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Made a quickie 2-channel guitar mixer at the weekend


irishstu

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I made this over the weekend. It's a two-channel passive mixer.

 

minimixer2.jpg

 

Parts required:

 

- 1x enclosure

- 3x 1/4" sockets

- 2x 10k log pots

- 2x knobs

- 2x 10k resistors

- some wire

 

Schematic...

 

minimix2schematic.jpg

 

 

Here's a photo of the guts (not that there ARE many).

 

minimixer2guts.jpg

 

 

This one won't get a snazzy paint job, since it's for a friend (in exchange for a bottle of Baileys), so it's just going to get the Dymo

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I made this over the weekend. It's a two-channel passive mixer.

 

minimixer2.jpg

 

Parts required:

 

- 1x enclosure

- 3x 1/4" sockets

- 2x 10k log pots

- 2x knobs

- 2x 10k resistors

- some wire

 

Schematic...

 

minimixschematic.jpg

 

 

Here's a photo of the guts (not that there ARE many).

 

minimixer2guts.jpg

 

 

This one won't get a snazzy paint job, since it's for a friend (in exchange for a bottle of Baileys), so it's just going to get the Dymo

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The schematic link isn't working. I checked the main page to see if their site is down but it is working, so maybe the pic was removed?

 

{edit}

 

Where did you buy the enclosure? All the ones I'm seeing are over $8. I don't think I could buy all the other parts you used for under $8 total.

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The schematic link isn't working. I checked the main page to see if their site is down but it is working, so maybe the pic was removed?


{edit}


Where did you buy the enclosure? All the ones I'm seeing are over $8. I don't think I could buy all the other parts you used for under $8 total.

 

 

Which link? You mean diystrat.blogspot.com?

 

I'm living in Taiwan and managed to find those boxes for about 5 US bucks each. They're not Canadian-made Hammonds or anything, but they do the job. The component parts cost pennies. You could of course box it in something else, even a tin can or something. There's no stomp switch, so the box doesn't even need to be very strong.

 

EDIT: Oh yeah, something IS screwy. It's the image itself though. Let me try and sort that out.

 

EDIT 2: Hey can you try now, katillac? Might need to hit refresh or something. This is the blog entry I originally made that schematic for, btw: http://diystrat.blogspot.com/2008/08/two-channel-mini-mixer.html . Just used an "el cheapo" plastic enclosure with a metal bottom that time.

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10K grounded pots? Major signal loss.

 

With a passive box thay should match or be higher than guitar pots. 2 in parralel maybe even doubble like 500Ks for single coils, 1 meg for HBs.

 

You can also wire them like a rickenbacker guitar with a floating ground on one leg so the signal doesnt drain to ground.

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10K grounded pots? Major signal loss.


With a passive box thay should match or be higher than guitar pots. 2 in parralel maybe even doubble like 500Ks for single coils, 1 meg for HBs.


You can also wire them like a rickenbacker guitar with a floating ground on one leg so the signal doesnt drain to ground.

 

 

I really haven't noticed much signal loss, but I'll do a test with and without it. Like I said though, I'm using it with a practise amp at home, rather than for anything of importance and it seems to work well for that.

 

I'd like to make it better if that's possible of course, so thanks for the advice. If I bump the pots up to, say, 1M each, what would you recommend for the resistors?

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500K pots should do the job and retain a linear turn on the knobs. If you use a strat you can try 300 or 250k, but remember the guitar has one in it as well so the signal is actually seeing the cummulative effect of both the guitar and the pots in the box. 2 X 250K will equal 125K. If you have a 500K in the guitar and a 1 meg in the box it it will only bring it down to 325K or so which should still be good. a 1 meg with a 250K may only bring it down 50 ohms.

 

 

The 10K resistors are in line with the signal, they will drop the signal as well. You can try it with them in there, Try jumping them out and see what the difference is with a signals passing. You can try doing without them if theres a great loss, or you can try like a 1 or 2mf cap instead. The caps would isolate any DC signal, while passing the usable signal. this might be useful when running foot pedals in. You can also put the caps in parallel with the resistors and try that. You'll get more signal through. The higher the capacitence the more bass will pass, but unless isolation is needed, go with the Caps only existing resistors with caps, or straight jumpers and let the pots do the job of separation.

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500K pots should do the job and retain a linear turn on the knobs. If you use a strat you can try 300 or 250k, but remember the guitar has one in it as well so the signal is actually seeing the cummulative effect of both the guitar and the pots in the box. 2 X 250K will equal 125K. If you have a 500K in the guitar and a 1 meg in the box it it will only bring it down to 325K or so which should still be good. a 1 meg with a 250K may only bring it down 50 ohms.



