I inherited my mother's Hammond M3 about 5 years ago. It is in 100% perfect condition too. Not one scratch or nick to be found anywhere on it. I even have the original can of oil that came with it when it was new. I've always wondered how I could modify it so it could be run through a PA system or studio. I don't have the skills to do this but I may try to find someone who can do it for me.
How do you wire the actual tonewheel generator line level output to a jack so that it bypasses the internal amp and speaker completely? That's what would be useful. Basically make the tone generator master output into a magnetic signal like a guitar pickup, then you could delete the amp and speaker, and run it into any standard preamp/ power amp, recording console, etc.
Thanks for the info, I just acquired an "M3" so need all the help I can get. Any thoughts on matching impedances for other outputs (AUX) for my "60's era stereo setup
Thanks for sharing your knowledge and for the detailed video on your M3 field coil speaker bypass/line-out mod. That’s interesting about the Lester G. A sales guy was trying to convince me not to buy the G and wait for K to restock -citing the input impedance wouldn’t be correct on the G for an organ. Yours sounds fantastic! Are you engaging the compressor as well? I have a ‘59 field coil model and no room for a Leslie. I just picked up a Behringer rm600 for less than $80; awaiting delivery. I know the build quality isn’t great but I won't be stomping on it. Hopefully, it sounds good and will suffice until I decide if something better sounding is required. Now I’ll create your speaker load/switching circuit. Did you eventually enclose it or mount the switch in the front or was it not necessary; just set it and leave it?
Could you possibly make a parts list for this project? Dont want to leave anything out or get the wrong thing. Im about to do thid mod to my 57 m3. Thanks for the great video!
Your welcome, glad you enjoyed it. I personally can't tell the load resistor changes tone. I'm using a ceramic wire wound resistor but I'm guessing if you changed to a metal film or different type, it could effect tone, (know this can effect tone in some circuits).
Hi @synthpro Do you know if the M3 preamp has the tone screw like the B3 preamp? I'm looking to saturate the pre but it has already been modified to have a 1/4 Jack. Thanks!
Hey Jareth, I recently bought myself a Hammond M3, just like yours including that field coil speaker. Apart from an Organ Mate reverb, there is no additional equipment in the organ. I gave your 1/4" output mod a try and managed to mute the internal speaker and I am getting sound signal from the 1/4" output. BUT ... seems, the lower frequencies are cut off somewhere and there is a distictive hum (not coming from the amp, as the hum is not present on the internal speaer), which causes my Lester-G to "create" some dirty leslie noises, even when no note is played. Furthermore I think, the output signal is way to low. I double checked all connections and I am pretty sure that I did not mess up completely. I know, it ain't easy to help from a distance but - maybe you read this and you have a clue directly what to fix/change... If not - at least I tried. THANK you for making such a great video! Kind regards, Fred
Hi Fred, Sorry to hear you are having troubles with this circuit. This almost sounds like you have a ground fault in the output circuit or a open ground between speaker and 1/4" jack. I'm not sure if the reverb could be causing a different behavior. I would say you may have failing capacitors but that would cause hum even in factory speaker as well. Not having correct load on the amplifier could possibly cause this as well. I will think this through and if I come up with any ideas, I will let you know.
