Audio splitter troubles

[moody07747]

today i built an audio splitter

the input is a 1/4" phone jack and a 1/8" phone jack
the output is three 1/4" phone jacks and two 1/8" phone jacks

everything is wires inside the case, no circuit board

a few minutes ago i swapped out some of the mono connectors with sterio connectors because i wanted sterio sound

anyways
i pluged my MP3 player and electronic drum set into the input and my headset into the output. When i turned on the MP3 player it sounded great but there was some static type noise. after that i turned on the drum set and set it to vol. 5 which is normally loud but when patched through my audio splitter it was really quiet. even at max. volume the drum set sound quiet.

so why is the splitter making my drum set quiet and why is there that static type noise from the MP3 player?


ill be resoldering everything tomarrow after i get some fuel for my soldering torch
it kept going out when i was soldering the mono to sterio connectors
maby theres a bad connection in there

oh, heres the wireing sheet for my splitter (see pic)

 

[Nigel Goodwin]

You can't just short the two inputs together!, it means you're shorting the output of your drum machine and MP3 player together - this will make them both quiet, and could potentially damage them.

What you should do is build a virtual earth mixer and mix them together!.

 

[moody07747]

You can't just short the two inputs together!, it means you're shorting the output of your drum machine and MP3 player together - this will make them both quiet, and could potentially damage them.

What you should do is build a virtual earth mixer and mix them together!.

ouch...

 

[moody07747]

ok
ive been searching the net today and have been to many sites searching for a "virtual earth mixer"

here are a list of sites i found that i think will work
(this first one looks like it will work and seems easy
i would just take out one of the mic inputs

**broken link removed**


these next two pages just confused me...allot

**broken link removed**
http://www.all-electric.com/schematic/simp_mix.htm

**broken link removed**


so thats what i found and overall i like the first page

there is no part list for this so i do have a few question that you guys might me able to help me out with

those small green boxes are resistors, right?
what are the green boxes labled "10k log, POTs?
and what are the circles by those 10k log things?

thanks
im hoping someone knows all this, someone should because i found this page throught this site

 

[moody07747]

oh and will this op amp chip work with the mixer?

https://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=276-1715

 

[Nigel Goodwin]

so thats what i found and overall i like the first page

there is no part list for this so i do have a few question that you guys might me able to help me out with

those small green boxes are resistors, right?

Yes, it's the internationally agreed symbol for resistors (although not green!), and has been for probably 40 years?.

what are the green boxes labled "10k log, POTs?

Volume controls.

and what are the circles by those 10k log things?

I presume it shows the ground connection of the volume pots.

 

[audioguru]

Since you don't have microphones, you need only the single opamp at the right side of your 1st link.
The TL082 is a dual opamp, you need only half of it for mono or make a stereo mixer with dual volume controls.

 

[moody07747]

thanks for the info

ill probably wire the audio splitter backwards so i have 5 inputs and 2 outputs

ill pick up those parts when i get some time

ive been buzy wiring my house with a 220 volt outlet for my new welder...i couldnt resist the blue color of the millermatic 175 :roll:

 

[moody07747]

redid the wiring on the paper

heres what im going to do

 

[moody07747]

i have lost of 24 guage audio wire
would that be big enough for this project or sould i go for some 16 guage wire?

 

[audioguru]

Hi Moody,
Your 5-input mixer circuit looks very good. Where's the 2nd output?

16 guage wire can carry about 12A. The current in this project is just a couple if mA so 24 guage wire is fine. :lol:

 

[moody07747]

I plan on building this in a metal case so i can just attach all the ground to the metal case

the wiring shows one output and i think thats all i need

ive been trying to figure out how to wire the output of this

the wiring sheet shows one wire for output...im confused by this
i want to attach 2 binding posts that will hold the wire going to the speaker but how do i do that with one wire?

is the pos. (+) the one they show and i just ground off the negive?

allong with the posts, i would like to have a 1/4" audio phone jack (sterio) so i can plug headphones into the output

as i said, that output is really confusing me

with a few questions i shouls be able to get this project done


im not too good at electronics now but the more i do these the better i get
i just need some taining on reading wiring sheets

 

[Nigel Goodwin]

This is a line level mixer, it needs to feed in to a power amplifier if you want to feed a speaker, or even headphones.

 

[audioguru]

is the pos. (+) the one they show and i just ground off the negive?

The schematic clearly shows two 9V batteries. One for the opamp's +V supply and the other for the opamp's -V supply. Where the batteries connect together is connected to the input ground, the output ground and the opamp's input ground.
You can't ground off the negative or you will short the negative battery and the opamp won't work.

 

[moody07747]

ok now im really confused, so confused that im getting ready to pay someone here $20 to build this thing for me :lol: (could be because its 1:30 am)

i have to feed this into a amp to run a speaker?
no problem, i can always build an 8 watt amp or something

does this put out mono or sterio sound?

will this chip work?
https://www.jameco.com/webapp/wcs/s...toreId=10001&catalogId=10001&productId=213137
if not, heres the list i have to pick from

**broken link removed**

 

[audioguru]

i have to feed this into a amp to run a speaker?

Yes, a power amp.

does this put out mono or sterio sound?

Mono, since each input is mono and it has a single opamp.

will this chip work?

To make it low power, it doesn't work well. Use a TL071CP for each channel.

 

[moody07747]

thanks
that cleared it up

so all the grounds connect to the ground between the batterys.

is there any way i can convert this from the mono into a sterio mixer?

 

[Nigel Goodwin]

is there any way i can convery this from the mono into a sterio mixer?

You build two of them (one for each channel), and use dual-gang controls, it's as simple as that!.

 

[moody07747]

ok that would be four 9 volts are needed correct?

i may want to run this on 120 volts now

 

[audioguru]

that would be four 9 volts are needed correct?

No. One mono circuit needs +9V and -9V. A stereo or even a 4-channel circuit still needs only +9V and -9V.
A power supply can power as many circuits as its current rating allows.
This circuit will draw a whopping 2mA from each supply for each channel.

It doesn't have to be 9V. It will work fine with+6V and -6V, +12V and -12V or +15V and -15V. :lol: