RIC COPY troll bridge update (amp inside guitar)

nopainkiller · #1 08-23-2008

http://homerecording.com/bbs/showthr...=1#post2964688

Had to make a new thread for this guitar, since the questions and the guitar are completely different now.

As of now, I have the neck wired for parallel and series, and the bridge for coil cut. Then after the 3 way, a master bass cut, then master mid scoop, then master tone. I'm waiting on coaxial wire to finalize everything, I'm also adding a distortion switch that will do what the black ice did, and turning the main tone pot into a push/pull for neck phase switch.

There is also an amp in my guitar now. I thought I'd biuld a little tiny amp to put into the hollow body so I could play anywhere. I wanted to biult the simplest one that I could find so it would take up little space, but wanted a good sound, and settled on a design I found at runoffgroove.com. It uses a LM386 IC and it;s a lot of fun to play. It took a bit to find the sweet spot where to stick it in the body, i settled on the top of the sound hole, 1/3 showing. I get amazing sutain and crunch without being plugged in. But I have a big problem with battery drain. The batteries seem to run out incredibly fast. It might be that I wired the amp for alot more bass for sustain, or something stupid I did wrong. Maybe the way I have it grounded. The amp circuit is grounded to the bridge, along with the battery, I dunno if this is ok or not. I dunno bout amps inside guitars!

It might be my imagination, but there seems to be signal loss. I think I should wire the on switch to connect the input when it turns on. I just got it in there so good, and tight, it's gunna suck to redo it. Especially to resolder the pc board! But is there a way to have it wired, so when I have it plugged in, and have the amp on at the same time without signal loss?? Am I even really lossing any signal??

Here is the schematic/diagram. It's really crude I just drew it up in paint. Then some pictures.

When drawing this, I forgot to put in the treble bleed mods on the volume pots.

nopainkiller · #2 08-23-2008

here's the amp, there's a ground wire from the bridge, and live one from the input jack.

nopainkiller · #3 08-23-2008

Here's how it looks. I used a speaker from some portable cd player speakers. They're 8 ohms and can do one watt. The amp puts out .5 I think. I might biuld a bridged one that would put out a full amp, but SO MUCH WORK!!! I tried out a bunch of different types of speakers ffrom a buncha different things, and this one sounded the best. The 8ohm .25 wat was nice, but I wanted the sustain, which is why I put the 470 uf in the amp instead of the 220 uf. Could THIS be the reason for the quick battery drain? Or is this just how fast they run out?

nopainkiller · #4 08-23-2008

Here's how I turn it on. It's in the lower part of the sound hole. Not as easy as it could be to reach, but it works fine.

I really want to get all the kinks out before I finalize everything witht eh shielded wire and really put the amp in there good. Is there any signal loss anyone can spot from the schematic??

nopainkiller · #5 08-23-2008

I put the speaker in really snug on the bottom of the cavity with velcro. I used velcro for the battery too, and velcro and electric tape for the amp. Both are attatched to the roof of the cavity. The battery comes out fine (I've had to change it many many times already), and everything is hidden ok, I think. I might put the thinkg in the main cavity with all other wiring, and wire the battery and speaker to the other side.

nopainkiller · #6 08-23-2008

nobody with any comments? Criticisms? Advice? Suggestions? Bashings? Anything! I wanna know what people think! I will record clip of me playing through it, and after finalizing it, will post pictures. Maybe I'll do a video. This thing is the SH*T!!!!

rayc · #7 08-23-2008

You do know how a semi acoustic guitar develops its tone don't you?
All that effort to rectify the circuitry so you could do this:
Are you related to Nero?

nopainkiller · #8 08-23-2008

you're not really saying anything, you just kinda said it was stupid. Maybe I don't know how it does. I know the hollow body contributes to the tone, I put the amp inside, so i could have it resonate and I could solo. This isn't for real playing, it's for taking it out and playing for fun. And it's easily removed. It's two wires.

I might put an onboard pre amp in.

..You might as well have just posted "ur gay" or something. You're that guy who goes around posting "ur gay" on all those blogs and youtube videos.

ido1957 · #9 08-23-2008

Stop putting down gays.....that's just gay

rayc · #10 08-23-2008

I'm not homophobic and I don't make such comments, not even by inference. I know folk now use the term, thanks in part to South Park, as a non specific put down but I don't. I also think folk often miss the irony (rarely done properly I know) of such usage by the SP crew.

