noob here for 6pin wiring help (doesn't want to electrocute himself)

And if you're interested, here's a picture of the box, currently:

https://ibb.co/4p2mVMF

Lord Valve

2020-05-16 21:47:59 UTC

Post by Ben Standage
first up, thanks for reading this. I've googled this as much as I can, but lacking the basic concepts of audio electronics, it's hard to know which information is relevant to this custom project of mine.

OK, dude - it's obvious that you don't know shit from apple
butter when it comes to Hammonds and Leslies - so I'll try
to answer your question, but I'm not optimistic that you'll
understand. So...

Post by Ben Standage
I have an M3, running a 21H, with a weird old custom out, not a standard leslie connector box, but it uses the 6pin cable, with pin 5 disconnected.

That's because pin 5 is the B+ (high voltage) takeoff that
is supposed to feed B+ to whatever console the Leslie is
attached to. This is because in the old days, Hammond consoles
had no HV supplies in them, and needed HV from the tone cabinet.
Laurens Hammond hated Leslies, and wouldn't allow his dealers
to carry them, so if you bought a Hammond, the dealer expected
you to buy a Hammond tone cabinet with it. Leslie knew that the
vast majority of his cabinets would be used with Hammonds, so
he provided this B+ feed (on pin 5) so the organs could work
with Leslie cabinets. YOUR organ, however, is much newer than
the 21H Leslie that you have, and has its own high-voltage
supply built in. Ergo, no pin 5.

Post by Ben Standage
I, like any sane individual, want to use guitar pedals with my organ, so I made a box that passes the AC, but intercepts the audio signal for 1/4" jacks.

I've been playing the Hammond B-3 (and now, the XK-5) for
59 years, and not once have I experienced any desire at all
to use craptastic guitar effects with it. The Hammond is one
of the finest-sounding instruments ever devised, and doesn't
need any help from solid-state guitar junk. I guess I'm not
sane, eh?

The input stage of a 21H is balanced, which means it ordinarily
has no ground reference. At this point, I need to know where the
signal is taken from in the organ. If you don't know how to find
out, you'll need to bite the bullet and find a competent Hammond
tech (rare as a hairy egg, these days) and pay him handsomely to
aid you with this.

BTW - the signal levels in Hammonds are HUGE, and usually distort
the shit outta guitar pedals, which are designed to receive the
wimpy levels available from guitars.

Post by Ben Standage
If I bridge the in and the out 1/4" plugs with a patch cable (TS or TRS) everything works as it did without the box.

OK, this means the box is wired correctly. Maybe.

Post by Ben Standage
When I add a distortion pedal to the chain (with a reamp box before it to bring the signal down to guitar levels) it also works fine, but when I turn the pedal off I get a heinous hum.

What do you mean by "turn the pedal off"? Bypass the effect, or
shut it down completely by turning off the power?

Post by Ben Standage
I still get signal in that scenario, but it's very quiet which I think is half of the regular signal flowing through the ground?

The signal doesn't "flow through the ground." Ground is ground,
period.

Post by Ben Standage
The AC for the leslie and the audio signal share a ground (pin 2) and I'm pretty sure that's where the problem lies.

The AC had better jolly well fucking NOT have anything to
do with ground, period. For a 6-pin standard Leslie
hookup, the AC belongs on pins 3 and 4, and it had damnwell
better not be anywhere else. For a 5-pin hookup (used when
B+ is not required by the organ) the AC is on pins 2 and 4.
Ground is on pin 2 for the 6-pin plug, and on pin 3 for the
5-pin type.

OK, here's where it starts to get hairy...

Post by Ben Standage
As soon as the signal leaves my box, it's unbalanced (because guitar)

Yeah? Was it balanced to begin with, and if so, how? I still need to
know where the signal is taken out of the organ. And if it indeed
was balanced, how do you "unbalance" it when it leaves the box?

and when it comes back in it needs to be balanced again.

So - you use TRS plugs or something equally squirrely?
Without a transformer or some sort of active circuitry,
I'd like to know how you achieve a balanced line. ???

Should I be sharing that ground with the audio signal at some stage (I'm obviously reluctant because of the 120v it's hanging out with)?

Dude, I am *WAY* FUCKING RELUCTANT to comment further at
this stage, because earlier you said "The AC for the leslie
and the audio signal share a ground." The AC should IN NO WAY
have anything at all to do with chassis/audio ground, and
if it does, you are fixing to kill your fool self. Dig?

Post by Ben Standage
I also have a Hammond 835 transformer that someone gave me that I could incorporate on the output side to rebalance the signal, but I'm pretty sure I'd still have to tap that ground.

OK, you have no idea what a balanced line actually is,
because a balanced line is not connected to ground
in any way, other than for shielding, which it may not
need at all depending on the signal level. The only thing
you can do with a balanced line as far as ground is concerned
is to connect the ground to the cable's shield.