@@synthpro Thanks Jareth for your quick reply! As far as the speaker load is concerned, I followed your idea of adding a 10 Ohm resistor. The capacitors, that have been causing hum, have been replaced in the amp - all hum was gone and still is not present in the internal speaker. May it be an option to take a ground reference directly from the amp (chassis)? Cause I think your hint regarding ground fault may be the most common possibility… I had another look at the noises from Lester G and hooked up a guitar instead of the organ, which lead to absolutely no noises anymore- that’s why I also think my issue could have something to do with ground Connection. All in all you would say you are getting a clean signal without any hum or other noises with your circuit? Best, Fred
@@derfred85 your welcome. Mine is clean, with just a little background noise but not hum. I'm running mine with studio monitors. Has your organ been modified with a three prong cord, (earth ground connection?) You may be experiencing ground loop between guitar amp and organ if so. I would also try a different instrument cable between Lester and organ just to possibly rule out a cable shield. You may be able to tie to the organ amplifier chassis but honestly unsure if they have the same ground relation
@@synthpro no, my organ has the two prong cord (Original) - no Earth ground Connection. I already tried several different cables with no change at all. I also tried different capacitors in the circuit, because I thought of some frequency division coming from the capacitor. I tried a standard polarized electrolytic capacitor as well as a bipolar coupling capacitor - issue remains the same. As soon as I find time again, I will check all ground connections in the circuit first. Maybe you find something else in the meantime?! I will let you know if I found the reason…
@@derfred85 good to know, sounds like you made the correct tests on cap values etc, my other thought was perhaps you had a bad coupling cap but ruled that out as well. I just had a look at schematics and what you have is a isolation transformer between 6V6 tube and speaker...the speaker is on the secondary windings of T3. Perhaps your Isolation transformer is unhappy with this circuit for some reason. I will definitely think this over.
It may could be done but you would have to build a secondary split in order to seperate the bass pedal VCA, (controlled by sustain etc) and preamp from main summing. My knowledge of tube based circuits is not as good so I can't honestly tell you the best approach to do this as far as filtering.
It depends on the serial number, early models use the electromagnetic field coil speaker and later used permanent magnet. I explain this in the video regarding changes made to Power supply.
Awesome vid dude. Been meaning to do this to my M3 for a while now.
I inherited my mother's Hammond M3 about 5 years ago. It is in 100% perfect condition too. Not one scratch or nick to be found anywhere on it. I even have the original can of oil that came with it when it was new. I've always wondered how I could modify it so it could be run through a PA system or studio. I don't have the skills to do this but I may try to find someone who can do it for me.
Make sure it's oiled well! :)
How do you wire the actual tonewheel generator line level output to a jack so that it bypasses the internal amp and speaker completely? That's what would be useful. Basically make the tone generator master output into a magnetic signal like a guitar pickup, then you could delete the amp and speaker, and run it into any standard preamp/ power amp, recording console, etc.
Very informative Jareth. I also prefer the Lester G over the K because you can set the time for ramp up.
Thanks, glad you liked it. I agree, having that ramp up time is very nice.
Thanks for the info, I just acquired an "M3" so need all the help I can get. Any thoughts on matching impedances for other outputs (AUX) for my "60's era stereo setup
I just acquired an early M3... Could you make this wire harness for me? I will certainly renumerate you fairly.
thank you, great information
Your very much welcome!
Nice! Now you need a Marshall stack for a Jon Lord sound.
Thanks for sharing your knowledge and for the detailed video on your M3 field coil speaker bypass/line-out mod.
That’s interesting about the Lester G. A sales guy was trying to convince me not to buy the G and wait for K to restock -citing the input impedance wouldn’t be correct on the G for an organ.
Yours sounds fantastic! Are you engaging the compressor as well? I have a ‘59 field coil model and no room for a Leslie. I just picked up a Behringer rm600 for less than $80; awaiting delivery. I know the build quality isn’t great but I won't be stomping on it. Hopefully, it sounds good and will suffice until I decide if something better sounding is required. Now I’ll create your speaker load/switching circuit. Did you eventually enclose it or mount the switch in the front or was it not necessary; just set it and leave it?
Could you show what the dpdt is on the amp of the m3 I have a line box and Leslie combo pre amp
Mine is cut down
RCA Phono jack on expression has low level signal.. I ran the signal to a pro art preamp and the 1/4 out into a motion sound pro3T..
Could you possibly make a parts list for this project? Dont want to leave anything out or get the wrong thing. Im about to do thid mod to my 57 m3. Thanks for the great video!
hi @taylorhc2308, did you get around to completing this mod? In the process of compiling a parts list myself and would love to know what you used!
Thanks so much for this video man. Does the load resistor make a difference to the tone?
Your welcome, glad you enjoyed it. I personally can't tell the load resistor changes tone. I'm using a ceramic wire wound resistor but I'm guessing if you changed to a metal film or different type, it could effect tone, (know this can effect tone in some circuits).