My comments referred to:
a) the connection of additional items to the soundboard that may effect it's ability to do its job properly;
b) the fact that you've turned a reasonable copy guitar into a Frankenstien axe after an awful lot of dithering, questioning etc without, apparently, any clear aim
&
c) Nero, apocryphally?, fiddled while Rome burnt (some say he wanted it burnt so he could rebuilt it to his vision). Vaguely speaking, you've fiddled with this guitar so much that it is no longer what it was.

I've seen & heard a few guitars with built in speakers and amps. Some are great some not. The design of both has to be a significant compromise as yours is, yet yours is even more so.

Have fun with it. Just don't be disappointed when, on occasion, someone doesn't share your enthusiasm for what is, in my eyes, pubescent clock exploration so publicly done.

nopainkiller · #11 08-24-2008

well thanks for the input finally. That helps alot!

I mess with with this guitar cuz it's not a real rick. I thought I could do anything I want. All the things I've done could be easily reverted.

When I got this guitar it was wired through the 3-way and bypassed to a main volume. I'm curious would you have left it that way? I know my wiring is crazy and crowded, but I like the tone options, and I'm still thinking about where I'm going to stop.

The only aim I really had with this guitar was to learn about wiring, guitar electronics, and getting good tone, and hopefully some info and history about ric copies, the lawsuits, and the companies. All of which I've acheived thanks so folks here, except for the latter. But I'm still not done.

Now by the soundboard do you mean the entire inside of the body? Or the plastic cover with the circuitry? U can't mean the amp chip itself, maybe place it somewhere else??

Also could you talk a little more about the guitars with amps in them?? I'm thinkin adding some mass to my headstock might help a bit with a few dead spots on the neck. The tone control helps with most of them.

nopainkiller · #12 08-24-2008

I think the actual amp chip is getting hot. That might be what's cutting the amp off. Not dying batteries.

Anyone know a good design for a really small onboard preamp with no variable gain or anything?? I just want something to compensate for the complex circuit load, and the capacitance of the cables. Preferably one that doesn't use a 9v battery. I heard talk of one that ran off two 3v calculator batteries. I hear of these things but can't find the designs anywhere!

Also, I could just get a stereo jack, and wire the second loop to the onboard amp, couldn't I?

I named renamed her Francine, after Raycs Frankenstein comment. Her name used to be Mary.

Anfontan · #13 08-24-2008

Quote:

Originally Posted by nopainkiller

I think the actual amp chip is getting hot. That might be what's cutting the amp off. Not dying batteries.

Anyone know a good design for a really small onboard preamp with no variable gain or anything?? I just want something to compensate for the complex circuit load, and the capacitance of the cables. Preferably one that doesn't use a 9v battery. I heard talk of one that ran off two 3v calculator batteries. I hear of these things but can't find the designs anywhere!

Also, I could just get a stereo jack, and wire the second loop to the onboard amp, couldn't I?

I named renamed her Francine, after Raycs Frankenstein comment. Her name used to be Mary.

Actually a pignose amp wouldn't cost much and would be almost as portable. It sounds like there is a short in the circuit that is heating up the 386 and draining the battery. A calculator battery wouldn't last long, maybe 100 milliAmp hours or so where the 9 volt is about 500 milliAmp hours.
And there is also an 8 watt IC chip in a regulator type package that you can install a heat sink on to dissipate the heat...
Check out the circuit below-
http://www.reconnsworld.com/audio_8wattamp.html

nopainkiller · #14 08-24-2008

ah thanks. I think I'll have to go back and check. The short wouldn't be casued by residual crap? You know like the resiny oily flux like stuff that flows when you solder, right? I guess I'll go in and check the grounds and everything. I don't want to have to rebuild the entire circuit.

the 2 3vs I was reffering to was for on onboard preamp in addition to the onboad practice amp. The preamp would just boost the signal before the normal guitar cicuitry. The 386 is different from the 383 that was in the schematic you showed me. I think the 386 is only able to put out 1/2 a watt. I'm surprised to see how the 383 can do 8, that's wierd.

nopainkiller · #15 08-25-2008

this is the third time I've untaped the chip and checked everything. I can't figure out what's shorting the signal! I even when in and scraped the spaces in between the connections, in case it was like oil or something. I tried reheating the solder to make cleaner connections in case I had cold joints. I don't know if I made it worse or what, but the amp chip is still getting really hot.

I taped the rim of the metal covor on the speacker so it would rattle and give me less treble. I overdid it I guess cuz now it's just plain bass. That might be driving it even harder. I don't know. This sucks.

