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Thread: Leslie 101

  1. #1

    Leslie 101



    I was given a Leslie 101 from a guy who had it stored in his garage for years.I play guitar in our band at church and am in the process of converting it to take guitar input(s).Sorry if this is a slap in the face to the organist community, but I've become a real tube amp nut and this thing really has my interest. So far, I have scanned and redrawn the schematic before the one on the amp vaporizes. I have figured out which channel operates which speaker. I need to get a new spinning connector for the bottom of the rotating drum. I have the top one. The wires are there, just no connector.



    What I don't know is the purpose of #6 and #7 on the schematic. They come from the console to the 9 pin input and then go directly to the 7 pin output plug to the "speaker connector chassis". I figured out the other 7 pins that come from the console. In fact, I have soldered separate 1/4 inch inputs for each of the channels and tested them. The all work. Now I have to figure out if I want to tie them all together or have 1 for the top three 6x9s, 1 for the 15, and another for the three 6x9s in the drum.



    Also, how many watts is each of these channels putting out. I'm not getting a ton of volume from any one of them. I'm wondering if the console puts out a hotter signal than my guitar. I am playing with passive pickups.



    Any input would be appreciated.



    thanks


  2. #2
    Moderator andyg's Avatar
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    Re: Leslie 101



    The local 101 expert will no doubt be along shortly! Where are you, JW? []



    As for the input levels, leslies are designed to be driven very hot, direct from the amp of an organ, 10-20 watts worth going in! So running a guitar into them with no amp in between is going to be pretty quiet.



    Best of luck with the project. Although we love our organs and would prefer to see leslies used with them, we'd rather they were used musically than sent off to landfill or parted out.



    Andy



    It's not what you play. It's not how you play. It's the fact that you're playing that counts.

    New website now live - www.andrew-gilbert.com



    Current organ: Kawai SR6 + Leslie 760 Walnut
    Retired Organs: Lots! Including Hammond T402, T500 x 2, X5. Conn Martinique and 652. Gulbransen 2012 Pacemaker. Kimball something-or-other.
    Retired Leslies, 147, 145, 760, 710, 415 x 2.

  3. #3
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101



    Hi. Some background info first ... This cabinet was used for Gulbransen organs. It has 4 separate channels and was not designed to be used with a guitar. To do that you will probably have to pre-amp the input signal. Andy, FYI, these 4-channel tube leslies did operate a line level from the organ (not organ amp/speaker level like some of those single-channel Tube Leslies) but for a passive instrument like a guitar it will most likely need to be pumped up (maybe line-out from another guitar amp???).




    IMPORTANT: Don't keep running the amp if the slip ring connector is missing from the bottom of the spindle. This is called a "Mercotac" and allows the signal to travel into the hollow spindle, there the speakers connect to it inside the drum. If that connector is missing, you will have an infinite load on the corresponding tube amp channels and you do NOT want that! You can find Mercotacs on ebay - they are not cheap. You can go to www.mercotac.com and order a brand new one for around 25 bucks so keep that in mind. I think they are a model 205. Do you still have the "cap" that would slip on to the Mercotac? The wires should connect to the cap, and from there the cap fits onto the Mercotac, then the Mercotac slips into the hollow spindle contacts. Be very careful not to break/bend the contact in the spindle too - it is NOT fun to repair! I may have some used ones laying around so if you really want to pursue this send me a PM and we can talk.




    OK the bottom line here is that the pins in question control relays which in turn determine which speaker the partifular channel is routed to. A +13v relay control voltage was used; the switching junction box was connected via a 7-pin mini cable. If you do not have this junction box/chasis you will have a difficult time building one from scratch (although I do have the service manual/scheamtics - let me know). You will notice that there are three stationary speakers on the top of the cabinet. There was a separate one for each of three channels (2,3,4) of the amp. ). Channel 1 was for the bass pedals and routes directly to the 15" speaker). What the relays did was decide whether the chanel went to the appropriate stationary speaker, OR to the channel's corresponding stationary speaker in the spinning drum. The drum ALWAYS spins.




    I am confused about something though - how did you trace which amp channels control which speaker - IF you don't have that extra chasis? That is where the speakers plug into.