Post by Ben Standage
So, long story short, how do I rebalance the post guitar effects audio signal without electrocuting myself.

I need to know how the signal was balanced IN THE FIRST PLACE,
because as far as I know there is no way to get a balanced
signal from an M3 without using a transformer or other circuitry.
And you keep talking about the AC sharing a ground with the audio.
No way, no how, ain't gonna happen.

Post by Ben Standage
and thanks again for reading to the end...

Here's a link to the 21H schematic. If you can read one,
it may help you understand what's going on in your Leslie:

Loading Image...

Lord Valve, ThD
Expert (fuck you)

(The "fuck you" is only for the people who
deserve it. They know who they are.)

Ben Standage

2020-05-17 15:17:26 UTC

Post by Lord Valve
OK, dude - it's obvious that you don't know shit from apple
butter when it comes to Hammonds and Leslies - so I'll try
to answer your question, but I'm not optimistic that you'll
understand. So...

Indeed, BUT I have read enough posts on this group to expect your ebullient response. thanks again for reading.

Post by Lord Valve
I've been playing the Hammond B-3 (and now, the XK-5) for
59 years, and not once have I experienced any desire at all
to use craptastic guitar effects with it. The Hammond is one
of the finest-sounding instruments ever devised, and doesn't
need any help from solid-state guitar junk. I guess I'm not
sane, eh?

Different strokes I guess. I do agree that the Hammond sound is unique and wondrous, especially when that horn starts to spin, but I work mainly in guitar based rock music, where even the Hammond sound wants a bit of dirt. I believe your XK-5 has a preamp tube in it specifically for distortion. I have a Korg SV1 (poor man's XK-5?) that does the same thing, and I love it.
Ideally I'd be modifying the Leslie amp to give me some tube based overdrive, but I don't want to mess with it because a) it's really old and b) it used to belong to my friend's late father.
So I figured that tapping the signal would be less destructive and cheaper. Hell, I have a guitar pedal with a tube in it...

Post by Lord Valve
The input stage of a 21H is balanced, which means it ordinarily
has no ground reference. At this point, I need to know where the
signal is taken from in the organ. If you don't know how to find
out, you'll need to bite the bullet and find a competent Hammond
tech (rare as a hairy egg, these days) and pay him handsomely to
aid you with this.
BTW - the signal levels in Hammonds are HUGE, and usually distort
the shit outta guitar pedals, which are designed to receive the
wimpy levels available from guitars.

I know. I read somewhere that if you play all the notes with all the drawbars out the signal voltage can get as high as 40v.

Post by Ben Standage
If I bridge the in and the out 1/4" plugs with a patch cable (TS or TRS) everything works as it did without the box.

OK, this means the box is wired correctly. Maybe.

What do you mean by "turn the pedal off"? Bypass the effect, or
shut it down completely by turning off the power?

Bypass the effect/ stomp on the button. The pedal is still in the chain. Incidentally, if I use a battery powered pedal, I also get the 60cycle hum when the effect is engaged, but if I use a pedal that uses a power supply (running on AC), I don't.

Post by Ben Standage
I still get signal in that scenario, but it's very quiet which I think is half of the regular signal flowing through the ground?

The signal doesn't "flow through the ground." Ground is ground,
period.

OK. Check.

Post by Ben Standage
The AC for the leslie and the audio signal share a ground (pin 2) and I'm pretty sure that's where the problem lies.

I know. It sounds odd, but I got this suggestion from maybe misunderstanding Captain Foldback himself.
On Uncle Harvey's guide to Leslie Pin Outs he says that Pin 2 is the signal/DC ground. I assumed DC, although clearly not AC, meant 120v.

The Organ itself has an AC ground (three pin plug), so I assumed the Leslie would need one too, and this was it. Currently it's wired to just continue along the cable, uninterrupted.

Maybe I should stick my multimeter on that pin and see what it's pushing?

If that's just the ground for the audio I could experiment with it without fear of death.

Lord Valve

2020-05-18 10:17:08 UTC

Indeed, BUT I have read enough posts on this group to expect your ebullient response. thanks again for reading.

Different strokes I guess. I do agree that the Hammond sound is unique and wondrous, especially when that horn starts to spin,

I rarely spin. I like straight tone, no slow rotor, even.

but I work mainly in guitar based rock music, where even the Hammond sound wants a bit of dirt. I believe your XK-5 has a preamp tube in it specifically for distortion.

