Line Out From A Spinet

Generally, the easiest way to wire a LineOut from a spinet is to tap into the speaker outputs of the pre-amp/amp. It's not rocket science, however there are some points to consider when doing this:

• The speaker level output is a bit hot, so depending on what you are piping it into, you might need to pad it some.
• Ground loops can be (but are not always) a problem. To fix this you'll need to add an isolation transformer of some kind to your LineOut circuit. (It might be easier just to buy a pre-made ?DirectBox.)
• Tube amps don't like to operate without a load, so if you disconnect the organ's built-in speaker, you should to replace it with a dummy load (power resistor).
• If you have an older spinet which uses an ?ElectromagneticSpeaker, you cannot disconnect the ?FieldCoil without modifying the amp (or replacing the field coil with a suitable resistor). You can disconnect just the voice coil (but then, see above.) If you want to remove the EM speaker altogether, see SpinetEMToPMConversion.

Here's a simple schematic for a line-out from an M-3. (The component values are not particularly critical.)

• Comment on 'Line Out from a Spinet'

I haven't personally tried this method on a Hammond, but want to point out that any tube amp loaded with a speaker will have it's frequency response modified by the variable reactance of the speaker. I've shot some response plots that show large variations with speaker connected, and nearly flat response with a load resistor or correct pad network. In short, disconnected speakers with a replacement dummy load resistor will give the flatest organ response with which to drive the device of your choice, be it a Leslie amplifier or a mixing console. Leaving the internal speakers connected will introduce a degree of coloration in the 'line out' signal. - Doug Williams, Electromagnetic Radiation Recorders 10/2007

• Another comment on 'Line Out from a Spinet'

I just completed this particular modification to my 1959 M3 and it worked like a charm! The speaker level output is indeed too hot to go directly into an amp or PA. This was easily solved by using a 8 Ohm, 3 Watt resistor (shown in the diagram as replacing the load of the speaker) and placing it inline with with "hot" feed just before the audio taper pot. When I plugged the M3 into a solid state, 100W half stack, I got beautiful Hammond tones, with a lot more bass, and absolutely no hum. Well worth the effort to make this simple line out box. Bruce Quade, Hammond Hobbyist, 5/2011

That Phono Plug on the Swell Capacitor Housing

That phono plug is designed to be an input, not an output. Nevertheless, it does connect to a node in the signal path, so if you try to use it as an output it will sort of work. It's certainly easy, but the results are not likely to be great.

TonyRodrigues and BruceBarnes report that if you increase the value of the internal coupling capacitor which connects to this jack it works better (as an output). Read Tony's report at GettingALineOutFromThePhonoJack. (I, personally, would not recommend this approach. --JeffDairiki)

I posted another variation at GettingALineOutFromThePhonoJack. -- Doug Williams

Experience says you should not mess up with the capactive volume box **** That Phono Plug on the Swell Capacitor Housing *** .. it will always disturb the frequency curve of the system aswell the volume of the output , since the whole curcuit is at a very high impedance in the mega Ohm range Benji Massy

comment from Slow Pony: I love this circuit and have used it successfully in many L and M series organs, changing resistor, pot and cap values to taste. Also worth mentioning, this circuit is not a good way to hookup to a Leslie (generally need lower impedance/more volume). I do use this circuit very successfully to pad down the organ for FX pedals to then preamp for a Leslie.

Now here's the IMPORTANT SERVICE NOTE The older M3 Hammond's (and possibly others) with the field coil speaker design don't play well with this circuit. It will work but from my experience two field coil M3s I have seen using this design (or the OBL2) have subtle issues related to how it plays with the circuit and it's grounding. If grounded to amp chassis, the circuit volume will drop severely, as will the internal speaker volume. A solution for a different output I found for this balanced style output is to use a 10uf(?) cap and resistors (I omitted) to a STEREO potentiometer so both speaker terminals resistance to ground can be adjusted simultaneously. This gives me a balanced output which is nice and hot but can be padded down as much as needed. The design for the switched speaker/mute with an 8ohm resistor remains the same. And of course you can then use an unbalanced TS cable anyways but somehow it still sounds way better, likely due to that extra 10uf cap on the other speaker terminal wire. Thanks!

--Slow Pony slowponyinc@gmail.com 12/15/24

TopicHookup TopicModification