The 10K resistors are in line with the signal, they will drop the signal as well. You can try it with them in there, Try jumping them out and see what the difference is with a signals passing. You can try doing without them if theres a great loss, or you can try like a 1 or 2mf cap instead. The caps would isolate any DC signal, while passing the usable signal. this might be useful when running foot pedals in. You can also put the caps in parallel with the resistors and try that. You'll get more signal through. The higher the capacitence the more bass will pass, but unless isolation is needed, go with the Caps only existing resistors with caps, or straight jumpers and let the pots do the job of separation.

 

Thanks WRGKMC,

That's some really useful information.

Cheers. :thu::thu::thu:

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I'm living in Taiwan and managed to find those boxes for about 5 US bucks each. They're not Canadian-made Hammonds or anything, but they do the job.

 

Oh heck yeah! Recycled aluminum FTW! That's one thing on the list of many things I miss about Taiwan. The last pictures I saw (taken about 5 years ago) of where I once lived in Tien Mou made me a bit sad and melancholy. The area where our house was is now all high-rise apartments and I can't even imagine how Taipei of today compares to when I lived there. Even then, as a kid, I enjoyed the bargain shopping, but these days... oh my goodness, I'd have to really watch my budget. One stop I know I'd like to make is further south to visit where that one guy (Antonio Tsai I think is his name) has the big shop that does custom guitar work and really cool inlay stuff. I think he's in Tainan.

 

The blog link works fine now =)

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Where did you buy the enclosure? All the ones I'm seeing are over $8. I don't think I could buy all the other parts you used for under $8 total.

 

 

You can get the cost WAY below $8. For example the "best" enclosure is an Altoid's mint tin. Buy it for a buck and you get some mint candy too. Skip the jacks. Use a 1/4 inch phono plug splitter cable. it will have three ends. Cut them off. Resisters cost only a few cents. You don't need pots and knobs, guitars have their own volume controls. Likely you can build a passive mixer with junk you have already.

 

I needed one of these so I could use a metronome with headphones. I wanted to hear both the amp's headphone output and the metronome's headphone output at the same time.

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You can get the cost WAY below $8. For example the "best" enclosure is an Altoid's mint tin.

 

That's fine for fartin' around with at home, but they're not good for travel and you can't turn the knobs with a foot very easily without denting the tin. I have a big boxful of Altoids and Jones Soda candy tins for projects. Makes 'em smell wonderful hehe

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heres an Idea that I'm thinking of and perhaps will make.

 

take this same design but add FX loops to each channel so you can mix two different guitar FXs without haveing them go into eachother.

 

with that set up you could run a POG and Hog at the same time or in my case a POG and a Boss OC-2 at the same time

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Reading schmatics is like reading a map. You need a key to tell you what the symbols are. Google up Electronic Symbols and you'll find a hundred sites. Knowing what those symbols are and what they do and how they do it is a whole other story. Youll either need formal training or need to buy books to get any real depth to anything beyond some basics. Most of the symbols depict what the components actually do to electricity.

 

For example, a zig zag line consumes some of the energy when the electrons pass through it.

Its like a car traveling a zig zag road is going to expend more energy than one driving a vs a straight one.

The zig zag, is a resistor and you can think of it as a voltage reducer/current consumer.

It has less conductance and lowers voltage and current. How it does it is more chemical/elemental than anything else. Carbon doesnt conduct electricity as well as copper so less voltage gets through.

 

If you were awake during science classes in school growing up you might remember things like valences and electron, tables of elements, how different substances pass electrons easily like metals, acids, and others insulated. This is all stuff that should be clearly understood as to know how and why things work. Some people have an aptitude for it and the heavy math formulas. The same formulas used in Algebra, Physics and Chemistry are uses in electronics. Electronics in its purest form is a natureal science. As with all natureal sciences you have to deal with limitations controlling it to do what you want. This is where the components come in. Different components are affected differently by electricity bot AC and DC. I've always loved it and considered it a magical thing because you couldnt see it untlll recently. With the electron microscope they can actually see electrons move through substances now and improove them, CPU chips in the past 15 years jumping in speed are one of the most succesful uses whn impurities were seen in slowing down electrons and refining was improved to reduce heat and make purer components.

 

Question two. All grounds can connect through the box if its decent metal. It shields against stray EMF (Electro Motive Force) and RF (Radio Frequencies)

 

I most cases, wires are also used for a secure connection so the thing doesnt get staticy if something loosens up, plus alluminum isnt as good a conductor as copper so copper wires are used to minimise sound loss and the box is just grounded to shield from noise.

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Reading schmatics is like reading a map. You need a key to tell you what the symbols are. Google up Electronic Symbols and you'll find a hundred sites. Knowing what those symbols are and what they do and how they do it is a whole other story. Youll either need formal training or need to buy books to get any real depth to anything beyond some basics. Most of the symbols depict what the components actually do to electricity.


For example, a zig zag line consumes some of the energy when the electrons pass through it.

Its like a car traveling a zig zag road is going to expend more energy than one driving a vs a straight one.

