Conn 550 tibias Middle C and Above Way Too Soft

[EricS]

Hi, organ folks:

I have a Conn Model 550 that I have recently rehabbed. My only real problem is that the tibia voices have two distinct volume levels. On the Tibia 8' as one goes up the scale, the volume of sound is as one would expect up to middle C. From Middle C up, the volume is about 1/3 of that in the lower note range. This anomaly is seen in both the accompaniment and solo manuals. If I go to the Tibia 4' stop, again, when the one reaches what is a piano MiddleC, the volume goes down by about 2/3 and remains there as you go on up the scale.

Any suggestions would be appreciated. I am a chemical engineer, not an electrical engineer, so if the explanation involes wires and not turning a screw somewhere, please be explicit! And thanks!

[TexDW76]

Re: Conn 550 tibias Middle C and Above Way Too Soft



Hi Eric,

I do not have a schematic OR much info about Conn organ , but this is a possibllity. On many organs, the designers split the keyboard into 2 or 3 sections. That is, they use seperate busses for each portion of the keyboard. It MAY be possible that the tone coloring circuits for the upper 2 sections may have a weak op-amp ? I am only speculating, as I do not have the schematics. Try to isolate the problem to one stop family.

Hope this helps and someone with Conn Organ experience will respond.

C Ya, Doug

[Guest]

Re: Conn 550 tibias Middle C and Above Way Too Soft



If it is only the tibias, I'd first check the leslie speaker. They have a crossover that splits the upper tibias to the leslie and the lower to a regular 12 or 15" speaker because those notes are too low for the leslie to have any effect on.

there are tibia keyer boards for each octave. Without a service manual, it is hard to tell you where to look. Since they all connect together, it could be a wire in the chain of boards has a bad connection. They all connect to a tibia filter board. I don't know if things are hard wired, but if there is a connector between the keyers and the filter board, it could be dirty contacts on the connector.

[EricS]

Re: Conn 550 tibias Middle C and Above Way Too Soft



Thanks to those of you who responded. Armed with this information, I started tracking things and found (guess what?) a loose wire between two circuit boards. Upon reattaching the wire, the tibia volumes were equal all over the range. Problem solved!

I appreciate the help and support of all organ-philes (or is it organ-isms?)