UVICS-3 Build Help -A few questions before I start-

[Kevin Mitchell]

There's allot of information on R.G.'s page and it's great stuff! But I'm still learning and some things are a bit unclear to me. So I'm here again hoping some of you fine fellows can help me out.
UVICS-3

At first I had the intention of using the the full baby board but after sourcing the parts and some contemplating I've decides to just source/rig the dual pot and an 18V DC adapter.

What should I omit from the board with those parts I have chosen? I know I have to replace the diode bridge with jumpers but what about the IC1(voltage regulator) and D7? Should I keep them in my parts list, omit them or replace them with something else?

For the 8 power caps, what should go there with 18VDC powering the board? I'm not sure what R.G. meant with "use a total capacitance which gives you appropriately little ripple, not necessarily to fill up all the capacitor positions". I - attempting to be a perfectionist would like to fill all 8 caps positions and I have no idea what total capacitance would be appropriate for me. Whatever you guys would recommend I'll place an order for a variation of appropriate caps.

Would it be alright to use those normal small LDRs? They fit better than the big-oldschool type from smallbear and it's better on my wallet. I also think the layout of the board calls for this due to the LDR size. -I scaled/edited the layout and transferred it to the component side of the board for a professional look and easier population-

I haven't worked with box caps yet so if you guys have any tips/warning please let me know!

If any of you have worked on this board I am very open to suggestions.

I'd like to apologize to R.G. for not getting back to him. We've tried to get my Neovibe running but while swapping out the voltage regulator the traces of the board lifted and now it's a big mess. Instead of working with what I have I've decide to go big and do everything as well and simple as I can. Well maybe not simple but this sure excites me more than that mutilated board sitting on my workbench...

[R.G.]

At first I had the intention of using the the full baby board but after sourcing the parts and some contemplating I've decides to just source/rig the dual pot and an 18V DC adapter.

That's a perfectly reasonable way to do it.

What should I omit from the board with those parts I have chosen? I know I have to replace the diode bridge with jumpers but what about the IC1(voltage regulator) and D7? Should I keep them in my parts list, omit them or replace them with something else?

That depends on how quiet your 18Vdc adapter is. The circuit is designed so you can stick in an AC adapter, and there is enough filtering space provided to make quiet enough DC for the regulator to smooth out. If your 18Vdc adapter is already smooth and quiet, you can ditch all the caps and the regulator and just run from the 18Vadapter. Or if it's only modestly quiet or even unregulated, you can leave in the 15V regulator and only populate one or a few of the filter caps.

For the 8 power caps, what should go there with 18VDC powering the board? I'm not sure what R.G. meant with "use a total capacitance which gives you appropriately little ripple, not necessarily to fill up all the capacitor positions". I - attempting to be a perfectionist would like to fill all 8 caps positions and I have no idea what total capacitance would be appropriate for me. Whatever you guys would recommend I'll place an order for a variation of appropriate caps.

Put in as many as makes you happy, and as few as keeps the audible hum and ripple down enough. As I mentioned, this depends on how smooth and non-ripple-y your incoming 18Vdc is. If the incoming DC is already regulated and quiet, you don't need any of them. Well, OK, maybe one.    But if you get an unregulated and unfiltered DC supply, you may need to put on any number from two to all of them, and choose by ear.

I haven't worked with box caps yet so if you guys have any tips/warning please let me know!

I love box caps. They are a consistent size and consistent lead spacing, unlike almost all other caps. About the only issue I have with them is that they fall out when you turn the board over to solder. So I like to populate the boards by height, lowest components first: all the bare wires first, then all the 1/4W resistors, then all the ICs, etc. When you get to the box caps, all the other parts are shorter, and you can simply put a sheet of cardboard or similar on top of the board, turn the sandwich over and place it -carefully- on the table and the parts won't fall out.

I'd like to apologize to R.G. for not getting back to him. We've tried to get my Neovibe running but while swapping out the voltage regulator the traces of the board lifted and now it's a big mess. Instead of working with what I have I've decide to go big and do everything as well and simple as I can. Well maybe not simple but this sure excites me more than that mutilated board sitting on my workbench...

No apology needed. I've ruined my share of boards while "improving" them. 

[Kevin Mitchell]

Thank you R.G!

For Q13 would a MPSA13 work fine? I happen to have those on hand and there isn't much explaining this transistor.

Also could you answer my question regarding the LDRs? Would it be alright to use the smaller kind? I have plenty left over from easyvibe builds.

[R.G.]

For Q13 would a MPSA13 work fine? I happen to have those on hand and there isn't much explaining this transistor.

