Dumbleator in Parallel mode

[bluesfendermanblues]

I'd like to share my version of the Dumbleator, which has a switch for parallel operation. It's not rocket science, but a simple design.

The difference between serail mode versus parallel mode has been debated often, and my purpose is to share info and ideas, not to argue for one over the other.

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 serail 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 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.  Enjoy

[Steven_nl]

Hi
I have thought about this. My reverb has an internal mixer so the dry signal stays analog.
Nonetheless series operation would be even better I think. But what happens when you use a chorus? For an optimal chorus sound the whole signal should pass through it right? besides some people think the fx loop makes the sound of the amp nicer.

What are your views?

Greets
Srteven

[bluesfendermanblues]

Hi
I have thought about this. My reverb has an internal mixer so the dry signal stays analog.
Nonetheless series operation would be even better I think. But what happens when you use a chorus? For an optimal chorus sound the whole signal should pass through it right? besides some people think the fx loop makes the sound of the amp nicer.

What are your views?

Greets
Srteven

Chorus wise I have an old TC chorus, which works fin in parallel mode in my loop.

Regarding the sound of the loop. The sound is intact, it's only a matter of where you do the mixing ...in the effect like you and RobbenFor d do ( ) or in the Dumbleator in parallel mode.

However, my opinion is that you should choose the operation mode and setup, that gives you the sounds you like - let your ears be the judge.

[erwin_ve]

Hi Blues, Great thinking!
I have one question; why is the direct signal, in parallel mode, fed directly to the grid?
I think the NFB is part of the smooth factor. In parallel mode only the fx signal is affected with NFB.
What are your thoughts about this?

Happy X-mas,

Erwin

[bluesfendermanblues]

Hi Blues, Great thinking!
I have one question; why is the direct signal, in parallel mode, fed directly to the grid?
I think the NFB is part of the smooth factor. In parallel mode only the fx signal is affected with NFB.
What are your thoughts about this?

Happy X-mas,

Erwin

You're right - have updated the Schemo....comments please

[mcinku]

Hi,

why using that extra 500p/220K network... why not just connecting before the existing network... would that work?
 

[bluesfendermanblues]

Hi,

why using that extra 500p/220K network... why not just connecting before the existing network... would that work?
 

You need a 'mixing' resistor in order to keep the direct and effected signal seperated, but try it without and see if you like it like that.

You can also experiment with the resistor values, if you want more or less output