hello, this is my first time posting here, and i have a problem.. i would like to build a tree-like vu meter for a gift. i made one with lm3915. the problem is that when i plug in my mic preamplifier, almost all 10 led turn on and stay that way.. can someone help me please, this is my first time doing something like this? max output from preamp is 500mV with 47 kOhm resistance, and i think that vu works, when i plug it into output for my computer speakers it works perfectly...

Schematic please :-)

Schematic for preamp: http://www2.produktinfo.conrad.com/d...r-Mikrofon.pdf (page 12), i am sorry i can't find an english version, and this is the lm3915 circuit: Circuits-Lab.com » Blog Archive » VU meter circuit using LM3915. i also made an lm386 amp for the preamp, vu didn't work properly, so i thought there was something wrong with the preamp, so i made one with another lm386...but it seems there is too much noise.. i was also wondering if i could use this schematic http://www.instructables.com/files/o...GSFLROK12R.gif but use lm3915 instead of lm3916? thank you

i gave it a quick try with 50 - 80 kohm, but still, 6/10 leds is on all the time. thank you for your time. i guess i should buy a new lm386 and lm3916 and make that circuit i was asking about earlier

i'm not sure if i did this corectly, i put the resistor between output of the preamp and it's ground, is that ok? it needs around 70 kohm to stop all the leds flashing, but then with me screaming at mic i get only 5 leds to light up. is that because preamp output is 0,5V and max input for lm3915 is 1,2V?if that is so, then i need a different preamp?
i tried disconecting pin 1 and 8 from the capacitor before, but it never changed anything.. should i try this one with resistor as well?
too bad that is a false schematic, i saw it on youtube and it worked kinda like i want it to work.. does anyone have a full schematic with lm386 for mic preamp and lm3915 vu , everything put together? chirstmas is coming and i'm affraid i'm runing out of time, it seems i wont be able to get this to work

yeah i know that lm386 is an amp, but i also saw schematic for its use as a preamp to an electret mic... so i made one preamp, one amp ( i had two lm386 ), and i bought one preamp ( the first schematic with transistors). i tried different setups of this three chips and none of it worked. i tried with gain 20 and 200, it was mostly the same... i guess i'm doing something wrong. well the mic in the preamp kit had only two wires. i have another one from an old telephone handle. why?thank you very much for your time

it shows a three-wire mic, but i got a two-wire one, red and black. along came a little book on how to solder the kit, it showed how to solder a three-wire mic (page 11) and how to solder a two-wire mic kit (page 12) . so i put black on - and red to + and nf. i'm not sure if that is allright.. thank you, i'm so happy you are willing to help me

thank you for your help audioguru, but i was really hoping for something simpler, even if i'm making this as a gift for my girlfriend i just think i lack experience to make that circuit, since i'm having troubles with simpler lm386 circuit. is there any way to get somekind of lm386 preamp to work with lm3915? you mentioned that LEDs would be dimm with that circuit that has lm386 for a preamp and lm3916 for vu, but it seems that it works:YouTube - Microphone LED VU Meter.. so could i just replace lm3916 with lm3915? i already have all the components that it requres, only 3915 instead of 3916.. if that circuit doesn't work, i will do my best to make yours, since i really want to make this thing to work. if that doesn't work, i'll just buy another plug for computer speakers and connect that to vu..