff, pluss there are a lot on line sites that explain a lot of the Basic principals of electronics.......
Good luck
ok, i can see i've got a lot of stupid questions, but here i go again...
the "speakerbox" i plan on building for this amp, is going to consist of 2 8" full range speakers and one tweeter that will give an added about 100W 8ohm.
what is it exactly that determines the wattage of the amp?
can i get by with the lm3886 dual kit, and a transformer that gives at least 200VA. (or have i got it completely wrong)
the "speakerbox" i plan on building for this amp, is going to consist of 2 8" full range speakers and one tweeter that will give an added about 100W 8ohm.
what is it exactly that determines the wattage of the amp?
can i get by with the lm3886 dual kit, and a transformer that gives at least 200VA. (or have i got it completely wrong)
Re the box: if the two 8" are twin cone and reasonably efficient, I'd leave the tweeter out for the moment. Leave space for it, but don't buy it, you may not need it. Also, array the drivers vertically, it'll sound a heap better, as will a well braced open back cab. The last one we built was a rectangular box with 5 sides including the baffle, with 2x12" vertically and an open back. Inside the 'box' was a brace shaped like this # (but square) that held the drivers firmly The tube pre was built into the top and the poweramp in the bottom for balance issues when carrying it. At 17W, with a harmonica cranking through it it's very, very loud.pojk said:
Power: using one of the chipamps, the output power will be determined by the power supply voltages and the load. Read the datasheets and around here for links about how to do itIf you're ging to buy one of the twin 3886 boards run one to each 8" as I beleive they're not as fond of low impedance loads.
Some useful info here;
http://www.audiosector.com/nigc_kit-users_guide.pdf
As noted above, 100W is a lot for this sort of amp.
I'd still suggest building the Kreuser pre, as it has a bit of distortion to it which will give it a bit of character.
Hi,
FWIW "homebuilt" music kit is hardly ever as as good a purpose built
stuff, as it usually misses out connectivity options, and the circuitry
used for live music amplifiers has (should have) little to do with "hi-fi".
The main differenced between an acoustic and electric guitar amplifier :
1) The speakers are not built / chosen for distortion characteristics.
2) The preamplifier is not built for distortion, can have a piezo input.
3) Has microphone inputs for miked up guitar and vocals.
4) Acoustic amplifiers are expected to reproduce voice also.
5) Can have phantom powered mic inputs
6) Facilities for controlling acoustic guitar feedback.
7) Different EQ and effects - suited to purpose.
8) Channel handling is different - again suited to purpose.
9) Built in compression to prevent power amplifier clipping.
Research the models available - I think you'll find building an even
approximate equivalent a daunting prospect - also note that the
reliability issues are very real - building for hard use is not easy.
Check out the various approaches here :
http://www.gear4music.com/Guitar_Amps/Acoustic_Amps.html
I think you'd have difficulty bettering the ACX450 from BEHRINGER .
/sreten.
FWIW "homebuilt" music kit is hardly ever as as good a purpose built
stuff, as it usually misses out connectivity options, and the circuitry
used for live music amplifiers has (should have) little to do with "hi-fi".
The main differenced between an acoustic and electric guitar amplifier :
1) The speakers are not built / chosen for distortion characteristics.
2) The preamplifier is not built for distortion, can have a piezo input.
3) Has microphone inputs for miked up guitar and vocals.
4) Acoustic amplifiers are expected to reproduce voice also.
5) Can have phantom powered mic inputs
6) Facilities for controlling acoustic guitar feedback.
7) Different EQ and effects - suited to purpose.
8) Channel handling is different - again suited to purpose.
9) Built in compression to prevent power amplifier clipping.
Research the models available - I think you'll find building an even
approximate equivalent a daunting prospect - also note that the
reliability issues are very real - building for hard use is not easy.
Check out the various approaches here :
http://www.gear4music.com/Guitar_Amps/Acoustic_Amps.html
I think you'd have difficulty bettering the ACX450 from BEHRINGER .
