UVICS - Univibe In a Crybaby Shell

[Brejna]

After more than 6 months of dawdling, it is finished.  here are few photos...
Thanks R.G. for helping me
Cheers
Brane

[Keeb]

Hello and let me start with thanking RG for his time and effort he's put into this project. I know this thread has been plauged by passive aggressivness and second guessing etc. and I hope I don't come across as a turd in the punch bowl with all these questions.

I have undertaken the Son of UVICS projects a couple of days ago (been eyeing it for a while but just etched the board!). So far this is a really fun project because of the challenges with the crybaby shell etc. I'm having a blast building and researching this thing!

I'm planning on building the Son of UVICS with the wah pot mod, cap switching, blinking led, and power it with 9VDC (so the charge pump is also added, rectifier left out). This thread has been a good read and sorted some of my questions but some still remain. Most are about the schematic and layout etc. (most of them are perhaps clarifications about the building doc for the son of UVICS.)

• For the blinking LED mod you can either use R2, R53 and U3 but leave off R54, R55, Q16 or vice versa (I'm assuming the build doc has a typo). Not of all these values are mentioned in the BOM or in the schematic. From reading this thread it seems to me that a R54 is 100K, R55 is 2.2K (determines the LED brightness) and that Q16 should be a darlington, MPSA13. Correct? I noticed what type of optoisolator to use if using the other method had been discussed so I'll leave that.
• On the schematic it states Q15 as a NPN darlington but on the BOM it says 2N5088. Does it matter?
• Some caps that are on the baby boards for the UVICS are not present on the Son of UVICS board, C39,40,41. These seem to go to ground on the baby boards. Does the son of UVICS need them? I'm planning on just leaving them off.
• For C28 and 29 it's recommended to use 10uF tantalum caps. The ones I have are only rated for 16V, are tantalum caps critical for noise or will electros do fine?
• Any recommendations for cap values to use for the cap switching mod? I'm more used to changing a single cap in chorus or changing input cap on a fuzz. Four different values seems a lot and I'm not sure what resistance to use to calcute cut off frequencies for the values listed. I planning on socketing them all and trying some different combos but som help to get started would be appreciated.
  

Oh, and one last thing the VLTC3/2 is the same thing as a  VLT5C3/2 right? Never used optocouplers before.

[Brejna]

Hi, I can share mine experience about Son of UVICS..
1.Blinking LED I never sorted right way so I implement another option which is independent of intensity knob.
2.For Q15 I've tried MPSA13, 2n3904 and 2n5088 and they all worked fine
3.I' ve used this combinations of caps: C5   C9    C12    C15
                                          -univibe 15n 220n 470pF 4n7
                             -RM voodoo vibe 15n 100n  47n    4n7
                                   -Resley tone 4n7  3n3   2n2    1n
4.I did put C28 and C29 tantalum, but probably it want make big difference if you use elect.
5.If you want LFO to work you must put jumper in position of R2 if you don't intend to use LED blinking method 2.
6.Yes, I also used VTL5C3/2
7.I reccomend to put 10k trimmer instead of R52 for easier adjustment of the speed
Cheers

Edit: Strongly suggest to socket Q12 and Q13..

[Keeb]

Thanks a lot! I'm going to socket all the transistors and parts of the LFO as well. I want to try this:

How do I increase the max speed?
If you're OK with increasing the min speed too, cut the 1uF caps in the LFO by half; that will increase both min and max. Changing Q11/Q12 to an integrated darlington or changing Q11 to a J201 and changing R40 to a higher value will give you a lower minimum speed before the LFO quits because of loading on the capacitor chain, so changing Q11/Q12/R40 and cutting the value of the capacitor chain will give you a higher max speed with the same min speed.

I was going to socket R52 but I'm going add a trimmer instead! Great suggestion! I'm ordering parts for this anyway so I'm going for tantalum caps.

[txomin]

another one, after 2 years of having made the pcb and populated, at last I've wiring, sounds fantastic, no changes to the original of R. G. only mpsw45  for BC517, thanks R.G. for your wonderful work.

And yes they have charge pump.

If something is wrong is the fault of the google translator

[R.G.]

You're welcome. Glad I could help! It's really nice to see that these get used and enjoyed.