1776 Cardinal Tremolo with vibe mod

[warriorpoet]

Sexy little thing.  Went 22n C6 and 3.9n on the toggle.  J201 Q1-2, 2N5457 Q3. Very, very vibe-y <3

[selfdestroyer]

Very clean build. The paint pen labeling looks great also.

[jkokura]

Yeah, I really admire the smooth writing you've got there. Wish I could label like that...

Jacob

[bcalla]

Yeah, I really admire the smooth writing you've got there. Wish I could label like that...

+1   One reason I use decals is that I can barely read my own handwriting - there's no way I could pull off hand labeling a pedal.  Very nice!

[Cortexturizer]

very impressed! incredible build man, wow. If I weren't so lazy I'd be searching for your other builds here on the forum right now

[midwayfair]

The red on silver looks great! Not a color combination I would have thought of, either. Awesome to see another vibe mod appear!

[warriorpoet]

Wow! Thanks guys!

Jon, one thing I noticed is positions 1 and 2 on the switch are slightly different, but not drastically so with the vibe mod.  Is there another mod that exaggerates the differences?  If not, it's a GREAT sounding effect, I just wonder if there isn't something MORE I can do

source: http://www.diystompboxes.com/smfforum/index.php?topic=101722.80

Pertinent text:

This is the Univibe mod! Very exciting. THEORETICAL So, Dane Kinser (eldanko) over on Madbean accidentally discovered that you can make the Cardinal sound like a vibe by replacing C6 with a much bigger cap, in his case 33nF. This got me thinking whether we could use a single toggle to replace the center mode with the vibe mode. It requires a DPDT on/on/on. It's wired thusly: DPDT on/on/on 1 4 2 5 3 6 -Jumper 1 and 5. -Replace R6 on the PCB with a much larger value, e.g. 33nF. 2: This is the ground connection (pad 2). 3: This connects to the pad on the PCB that goes to C6 (pad 1) 4: This connects to the pad on the PCB that connects to the gate of Q3 (pad 3) -Solder a smaller value cap across lugs 3 and 6. (See below for values and cutoff frequencies.) We will call this the "switched" cap. The modes will now be: Up/right - Normal tremolo Center - Harmonic Down/left - Vibe How this works: In the center, C6 + switched cap create series capacitance. When the switch is up/right, the emiter of Q3 is connected to lug 5, which is jumpered (internally) to lug 1, which is now connected to the ground connection. When the switch is down/left, C6 is connected to ground, and the cap across lugs 3&6 are disconnected. Switched + C6 cap values and calculations: -2.7nF + 33nF will equal ~2.5 nanofarads. Cutoff frequency will be 6366. This isn't that close to the original 7234, but remember that we're dealing with harmonics and it's better to go a little lower rather than higher with the cutoff. -3.9nF + 33nF will equal ~3.5 nanofarrads. Cutoff frequency will be 4547 (not too far from Dane's 4822 with a 3.3nF) R5 could be (VERY) mildly adjusted as well if you want to hit a particular cutoff frequency. For instance, if you want to get even closer to the cutoff frequency of the stock values, you can use a 9.1K with 33nF and 2.7nF caps to get a cutoff of 6995. Or to get really really close to Dane's original cutoff, you can use an 8.2 with 33nF and 4.7nF caps. It would be best to experiment with the larger value cap in C6 first to get the vibe sound you want and then calculate the switched cap based on that. I will give this a go in one of my builds, maybe in the tap tempo version since I need to open it up to add Josh's optical bypass to it. Thanks to everyone in the switch thread that showed me the DPDT on/on/ons (armdnrdy, GGBB, slacker).

[midwayfair]

Is there another mod that exaggerates the differences?

I think it's more of how much you can actually get out of the crossover. We're only talking about two stages here; there's only so much that can be done.

The output cap coming from Q3 is a lower limit. You could try increasing it to 2.2nF or 1n5. This will lower the output crossover down from a little over 1.5KHz in the original, which will put it more in range of the treble cut added to Q2 and crossover more signal. It'll cut a little bit of highs from the full-range side. It won't be bad, but it might be noticeable. (You might consider pulling the 150pF cap, or lowering it 22pF-47pF, to get back some of the treble.)

Keep in mind, too, that the cuts are gradual, single-pole filters. Small changes can do a lot.

I suggest using a frequency calculator to see if you can optimize what you want. The relevant resistances are 10K (treble cut) and 100K (output pot). You can input the various capacitances to see where it puts the cutoffs. Use what you have so far as a reference.

[hylandren]

Yeah, that thing is definitely sexy on the outside and super clean on the inside!

[warriorpoet]

Here's a pic of the mod for all you mod-aholics:

Switch is on-on-on mini-toggle, cap calculated according to desired corner frequency.

[warriorpoet]

Not to spam my own thread, but...

I've re-settled on a new set of values.

R5- 12k
C6- 32n (22n, 10n in parallel)

Cm- 3n9

Subtle but noticeable bass boost in full range tremolo, full, rich, silky harmonic tremolo, forward vibe.

Even cooler!

[Stomptown]

Beautiful all around! The top soldered components are a thing of beauty!!! 

[cooder]

Excellent and most beautiful!!! What on/on/on toggle is it to use here, I believe there's two different varieties that contect the lugs somewhat differently, is it this one from Smallbear http://www.smallbearelec.com/servlet/Detail?no=900 ? Thanks!

[midwayfair]

Excellent and most beautiful!!! What on/on/on toggle is it to use here, I believe there's two different varieties that contect the lugs somewhat differently, is it this one from Smallbear http://www.smallbearelec.com/servlet/Detail?no=900 ? Thanks!

That's the correct switch.