A-100 to Studio Monitors

[Grez A-100]

This will be an exceedingly easy question to answer, so don't worry, no mysterious "my tonewheel generator is receiving the local AM radio station, what can I do?" I need correct cabling/adapters to get both left and right studio monitors hearing my A-100. Currently I only get one speaker, and it's obviously a stereo/mono mix up in the signal chain. See photo. I built my own 1/4 outbox box that works fine (G-G). From the box (which uses a 1/4 mono input) I have plugged a 1/4 to 1/8 adapter shown, and then into this, I have plugged in the splitter cable shown. The backs of my M-Audio monitors say "TRS" next to the input jacks, so obviously they are not expecting "TS" which is what they are now getting. What's the simplest fix for this issue? Thanks, and sorry, I know I'm being tripped up by something very basic!

[andyg]

Could be the cables picking up the AM signals. Find some decent sized ferrite rings and wrap the cables from the organ to the box and the box to both monitors around them, you may have to experiment a bit.

But could you also try headphones on the G-G terminals, just to rule out any AM radio pickup in the organs pre-amp?

[Grez A-100]

Sorry, Andy, I guess my dry humor didn't land well. I have no issues with AM radio interference. My issue is with the mono/stereo mix up to my studio monitors.

[Papus]

The problem is probably the 1/4" TS to 1/8" stereo conversion. It looks like your 1/4" TS adaptor is simply a straight-through 1/4" TS to 1/8" TS barrel.
On your 1/8" TRS to 2x 1/4" TS breakout cable, the Tip is the Left channel, the Ring is the Right channel, but you're plugging that into a 1/8" TS jack - so the Ring of the TRS end is actually connected to the Sleeve of the organ's 1/4" line out, in other words: the Right channel is shorted to Ground.
Obtain or fabricate a proper 1/4" TS to 2x 1/4" TS Y-splitter cable, skip the unnecessary 1/8" conversion.
You could easily convert your existing 1/8" cable by chopping off the 1/8" connector and replacing it with a 1/4" TS connector.
Solder the Tip of the new TS connector to the two tip conductor wires from the existing TS connectors.
Solder the ground braiding to the Sleeve of the new TS connector.
Confirm correct continuity with a multimeter and you're good to go.

[Grez A-100]

Thank you, Papus! My intuition got me about 80 percent there, you helped me the critical other 20 percent. Appreciate it.

[Grez A-100]

Just to confirm, this is what you are recommending: https://www.amazon.com/Foot-Inch-Mon...436461&sr=8-26. Even though the back of my monitor speakers have the 1/4" input labeled as "TRS"?

[Papus]

That cable is correct. TS to TS all the way, two conductors throughout - same as the source.
The output from your organ is currently wired for unbalanced mono, so its pointless trying to use the full TRS balanced functionality of your monitor speakers.
In fact if you try to use the Ring on your monitor inputs you might end up with no audible signal as the differential balanced input will try to cancel out the Tip vs the Ring (this is how it eliminates hum and noise in a balanced signal, by inverting the Ring signal and summing it with the Tip, any commonalities such as hum are cancelled out by destructive interference, this is called Common Mode Rejection).
You COULD make the entire signal chain balanced if you wire a proper balanced TRS jack from the organ's preamp terminals, and run it to your speakers via a TRS Y-splitter cable which splits into two TRS plugs, BUT I don't even know if such a cable exists, because it is very bad practice to passively split a balanced signal.
You can easily obtain what is known as an "Insert Cable" which is TRS split out to a pair of TS plugs, with one plug carrying the Tip and the other plug carrying the Sleeve - this will NOT work in your situation, you'll actually end up with your monitors out of phase with each other. So don't even be tempted to go down that route.
Passively splitting unbalanced signals is common because it works 90% of the time, and it's cheap - but once you decide to go full balanced, you have to commit to doing it properly. There's reason pro's use balanced signals, and it isn't just because it costs more.
If you really want proper balanced signal throughout the chain then you're better off investing in a small mixer ($50 or less), connect the balanced line out from the organ to a balanced line input on the mixer, then use the mixer's stereo balanced outputs to feed your monitors. This also opens up the possibility of mixing in effects such as reverb or delay via the auxiliary busses on the mixer.
The other advantage of using small mixer between the organ and the speakers is to provide a degree of electrical isolation between your 50-80 year old antique electronic device and your expensive modern speakers which you don't want to blow up. Better to sacrifice a $50 mixer in the event that your ancient organ blows up and takes out anything connected to it.
TBH feeding balanced out to a small mixer is probably how the majority of people split the signal out to a stereo pair of speakers.

There is another way, and it opens up the pandora's box of guitar effects.
Run unbalanced mono out of the organ, attenuate the signal with a resistor network or an off the shelf attenuator, and feed it into a Boss stereo guitar pedal such as chorus, delay or reverb. Then feed the stereo output of the pedal into your speakers.
This will provide a nice fully buffered signal to your speakers, regardless of whether the effect is actually engaged or not. Boss pedals have an always-on input and output buffer no matter what state the effect is in.
Many guitarists use a cheap Boss stereo pedal as a way to split their signal to a pair of amps. They don't even engage the effect half the time, it's just a splitter. Plenty of unloved Boss stereo pedals on the used market for $100 or less.
If you find the resultant signal is too low, you'll need to boost it with a mixer.

[Grez A-100]

Thank you! I ended up just buying a TS solder on jack and modified the existing Y cable. Works fine, but key-click-o-plenty, even with percussion off. I went from weak no-punch with the internal A-100 speakers to very aggressive pop and spit with the studio monitors. So much so that I clipped the bleed capacitor in my Motion Sound DIY Interface.