two guitars one amp - plus pedals

[stezza]

Hi All,

I was having a jam with some friends last night and we have been using a simple adaptor so we can plug 2 guitars into a solid state crate amp. This seems to work fine (until I finish building my amp) but I noticed when one of us would kick on a fuzz face, the volume of the other guitar would decrease, and the volume pots of each guitar would effect the other. Can anyone suggest a way to solve this? I've tried searching but obviously I get many hits with the search words 'two guitars one amp'. I'm guessing some sort of buffered mixer is required?

[PRR]

Try two 68K resistors as a passive mixer.

This worked in the 1950s when we could not afford an amp for every axe. It is standard in 2-jack Fenders and clones. It will keep the guitars (or effects) from "seeing" each other directly. The 68K is a compromise between isolation and loss. If 47K or 100K is handier than 68K, try that.

[alparent]

Something like this?

[space_ryerson]

Try two 68K resistors as a passive mixer.

This worked in the 1950s when we could not afford an amp for every axe. It is standard in 2-jack Fenders and clones. It will keep the guitars (or effects) from "seeing" each other directly. The 68K is a compromise between isolation and loss. If 47K or 100K is handier than 68K, try that.

Paul, would this work ok for synthesizers as well? I've been pondering a way to get 4 synthesizers into two inputs of my audio interface, and don't want to introduce any noise from using a active mixer, if possible.

[PRR]

> 4 synthesizers ... don't want to introduce any noise from using a active mixer

?? The output from a synth has already been through 43 "active stages". One more well-designed stage (mixer) shouldn't be an issue.

All mixers obey the same basic rules. Most "active" mixers mix passively but buffer before and after.

Will it work for you? It sounds like a $0.96 experiment. Eight resistors. Try 10K.

[space_ryerson]

> 4 synthesizers ... don't want to introduce any noise from using a active mixer

?? The output from a synth has already been through 43 "active stages". One more well-designed stage (mixer) shouldn't be an issue.

All mixers obey the same basic rules. Most "active" mixers mix passively but buffer before and after.

Will it work for you? It sounds like a $0.96 experiment. Eight resistors. Try 10K.

Thanks Paul. Sometimes I need the obvious pointed out to me! The last mixer I tried was noisy in general, so this solution is a bit of knee-jerk reaction. If it doesn't work, I'll get a better mixer.

[familyortiz]

The first stage of the circuit shown at the gallery link is a summing junction. It will blend the sound of both inputs and it does not matter if one is not plugged in. The level/drive of one input will not affect the other. Forget the input switches... I was on some other train of thought when I put those in there. The second stage adds some gain/attenuation and re-inverts to retain the original phase. I designed and use this for my acoustic setup where I can have 2 different guitars plugged in and not have to switch cables. Cheers.


http://www.aronnelson.com/gallery/main.php/v/familyortiz/2CH+COMBINER+STAGE+WITH+ADJ+GAIN.JPG.html?g2_imageViewsIndex=1