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About AndrewCE

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  1. dude you hit the jackpot by coming to this site. there is a thread pinned to the top called "sustainer thread" or something. it has like 300 pages of how to make your own sustainer.
  2. thanks, but i dont think I'm quite ready to deal with transistors yet. i know how they work, but to actually see them implemented in a circuit spins my head around. (maybe you could refer me to a good site/article on transistor tips and how to read transistor schems?) by the way, i have an updated schem, now with an LED and switch. Also, i fixed the wall-wart power supply problem. unfortunately i think radio shack STOPPED stocking and selling op amp sockets, and my town only has one other electronics store (which doesnt stock them) so i seem to be at a dead end as far as soldering up a board goes.
  3. oh that makes sense. thanks, keith.
  4. It seems that a pot configured as a simple variable resistor would be configured: one lead at the end of the resistance track, and the other on the wiper (opposite end of the wiper left open) . But I have seen in many schematics that the 3rd prong of the pot is to be connected to the wiper. Does this matter? theoretically the resistance is the same between the two configs at all parts of the rotation. Does this reduce scratchiness or something?
  5. yes, i've read many articles like this before, and the "low output impedance, high input impedance" system is the best for stompbox-to-stompbox, or from guitar to amp, etc etc, but like the article says, when driving speakers you need a matched impedance for maximum power transfer. i'm sure the concept applies when driving a 0.3" speaker just the same as when driving a 12".
  6. i would normally have the headphone amp at the end of my pedalboard. then, i would unplug it, thus switching into battery-power mode, and velcro it to my guitar strap. at that point i would have no FX, just guitar -> patch cable -> headphone amp -> headphones. that's ultimate portability. or, if i want, i can build the headphone amp INTO my guitar, add a headphone out jack, and only use the 9v power supply to recharge the internal battery w/o removal
  7. eh, my pcb is extremely cluttered. i'll show you a pic as soon as i get one. i think its possible to remove it, but not worth the effort. especially since i would have to remove, and maybe even desolder, some of the jack and pot connections to remove it from the chassis. i think it's easier just to build another one. and i got a larger enclosure this time, bigger than my 1x2x4 that my amp is in now, so it should be easier. i'll just have to reacquire all the parts. i might even re-breadboard are you absolutely sure that i want the lowest possible impedance? i know from speaker cabinets that you want your impedances to match for max power transfer. but i also know that headphone/earphone impedance vary considerably. i'm wondering if i can get by with a lot less gain if only i could match the impedance. is a transformer the only way to do this? p.s. how do you even measure an earphone's impedance? i can only get a DC resistance. and how do you measure output impedance of the amp?
  8. ok, so i just checked, and the lead temp for soldering is 260C. I use a 450C soldering iron. I probably burnt the chip. I shouldve used a socket. Now i cant even remove the probably-burnt chip. Maybe i'll convert it into a fuzz box effect pedal. I think i'll retry this with a socket, and get one of those higher quality opamps. If in the meantime anybody sees an error in my schem that can be fixed, please notify me. I have switched the leads of the power supply so that it matches the schematic exactly. The current state of operation is: with battery power, I get a lo-fi fuzz effect with almost no sustain; it just craps out when the volume gets low. When plugging in the power supply(and therefore cutting off the battery power) i just get a whooshing sound, completely devoid of my guitar signal. I'm not chained up to any other pedals, so thats not the problem.
  9. no the gain is "r1/r2 + 1" so the gain is never less than 1. well before i worry about the pot taper i have to figure out why it sounds like a lo-fi fuzz box.
  10. well as a college student i would like to be able to listen thru headphones so as to not piss off my rommate, and then if i want to move away from my pedalboard i would like to attach the unit to my guitar strap (with the unit now on battery power) and make the amp more portable.
  11. grrrrr i got it set up, but i get no signal through the headphones. just pure hum. i'm gonna check all my connections, but here's my schematic as of now. does anybody see where i went wrong? I added a DC jack for a 9v input. there are 2 connectors that are "normally closed", and when the DC plug is in, one of them is the shell and the other is not connected. the node labeled "dc jack center pin" is not involved in the switching. the reason i added this is so that when my 9v adapter is plugged into it, the adapter powers it. then when it is removed, it goes to battery power. right now i get no signal on either power source. any help? ive done plenty of continuity checks i wonder, was i supposed to use a heatsink when soldering my chip? cause i didnt. could i have burned out the chip? and how do i check for that? ps. when i touch the pot shaft (or even put my finger near it) the hum gets louder. im using a plastic enclosure(all radio shack has, and my altoids tin won't fit a 1/4 in jack). EDIT: ok, i didnt change anything, and now with the battery supply it sounds like an extremely low-fi fuzz box. and the pot taper has problems, which, btw, it has never done while in the gain-control configuration. there is no sound in the power supply operation (but i'm in the process of correcting that) can anyone spot the reason for my fuzz ?
  12. You'd need a multimter with a sample and hold peak detector. Pickup manufacturer's sometimes post this information, but it's a big window at best. That's unfortunate. I'd really hoped to see this worked out. Have you tried playing with capacitor values? As we said in the beginning, the TL082 is better than an LM741. The TL072 is a lower noise version of the TL082. Still, all of these are general purpose "penny" chips because they are outdated by newer technology and you can buy them on the penny. Here's an interesting page, though it's 5 years old. Even then, the TL082 was outdated. http://tangentsoft.net/audio/opamps.html Take a look at this and order yourself some free samples... http://www.linear.com/pc/productDetail.jsp...009,C1026,P1293 This one looks just right for you IMO... it should be more output, less noise, and, you can get free samples... http://focus.ti.com/docs/prod/folders/print/opa627.html yes, i've tried playing with capacitor values. i either get much noise or a dark sound. i opted for the small value cap ("much noise") and i can keep tabs on the noise by rolling down the gain knob. thanks for all those resources. i would get one of those better chips, if i hadn't just finished soldering my PCB and prepping my enclosure. this thing should be finished by this time tomorrow (hope it works!)
  13. i must just be one of those lazy people. actually i have more of a problem with HAVING a charger than USING it. if I could do with no charger, just a 9v supply, that would be awesome. one less thing to worry about losing.
  14. Does anybody know of a 9v power supply that basically acts in this way: you put it in your guitar or pedal, and it acts as a battery supplying 9vDC. When you plug in a 9v adapter, the adapter powers the electronics AND recharges the battery. Then if you need to unplug the adapter the battery is still inside. Has anybody heard of this? I assume if it existed it would be implemented in many, many stompboxes and guitars.
  15. well idk how to really measure my guitar's max voltage swing, i think i'm just gonna have to get by with the variable gain config. my setup now (with the 100k gain rheostat) is really really dark on the low gain settings, then theres that fast jump up to LOUD, and then it starts to clip. I think i'm gonna have to set this thing right on that edge, and find the sweet spot, and if it's clipping just back off on my guitar's volume. It's too much work, but oh well what opamps are better than the TL082 i'm using? i was told that was an "audio" opamp. which are the better ones?
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