How to get both phases from Sluckey Trem-o-nator

[Fraggy0117]

I've been trying to figure out a way to get two out of phase tremolo signals using vactrols like Sluckey's Trem-o-nator and I think I've been over thinking it this whole time.

Can I add an additional vactrol in parallel but facing the opposite way, and have it pulse on the opposite phase? Do I need to add additional LEDs in parallel to keep bias voltage the same?

Maybe another way to explain it is if I built the tremolo and put two LEDs in parallel, but facing opposing directions, on the cathode, would they flash opposite of one another?

Thanks!

[SILVERGUN]

You do understand that sluckey's design is just shunting the signal to ground at an insertion point, right?


And, I believe that the answer to your question is...
If you then shunt the part of the signal that wasn't being shunted then you will never have a signal passing that point.
Maybe you are under-thinking it? 

[Fraggy0117]

Thanks Silvergun,

I get what you're saying, but I was thinking about shunting signal in two different places. So, doing something like a harmonic tremolo where it's split into two different frequencies or using it on two separate signals for stereo tremolo (knowing it would be two different power amps, etc.)

I'm hoping to have identical resistance, but on opposite phases

[SILVERGUN]

I think you'll have to post a schematic (or at least a cave drawing) of an actual plan

[Fraggy0117]

I'm happy to, though at this point it's more "inspired by" instead of concrete plans. At this point I'm just trying to see if having those two vactrols will flash at opposite rates.

I've attached a pedal schematic that using two vactrols to emulate the harmonic trem (Build doc:https://cdn.shopify.com/s/files/1/0022/3952/9069/files/Cardinal-Trem-V2.pdf?16138734983046189115).

If you don't want to read through it, the short version is the middle section is the audio path, and after the signal is split with highpass/lowpass filters, the vactrols vary the signal before they are summed. It's built to be nearly the same as the Fender harmonic trem, but tweaked since it's a pedal. The bottom section of the schematic is the oscillator, and looking at the bottom right corner you can see that two vactrols are in series with part of the IC intersecting between them. What this does is one vactrol pulsing on one side of the waveform, and the other pulsing opposite.

My thought is, if I can get the same opposite-pulsing vactrol function from the Trem-o-nator, then I can use it in a similar method as the pedal - of course tweaked since there's a difference in signal level.

The other idea of a stereo trem would basically be a single preamp -> signal split -> one vactrol shunting each separate signal path -> each signal goes to it's own power section -> the audio would 'bounce' back and forth between two speakers (one speaker per power section).

[Fraggy0117]

If you were asking for how I'd hook up the vactrols, here's a quick drawing.

[Keppy]

That won't work, because the cathode is always above ground potential so only one of those LEDs will conduct.


It might kinda-sorta work if you put a coupling cap between the LEDs and the cathode, but since the AC tremolo signal will be shunted to ground through the LEDs, it will mess with your gain, plus the low impedance will likely prevent tremolo frequencies from getting through the coupling cap.

[Williamblake]

You would need the 2nd led at the plate but you will have to look up what voltage between led and ldr is possible. You could also use the signal from the plate to drive another triode with vacontrol at the cathode. Or use the signal from the plate like a normal oscillator does.

[Fraggy0117]

That won't work, because the cathode is always above ground potential so only one of those LEDs will conduct.

I knew it was too good to be true! Thank you.

You would need the 2nd led at the plate but you will have to look up what voltage between led and ldr is possible. You could also use the signal from the plate to drive another triode with vacontrol at the cathode. Or use the signal from the plate like a normal oscillator does.

I was thinking the 2nd LED at the plate would have to be the next consideration. Off to research the datasheets!

[PRR]

This *may* make push-pull blinks. But it can't have a Depth control, which may be important.

Why use tubes to make artificial waves? That does not add "tone". Use opamps. Steal the plan you posted.

[Fraggy0117]

This *may* make push-pull blinks. But it can't have a Depth control, which may be important.

Why use tubes to make artificial waves? That does not add "tone". Use opamps. Steal the plan you posted.

I know the tube for the oscillator doesn't add anything, and the oscillator circuit from that plan would actually give more functions.... It's probably the easiest way to end up adding it. In some way I thought dealing with rectifying the heater tap for the chip would be harder to deal with, ha ha.

Thank you