Serial mode: An 'ordinary' dumbleator run the effect in serail mode and mix the relationship between direct signal an effected signal in the effects unit. This is the classic operation as used by Robben Ford, and since the TC2290 has an analog signal patch for the direct signal, you dont' degrade your signal.
Parallel mode If you don't have a fine apperatus like the 2290 and like me use simple delay pedals, you might consider parallel operation, in which case you mix the direct/effects ratio in the dumbleator instead of in the effects unit.
Difference between this design and the 'original' dumbleator:
- all I did was adding a 220k serial resistor and 'moving' the return volume from after V1b to before V1b. Hereto adding a small capacitor compensating for the lack of high end loss, from not having the direct signal travelling through feets of cable. You can off course leave that out if you want to preserve high end.
- The cathode resistor combo on V1a can be either 27K/1.8K or 10K/1.5K as per the 'official' schematic.
- I left out the bright switches - never use them.
The return pot is 'master volume', when used in serial operation and 'mix control' when used in parallel mode. If the direct signal is too hot in parallel mode, put a trimpot or ordinary pot in instead of the 220K output resister.
Hope this schemo might be usefull to DIY'ers with less than studio grade effects, who want to try parallel operation. All it takes is adding a DPDT switch (or converting one of the bright switches) plus a resistor and a pot change place in the circuit.
It's a simple modification to a fine design.
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