The zig zag, is a resistor and you can think of it as a voltage reducer/current consumer.

It has less conductance and lowers voltage and current. How it does it is more chemical/elemental than anything else. Carbon doesnt conduct electricity as well as copper so less voltage gets through.


If you were awake during science classes in school growing up you might remember things like valences and electron, tables of elements, how different substances pass electrons easily like metals, acids, and others insulated. This is all stuff that should be clearly understood as to know how and why things work. Some people have an aptitude for it and the heavy math formulas. The same formulas used in Algebra, Physics and Chemistry are uses in electronics. Electronics in its purest form is a natureal science. As with all natureal sciences you have to deal with limitations controlling it to do what you want. This is where the components come in. Different components are affected differently by electricity bot AC and DC. I've always loved it and considered it a magical thing because you couldnt see it untlll recently. With the electron microscope they can actually see electrons move through substances now and improove them, CPU chips in the past 15 years jumping in speed are one of the most succesful uses whn impurities were seen in slowing down electrons and refining was improved to reduce heat and make purer components.


Question two. All grounds can connect through the box if its decent metal. It shields against stray EMF (Electro Motive Force) and RF (Radio Frequencies)


I most cases, wires are also used for a secure connection so the thing doesnt get staticy if something loosens up, plus alluminum isnt as good a conductor as copper so copper wires are used to minimise sound loss and the box is just grounded to shield from noise.

 

 

ohhh thanks a lot

im in high school lol, but i really like all these DYI stuff, it makes everything cooler =D

thanks again dude

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The 10K resistors are in line with the signal, they will drop the signal as well. You can try it with them in there, Try jumping them out and see what the difference is with a signals passing.

 

 

The difference will probably be negligible considering the output load is likely to be 100s of kohms. 10kohm won't do much. It's like backing your volume pot from 10 down to 9.5 on the guitar.

 

Removing them or replacing them or parallelling them with a cap isn't a good idea though, because if you turn down one channel you ground the output, so the other channel doesn't get passed either!

 

A reasonable compromise might be replacing those 10k with the second gang of a dual-gang pot. As you increase the attenuation of a channel you increase the value of that resistor. At "0" you get the series resistor equalling its highest value, thus making its effect on the other channel negligible. And at "10" you get 0 series resistance. You do end up with both channels 'shorted' together when both are set to max though - There will always be compromises with a passive mixer I guess!

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Eltonto, thats why I mentioned wiring the pots like a rickenbacker does. Right now its wired like a gibson so when you turn one knob off the other channel is affected.

 

If the incoming signal wire is swapped to the center leg and the output is connected to the outside leg you can turn the pot down and it wont ground the other channel, it just grounds the incoming signal eliminating the need for the resistors.

 

If high value pots are used I agree the 10K might not mean much, but with all they hype about true bypass switches and such, if losses arent nessasary, why run your signal through additional resistance for no reason.

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I made this over the weekend. It's a two-channel passive mixer.

 

Parts required:

 

- 1x enclosure

- 3x 1/4" sockets

- 2x 10k log pots

- 2x knobs

- 2x 10k resistors

- some wire

 

Schematic...

 

 

 

Here's a photo of the guts (not that there ARE many).

 

This one won't get a snazzy paint job, since it's for a friend (in exchange for a bottle of Baileys), so it's just going to get the Dymo

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  • 4 years later...
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so you seem pretty knowledgable on the wiring stuff. I'm planning to do the same type of thing, but instead of 2 1/4 input jacks, i'm using 3 (or six with some series wiring) piezo disc or rod pick-ups. And i wanted to know, should i use any resistors? Or just wiring and pots? By the way, it's plugging into an amp.

the specs for the piezos would be: more likely the first one though

 

Resonant Frequency (kHz): 6.3 +/- .6kHz

Resonant Impedence (ohm): 1000 max.

Capacitance (nF): 10.0 +/- 30% [1kHz]

or

Resonant Frequency (kHz): 4.6 +/- 0.5kHz

Resonant Impedence (ohm): 300 max.

Capacitance (nF): 20.0 +/- 30% [1kHz]

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also, what do you mean by the second paragraph? What do you mean by center leg and outside leg or leg in general. i don't understand the term and i'm trying to make one as you say so that i can turn the channels up and down independently of each other.


WRGKMC wrote:

 

Eltonto, thats why I mentioned wiring the pots like a rickenbacker does. Right now its wired like a gibson so when you turn one knob off the other channel is affected.

 

 

 

If the incoming signal wire is swapped to the center leg and the output is connected to the outside leg you can turn the pot down and it wont ground the other channel, it just grounds the incoming signal eliminating the need for the resistors.

 

 

 

If high value pots are used I agree the 10K might not mean much, but with all they hype about true bypass switches and such, if losses arent nessasary, why run your signal through additional resistance for no reason.

 

 

 

 

 

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