ODS FET

[gary sanders]

I built my D clone without the FET.Im wondering if I should add it now.Are there any clips or something on the forum I could listen to so I could compare the difference the FET makes in tone?

[martin manning]

You can get an idea for yourself by putting a clean boost of 20dB or so ahead of the normal input, or you could build the Dumble FET booster (not much to it) and run it that way, powering it with a couple of 9V batteries. If you like it, then you can install it in the chassis and rewire the input jacks.

[Mac Daddy]

This one is with the fet channel

http://youtu.be/gDW4BJfgDBo

[Structo]

I ended up building a FET board and installing it on my amp mainly just to complete the package but I do like it with weaker pickups such as a couple Strats that I have.
I haven't tried it with piezo equipped acoustic yet but that is one of the reasons I wanted it as well.

I used JBorders pcb board for mine.

[sonicmojo]

I was tired of switching jacks and pulling the chassis to dial the FET so I made a D-Style FET in a pedal and also added some clipping diodes before the output as a switch option for flavor. I love it. Right now I'm using it as a sort of boost.

[Max]

Are there any clips or something on the forum I could listen to so I could compare the difference the FET makes in tone?

Here are some clips that have been recorded by using the FET input of an original Dumble ODS:

https://tubeamparchive.com/viewtopic.ph ... 483#136483
https://tubeamparchive.com/viewtopic.ph ... 484#136484
https://tubeamparchive.com/viewtopic.ph ... 802#140802
https://tubeamparchive.com/viewtopic.ph ... 973#134973
https://tubeamparchive.com/viewtopic.ph ... 368#129368

Cheers,

Max

[alvarezh]

Hi Sonic, interesting, thanks for sharing. Couple of questions (3 actually):

Is the internal trimpot for bias?

Where specifically did you install the clipping diodes?

Are you running it with an 18vdc PS?

Thanks again.

[sonicmojo]

Hi Sonic, interesting, thanks for sharing. Couple of questions (3 actually):

Is the internal trimpot for bias?
That is the typical 10K trimmer on the D Fet boards but I didn't get hung up on measuring things. I like to keep it turned up between 2/3 and 3/4. I would mount a control on the outside as a gain option if I had more room.

Where specifically did you install the clipping diodes?
You can see an opposed pair of them on the red 3-way switch, one side goes to the output(blue), one side goes to ground(green). At the time I was experimenting with the Electra distortion circuit and that's where I got the idea to try it here. In the picture I have 1N752A Zeners on it. Since the picture, I put a couple of germanium diodes on the other side. Middle is diode bypass. I can't remember what germaniums I used exactly but some combination of 1N60, 1N750, and 1N34. I think I paired a 1N34A with 1N750 for the sound I most liked. Using a pair of 1N60s gave me a wild sub-octave thing on some double stop bends.


Are you running it with an 18vdc PS?
No, just standard 9vdc and it gives a nice boost. I eliminated the 150K resistor that is typically on the power inbound before the big cap.

[noworrybeefcurry]

Any chance i might be able to get a look at a schematic?

[sonicmojo]

Any chance i might be able to get a look at a schematic?

Sorry, I don't have one. The concept is straightforward, just take a basic D-Style FET board, add input and output jacks, 9vdc power supply, stomp switch, 100KL pot for output volume, 3-way switch for diodes(optional), and an LED with I think a 1K resistor to it. I used a Ceriatone OTS FET (check their website for layout specifics), but you could likely use any of the FET layouts in the Dumble files here.

[alvarezh]

Thanks for the details Bryan.

All the best.