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to those who built one--question

:

1/15/2001 9:53 PM

to those who built one--question

i built one today, and it's as buzzy as a circuit cpuld possibly be. totally useless. i see 2 possible reasons.

1]-i used a 386, but not the jrc, but an LM386. can that make the diff? i can't see how, but....

2]-there is one capacitor that is connected to pin 7 with a question mark next to it. i must assume that since the cap does have a value listed that it means the polarity is unknown. how'd you all wire it as far as polarity.

any other ideas as to why it sounds so bad are welcome. anything i'm missing? by the way, i've built a ton of pedals for years, so i'm not a beginner--just so u know u don't have to suspect simple mistakes on my part.

thanks,-dale

1/15/2001 10:05 PM

LM386 cross references to the same ECG part number as the JRC386, so no prob there.

I don't see the question mark you ask about, just the number 7. The positive terminal of the cap should go to pin 7.

Observe the circuit in the link listed in the messages above, since the battery is negative grounded, only voltages positive with respect to ground will be present. So put cap negative to ground and the positive terminal to pin 7.

I haven't built one, this is all just me talking.

Chris

1/15/2001 10:30 PM

It's been a while, but if I remember correctly the LM386 seemed to sometimes be a little difficult to get working due to board layout considerations. I would make sure you have a bypass capacitor as near to the power pins as possible. It may also help to read the National Semiconductor data sheet to see if they have any special considerations in there.

My apologies if this seems vague, I will try to look in my archives at home to see if I can find the problem I had with the part.

1/15/2001 10:41 PM

thats what i did, that is, i put a 47 microfarad electrolytic with the positive to pin 7 and neg to ground. could it be that everyone else just doesn't care how buzzy it is cuz it's so simple and cheap? i've never heard anything buxzz this much tho, at least not anything for guitar purposes.

oh, and as for the question mark i mentioned, that was just the number 7 that looked like a question mark during a brain fart i must've had. *S* i saw it as # 7, but later must have spaced.

-dale

1/15/2001 11:03 PM
BOB O	Effects done with the smokey i Heard that if you put the smokey amp in the bottom of a 5 gallon bucket.....you get REVERB.lol Bob

1/20/2001 10:13 AM
Steve A.	Bob: i Heard that if you put the smokey amp in the bottom of a 5 gallon bucket.....you get REVERB.lol So I guess you'd then swing the bucket around and around to get vibrato? Definitely some sort of rotating speaker effect... --Thanks! Steve Ahola

1/15/2001 10:59 PM

figured it out !

it was the speakers i tried ! i tried 3 speakers from home stereo type applications and a couple tiny 3" ers from old radios and such. they all sounded horrid, but having tried so many i figured it can't be the speaker. but low and behold i tried the little 8" speaker in my park practice amp and there is was---clean to distortion without all that buzziness. this is very cool because every year i go to a big river rafting trip with about 30 people and we have a campfire jam every nite for 3 nites. last few years more people have brought guitars, and some are amped up with battery powered amps. this memorial weekend i'm gonna be there with a smoky, rat, and tube screamer pedals !! LOL should be a kick.

by the way, i wonder if i should make a cabinet for it that holds D cells. i can't imagine a 9volt lasting more than about a 1/2 hour at full volume. on the other hand, i think 6 D cells should last many hours. anyone know how long an alkiline 9 v will last in this thing when cranked?

thanks,-dale

ps--damn this thing is loud for a chip and 2 caps !!!

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