/sreten.Hey! As I'd like to start building an acoustic guiatar amp for my new CORT CJ-10X I'm wondering about the progress of this post writer project....how was the work? have you got good results?....
Thanks a lot
Leo
ps: I've already built a Vox AC30 for my electric guitar but one of the few thing I know is that i say generally, dark tube amps are not the best choice for bright acoustic guitar, so what do you say/suggest?...
Thanks a lot
Leo
ps: I've already built a Vox AC30 for my electric guitar but one of the few thing I know is that i say generally, dark tube amps are not the best choice for bright acoustic guitar, so what do you say/suggest?...
ACOUSTIC guitar amp.
the requirements to make a decent sounding amp for an acoustic guitar... with (perhaps) a piezo pickup... are entirely different than what a 'punk-rock'... shredder guitar player is looking for. Everyone compromises. Impedance matters!. It IS easier to buy older equiptment and make it work for what you want it to do. Cheaper too... isn't there a design using one fet to match impedence for an (ac-30)(any tube amp) to an acoustic ... and still maintain the 'brightness'... and sound of an acoustic guitar?. I've forgotten. It's a 9 volt supplied 'impedance matching' circuit. -
the requirements to make a decent sounding amp for an acoustic guitar... with (perhaps) a piezo pickup... are entirely different than what a 'punk-rock'... shredder guitar player is looking for. Everyone compromises. Impedance matters!. It IS easier to buy older equiptment and make it work for what you want it to do. Cheaper too... isn't there a design using one fet to match impedence for an (ac-30)(any tube amp) to an acoustic ... and still maintain the 'brightness'... and sound of an acoustic guitar?. I've forgotten. It's a 9 volt supplied 'impedance matching' circuit. -
ACOUSTIC guitar amp
One of the few things I've understood about acoustic amps is that are very very different from punk-rock vox-fender-marshall-orange like amps in fact I'm here asking for schematics and also cabinet tips (wood, size and kind), I've said I've built a vox only to say that i'm quite skilled i soldering and wood working for the cabinet but, again, I'm here for finding the way to follow as i don't know it.
Reading various posts it seems that the Kreuser pre should be a good choice but I have no schems, and what about power stage? and again what kind of cab? open or closed? dimension and cab shape?
Thanks to all
Leo
One of the few things I've understood about acoustic amps is that are very very different from punk-rock vox-fender-marshall-orange like amps in fact I'm here asking for schematics and also cabinet tips (wood, size and kind), I've said I've built a vox only to say that i'm quite skilled i soldering and wood working for the cabinet but, again, I'm here for finding the way to follow as i don't know it.
Reading various posts it seems that the Kreuser pre should be a good choice but I have no schems, and what about power stage? and again what kind of cab? open or closed? dimension and cab shape?
Thanks to all
Leo
One option for a acoustic guitar amp
I know this is a pretty old thread, but I want to give it a bump, and suggest some web resources for anyone who finds it with a google search. I'm planning on building an acoustic amp for my acoustic electric, and here's the rough outline:
Preamp: Universal Preamp/Mixer from Rod Elliott's ESP (Elliott Sound Project) pages -Project 94
PowerAmp: Single Chip 50W Power Amp from ESP - Project 19
Power Supply - Dual Power Supply (60W), from ESP - Project 04
(Clearly I'm a fan of Rod Elliott's work. You can also buy PCBs from him to support his providing all these great circuits to us all.)
Speaker: Wild Burro Audio's Betsy-K - Wild Burro Speakers
(These are full range audio speakers, not guitar speakers.)
Cabinet - homemade H style enclosure (open back), with speaker slanted slightly upwards, probably from some nice hardwood (haven't decided what yet, used oak for my last cabinet).
Other sundry bits - separate power supply for the preamp, cobbing power off the main supply and running it through plus and minus 15V regulators, or an LM317 and LM337 for slightly lower noise and better adjustability at the expense of a few more resistors. Down the line I might add more inputs, possibly a mic input - it's trivial to add them with the mixer as set up - just need space for the gain, treble and bass pots on the control panel. Further down the line is the possibility of adding effects (tremolo, vibrato, reverb, distortion, etc., with good circuits at ESP). Curious to hear what a uber clean acoustic signal would sound like with reverb.