Thanks a lot
Hi @synthpro
Do you know if the M3 preamp has the tone screw like the B3 preamp? I'm looking to saturate the pre but it has already been modified to have a 1/4 Jack. Thanks!
I will have to look and see but I do believe it does if I'm not mistaken.
Is that the trim pot inside of the Expression pedal enclosure on the rear with a cap/plug covering the hole?)
Hey Jareth, I recently bought myself a Hammond M3, just like yours including that field coil speaker. Apart from an Organ Mate reverb, there is no additional equipment in the organ. I gave your 1/4" output mod a try and managed to mute the internal speaker and I am getting sound signal from the 1/4" output. BUT ... seems, the lower frequencies are cut off somewhere and there is a distictive hum (not coming from the amp, as the hum is not present on the internal speaer), which causes my Lester-G to "create" some dirty leslie noises, even when no note is played. Furthermore I think, the output signal is way to low. I double checked all connections and I am pretty sure that I did not mess up completely. I know, it ain't easy to help from a distance but - maybe you read this and you have a clue directly what to fix/change... If not - at least I tried. THANK you for making such a great video! Kind regards, Fred
Hi Fred,
Sorry to hear you are having troubles with this circuit. This almost sounds like you have a ground fault in the output circuit or a open ground between speaker and 1/4" jack.
I'm not sure if the reverb could be causing a different behavior. I would say you may have failing capacitors but that would cause hum even in factory speaker as well.
Not having correct load on the amplifier could possibly cause this as well. I will think this through and if I come up with any ideas, I will let you know.
@@synthpro Thanks Jareth for your quick reply! As far as the speaker load is concerned, I followed your idea of adding a 10 Ohm resistor. The capacitors, that have been causing hum, have been replaced in the amp - all hum was gone and still is not present in the internal speaker. May it be an option to take a ground reference directly from the amp (chassis)? Cause I think your hint regarding ground fault may be the most common possibility… I had another look at the noises from Lester G and hooked up a guitar instead of the organ, which lead to absolutely no noises anymore- that’s why I also think my issue could have something to do with ground Connection. All in all you would say you are getting a clean signal without any hum or other noises with your circuit? Best, Fred
@@derfred85 your welcome. Mine is clean, with just a little background noise but not hum. I'm running mine with studio monitors.
Has your organ been modified with a three prong cord, (earth ground connection?) You may be experiencing ground loop between guitar amp and organ if so.
I would also try a different instrument cable between Lester and organ just to possibly rule out a cable shield.
You may be able to tie to the organ amplifier chassis but honestly unsure if they have the same ground relation
@@synthpro no, my organ has the two prong cord (Original) - no Earth ground Connection.
I already tried several different cables with no change at all. I also tried different capacitors in the circuit, because I thought of some frequency division coming from the capacitor. I tried a standard polarized electrolytic capacitor as well as a bipolar coupling capacitor - issue remains the same. As soon as I find time again, I will check all ground connections in the circuit first. Maybe you find something else in the meantime?! I will let you know if I found the reason…
@@derfred85 good to know, sounds like you made the correct tests on cap values etc, my other thought was perhaps you had a bad coupling cap but ruled that out as well.
I just had a look at schematics and what you have is a isolation transformer between 6V6 tube and speaker...the speaker is on the secondary windings of T3. Perhaps your Isolation transformer is unhappy with this circuit for some reason.
I will definitely think this over.
Can the bass pedals output be separated? :-/
It may could be done but you would have to build a secondary split in order to seperate the bass pedal VCA, (controlled by sustain etc) and preamp from main summing. My knowledge of tube based circuits is not as good so I can't honestly tell you the best approach to do this as far as filtering.
@@synthpro thanks for the reply! I'll look into it more
I believe the field coil speaker uses an electro magnet instead of a permanent magnet.
It depends on the serial number, early models use the electromagnetic field coil speaker and later used permanent magnet. I explain this in the video regarding changes made to Power supply.
Could you add some mods to a TD-3 or would you do some TD-3 mod videos.