Can hear only B3 but not other organs

[Skylight]

I'm really hoping I didn't miss something obvious. Please forgive my ignorance.

I was using Farfisa to play along with tunes on Spotify (phone plugged into NS3C, listening through external speaker). I unplugged my phone and the Farfisa went out. I had only B3 out of all the organs working. I tried turning the NS3C off and on again, turned organ off and tried pianos (fine) and synth (fine). Just missing all the organs except B3! What the heck.

Please please tell me this is an easy fix! A person in my house suggested a factory reset......

[baekgaard]

I'm really hoping I didn't miss something obvious. Please forgive my ignorance.

I was using Farfisa to play along with tunes on Spotify (phone plugged into NS3C, listening through external speaker). I unplugged my phone and the Farfisa went out. I had only B3 out of all the organs working. I tried turning the NS3C off and on again, turned organ off and tried pianos (fine) and synth (fine). Just missing all the organs except B3! What the heck.

Please please tell me this is an easy fix! A person in my house suggested a factory reset......

There are usually one of two things causing these kind of issues 1) Either listening via headphone output using a faulty minijack adaptor (happens more often than you'd think) or 2) you have a pedal connected that in B3 mode works as swell and as volume control for the other organs, and it's at the lowest setting, in which case you can still hear the B3 but not the other organs. Sometimes this is an incorrectly connected sustain pedal.

Do you have a swell pedal connected? Try to remove all pedals and test again and then make sure to plug them in correctly and set your swell pedal at max.

Sent from my phone in brevity

[Hlaalu]

listening via headphone output using a faulty minijack adaptor (happens more often than you'd think)

Just curious: how can a faulty minijack adaptor plugged into the headphones out only silence certain sound engines/sound and not others? By the way he said he was not listening through headphones.

To the OP: another thing that comes to mind is rotary emulation: which channels are you using as main outs? The rotary emulation will route the output to 1-2 no matter what, so of it's switched on for certain organs/engines you may end up with a silent output altogether on other channels.

[Skylight]

To the OP: another thing that comes to mind is rotary emulation: which channels are you using as main outs? The rotary emulation will route the output to 1-2 no matter what, so of it's switched on for certain organs/engines you may end up with a silent output altogether on other channels.

This is what I'd suggest too, the OP should check the Output routing of the Organ section and ensure it is still on 1-2

[baekgaard]

listening via headphone output using a faulty minijack adaptor (happens more often than you'd think)

Just curious: how can a faulty minijack adaptor plugged into the headphones out only silence certain sound engines/sound and not others? By the way he said he was not listening through headphones.

It has happened to me once in a setting where one channel was inverted and summed with the other to a mono signal sent to my monitor. It is similar to converting the sound to M+S (mid and side) and then remove the M signal. So everything that is dead center is removed but the stereo part of the signal remains.

If you experience this, a B3 through the rotatory will sound (although slightly weird) but a mono organ will not. Some mono samples will also not sound, and an EP will only sound when you use stereo effects like chorus of reverb. AP will also make some sounds.

If you have never tried this, it can be good to test out too be able to spot the problem when it appears - I wasn't clear immediately when it happened to me.

I don't think this was the most likely explanation though, but even if not listening through headphones, the headphone output could still be involved with a stereo cable to your amplifier (I sometimes do that - for instance if connecting a 2nd board to the Nord speakers using a jack to minijack connection).

I agree that output routing could also be the culprit - good suggestion. But since the OP said it happened after touching cables I would think some mechanical change (adaptor moved, expression pedal setting or being plugged out slightly) is a bit more likely.

It will be interesting to hear from the OP - we're all just sharing our own mistakes, I guess

Sent from my phone in brevity

[Hlaalu]

If you experience this, a B3 through the rotatory will sound (although slightly weird) but a mono organ will not. Some mono samples will also not sound, and an EP will only sound when you use stereo effects like chorus of reverb. AP will also make some sounds.

I agree that output routing could also be the culprit - good suggestion. But since the OP said it happened after touching cables I would think some mechanical change (adaptor moved, expression pedal setting or being plugged out slightly) is a bit more likely.

It will be interesting to hear from the OP - we're all just sharing our own mistakes, I guess

Yep let's wait for the OP to further clarify, because both yours and mine possible explanations above imply that the OP was consistently switching the rotary sim off for farfisa and vox, while switching it back on again as soon as he changed back to B3, which is a bit of an unlikey scenario.

@baekgaard: whether that is the OP's case or not, I'm just curious to better understand what you said technically: other than shorting the L or the R to ground, or shorting the L to R themselves, what else can a faulty adapter do inside of a jack to explain such outcome? Because if it shorted L and R together, it seems to me you would indeed get a mono summing, albeit in the wrong way because there's no resistor, but this would be precisely that, a mono signal. I am sure I am missing something here, but I don't see how any misconnection between T, R and S can cause such a result.

[maxpiano]

Yep let's wait for the OP to further clarify, because both yours and mine possible explanations above imply that the OP was consistently switching the rotary sim off for farfisa and vox, while switching it back on again as soon as he changed back to B3, which is a bit of an unlikey scenario.

