[HAM] Tone Generator

[David Anderson]

Yes, the load does affect the output, and the manual resistance wires  
are essential because the load not only affects the output, but the  
resonant frequency of the filter since the inductors are also step- 
down transformers and reflect back the load impedance they see. You  
need some resistance between the TG output terminals and the matching  
transformer to keep the tuning of the filters from being thrown off  
too much. I've used a 33 Ohm resistor and found that had no  
discernible effect on filter tuning.

This is probably another reason why the method of measuring outputs  
by connecting a wire from the preset panel to the TG terminals, as  
described in the service manual, is a strange idea.

David

If you try to

On Mar 14, 2007, at 1:00 PM, Hugh wrote:

> I think the purpose of the shunt resistor for measurement is more to
> simulate the load that the rest of the organ, i.e. the matching
> transformer and resistance wires, puts on the TG. Wouldn't this load
> affect the output? I would think that it would but I don't know the
> impedance of the matching transformer. If it's low, then it could
> have a huge effect on the actual levels produced by the TG,