Univibe Style Mod on MXR Phase 45 vero build

[mikepurcell]

I just built an MXR Phase 45 from the attached layout - it works great. I was researching the univibe mod, which changes the 47n caps on the drains of the JFET's to a set of caps with a 10:1 ratio. I found that people have been using a 100N and 10N config for the univibe mod. I figured an easier way to get there was to just swap out one of the 47N's for a 4u7. It seems to achieve the desired effect, it might not be the exact same as the 100N/10N combo, but it sounds cool.

In order to do that, I used an electrolytic - it works with it oriented both ways, but I'm worried about the reverse voltage across it. Both side of the connection are 4.69v dead on. Am I going to run into a problem with this cap blowing with a reverse voltage, or will it be ok?

I also had the idea to make a non polarized 4.7u by connecting them together by connecting one 4.7u negative to a 4.7u positive. Is that necessary, or is all this just a bad idea?

Thanks!

[ElectricDruid]

I'd guess that you'll get away with the electrolytic in the situation you have it for a good long while. Ok, it's not ideal, but it'll probably survive well enough, and I'd be very surprised if it actually blew up. Just not enough juice for that.

If you want to make a bipolar electrolytic by connecting two normal ones, you need caps of twice the value. E.g. for a 4.7uF bipolar, you'd use two 10uF caps. Someone else better versed in capacitor theory and with a better memory than mine can tell you the details of why...

[RickL]

Haven't you gone 100 to 1?  Ten time 0.047uF is 0.47 uF not 4u7. Not saying it doesn't sound good, just maybe not what you think it is.

[mikepurcell]

Yep, I do have 100 to 1. Thank you for pointing that out. I'll swap it out and see how it sounds.

The 4.7u adds more depth to the sweep on the phaser, glad I tried it.