It has a two-tube processor which, among other things,
can produce distortion. I don't care much for distortion;
*anything* will distort. It's pure tone that is difficult
to achieve. The tube circuits in the XK5 are essentially
an effects processor; one of them is distortion. It's a
fairly advanced design, using one 12AX7 and one 12AU7.
Many different routings through the four available triodes
are possible. It does not, however, produce the sonic image
which most people have of what a distorted Hammond sounds
like, because that comes from the output stage in the
Leslie's amplifier, and because of the circuit topology
in that stage, a considerable amount of crossover notch
distortion is produced when the amp is driven hard. Audio
nerds have for decades upon decades been trying to get rid
of crossover notch - engineers are trained from the git-go
to shun it like the plague. However, in this particular
case the large crossover notch distortion component which
a Leslie produces is an intrinsic part of the "Hammond
sound." I have no idea why the nerds (on both sides of the
Pacific) have so far failed to notice this; I have yet to
encounter a Hammond/Leslie emulation which produces
anything other than various forms of clipping or other
nonlinear effects - *except* crossover notch. Go figure.
A guitar amp which produces large amounts of crossover
notch will sound like crap, and the tech who works on it
will notice this distortion as part of the preliminary
checkout - and he will address getting rid of it as the
first priority. Guitarists, you see, *hate* notch
distortion. Starting to get the picture?

I have a Korg SV1 (poor man's XK-5?) that does the same thing, and I love it.

An excellent board; I'd own one if the action didn't feel
like driving a truck with busted power steering. I'm an
*organist*, I don't care for slamming the keys all the
time.

Post by Ben Standage
Ideally I'd be modifying the Leslie amp to give me some tube based overdrive,

It doesn't need any modifications to do that - it's built in.

but I don't want to mess with it because a) it's really old and b) it used to belong to my friend's late father.

Ah, yes... It's "Ye Olde Friend's Late Father Disapproval" routine.
Wouldn't want some spook throwing shade (DAMN I'm good!) on your
playing, ectoplasmically grabbing your fingers now and then to cause
excess clam production, would we? I think not. So "messing with it"
is definitely contraindicated.

Post by Ben Standage
So I figured that tapping the signal would be less destructive and cheaper.

That's not a tap, it's an incorrectly done interrupt.

Hell, I have a guitar pedal with a tube in it...

In fact, I *build* a pedal with "a tube in it," the infamous
Roogalator. Handwired point-to-point, utilizing a weapons-
grade (built for the US Air Force, in fact) subminiature
dual triode. Unlike the pedal you have (and I can say this
fairly confidently, even though I don't know what your pedal
is) there are no solid-state devices anywhere in the audio
signal path. I once looked inside a Roland "tube" effect,
and I counted ELEVEN integrated circuits - there may have
been more on the underside of the PCB. It was immediately
obvious that the device was a solid-state distortion effect
with a tube in it for marketing purposes. Mine is 100% tube
from input to output, and there ain't no little gay-ass
window in it so people can look at the tube. Not cheap.

I know. I read somewhere that if you play all the notes with all the drawbars out the signal voltage can get as high as 40v.

You got something against answering this question?

Post by Ben Standage
If I bridge the in and the out 1/4" plugs with a patch cable (TS or TRS) everything works as it did without the box.

OK, this means the box is wired correctly. Maybe.

What do you mean by "turn the pedal off"? Bypass the effect, or
shut it down completely by turning off the power?

All part of the same problem.

Post by Ben Standage
I still get signal in that scenario, but it's very quiet which I think is half of the regular signal flowing through the ground?

The signal doesn't "flow through the ground." Ground is ground,
period.

OK. Check.

Post by Ben Standage
The AC for the leslie and the audio signal share a ground (pin 2) and I'm pretty sure that's where the problem lies.

That last sentence is incomprehensible. <shrug>

Post by Ben Standage
The Organ itself has an AC ground (three pin plug), so I assumed the Leslie would need one too, and this was it.

Wrong.

Currently it's wired to just continue along the cable, uninterrupted.

Post by Ben Standage
Maybe I should stick my multimeter on that pin and see what it's pushing?

Egad,

Post by Ben Standage
If that's just the ground for the audio I could experiment with it without fear of death.

There is no "ground" for the AC, other than where the incoming
power cable's green wire is attached to the chassis. Once this
is done, any ground you care to talk about (DC, audio signal)
is connected to the planet via the green (in the USA) earth
lead so the electrons can finally get home.

Since you neglected to answer several questions I asked,
I cannot further comment on your problem or suggest a
solution.

Lord Valve, ThD
Expert (fuck you)

Ben Standage

2020-07-27 22:02:18 UTC

just wanted to follow up with what I did, and give something back to the forum.

I got it to work, taking the two AC contacts and sending them to the Leslie with no interruption, and taking the three signal wires, sending them through a reamping circuit (the diyrecording L2A) to reduce the signal voltage to guitarish levels. I rebalanced the signal on the way out using a 1:1 transformer. It all works, is relatively un-noisy (depending on what pedal you're using). But I lost motor control, which I think was on whichever audio pin I abandoned when the signal goes unbalanced.

I had a weird issue with the original custom wiring anyway - the Leslie powered back up again as soon as you turned the organ off, and I rarely play without the Leslie spinning anyway, so it's no great loss.

Here's the innards of the finished product: https://ibb.co/92mx0jv

Lord Valve

2020-07-28 09:35:05 UTC