The notion that an acoustic amp can be exactly the same as an electric guitar amp is, well, a bit misleading. One can certainly use an electric guitar amp to amplify an acoustic (assuming one has a buffer amp to match impedances). But to really hear what the acoustic sounds like in all it's glory, one should treat the whole amplification chain like an audiophile sound system. That's why I'm using a chip amp (very very good sound with low cost and easy construction), and the full range speaker. WRT the speaker, I chose the Betsy-K over the regular Betsy for the flatter low end, slightly higher efficiency, and the tighter control from the larger magnet. I suspect this would not be a good amp for an electric guitar, in part because of the very high frequency content. (Electric guitar amps usually attenuate the response above something like 7 kHz, to cut out the high frequency buzzing and "ice-pick" harshness. This amp would preserve and transmit all of that really well.)
This project is in process, I've already received the single speaker from Wild Burro (thanks, Doug, for the rapid shipping), and have many of the parts, mostly from MCM Electronics. They have a nice line of reasonably priced toroidal transformers (less weight and stray magnetic fields than conventional trannies) as well as good deals on many parts, like the LM3886 chip, bridge rectifiers, metallized polycarbonate film caps, and so forth. Their prices are very good, and they occasionally have discounted shipping (or even free shipping) for medium sized orders, as well as free shipping for big orders. Website can be a little wonky at times, and they occasionally have pick errors, but are very good about making it right.
If there's interest, I'll post how it all works out here once I'm done with the build. And if any of you have ideas or critiques, I'm happy to hear them.
Regards,
Martin (aerodoc)
I know this is a pretty old thread, but I want to give it a bump, and suggest some web resources for anyone who finds it with a google search. I'm planning on building an acoustic amp for my acoustic electric, and here's the rough outline:
Preamp: Universal Preamp/Mixer from Rod Elliott's ESP (Elliott Sound Project) pages -Project 94
PowerAmp: Single Chip 50W Power Amp from ESP - Project 19
Power Supply - Dual Power Supply (60W), from ESP - Project 04
(Clearly I'm a fan of Rod Elliott's work. You can also buy PCBs from him to support his providing all these great circuits to us all.)
Speaker: Wild Burro Audio's Betsy-K - Wild Burro Speakers
(These are full range audio speakers, not guitar speakers.)
Cabinet - homemade H style enclosure (open back), with speaker slanted slightly upwards, probably from some nice hardwood (haven't decided what yet, used oak for my last cabinet).
Other sundry bits - separate power supply for the preamp, cobbing power off the main supply and running it through plus and minus 15V regulators, or an LM317 and LM337 for slightly lower noise and better adjustability at the expense of a few more resistors. Down the line I might add more inputs, possibly a mic input - it's trivial to add them with the mixer as set up - just need space for the gain, treble and bass pots on the control panel. Further down the line is the possibility of adding effects (tremolo, vibrato, reverb, distortion, etc., with good circuits at ESP). Curious to hear what a uber clean acoustic signal would sound like with reverb.
The notion that an acoustic amp can be exactly the same as an electric guitar amp is, well, a bit misleading. One can certainly use an electric guitar amp to amplify an acoustic (assuming one has a buffer amp to match impedances). But to really hear what the acoustic sounds like in all it's glory, one should treat the whole amplification chain like an audiophile sound system. That's why I'm using a chip amp (very very good sound with low cost and easy construction), and the full range speaker. WRT the speaker, I chose the Betsy-K over the regular Betsy for the flatter low end, slightly higher efficiency, and the tighter control from the larger magnet. I suspect this would not be a good amp for an electric guitar, in part because of the very high frequency content. (Electric guitar amps usually attenuate the response above something like 7 kHz, to cut out the high frequency buzzing and "ice-pick" harshness. This amp would preserve and transmit all of that really well.)
