Gulbransen model E reverb

[Guest]

Hi Jimmy, Thank you for the info. I have tried what you said, and the percussion long and short work just fine, but the reverb long and short do not work at all, also the chimes work perfect. Could you tell me where the sustain capacitors are located and I will check themout to see if any are bad, as I do not have the schematics of the organ. By the way, I like the organ very much, I am not sorry that I got it, as far as I am concerned the tone and sound is great. I also have a Baldwin Orgasonic spinet w/ a two speed leslie and it doesn't hold a candle to the Gulbransen as for a tone and sound.

[jimmywilliams]

Re: Gulbransen model E reverb



Hi Gordie. By the way, you can respond to my responses - this way we can keep all the messages in the same thread instead of starting a new one each time.</P>


If long and short systain ARE working then the sustain caps may be OK; as I said the reverb is barely perceptable. I used to use "Reverb Long" on my Model E and the effect is most noticable when you are playng something like a hymn or a classical piece - anything where you play in a legato style (you will barely notice the effect if you are playng in the more "stacatto" theater/pop style). Try playing a sinple scale or two smoothly, maybe try a smooth transition between chords, etc. and see if you notice ANY "bleed" of the old notes into the new. If so, the reverb is OK. Try this woth the cancel piston pressed (should notice no effect at all), then try again withthe Reverrb Long right arterwards as a comparison.</P>


If you want to check the caps out - well it depends on which revision of the Model E you have. Does it have a single or 2-speed tremolo? Does it have asolid-state or tube amp? If you took the back off the organ, and looked at the tibia generator set (12 chasis mounted on the right side lookinf from the back) - what is the "TG" number stamped on them? Older organs had a separate "omega" board (may have been mounted near the back of the solo manual keyswitch - you would have to life the manuals up to see it clearly) with 72 capacitors. The newer revisions incorporated the sustain caps into the TG chasis itself. So I would need that information.</P>


Usually if these caps start going bad you will get NO sustain effects at all (and other weird things), so that might not bea problem. Also, does the amber "reverb" light go on when you press the reverb pistons? There is a rare chance that something may be wrong with a relay or the pitson mechanism itself, but if the light goes on chances are that could be ruled out (I think...).</P>


The Baldwins used divider generators that filtered from sawtooth waves - the tibias/flutes in those did not produce as pure a tone as the old Gulbransens. These old Gulbransens had individual oscillators for each pitch that produced very clean sine waves from the get-go. On the Model E, all stops are either single-pitch tibia/flute tones, or combinations thereof. </P>


If you are good with electronics I do have some schematics. </P>


- jim</P>
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[jimmywilliams]

Re: Gulbransen model E reverb

Oh I forgot to mention this - the sustain effects are NOT applied to the lowest octave pitch (i.e. if you use the 8' tibia only, the first octave on the keyboard will nave no sustain whether the pistons are pressed or not) - that is normal.

[Guest]

Re: Gulbransen model E reverb

Hi Jim, Yes I saw the quick reply after I sent a new message, guess that comes with being new on the forum, I will learn I hope. I will try what you suggest and get back with you. My model e is a one speed tremelo has transistors but the amp is tube type with two 12au7's two 6L6's and a 5U4 rectifier. I was an electronic tech before I became disabled did mostly TV repair, so organs are fairly new to me, don't have much equipment anymore,but enough to get by I guess. I would like to get the prints of this organ, as I don't intend to get rid of it anytime soon, maybe never. Maybe I can work something out with you sometime. Will get back with you after I try what you have suggested. Thanks again.

[jimmywilliams]

Re: Gulbransen model E reverb



Hi Gordie. I'm "on the clock" now so I'll have to be quick ...</P>


I'll get those schematics together maybe over the weekend. You have a Gulbransen Model E-1 - the first Model E ever made (circa 1958). Your tone generators use PNP transistors (not NPNs like mine did) and I believe the sustain caps are NOT on those older tone generator chasis- you would have to check the TG number - let me know what that is and I can tell you for sure. You may have TG-3 generators in there. Your tube amp/power supply is probably an "APS-5"; if it is another number let me know as well. I need these numbers to make sure I pull the right diagrams.</P>


This organ is worth keeping and sounds very nice when working correctly. Only reason I got rid of mine was that I didn't have enough room for 2 organs - and I really needed the AGO pedalboard on the Gulbransen Model D.</P>