Here's a pic. the very bottom are the grounds

danw · #16 08-25-2008

I don't know anything about amplifier circuits, so there's nothing I can really offer you in terms of advice. But I would like to hear some sound samples.

nopainkiller · #17 08-25-2008

Ok, I guess in the next few days I'll hook up the mics and record a few diddies. I drew that freakin schematic mainly so you could see what I did, Danw, since you helped so much. You asked to see the mid scoop and the bass cut. Should I just upload the clips to the forum or is there somewhere i can put them and give a link? I record onto tape too, so then i'll have ta put in onto the comp.

I'm still getting it how I want it, I put tape on the inside rim of the metal cover that goes over the speaker to get rid of the rattle. I had to replace the portable cd speaker with the other because I'd broken the lead and can't fix it. But the other ones cover rattled too much. Now with it taped around the edge there's no rattle and it's fat tone. I kinda like it, but need some of the rattle back it think. So I gotta go back in and take the speaker out, which is the hardest thing to remove in there. BLAH!

At least I get an hour or so straight of playing before it goes out. Then I gotta let it rest. Dunno if it's the battery or the chip. Maybe I should just totally redo the grounds, or just rebuild the amp in the 1W version with two bridged 386s. There would be less battery life, unless it was an error in building the amp. Still deciding. I am really thinking about on onboard amp just to boost the signal enough to compensate for the capacitance of the circuit and cable. And maybe a tiny bit more on the high side. This was what I was thinking would only need 2 3v calc battereis to run.

As for a heatsink Anfotan mentioned, I don't think I could fit one of those in my guitar.

danw · #18 08-26-2008

Thanks, by the way, for the schematic. Amps in general do tend to get hot, but I don't see why this one should be getting any hotter than, say, a battery-operated clock radio. There's got to be an error in the wiring in there somewhere, I just don't know where.

As for clips, I'd upload to lightningmp3.com and post a link. I don't know of a way to upload it directly to the forum.

danw · #19 08-26-2008

Here's another silly idea. I've seen amps heat up if the impedance in the speaker is too low for the amp. If you haven't already, you might check and make sure you're using a speaker with enough ohms.

nopainkiller · #20 08-26-2008

the amp need a minimum of 4ohms. I think even less. My speaker is can do 1 watt and has 8 ohms. The amp can put out .5 watts. If I do a bridged one it'll be the full 1 watt, but It would drain the battery even faster. the one I first used was 8ohms but only .25 watt. I gotta freakin find where the short is. I'm gunna check *sigh* once again.

nopainkiller · #21 08-26-2008

Actually, it's not a short or anything. Because it works. The chip has an auto shut off to protect itself against heat. I DO need a heatsink. I dunno how hard it'll be to install. Or how small I can get one. Also, the 9V batteries aren't supposed to put out that high voltage for long times. Dammit.

danw · #22 08-27-2008

Well, it's good to know it's not the wiring. And it's a good thing that chip shuts off before it sets your guitar on fire. I have a feeling a heat sink is going to have to be kind of large in order to function -- that's the point, right? I'm thinking it's a big chunk of metal used to dissipate heat.

I'm sure others have made this suggestion, but I'll encourage you again to just make a separate enclosure for the amp, and get it out of the guitar. Firstly, the guitar will likely sound better when it's not stuffed full of all this stuff. Secondly, I don't think it's a good idea to put anything that generates substantial heat inside a wooden guitar that you value. Also, it occurs to me that sitting inside this tight wooden box, you're not getting a lot of ventilation to this thing, so it's going to be quicker to heat up. So far you haven't made any irreversible changes to the guitar, and I'd like to see you continue that. In a separate box, you could put as many holes/vents in the outside as you like and get this thing cooled off.

I've seen these done in fun ways, too. Years and years ago, a buddy of mine made a belt-mountable amp out of a He-man shower radio. I'm sure you could find an interesting box to fit this stuff into.

stevieb · #23 09-05-2008

My first impression was, Why bother?

Then I thought about it a little more, and realized that the reason is to have some fun doing something a little different. Sure, you could have probably just snagged a Danelectro Honeytone and clipped it to your belt (or taken it out of it's case and mounted it in the guitar) but what would you have learned doing that? Almost nothing.

So, have fun.

muttley600 · #24 09-05-2008

Quote:

Originally Posted by stevieb

My first impression was, Why bother?

Then I thought about it a little more, and realized that the reason is to have some fun doing something a little different. Sure, you could have probably just snagged a Danelectro Honeytone and clipped it to your belt (or taken it out of it's case and mounted it in the guitar) but what would you have learned doing that? Almost nothing.

So, have fun.

I guess I never got pas the "why bother" bit.