    Channels 2 and 3 are switched simultaneously (they both carried the main/complex voices in the organ - was split into 2 channels to isolate 4th and 5th harminics). Channel 4 carried the flute/tibia tones.




    It is actually more complicated than this though because IIRC even when the main/complex channels (2 and 3) were switched to the rotary drum, some signal was still allowed to persist through the corresponding stationaries (by using resistors, etc. in the junction box). This is because a full-on throbbing tremulant wouldn't sound appropriate for strings and reeds. EDIT: Also, filter chokes inline with the associated speakers in the drum allow for sound to come out of all 4 speakers (2 stationary, 2 in drum) and keep a balanced level as when just the 2 stationaries are switched. If you DO have the speaker junction/chasis (and I think you do if you were able to trace a signal to the speakers) then you can apply +12v to pin 6 to swirth channel 4 from drum (default) to stationary (switched). However, channel 2/3 works just the opposite. You can apply +12v to pin 7 to switch from stationary (default) to the drum (switched).




    Pins on the 9-pin input connector: pin 1 is audio ground. Pin 2 is bass input(ch 1). Pin 3 is tibia input(ch 4). Pins 4 and 5 carry main/complex voice input(ch 2 and 3). Pin 6 - ch 4 switch from drum to stationary. Pin7 - switch ch 2 and 3 from stationary to drum. Pins 8/9 is for AC wall power.




    As you can tell adapting a multi-channel cabinet like this for guitar use is not easy and may not even be practical. It would depend on (1) you have the speaker relay/junction box, (2) what you want to run into each channel, and (3) how you plan on switching the channels from stationary to drum.




    This may be a lot to digest - if you have any questions let me know.




    -jim

    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

  4. #4
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101



    Oh ... forgot the other question - this amp is is 16 watts per channel. 4 separate channels.




    Reading your post again it does seem that you have the speaker connector chasis. Sorry for the confusion. The relays I mentioned are in that chasis.




    -jim


    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

  5. #5
    Moderator andyg's Avatar
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    Re: Leslie 101

    [quote user="jimmywilliams"]

    Andy, FYI, these 4-channel tube leslies did operate a line level from the organ (not organ amp/speaker level like some of those single-channel Tube Leslies)



    [/quote]



    Thanks for the heads up on this. Will they take a hot signal without complaining, then? I'm thinking about models like the 610, similar to the 1xx and 2xx. I can remember hooking the kit box up to the speaker signals on Hammond R and H models. I wonder if there was some form of padding in the kit that took the level down?



    Andy


    It's not what you play. It's not how you play. It's the fact that you're playing that counts.

    New website now live - www.andrew-gilbert.com



    Current organ: Kawai SR6 + Leslie 760 Walnut
    Retired Organs: Lots! Including Hammond T402, T500 x 2, X5. Conn Martinique and 652. Gulbransen 2012 Pacemaker. Kimball something-or-other.
    Retired Leslies, 147, 145, 760, 710, 415 x 2.

  6. #6
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101



    Hi Andy.




    I'm not familiar with the 610 hookup kit; I would guess that there was circuitry to pad down the speaker-level signal before it hit the amp input. I do know for sure that when the 102 (almost the same amp as the 610) was hooked up to the Gulbransens Premiere, President, and Model D (with special adapter), indeed the hot speaker signal was attenuated down by using resistors. So I would guess the same would be true for the 610. I do have some service info for the 610 and the electrically-identical 205; I'll let you know what I find out - give me some time to dig them up.




    The 101 also has the same basic amp components as the 610 (except for the switching stuff) but the 101 and 100GK had the more beefy output transformers on all the channels (not just the pedal channel).




    I will scan in the service manual for the 101 (in case my explanation was not very clear) - when I have some time. It is Labor Day holiday weekend in the US and we have some other things to do ....




    Take care,




    jim


    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

  7. #7
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101

    I just looked at my 101 service manual - see the edit in my detailed post. I was trying to do this from memory and some things get mixed up! I'll work on getting this scanned.
    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

  8. #8
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101



    Complete Leslie 101 Service Manual scanned and posted. This scan actually came out pretty good (compared to some of my other scans)... will be the first thing I upload to archive.org once I create an account there. Please note that this manual was printed in "half-page" format (if that's what it is called). So the document will appear sideways, and you will have things like page numbers2/3 on one page, then page numbers4/5 on another page, so when you scroll down it wil first appear that "page number 5" somes after "page number 3". So, for clarity, it is better to print the document out.




    http://www.jimmyandsharonwilliams.co...sen/L101SM.pdf




    I hope this helps answer your questions adequately.