Not so unlikely if the OP was switching Programs (and Vox/Farf patches in most cases have Rotary off) but let's wait for him to come back and tell us more

[baekgaard]

@baekgaard: whether that is the OP's case or not, I'm just curious to better understand what you said technically: other than shorting the L or the R to ground, or shorting the L to R themselves, what else can a faulty adapter do inside of a jack to explain such outcome? Because if it shorted L and R together, it seems to me you would indeed get a mono summing, albeit in the wrong way because there's no resistor, but this would be precisely that, a mono signal. I am sure I am missing something here, but I don't see how any misconnection between T, R and S can cause such a result.

Very valid question I guess the burden is on me to at least indicate some plausible scenarios:

First, a bad connection is usually not "just" a question of a short or an open connection. There can be both resistive, capacitive and inductive coupling between the wires and there can even be non-linear effects similar to a semiconductor junction (i.e. a rectifier -- which is what could cause strong RF signals to be demodulated so that e.g. some local AM modulated radio station was audible in your guitar amp).

Anyway, let's analyse a couple of scenarios. Let's call the output signals Lo and Ro which, in the case of the Nord, are unbalanced output each vs a common ground, Go. Similarly, let's call the signal that goes into the amplifier for Li, Ri and Gi respectively. When all is well, Li = Lo, Ri = Ri and Gi = Go. Also, for simplicity, let's refer to the mid-side conversion so that L = M + S and R = M - S -- which implies that M = k (L + R) and S = k (L - R) where k = 1/2.

You mention the case that Ro and Lo are shorted, which effectively sums them. Hence Li = Ro + Lo and Ri = Ro + Lo (and Gi is still equal to Go). This will create a signal in both channels that is equal to a mid signal, i.e. you will hear the M signal clearly and the S signal is lost. You don't actually need the resistors in a summing network (although I wouldn't recommend building one on purpose like that!) since each output usually has some non-zero output impedance. I GUESS that the Nord's may have some kOhm output impedance, but it could be lower (and then cause quite a load on the output amps if it's very low).

Now, imagine that Go is disconnected instead, and e.g. Ro is connected to Gi and Li and Ri both see Lo. Then each channel will see the Lo - Ro, which is similar to the side (S) signal. This means any dead center signal will not be audible but stero signals will be (anything panned hard sounds almost as expected).

This is similar to what could happen if you connect an unbalanced stereo signal to a mono balanced input.


There may also be other failure modes. E.g. what would happen if the G signal is disconnected, so that Go and Gi are no longer connected? Inside the input amplifier, there is often a common ground between the two channels and each input has an effective input impedance of maybe some kOhm. This means that Gi "floats" but depending on the actual cirtuitry, you can imagine the input having some resistive divider network (maybe a T-like network (ladder)) connecting also Li/Ri (the hot signals) to the ground, Gi. Thus Gi will be connected to the sum (or average or in between) of Li and Ri, and hence the amplifier will see Li = Lo, Ri = Ro and Gi = k (Lo + Ro) where k is "some number" the depends on the output impedance and input impedance and the actual circuit, but could be close to 1/2 in some cases (explanation simplified a bit here).

As the signal being amplified is Li - Gi and Ri - Gi (respectively), each channel will see Li = Lo - k(Lo + Ro) and similar of Ri. Again, if you have a signal that is dead center, then Ro = Lo, and if k happens to be close to 1/2 then centered signals will be strongly attenuated -- but hard panned signals will not.

Something like this happened to me in a mains network some years ago. The net effect was that the light bulbs connected to one phase in the room would vary in intensity depending on how high a power you set the cooking plate to at the stowe top, unless you switched on the oven...

There can probably be other even weirder cases, but the ones above are not -- in my view -- completely impossible to see for bad connecters, weird cables or partially plugged connectors?

I may of course be wrong -- but as said, I've seen at least the first case in practice above in a live setting (albeit slightly different setup not involving a converter but a badly wired cable etc)

Comments/corrections welcome, of course!

[Skylight]

You all must be geniuses. Thank you for sharing your discoveries.

The very first suggestion, that it was a swell pedal, solved it. I don't know why I didn't try that, other than I never use it and thought I didn't even touch it when I unplugged my phone (my phone was not near my foot!).

As soon as I pressed the swell pedal all the way down, there were Farfisa, Vox, and Pipe Organs.

I did have the Rotary Speaker on at 10 at the time, trying to recreate the first verse of the Tornadoes' Telstar (coming along pretty well!)

Thanks again, everyone. This is a terrific forum!

[Hlaalu]

Thanks baekgaard for the detailed take. I think I understand parts of it, but I gotta get more familiar with the electrical/sound technology related aspects in general, not my expertise... Surely I won't be the one correcting your post, or judging whether such scenario is compatible with the OP's issue.

Just a curiosity regarding your psychedelic kitchen: did the bulbs dim down accordingly to the power absorbed by the cooking plate in a proportional way (as when it happens normally whenever a load causes the voltage to drop) or were those "interferences" kind of random?

By the way I hope the OP will keep us updated 'cause I am interested in finding out what the problem was.

EDIT: Ha! Cross post. I am glad you solved.