Hi.  I recently acquired some tech manuals for the very rare Gulbransen Model F church organ, and some photos of one.  The original model had to use at least 3 leslie cabinets (great, swell, pedal).  But, there was a subsequent "stripped down" model called the F-204 which used a main channel and tibia channel, similar to the Gulbransen Model D.  It was designed to only use a pair of Leslie Model 204 speaker cabinets.

I went to the Captain Foldback Leslie page but could not find any mention of any Leslie cabinets with a model number 204.  Does anyone here know anything about a Leslie Model 204?  I'm just curious.  Any info would be appreciated.  Thanks. 

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

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Nathan Wilcox

Well, if the organ is called F-204 and the Leslie is 204, then I am assuming it is a proprietary Leslie.  Info on those is definitely hard to come by.

Good luck...

-Jon 

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"Unit" is a four letter word!

It appears that the Model F-204 was also known as a model "CP" and came out around 1965.  It appears to be very similar to a Model D (without the internal speakers) but has a piano.  It doesn't seem to bear a whole lot of resemblance to the original Model F.  Also, there are 4 channels of sound but they are tibia, main, pedal, and piano.  The main is not split into the C and C# sides like in the Rialto K.  The only thing about the cabinet I can gather from the document is that the Model 204 Leslie is a 4-channel speaker cabinet.  I guess it is similar to the proprietary 100GK, 101, or 102 cabinets?  I think there was a non-proprietary Leslie called a 610 that was also 4 channels.  That's about all I know.  Maybe the Model 204 Leslie is mentioned in the old Blue Book under the Gulbransen Model CP organ?

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

I got the scoop on this cabinet from George Reynertson...it was a 4-channel similar to the 100GK except it had 5x7 stationary speakers instead of 6x9.  It was only made for the Gulbransen Model F-204 (AKA Model CP) and there were very few actually made (about 20 of them if I recall correctly) so that's probably why there is little info about it.   The "real" model F also used a proprietary cabinet for the great/swell and that was called a model 201.   Same goes for the quantity there too.

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

Wow - here is a real life Leslie Model 204 (in pretty bad cannibalized shape unfortunately).  It really does exist.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270272053628

It seems to have 2 rotosonics though ... different than the original description I had for it.  I wrote the seller for more info about the stationary speaker he mentioned (I could not see it clearly).  I also asked some others about it as well.  I'll post whatever I find out.

-jim

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

Looks pretty much like the 202 and 205 cabs, with the main lower Rotosonic for tibias and the upper rotosonic having two speakers and running at 1/2 speed for a gentler tremolo on the complex voices.

Yet another one to add to the list, even if there were only ever a handful made.

Can you imagine a company agreeing to a production run of 20 units these days?

Andy

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

Hi Andy.

George R says there should be 3 stationaries on the top - although smaller than the "usual" stationaries in these types of cabs - he will look more into it. The seller mentions only one stationary on the top - that's what threw me way off.  Maybe he jsut assumes there is one - to me it looks like a board is covering up the stationary(ies).  I know that the organ this was meant to be used for had 2-speed tibia tremolo.  So, I guess the bottom drum had a 2-speed motor?  Also, if the top rotor is running at 1/2 speed, does this mean there was a different type of motor used than the "standard" one?  The seller took the motors out for "spares" so I can't see what they look like.  I can't imagine who would have any use for the 4-channel amp in this cabinet (as the internals were specific to this particular cabinet/organ from what I can tell) but it's gone.  I know the 4 channels are pedal/tibia/piano/main.  Lows for all channels were crossed-over into the pedal channel (from inside the organ before it got to the cabinet).  Based on what you are saying I would assume the mids/highs for the piano remained in a stationary speaker.

Too bad the cabinet is so thoroughly gutted.  RI is a drive from here but it is do-able.  I would have considered getting this cabinet just to say I had one - if it was working and still dirt cheap that is....I would have figured out some way to hook it up to my Model D.  Now it's really nothing more than a shell - the seller makes no bones about that.  Oh well...at least I got to see one.

-jim

 

 

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

Hi Jim

The plot thickens, and if anyone knows about this cab it would be George. 

