Key Board stereo headphones to mono input

Synth schematics are a bit like rocking h.ds.

But the one I found for a Korg looks pretty standard for deriving a mono sum from the headphone amps?

Dave.
 

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ecc83 said:
Synth schematics are a bit like rocking h.ds.

But the one I found for a Korg looks pretty standard for deriving a mono sum from the headphone amps?

Dave.
Click to expand...
At this point we're only seeing the headphone amp, and yes it's just two amplifiers doing exactly the same thing to two separate signals. The big question is exactly the hell are those two signals? Can't see it in the schematic, and if the stereoization happens in the digital realm (as it most likely does) then the schematic won't tell us anything about it.

The information that Broken_H provided is exactly what we needed, and I bet he figured it out within minutes of using the cable he already had to try it.

JLondon - sorry I got a little touchy there. I have plenty of poor excuses. Now I get the joke, and it's kinda funny, except if you have to explain it... ;)
 
Indeed. Knew it as soon as we had to tweak the junk out of the EQ at the board. Used almost identical schematic to what Arc first posted. simple combiner with 20k resistor...sound guy did the design and work, but I remember buying the 20k resistor at Radio Snack...as well as some other smaller ones 400-500 I think...
 
TimOBrien said:
Check your manual FIRST.

Every keyboard I have had used the left out for mono...
Click to expand...

This is all the Manual says:
Setting Up
NP-31/NP-11 Owner’s Manual

Make sure to properly connect all external devices you are using
BEFORE turning the power on.
A pair of stereo headphones with a 1/4" stereo phone
plug can be plugged in the PHONES/OUTPUT jack
for convenient monitoring. The speakers are automati-
cally shut off when a plug is inserted into this jack.
The PHONES/OUTPUT jack also functions as an
external output. You can connect the PHONES/OUT-
PUT jack to a keyboard amplifier, stereo system,
mixer, tape recorder, or other line-level audio device
to send the instrument’s output signal to that device.

So I guess that when I plug into headphone jack, it disconnects the power amp to the speakers and now I have Line Out. I've been looking for a NP11 schematic with no luck>
 
The only reason I say that is because some keyboard patches are made stereo by using some sort of stereo chorus or polarity inversion. If you sum the two sides together in any way, you will get a bunch of phase cancellation. Unless you are recording the patch in stereo, go ahead and just record one side or the other.
 
Try calling the Yamaha USA number (714-522-9011) They might be able to get you a schematic if you still want a schematic if you still want one. (it may cost a few $$)
 
I think we're making this far too hard. The only keyboards I've seen and heard that don't have a proper output and just have a stereo phone connector don't exactly score well on the quality front, so sonic differences could well be a bit pointless even thinking about?
 
rob aylestone said:
I think we're making this far too hard. The only keyboards I've seen and heard that don't have a proper output and just have a stereo phone connector don't exactly score well on the quality front, so sonic differences could well be a bit pointless even thinking about?
Click to expand...
Here it is:
NP-11 - Piaggero - Portable Keyboards - Pianos & Keyboards - Musical Instruments - Products - Yamaha United States
Yeah it may suck, but it may sound OK to be in the track background. (haven't been able to do that yet)
PS :I don't tickle the Ivory's so that will really make it suck>>>HAHAHAHA
 
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I forgot to mention, if you need the right channel instead of the left for some reason, plug a guitar cable into it just to the first click. That will give you the right side, all the way in will give you the left.

If you are using it for background pads, you might want to record in stereo if you have the tracks. It is easier to make them sit in the background that way. For that, you would just need the TRS to two TS adapter.
 
Nobody was ever talking about getting an actual stereo output for this thing. That part is just too easy! The point is to plug it into a guitar amp (mono input) and get something decent out of it.

If it sounds good with the mixer that you've built then to with it. I'm pretty sure you'd have noticed by now if you were losing all the bass due to phase cancelation. The active mixer you linked from AMZ won't help that anyway. The Behringer mixer might, if it has polarity switches on each channel (I didn't click through to check), but if it really was fake stereo like that you'd do just as well to simply throw away one of the channels.

...But the fact that it sounds fine combined with Broken_H's information that it is an actual stereo signal with actually different sounds on each side (low notes left and high notes right) leads to just go with what you've got.
 
It's a typical budget keyboard for schools with some OK sounds, but they hiss quite badly by proper keyboard standards, and running them one sided really won't muck up the sound that much - with these, I'd just stick a guitar lead in and it will be fine. The kinds of differences we're talking about are a bit lost - because a guitar amp is also pretty naff sounding on keyboards, having a tailored sound suitable for er, guitars. So plug it in, and away you go.
 
Ashcat>Yeah I get good lows and highs the whole thing sounds good and that 25k pot really works good.
I turn it up as high as I can to get rid of any back ground hiss (until the amp starts to crap out) and then dial it back.
 
I ran the separate L + R outputs from my Casio through an ancient Radio Shack 4-input mono mixer with no phase issues on any of the sounds I used. I'm sure any passive mixer set-up would work just as well.
 
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