I've got an old organ I would like to give a 1/4" TRS out jack to. The organ is stereo—it has one speaker for reeds and strings, and another for flutes. How would I do this?
Check for the brand and model number and post them. Someone will dig out the schematic and there will be some suggestions. I can be done! You can most likely find the schematic and post it too,. that would be even better.
Not sure what make and model you've got. But Captain Foldback may be of help:
Captain Foldback Organ & Amp Service
Captain Foldback Organ & Amp Service
A fairly straightforward way would be to run a 150K resistor from each speaker's +ve terminal to the tip and ring (one for each speaker) connections on the TRS jack. The ground can be taken from the negative speaker terminals. You could also stick a pot in there to adjust the line level.
It would help to know the make and model of the organ though. And I do have a few schematics here for really old models.
Edit:
Posted before I saw the model... I'll have a look in my collection of schematics. 🙂
It would help to know the make and model of the organ though. And I do have a few schematics here for really old models.
Edit:
Posted before I saw the model... I'll have a look in my collection of schematics. 🙂
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I just posted it above: Conn 427 Caprice.
Edit: and I posted before I saw that you saw the model 🙂
That sort of thing, but with a value 100 times bigger... 😉
I've had a quick look through my pile of schematics, but I don't have anything for the Caprice.
However, running a line out from the speaker terminals is still pretty safe and straightforward. I'm just hunting for a link to an example schematic for you...
Take a look at this page and you'll see a few options for fitting a line-out socket.
Most of the ones on that page are for valve guitar amps, but the principle is exactly the same. The version shown in the middle, the "FireZog" is probably closest to what you need to be looking at. You'll need one resistor and one pot for each speaker connection.
You're probably already aware of this, but valve gear carries high voltage that is potentially lethal, even when it's not plugged in! Be careful!
Most of the ones on that page are for valve guitar amps, but the principle is exactly the same. The version shown in the middle, the "FireZog" is probably closest to what you need to be looking at. You'll need one resistor and one pot for each speaker connection.
You're probably already aware of this, but valve gear carries high voltage that is potentially lethal, even when it's not plugged in! Be careful!
The amp has a single out plug, which has seven or so cables running into it (five for the 5.25" flute speaker [a thick red, black, and yellow, and a thin red and black] and two for the 12" reed/string speaker [a thin red and black]). The plug is located right next to the two transformers. I'm a little confused about which wires I should splice on the 5.25". Any help?
Ouch!
Now I'm not so sure... Are you in a hurry to try this mod? It may take a little while to find a schematic for the Caprice, but I think it would be the safest way forward. The speaker could be an electrodynamic one, hence the extra wires.
I'll do some more digging for you. 🙂
Now I'm not so sure... Are you in a hurry to try this mod? It may take a little while to find a schematic for the Caprice, but I think it would be the safest way forward. The speaker could be an electrodynamic one, hence the extra wires.
I'll do some more digging for you. 🙂
What do you want to use this 1/4" TRS output for?
Is it for headphones, or recording / PA use?
Do you need the speakers muted when the line out is in use, or still connected?
It's for hooking it up to either a guitar amp or an auditorium sound system. The speakers would have to be muted, yes.
If you turned up at a gig with your organ as is, any respectable PA guy would probably just mic up the speaker cabinets.
If you want to directly connect this instrument to external amplification is it necessary to disconnect the existing speakers? I would be tempted to use a pair of DI boxes that were suitable for direct connection to the speaker outputs (as commonly used for guitar amps) this would give you a pair of balanced XLR outs for connection to a mixer.
The advantage of using a transformer coupled output is electrical isolation, which would avoid any safety issues, and ground loop problems.
If you want to directly connect this instrument to external amplification is it necessary to disconnect the existing speakers? I would be tempted to use a pair of DI boxes that were suitable for direct connection to the speaker outputs (as commonly used for guitar amps) this would give you a pair of balanced XLR outs for connection to a mixer.
The advantage of using a transformer coupled output is electrical isolation, which would avoid any safety issues, and ground loop problems.
Maybe post some pictures of the speaker setup. Even if it is not a field coil (electro dynamic) speaker the output transformer may be mounted on the speaker driver which would still mean a few hundred volts on that connector so you really need to know what you are dealing with.
Muting the speakers would add another "issue" to the whole process. Some sort of dummy load would have to be applied. For that, we need to find out the output power of the amp as well as a clue about he impedance of the speakers.
In answer to your earlier question about what is an electrodynamic speaker... they were common in old systems in the fifties where the speaker's magnet was an electromagnet powered by HT from the amp. The coils could also form a choke as part of the power supply filtering. I'm not syaing that's what you've got fitted. But I'd like to be sure before giving any advice about splicing into your speaker connections.
I'm inclined to agree with Xoc1 about micing the organ for performance. It'd be a LOT simpler in the long run! 😉
Is the "tick" actually the loudspeaker? Or is it the amplifier?
I'm still looking for a schematic. However, I picked up from one of your other threads that you've been able to chase down a manual for the Caprice. It might be easier to wait for that to turn up. It might turn out that it would be a lot simpler to break into the circuit somewhere ahead of the power stage of the amplifier and add a buffered line out with switching...
Damn! This whole job would be a lot simpler if you lived a bit closer to me... 😀
The 12" is 8 ohm. The 5.25" is a 6.4 ohm.
And here are some pics:
Austin Leeds's Photos | Facebook
Austin Leeds's Photos | Facebook
And here are some pics:
Austin Leeds's Photos | Facebook
Austin Leeds's Photos | Facebook
Wow, what is that tube that is glowing to beat the band? Is that a gas regulator tube or something? OK so it looks like a permanent magnet speaker with the OPTs on the PA chassis. It looks like there are two RCA plugs coming going into the PA chassis.
If those are coming from the expression pedal you might be able to tap in there and get a line level or mic level signal there and then just replace the speakers with dummy loads (switchable).
If those are coming from the expression pedal you might be able to tap in there and get a line level or mic level signal there and then just replace the speakers with dummy loads (switchable).
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