It will be fine.

Also could you answer my question regarding the LDRs? Would it be alright to use the smaller kind? I have plenty left over from easyvibe builds.

Sure. If you have them, try it. If you don't like the results, you can always change to other parts later.

Not much of an answer, but it's what I'd do.

[Kevin Mitchell]

Hopefully this thing is put together and running by the weekend!

I have a question reguarding UVICS-4. You said it adds a cancel function as the original Univibe had (rocker all the way to heel to cancel) is there a way of adapting the UVICS-3 to do this? I figured I would put a small switch at the heel of the foot rocker for that unless there's a better way? Also I would add a switch to trigger this effect if it's not desired. If you still have info for UVICS-4 please send it over!

I also plan to use a 3PDT toggle for controlling speed with the foot rocker or a knob on the side -still have that 100k rev log-. Thought that could be useful.

[R.G.]

Hopefully this thing is put together and running by the weekend!

Good. Yell if you run into problems.

I have a question reguarding UVICS-4. You said it adds a cancel function as the original Univibe had (rocker all the way to heel to cancel) is there a way of adapting the UVICS-3 to do this? I figured I would put a small switch at the heel of the foot rocker for that unless there's a better way? Also I would add a switch to trigger this effect if it's not desired. If you still have info for UVICS-4 please send it over!

That particular part of it was mostly PCB gymnastics, in that it brought out the "cancel" point so you could add a momentary switch to the rocker. The hard part is still the mechancial work of putting the switch in the rocker. It is possible to do this same thing with an added-on wire to the right place on UVICS-3. There was probably some rearrangement for the switch and so on. I can go dig it out of the archives if you really want to make yet another PCB.

I speculated, but never tried out, that one could add the switch to the rocker by some combination of optical, mechanical, or magnetic (Hall effect or reed switch) switches in a rocker. My favorite for easy was a reed switch glued to the main housing at the heel end, and a magnet glued to the heel of the rocker to click the reed when it was heel down. That's easy and fast, but will be the dickens to get adjusted to the right position. Optical and mechanical would be more precise, but more difficult mechanically.

I also plan to use a 3PDT toggle for controlling speed with the foot rocker or a knob on the side -still have that 100k rev log-. Thought that could be useful.

That will work fine.

[Kevin Mitchell]

Thank you! You don't have to dig around.

I had the same idea as you with using some kind of optical or magnetic switch at the heel. Does seem like a cool idea but not any more practical than using a soft touch momentary switch. Before I posted the question I added a small momentary switch to my order so I'll go with that approach.

[Kevin Mitchell]

Okay so most of the board is populated minus the 1uf box caps. The wall wart I ordered is a hunk of crap and blew while reading it's output. Now I'm more attracted to the idea of a charge pump so I could just use my PP2.

For the charge pump I'm looking at a single parts supplier and they seem to only have 16 volt tantalum caps although this rating is marked as 16+.
Something like this;


Can these caps handle the extra voltage? I'd say yes. I always do my own research but I find it best to cross check with any of you guys on this site. I read that solid tantalum caps could handle X4 it's voltage rating. But I also read about tantalum voltage derating but I don't think that applies to solid electrolitic caps. Also I'd use 1N5818s instead of the 1n5817s due to availability. That should be fine as well but looking into these charge pumps/voltage doublers I'm a little nervous about it not working out. Although that's why we debug.

[Kevin Mitchell]

Sorry for the late update. Not enough time in a day!

After getting everything set up and the charge pump put together I was left with some unsatisfactory work. I've picked up a new soldering iron and learnt the hard way that it gets wicked hot very fast. Resulting with some melted traces after spending too much time cleaning up some fixes and bad traces. The pump worked for a little but not long enough to get far debugging the main board -the voltage doubler IC blew. Before it blew the bulb didn't light and the sound signal wasn't there. I'm fairly certain that this was not due to a wiring issue but bad parts and/or bad traces. So I have to test all of the transistors before reusing them. I might breadboard the LFO section of the circuit to ensure my parts work fine even though I used parts to accommodate the BOM.

Since I'm trying to be a perfectionist however I can and will admit when I'm not satisfied I'm going to make a new board and reuse almost all of the components from the previous board. Any tips on reusing components (only worried about the transistors really) are very welcome.

I have the wah pedal all set up and painted waiting for it's new life. It was impossible sourcing an appropriate speed pot. With a little ingenuity and JB weld I modified a 24mm dual ganged pot shaft that works perfectly and has held up to some test abuse. Can't wait to share the finals results.