Yes, another L100 760 connection thread..

[berra.b]

Hello guys and gals! Long time rider, first time poster.
I has had an L100 for a while now and of course I also have an Leslie, a 760 to be exact.
The previous owner installed a headphone jacket so he could play with his Leslie through a
Combo Preamp. I have been doing this as well, I have looked over the circuit the previous owner did and I think it's look a bit strange..
So how should I do it if I want to plug the Leslie in for real? I would still like to have a jacket for headphones though because I have a small child and I want to be able to practice when she is asleep with headphones. I know I need a 10 ohm 10 watt resistor, but how do I do it?

Here is a drawing of how the previous owner did the circuit, I'll hope you understand how I mean. “Vit sladd” means white cord.

[Stefank]

Should be ok in my view (but I would wait until you have a double confirm).
switch to the left and the grey wire powers the speakers.
switch to the right and the switch powers the resistor string.
the resistor string devides the power by about a factor 5 towards the top of the 120ohm resistor.
so there you have 20% power.
the two 43ohm resistors get in series with the headphone and either damp more power (if the headphone is low impedance) or just protect against excessive current in case “something gets shorted”.

[berra.b]

Should be ok in my view (but I would wait until you have a double confirm).
switch to the left and the grey wire powers the speakers.
switch to the right and the switch powers the resistor string.
the resistor string devides the power by about a factor 5 towards the top of the 120ohm resistor.
so there you have 20% power.
the two 43ohm resistors get in series with the headphone and either damp more power (if the headphone is low impedance) or just protect against excessive current in case “something gets shorted”.

Thank you Stefank! Can anyone confirm this? I made this picture, is there anyone that want's to help me draw the lines?
I know number 6 and 7 goes to the speed control but how should I do the rest? The switch in the picture is not for the speed but for to be able to choose between internal speakers/leslie or headphones. Do I need the 43 ohms resistors?

I am about to get but I need to get the final push over the edge to really get it.

[Drawbar Dave]

I have just copied the proper Leslie kit schematic in the past when I've had 760/770s. Very simple circuit, It's called the 7270 kit.

[Stefank]

Hi,
I have no knowledge about the pinning of the Leslie connector.
In you'r original circuit all has a purpose, only the 2x 43ohm could have been 1x 22ohm and the 620ohm +1k5ohm could have been 500ohm. Most likely the original guy just played with components until he had the volume he wanted.

the 120, 620, 1k5 implements a 1/5 reduction but also makes sure there is a “load” on the output of the amplifier. Without load tube amps can go haywire.
the 2x 43ohm give protection in case the output is shorted, but if used with 8ohm phones give a 1/6 reduction.

so,... would just keep as-is.

[berra.b]

Hi,
I have no knowledge about the pinning of the Leslie connector.
In you'r original circuit all has a purpose, only the 2x 43ohm could have been 1x 22ohm and the 620ohm +1k5ohm could have been 500ohm. Most likely the original guy just played with components until he had the volume he wanted.

the 120, 620, 1k5 implements a 1/5 reduction but also makes sure there is a “load” on the output of the amplifier. Without load tube amps can go haywire.
the 2x 43ohm give protection in case the output is shorted, but if used with 8ohm phones give a 1/6 reduction.

so,... would just keep as-is.

As it is now it's a bit low when I use it with my headphones even with the expression pedal at maximum. Sorry that i'm a nag Stefank :)
Number 1 is ground, 2 is signal, 6 and 7 is for the speed of the Leslie. The others one are nothing that i have to bother with.

[Stefank]

Than I would disconnect the 2 43ohm resistors from the 120ohm resistor and connect them directly to the yellow wire. That case you bypass the 1/5 reduction.
probably best to keep the 120, 620 &1k5 where they are. They provide a bit of “load” to the amplifier and tube amplifiers “like” that. They may run in some overdrive if you donot load them. Now... I guess the loading is not super strict (some others may argue it isn't necessary), but since they are there I would simply leave them there.

[berra.b]

Than I would disconnect the 2 43ohm resistors from the 120ohm resistor and connect them directly to the yellow wire. That case you bypass the 1/5 reduction.
probably best to keep the 120, 620 &1k5 where they are. They provide a bit of “load” to the amplifier and tube amplifiers “like” that. They may run in some overdrive if you donot load them. Now... I guess the loading is not super strict (some others may argue it isn't necessary), but since they are there I would simply leave them there.