As for the 1/2 speed set-up, I'd guess they used the normal motors but with a double sized pulley at the motor end, giving 1/2 speed at the rotor. Leslie used the 1/2 speed, double speaker Rotosonic in the 600/610 and also in the 20x Wurli cabs. They even used a double scoop, 1/2 speed baffle type in the 120C and 112, to handle complex voices, with the Tibias going through a matching 120 or 110. The small Rotosonic was 2 speed in the 610/20x, to offer a light celeste on the complex voices, but the tibia Rotosonic was only single speed.

I can see the 4 way channeling as you're saying. Tibia - either straight, through the piano channel or rotary, through the Rotosonic (if it was switchable between them from the console). Bass - through the bass amp! Main - through the 2nd 1/2 speed Rotosonic. Piano - through the piano channel.

That way you'd get the light trem on the complex voices without messing up the piano. Does that all make sense?

As for the seller, I guess someone thinks there are some bucks in a tube amp.

Andy

 

 

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

I examined my schematics for the Gulbransen F-204 (CP) organ.  Here is what I can gather regarding the routing on the Leslie 204.

Tibia is slow or fast.  TIbia tremeolo is controlled via a tab on the organ.  Main uses an electronic vibrato.  These specs are the same as the Model D (the CP was more or less an enhanced Model D - it had piano and separate bass channel, 4 level controls, and no internal speakers - almost everything else is identical).

Pedal, Tibia, Main, and Piano are definitely the 4 channels as mentioned earlier.  The tibia and piano have the lows crossed over to the pedal channel from inside the organ (there would be no crossovers in the cab itself).  Main (excluding the pedals of course which are separate in the CP from the get-go) is not crossed over as its compass did not reach that low.

As the seller was not sure if there was one or 3 stationaries on the top (they are behind a wood baffle), and that George thinks there were three and that they were smaller than the normal 6x9s (this would allow room for the top drum), I will assume there are in fact three small stationaries.

Given the above, here is the only routing in the speaker cabinet that makes sense to me:

Main and Piano channels go to the small stationaries.  Pedal channel goes to the 15".  Tibia switches between stationary, slow rotor (top), and fast rotor (bottom).  There are 2 speakers in the slow rotor to get the more "mellow" celeste effect.

This would allow for the 9-pin cable to carry 2 lines for AC, 4 lines for audio, 1 line for common audio ground, and 2 lines for the two relays necessary to switch the tibia to the appropriate rotors.

The seller had said he parted out the amp and mercotacs but was not able to remember exactly who had them.  I tried calling some of the Hammind/Leslie shops in his area area but nobody I contacted had the missing 204 amp.  Of course, none of them dealt with the 4-chnnel rotosonics at all (for the most part they have no substantial value and are of no use to the Hammond people).   Without the 204 amp, the cabinet is pretty useless - I don't think it would be possible to cobble another one of the 4-channel amps in there because of the dual relay setup on the tibia channel (unless anyone out there knows better).  So, I did not place a bid on the cabinet.  Nobody else did either.  I did mention to the seller that I would be interested in the cabinet if it were complete.  Who knows - maybe those parts will turn up, maybe not.  Figured I would try - nothing else I can do.

Thanks for all the tips on this cabinet.  Maybe one day I'll see one hooked up to a Gulbransen CP???

 -jim

 

 

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

Scratch what I said previously.  I got the whole story on this cabinet.  In fact, I have the cabinet (or what remains of it - EDIT - I do have both motors and belts too - yes the top rotor motor has a different sized pulley - and is mounted upside-down).  George Reynertson sent me some additional info and diagrams too.

Regardless of what the literature says, tibia is only one speed.

So...

Pedal: goes to 15" stationary

Main: Goes either to 5x7 stationary OR the double 5x7 top rotor. 

Piano: Goes to second 5x7 stationary.  (Lows go to 15")

Tibia: Goes to 6x9 stationary OR 6x9 in lower rotor. (Lows go to 15").

So Andy wins!

The amplifier originally used with this was a Leslie Type 6054-1.  4-channel tube amp.  9-pin connector attaches from amp to console.  But from the amp, there is a 7-pin line that goes to a smaller speaker/relay chasis.  I am trying to track down whatever happened to this amp and relay chasis, since the set appears to be useless useless for any type of cabinet EXCEPT the 204.  Even with similar cabinets, like the 101, the relay switching voltage/transistor switching circuit will be wrong.