This project is in process, I've already received the single speaker from Wild Burro (thanks, Doug, for the rapid shipping), and have many of the parts, mostly from MCM Electronics. They have a nice line of reasonably priced toroidal transformers (less weight and stray magnetic fields than conventional trannies) as well as good deals on many parts, like the LM3886 chip, bridge rectifiers, metallized polycarbonate film caps, and so forth. Their prices are very good, and they occasionally have discounted shipping (or even free shipping) for medium sized orders, as well as free shipping for big orders. Website can be a little wonky at times, and they occasionally have pick errors, but are very good about making it right.
If there's interest, I'll post how it all works out here once I'm done with the build. And if any of you have ideas or critiques, I'm happy to hear them.
Regards,
Martin (aerodoc)
Hadn't thought about it, but it should be pretty easy to add in, just take the stage right after the mixer, drop in a coupling cap and a jack, or to make it balanced use a unity gain buffer and an inverting buffer. But my focus is using it as an amplifier and possibly adding some effects. Could put a headphone jack on it for practice purposes.
I'll update as the project progresses.
Regards,
Martin
For that "HiFi" production clarity of acoustic instruments, also put serious thought on bi-amping - or at least for a generic passive 2-way crossover scheme. Yes, I know the speaker is "full-range", but look how awfully uneven response it has at the higher frequencies: 10 dB variations all over the place! This will heavily colour your instruments tone! ...Not to mention, dispersion characteristics of a single, moderately large speaker are very "beamy".
For natural reproduction of your instruments tone, and for wider dispersion characteristics at all frequencies, you need another transducer with flatter response at those frequencies, IOW a dedicated high frequency driver. Then you need to ponder which one is easier/cheaper/better to implement a passive crossover or an active crossover plus another 10W-20W power amp for the highs. Parts for both will probably cost as much, the passive might even be more expensive. And if you "bi-amp" you reduce a lot of intermodulation distortion, which would take place in a full bandwidth amplifier... And thus the thing can even further more accuratelu reproduce the natural sound of your acoustic instrument.
For natural reproduction of your instruments tone, and for wider dispersion characteristics at all frequencies, you need another transducer with flatter response at those frequencies, IOW a dedicated high frequency driver. Then you need to ponder which one is easier/cheaper/better to implement a passive crossover or an active crossover plus another 10W-20W power amp for the highs. Parts for both will probably cost as much, the passive might even be more expensive. And if you "bi-amp" you reduce a lot of intermodulation distortion, which would take place in a full bandwidth amplifier... And thus the thing can even further more accuratelu reproduce the natural sound of your acoustic instrument.
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Teemuk,
Thanks for the reply. I'm intrigued as to how this will sound. Given that the fundamental frequencies of the open notes on a guitar vary from 82 Hz to 330 Hz, the Betsy-K is very flat over that range (while the regular Betsy starts dropping off right around 80 Hz). The attenuation between 500 Hz and 1kHz loosely mirrors the traditional mid cut used in Fender tone stacks (for electric guitars, of course), and the increase after that also mirrors the high boost in those Fender stacks. Also, the attenuation in the Fender stacks is much larger (about 15 dB, not the 5-10 we see here). So this might be a really good fit for an acoustic-electric.
All that said, if I'm not happy with the high end response, I can turn down the treble, either on the amp itself, or on the guitar, where I have bass/mid/treble/presence, functionally a 4 band graphic equalizer. Further, if it really bugs me, an Linkwitz-Riley 1-2 pole filter at 1.5 kHz should flatten off the region from 1 kHz to 3 kHz pretty well. If none of that helps, then I'd consider adding a tweeter to clean up the high end. The great thing about DIY projects is that if you're clever when you start, you can keep building and working it to improve it along the way. And clearly I'm better off with a full range speaker that I've built than a 2-way system that I've started and stopped working on because it's complex. Divide and conquer, etc.