It came to me like a flash from a clear sky, okay maybe not but I made this picture. It looks about right?
In the manual they say one resistor of 47 ohm if you want headphones (https://archive.org/details/HammondL...earch/earphone), so is it maybe enough with one resistor, or maybe non at all? Is it like I think it is, they are only there to adjust the volume?
Except the one on 10 ohm 10 watt that is for a load.
Here's the picture:

[Stefank]

Looks ok with few things.
yes, the 1 or 2 43 ohm resistors are Just their to adjust volume. You can simply try.
its good the have a load resistor, but 10ohm will burn. Originally you had 120 + the 620/1k5. That totals up to about 600.
for simplicity you can maybe just reuse the 620ohm resistor.
than the Leslie,....
i don't have this connector, I have a little passive box. But........
1/.... in my setup there is a filter. Bass still goes to the internal speaker, mid&high go to leslie.
2/... doing it this way you cannot choose the Leslie. It is now just in parallel to the internal speaker while it should be choosable similar that you can choose phones and speaker.

the choose wiring I could provide. The filter is a different beast. You'll need to search that or an other forum member may have the diagram.

[Wes]

Do you really need all that crap?

If this was my rig -- and take it from a guy who has one and gigged it a lot -- I would rip out the headphone jack, connect the speakers directly to the amplifier like the factory did, then take signal off one of the speakers and send it to the 760. Easy, sounds great, done. Crank the master on the 760, crank the bass, crank the treble, and then pull either the treble or the bass back and bit to suit your preferred tonality.

Wes

[berra.b]

Looks ok with few things.
yes, the 1 or 2 43 ohm resistors are Just their to adjust volume. You can simply try.
its good the have a load resistor, but 10ohm will burn. Originally you had 120 + the 620/1k5. That totals up to about 600.
for simplicity you can maybe just reuse the 620ohm resistor.
than the Leslie,....
i don't have this connector, I have a little passive box. But........
1/.... in my setup there is a filter. Bass still goes to the internal speaker, mid&high go to leslie.
2/... doing it this way you cannot choose the Leslie. It is now just in parallel to the internal speaker while it should be choosable similar that you can choose phones and speaker.

the choose wiring I could provide. The filter is a different beast. You'll need to search that or an other forum member may have the diagram.

Well this is the problem, I want to be able to choose between the speakers and the leslie (and headphones). The connector in the picture is a 9 pin amphenol and this was the standard even tough it's on it's way out know.
The reason I am choosing a 10 ohm resistor is because this is what i've have heard from several people will work (not because the one I have know isn't working), https://organforum.com/forums/forum/...ond-l100/page2 here's a thread were Enor is mentioning it. In Sweden he is a Hammond god, or at least he is very good at Hammond player and technician. Like you said earlier Stefank, the previous owner probably played around with resistor to get good results with the volume. As he also had a combo preamp to use for audio signal I think he used the 120 ohm resistor to get the signal a bit less hot.

Do you really need all that crap?

If this was my rig -- and take it from a guy who has one and gigged it a lot -- I would rip out the headphone jack, connect the speakers directly to the amplifier like the factory did, then take signal off one of the speakers and send it to the 760. Easy, sounds great, done. Crank the master on the 760, crank the bass, crank the treble, and then pull either the treble or the bass back and bit to suit your preferred tonality.

Wes

I'm not a gigging musician just a happy home player and in an apartment you can't crank the volume so this is why I need all this crap Wes :)

[tpappano]

I'll make a small suggestion, connect your headphone jack to the amp instead of the Leslie side of the switch and use a "center off" switch. This would give you the choice of 'organ speakers', 'Leslie speaker' or 'none'. Your headphone jack would always be live so you could use them by themselves or in addition to either speaker.

[Stefank]

Tpappano,... ouch... I could have thought of that :-)

[berra.b]

I'll make a small suggestion, connect your headphone jack to the amp instead of the Leslie side of the switch and use a "center off" switch. This would give you the choice of 'organ speakers', 'Leslie speaker' or 'none'. Your headphone jack would always be live so you could use them by themselves or in addition to either speaker.

Do you mean that the lime green wire goes directly to the switch? I'm thinking that the amp needs a load. Sorry i'm a bit slow. I'm blaming it's on a Friday evening.

[tpappano]

That is a valid point. Your phones, if they are low impedance will provide some load with the series resistors. It is true however, that Hammond lets 6BQ5 (reverb) amps run completely unloaded in A100s, M100s etc. whenever the reverb is switched 'off', the amp still remains fully driven. Another thing that helps is that the amp takes negative feedback from the output transformer, so I don't think you can hurt it.