Keep in touch-</P>


jim</P>
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[Guest]

Re: Gulbransen model E reverb

Hi Jim, I checked and you are correct the organ has TG-3 generators and a APS-5 amp/supply. I tried playing things slow and still can't hear the reverb, also the reverb light does come on. Maybe it is working and I just can't hear it, oh well if it works it works if it don't it don't, if guess I can live without it if I have to. Just let me know how you want to handle the prints when you have time. Thanks again. Gordie

[jimmywilliams]

Re: Gulbransen model E reverb



Hi Gordie. WIth TG3 generators,the sustain caps are not on the generator chasis but are on a separate board (called the "Omega" board). In MOST cases they are on a long board mounted in the back of the top manual keyswitch mechanism. The board contains diodes and 72 axial capacitors (mounted vertically with negative ends all attached to a common bussbar wire) in groups of 12 - one group for each octave. IIRC they are in groups of 75,100,125,150, 175, and 200uF. Chances are they have never been replaced and at this age they should be. If they are going bad (but not completely shot) you may get the symptoms you are describing - would indicate they are nor retaining enough of a charge and that would be more apparent with the shorter decay times with the Reverb pistons. When I've replaced these before, I used the currently-available cap values 82, 100, 120, 150, 182, and 220uF - with good results. If this board is not where I am describing - it MIGHT be accessible from the Front of the organ instead - underneath the rails that the TG3 chasis plug into. Some of the very old organs had it located there. Let me know if you can locate the Omega board and we can take things from there. Take careful note of which values are grouped where - diagrams for this board are not always consistent. I am getting some diagrams together - will write back later.</P>


- jim</P>

[Guest]

Re: Gulbransen model E reverb

Hi Jim, Found the Omega board, it was behind the front panel as you said it might be. Guess I got one of the grandaddy models the serial # is 16417. You sure seem to know your Gulbransen organs, what would I do without you. I would guess that you sure like your Gulbransen organs, as I said before I sure like mine. Have a good day. Gordie

[jimmywilliams]

Re: Gulbransen model E reverb



Hi Gordie. I haven't had much time to scan all the schematics and doesn't look like I will be getting them done today(long story)... anyway, these ones I scanned this morning should get you started:</P>


http://www.jimmyandsharonwilliams.co...en/schematics/</P>


Hope this helps. - jim</P>

[Guest]

Re: Gulbransen model E reverb

Hi Jim, Got the prints that you scanned, they came out great. Thanks so much, hope I can help you sometime. I will keep in touch. Gordie

[jimmywilliams]

Re: Gulbransen model E reverb



Hi Gordie. Glad the scans came out well. I saved them as GIFs at 300 DPI so no quality would be lost. THe source material wasn't the best but that's all I have to work with. I'll try to get the rest done soon. I can't just scan the whole batch into a PDFbecause my scannersoftware wouldconvert themto JPEGs - no good. First thing I would do is make sure all the voltages are correct from the power supply - that could affect the entire Omega system if the snubbing voltage is not correct. For that matter, make sure ALL working voltages are correct from the get go. Also pay attention to the piston assembly schematic; you will see that there are resistors in there; if they driftedout of specthat could cause a problem with the sustain effects as well. Regarding the electrolytic caps in the Omega board itself - I would highly recommend that the all be replaced as a general rule in any case. Remember this organ is 50 years old and chances are ALL electrolytics may need to be replaced to do a complete restoration. Let us know how things turn out. Good luck!</P>


-jim</P>

[jimmywilliams]

Re: Gulbransen model E reverb



Gordie, also please take careful note of which wires go where if you disconnect the Omega board. For some reason or another the wiring diagrams for that board are either non-existent or not completely accurate, based on theservice manualsI have been digging through. Beats me.</P>


-jim</P>

[Guest]

Re: Gulbransen model E reverb



Hi Jim,</P>


Sorry it took me so long to get back to you,seems like I have been busy doing everything from soap to nuts. I haven't even been playing my organ. Well today I was able to play it, and found out the reverb is working. Guess a week or so ago my hearing was going bad or something, soguess I have no problem after all. I again what to thank you for all your help, as I said before you sure know your Gulbransen organs. I will keep in touch and God Bless. Gordie</P>
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