A compressor sounds like a great idea, and Rod Elliott has one that runs off of an LED/LDR. Also, tremolo is high on my list because I'm a huge fan of Nancy Sinatra's version of "Bang Bang" (link), and would love to see if I could play it comparably on an acoustic electric with the right amp (I can't sing like her, being, well, male).
An FX loop is definitely in the plans, but my preference is to build everything myself, and then it's usually easier to just install any FX directly in the amp. I don't plan on making multiple acoustic amps - this should last me the rest of my life, hopefully, especially since I should be able to repair it if anything goes wrong - and anything I'd make for an electric guitar would be built a little differently, so I wouldn't need it to be external. Further, a DPDT center off switch could provide a bypass/mute/external option for the loop.
Not sure what you mean by a feedback eliminator. Could you explain further, perhaps with a link to an example circuit? Would this be relevant given that I'm using a piezo pickup?
I did have one fun incident while testing another, simpler amp with my guitar (amp was for another device). Pointing the speaker right at the body of the guitar, I could play certain notes and listen to them slowly increase in volume (over several seconds) as the output excited the string vibrations. Damping the string killed the phenomena immediately, and it worked for several different notes, with different response times. Turning the guitar so the soundboard wasn't square on to the amp stopped the effect too. Kind of a lucky accident to have a really small but positive value for the exponential feedback so the effect is slow.
Regards,
Martin
Thanks for the reply. I'm intrigued as to how this will sound. Given that the fundamental frequencies of the open notes on a guitar vary from 82 Hz to 330 Hz, the Betsy-K is very flat over that range (while the regular Betsy starts dropping off right around 80 Hz). The attenuation between 500 Hz and 1kHz loosely mirrors the traditional mid cut used in Fender tone stacks (for electric guitars, of course), and the increase after that also mirrors the high boost in those Fender stacks. Also, the attenuation in the Fender stacks is much larger (about 15 dB, not the 5-10 we see here). So this might be a really good fit for an acoustic-electric.
All that said, if I'm not happy with the high end response, I can turn down the treble, either on the amp itself, or on the guitar, where I have bass/mid/treble/presence, functionally a 4 band graphic equalizer. Further, if it really bugs me, an Linkwitz-Riley 1-2 pole filter at 1.5 kHz should flatten off the region from 1 kHz to 3 kHz pretty well. If none of that helps, then I'd consider adding a tweeter to clean up the high end. The great thing about DIY projects is that if you're clever when you start, you can keep building and working it to improve it along the way. And clearly I'm better off with a full range speaker that I've built than a 2-way system that I've started and stopped working on because it's complex. Divide and conquer, etc.
A compressor sounds like a great idea, and Rod Elliott has one that runs off of an LED/LDR. Also, tremolo is high on my list because I'm a huge fan of Nancy Sinatra's version of "Bang Bang" (link), and would love to see if I could play it comparably on an acoustic electric with the right amp (I can't sing like her, being, well, male).
An FX loop is definitely in the plans, but my preference is to build everything myself, and then it's usually easier to just install any FX directly in the amp. I don't plan on making multiple acoustic amps - this should last me the rest of my life, hopefully, especially since I should be able to repair it if anything goes wrong - and anything I'd make for an electric guitar would be built a little differently, so I wouldn't need it to be external. Further, a DPDT center off switch could provide a bypass/mute/external option for the loop.
Not sure what you mean by a feedback eliminator. Could you explain further, perhaps with a link to an example circuit? Would this be relevant given that I'm using a piezo pickup?
I did have one fun incident while testing another, simpler amp with my guitar (amp was for another device). Pointing the speaker right at the body of the guitar, I could play certain notes and listen to them slowly increase in volume (over several seconds) as the output excited the string vibrations. Damping the string killed the phenomena immediately, and it worked for several different notes, with different response times. Turning the guitar so the soundboard wasn't square on to the amp stopped the effect too. Kind of a lucky accident to have a really small but positive value for the exponential feedback so the effect is slow.
Regards,
Martin
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