Valvecaster diode question

[Esppse]

Hello,

I built a straight up valvecaster here.

http://3.bp.blogspot.com/-T3vLzoKL6e4/Us_tZPOeDZI/AAAAAAAAF5k/udhchaX_7X0/s1600/Matsumin+Valve+Caster.png

I was on YouTube and saw some had switches to activate diode clipping.

How would I incorporate this into the circuitry?

Thanks

[Marcos - Munky]

Instead of connecting the wires "from volume pot" and "to output jack", just use a wire connectiong the switch to vol3 in the layout you used.

[Esppse]

Oh wow thanks so much for the diagram! Now there's no way my foolish self can mess this up... 😀

[Renegadrian]

easy way is to put diodes to ground on the output.


There is another way of adding diodes but i never tried...

[Renegadrian]

Tried the second solution, it gives the same result as the first, both with the el. cap and without...dunno what may be the difference theorically, but they sound the same at the end.

[anotherjim]

I think the feedback arrangement diodes are gating negative feedback. Small signal doesn't get any clamping until big enough to bias the diodes on. Should (I think) have a soft limiting effect.
With clipping diodes on the output, the effect will depend on the output volume control setting. If you go between the output cap and volume control, it will depend only on what the tubes are pushing out.

You could put clipping diodes on the grid of the second tube, then the clipped signal will get amplified by the second valve, but with only the first triode in front , there may not be enough to bias the diodes, even if germanium, but an on-off-on switch could connect to either place.

I've heard these things work better if you can use a 12v DC power supply, then the heaters get a proper cooking.

[stallik]

+1 on the 12v suggestion.
When adding the diodes, I didn't like the volume drop so arranged a 2pdt on/ off/on switch to incorporate a resistor when the diodes were not in circuit. This gave me the same volume output between diodeset1/none/diodeset2

[Renegadrian]

I've heard these things work better if you can use a 12v DC power supply, then the heaters get a proper cooking.

12V are mandatory!