Neovibe Light Box Tip

[plankspank]

Here's a quick,easy, and cheap way to fabricate a metal light box enclosure for your Neovibe builds (as you may know, the original Univibe ulilized a metal box, and several "Bootique" pedals use it and heavily advertise this fact.)

During my recent Neovibe build, on the breadboard version I A/B'd both metal and plastic and noticed a distinctive tonal difference; the metal had a more clearer, less darker sound. I ended up going metal..

Just grab an old "Altoids" mint tin- its insides are highly, almost mirror polished. I used metal tinsnips to cut out a nice flat section. Polish both sides with some 0000 steel wool, then using the template in the GEOFEX build report, trace the pattern on it with a scribe or sharpie and cut away. The side edges can either be soldered shut (it solders very easily with some rosin applied), or use some aluminum tape like I did. The legs can be soldered on to the sides with some bare solid 18 AWG copper wire for an easy mount to the PCB.

Now we have another Neovibe variable to play around with and argue over as to which sounds best....

[momo]

I also think the metal box has something to do with the tone.....but more important than that, how are your sensor oriented around the led....do they get half direct light, half reflected, are they beaming directly on the led, or on the 'roof'??

I did not play around enough with my positions and Id love to hear how everyone is orienting these when you use a 'mirror' finish metal box.

[snoof]

Foxrox uses a metal thimble for the light box!

[axg20202]

This thread motivated me to revisit my own Neovive to improve it's 'swish'. I originally built it using the film cannister light shield. Despite doing the various circuit tweaks including the increased top speed mod, the output mix trim pot mod, and increasing R49 to soften the waveform of the throb, I've never been totally happy with the tone. It sounded quite dark and was still too choppy sounding. So, I thought what the hell and decided to switch to the metal light shield with LDRs mounted flat to the PCB and also to try to optimise R49 and the bulb brightness trim pot.

The changes didn't take long and were definitely an improvement. As aynone who has built one of these will know, the best tone and "swish" is determined by lots of factors (LDR position, light shield, lamp brightness, output mix etc etc) and tweaking one of them can require tweaking all the others - it can take a while. The tone is now clearer with more swish and I'm glad I changed to the metal shield. Changing R49 to a 50k trimmer has probably made the biggest improvement - I have this controll pretty much maxed out, but the softness it lends to the throbs gives more vibe and less ping-pong - I had originally increased this to 10k, but clearly this wasn't high enough for my build. Anything over 50k and the swish was too subtle though. I think anyone building a neovibe should use the metal light-shield and consider including the R49 50k trimmer.

[plankspank]

Hey, glad this worked for you too. To clarify my original post, my LDR's are oriented straight up also (as per the original Univibe). I'm using a Radio shack lamp-12v 50 ma. lamp p/n 272-1154.

[momo]

Hmmm, ill have to check if I had done the r49 mod, but ill also have to try putting the sensors flat, right now they are high half facing the bulb/half towards the cieling. Are you guys saying the sensors are basically lying low....at the base of the pc board?, maybe mine are too high up, ill defenitely check it out, thanks for the info.

[axg20202]

Yes. My LDR's are pulled flat tight to the surface of the PCB, facing directly up. You need to make sure that the inside of the metal light shield is nice and reflective.

[plankspank]

Are you guys saying the sensors are basically lying low....at the base of the pc board?,

Mine are located up off the PCB, just a few mm below the top of the lamp.....

[DeeBug]

Right then, if you're using a film canister, not to worry.  A bit of reflective foil ought to spruce things up for you.  In any case, that's what I'm telling myself 

[axg20202]

Maybe, assuming you're building it afresh, although I tried adding foil to an already built neovibe before ripping out the cannister and going the metal shield route. The problem with lining the inside of the cannister after it has all been built is that if you've left nice long legs on the LDRs to flex them into shape, they risk getting shorted out on the foil unless you do a very tidy job. Tricky to do if the cannister and all the works are already installed. If you've got to remove the LDRs to do a good job, you may as well install the metal shield, which I think is easier to fit anyway and in my view sounds better.

[spudulike]

Check ebay for RF shields - like mini-enclosures with removable lid.

[BRingoC]

Another possible source for the light shield.  I just made one out of a tea light candle, the aluminum piece that the wax sits in is very plyable, it is almost the exact size of the layout for the ldr arrangement.  I flattened the top by rubbing the back end of a pen on it, which resulted in a very shiny surface with no additional work needed.  I held it in place with a couple pieces of solid core wire attached to the board and running over the top of the shield.  Very easy to do this because it is the correct size as is.

[R.G.]

Hmmm...

spray adhesive on shirt cardboard, rub down kitchen aluminum foil, cut into a fold-up box and hold on the board with sewing thread or nylon cable ties.

Spray the inside of half a plastic easter egg with silver spray.

Mirror polish the inside of the whole box the 'vibe is in and don't use any light shield.

Leave it out in the open, and wave your foot over the LDRs to make it whoosh when you want to.

[BINGEWOOD]

I've been planning on revisiting my neo which I housed in a rotovibe shell I found.  I got some metal mirrors at All Electronics:

http://www.allelectronics.com/cgi-bin/item/MIR-22/search/SHINY_METAL_MIRROR_.html

A couple tries later I got a lil mirrored box.  I'll post when I get back around to the vibe if there is any noticeable difference.


R.G., I dig the manual whoose principle.

[Paul Perry (Frostwave)]

There has to be a "smoke and mirrors" gag here somewhere - but, maybe someone will want to experiment with the reflective shells of small halogen lights.