    - jim

    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

  9. #9

    Re: Leslie 101



    Wow!



    Thank you so much for all the info. I will definitely have to chew on this for awhile. And I also understand when you say this may or may not be practical for a guitar, but being an old sound guy, I have a few creative thoughts in my head. I just couldn't let this little treasure sit and collect dust for the rest of its life. Thank you also for the manual. It was the one missing link that we needed. One of our sound guys at church teaches electronics at the college where I work and has been very helpful. The manual is just what we need to make this happen.



    I'll keep you posted.





    thanks again,



    Park


  10. #10
    Senior Member jimmywilliams's Avatar
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    Re: Leslie 101



    Hi Park. Any word on how you are coming along? Does the diagram make sense to you and the other sound guy?




    Just a clarification - on your diagram pins 6 and 7 are designed to carry a +13 switching voltage from the organ; a +12 voltage will work fine. The switching voltage will actually control switching transistors inside the speaker/relay chasis in the 101 (which in turn control the relays). That is why there is no 12v return accounted for in the 9-pin connector. So if you were using for instance a standard wall unit 12v adapter as the source of your switching voltage, you would have to ground out the return side (possibly to pin 1 butI'm not certain howthat will affect the audio ground that must also go there). Obviously you would also have to put on/off switches on the 12v supply lines before they hit pins 6 and 7 (one for each) to allow for the two types of tremolo controls.




    All the grounds for the four audio inputs must also be tied to pin 1. Again, it is up to you to decide which channels you want to use, and what you want to feed into each. You could do something interesting like plugging a pre-amped bass guitar into channel 1 (pin 2) for the 15" speaker, and splitting a pre-amped guitar signal to the remaining 3 channels. Whatever you want ... but if you decide to NOT use certain channels, you can pull the tubes from the unused channel(s) - no point in keeping them heated up if you are not using them for anything. Then you can have some spare tubes.




    However you want to handle the AC for pins 8 and 9 is also up to you - I do advise that you provide an appropriately-rated on-off switch (be sure to switch the hot side if you are hooking up a polarized AC plug) and that you work very carefully.




    To actually connect everything to the pins you should wirethe leadsup to an appropriate female 9-pin amphenol connector to allow for easy connect/disconnect to the 101 amp (pay very close attention to the pin numbers!). You can find these on ebay. Do you already have a 9-pin cable for this cabinet? If you do, then you can make a box with the input jacks, power lines, switches, etc. and mounta new 9-pin female amphenolon the box. That will allow you to just use the 9-pin cable - male side can plug into your box, and female side can plug into the 101 amp. 9-pin cables also come up on ebay from time to time (usually around 30 bucks). If you want to make your own cable/harness to run from your circuit to the 101 amp, then be sure you also get the end-cap too.




    Important safety issue: double-check the 9-pin male input on your 101 amplifier chasis. Be sure that the middle guidepost is still there (it is "keyed" to only allow the cable to connect one way). I have seen several cases in which it was snapped off. If this is the case it is very easy to attach a cable in the wrong orientation, which will send AC to places you don't want it to go. If yours is in this condition, then I strongly recommend that you get a new 9-pin amphenol male connector and replace the bad one. If your center guide post is still there, one less thing to worry about.




    I have an idea to make up passive adapter boxes for the Gulbransen Leslies (like the 100GK, 101, 102, and 103), possibly using foot switch buttons to control the tremolo switching. I've been cobbling together some circuit diagrams and maybe I'll get around to prototyping someting during the next few weeks. I'm very glad that there is an interest in putting these Gulbransen Leslies to use for other applications (you are not the only one who has expressed an interest in this - I'm working with someone else on the forum who wants to run a guitar to a 103 cabinet). Anything is better than seeing them parted out and ruined! Thanks for saving another one from destruction.




    - jim





    Jimmy Williams
    Hobbyist (organist/technician)
    Gulbransen Model D with Leslie 204
    Farfisa Compact / Leslie 860 and Combo Preamp III / Hammond Porta-B

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