My project over the next few months will be to rig up my 2-channel Model D to work properly with the Leslie 204 cabinet (use a low-pass active crossover to make a "fake" pedal/low channel, design a console switch control, etc.).  Then, re-build the 204 cab itself.  If I can't track down the original amp and relay box, I have 2 options: re-wire a 100GK amp, or cobble in a solid state quad amp I ordered recently.  Either way, if I do not find the original relay box, I will have to construct the speaker/relay circuit myself.  I'll have fun with it.

For reference, I copied/pasted the basic Leslie 204 info below.  This is from a document I am preparing that describes the 5 Gulbransen Leslie cabinets (100GK, 101, 102, 103, 204).  They 100GK, 101, and 102 are not as similar as I previously thought - but live and learn!  I also have the spec sheet (with errors!) and the speaker switching circuit diagram for the 204; I'll post these when I get a chance...

Thanks everyone for your input. 

- jim 

Model 204

 

Used for the Gulbransen Model CP (AKA Model F-204) Organ only.

 

204 9-Pin Cable

1	Black	Signal Ground
2	Red	Bass Channel: Pedals, and bass from Tibia and Piano (Amplifier 1)
3	Yellow	Tibia Channel (Amplifier 4)
4	Orange	Main Channel (Amplifier 2)
5	Green	Piano Channel (Amplifier 3)
6	White	Lower Drum Control for Tibia channel –  voltage to transistor-switched relay circuit (-13v DC)
7	Violet	Upper Drum Control for Main channel – voltage to transistor-switched relay circuit (-13v DC)
8	Gray	AC Power
9	Blue	AC Power

 

204 Signal Path

Amp 1	To Stationary 15” speaker
Amp 2	Switch between stationary 5x7 A and the two 5x7s in the upper drum
Amp 3	Stationary 5x7 B
Amp 4	Switch between stationary 6x9 and single 6x9 in lower drum

 

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician

Great detective work there! Sounds like the 204 was pretty much like the 610. Let us know how the project goes, as the organ and speaker should match up well.

Andy

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

Andy,

About the Leslie 610 - yes it has a somewhat simlar design to the 204 (besides amps 2 and 3 wired together in the 610 because it is for a 3-channel organ) as it has the slow and fast drums, but there is a major difference - on the 610 there is a 125 volt DC line that seems to come from the Leslie amp to the console??  That would certainly cause big problems with a Gulbransen.  I discovered this when investigating other possible amps/relay switches to use for the 204.  I guess the 610 was made for certain Hammond models?  I don't know what that voltage is for.  The closest Gulbransen Leslie was the 101 - it only has one rotor but did switch the mains from stationaries to the drum (tibia and mains used the same drum - the drum has 3 speakers in it).  The conceptual difference there is that the mains were split isomonically; in the 204, you only had one main, and the piano which was always stationary.  But the switching circult relay voltage would be the opposite polarity from what I can tell.  The switching voltage from the console from a Gulbransen K and organs of that vintage that used PNP transistors would be positive, but would be negative from the CP (or Model D in my case).  The switching/rotor control voltage is borrowed from the solonoid/magnet supply for the bussbars in the organ.  I've been poring over the various schematics to compare, and also reading up on transistor switching circuits in general too.  Slowly, things are starting to make sense...

To hook the 2-channel D to the 4-channel Leslie 204, I can account for the main, tibia, and bass channels (by means of an active crossover), but I am still deciding what to do for the piano channel, as the D does not have a piano.  I was thinking of possibly also routing the tibia through the stationary piano channel and switching it on/off at the console.  I was hoping that by doing this I might be able to "fake out" the cabinet into producing a celeste effect - i.e. having the tibias go through both the fast rotor, and also thorugh the stationary.   I mostly use the slow/celeste tibias on the D as it is now.  It's been a loooong time since I took an acoustics class in undergraduate college though, so I'm not quite sure if that is the effect that will result.

 I'll let you know how things come along. 

-jim

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Jimmy Williams
Gulbransen Model D, Leslie 204 (still restoring it), hobby organist/technician