Quote from: jkokura on January 15, 2014, 02:03:48 AM+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!
Yeah, I really admire the smooth writing you've got there. Wish I could label like that...
| 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). |
Quote from: warriorpoet on January 15, 2014, 06:21:57 PMIs there another mod that exaggerates the differences?
Quote from: cooder on January 16, 2014, 08:12:33 AM
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 (http://www.smallbearelec.com/servlet/Detail?no=900) ? Thanks!