Univox - Univibe (Uni-vibe)
- analogguru
- Old Solderhand
Information
Here are some hires-guts:
https://cgi.ebay.com/Univox-Uni-Vibe-or ... dZViewItem
and another one:
https://cgi.ebay.com/VINTAGE-UNI-VIBE-U ... dZViewItem
Interesting the 470pF ceramic cap for the phase stage in the lower middle of the pcb.
analogguru
https://cgi.ebay.com/Univox-Uni-Vibe-or ... dZViewItem
and another one:
https://cgi.ebay.com/VINTAGE-UNI-VIBE-U ... dZViewItem
Interesting the 470pF ceramic cap for the phase stage in the lower middle of the pcb.
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
- lolbou
- Old Solderhand
On the original schematic, the speed pot is a 250k rev. log. But on RG's and others I found, it's a dual 100k...
What's wrong with it? This must change the lowest frequency? What's the value found in the stock pedal?
What's wrong with it? This must change the lowest frequency? What's the value found in the stock pedal?
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
There's really very little mystery left in the Univibe. I've measured both 250K and 100K pots in original univibes given to me to repair. Both work.
The originals are actually dual log pots, turned into reverse log by the direction the shaft is turned mechanically, I believe. I haven't seen a real univibe footpedal in a long time, but that's what I remember. You want reverse log for this, just like any phase shift oscillator to make the change in frequency per pot rotation seem even, not bunched on one end or the other.
The originals have both series and parallel resistors to the pot to limit what the pot does electronically. So the pot value is not hyper-critical. Small bear stocks a dual 100K reverse log pot that will go into a crybaby enclosure and do the trick. My PCB layout for a vibe clone predates the world wide web, and is from a time when the only communications medium was usenet posting. It's been updated several times for better fit, easier soldering, etc. The current Neovibe board can be mounted inside a crybaby pedal. Several people have done that. I have a new layout I haven't released yet that is designed to fit the mounting bosses for a crybaby deliberately. This version includes a tremolo (like the 'vibe's precursor, the RT-18... that's Resly-Tone...) and a single pot driving a dual Led/LDR for the speed control to get rid of that pesky dual reverse log pot.
The most common problem with vintage vibes is burnout of the lamp driver.
I got a raft of equine solid waste material when I released what was to become the Neovibe. The entire Neovibe is a part-for-part repro of the Univibe, but I ditched the R-C filtering for a three terminal regulator. There were some Very Offended People who held the opinion that the repro could not sound anything like the original because it now had clean DC to the audio path. Silly, I know, but the internet was even less civil back then.
The Neovibe has satisfied hundreds? Thousands? of people over the more-than-a-decade that it's been available. The ones who haven't been satisfied have mucked up the build. All of those I found out about I got running.
It ain't magic. It's a collection of parts.
The originals are actually dual log pots, turned into reverse log by the direction the shaft is turned mechanically, I believe. I haven't seen a real univibe footpedal in a long time, but that's what I remember. You want reverse log for this, just like any phase shift oscillator to make the change in frequency per pot rotation seem even, not bunched on one end or the other.
The originals have both series and parallel resistors to the pot to limit what the pot does electronically. So the pot value is not hyper-critical. Small bear stocks a dual 100K reverse log pot that will go into a crybaby enclosure and do the trick. My PCB layout for a vibe clone predates the world wide web, and is from a time when the only communications medium was usenet posting. It's been updated several times for better fit, easier soldering, etc. The current Neovibe board can be mounted inside a crybaby pedal. Several people have done that. I have a new layout I haven't released yet that is designed to fit the mounting bosses for a crybaby deliberately. This version includes a tremolo (like the 'vibe's precursor, the RT-18... that's Resly-Tone...) and a single pot driving a dual Led/LDR for the speed control to get rid of that pesky dual reverse log pot.
The most common problem with vintage vibes is burnout of the lamp driver.
I got a raft of equine solid waste material when I released what was to become the Neovibe. The entire Neovibe is a part-for-part repro of the Univibe, but I ditched the R-C filtering for a three terminal regulator. There were some Very Offended People who held the opinion that the repro could not sound anything like the original because it now had clean DC to the audio path. Silly, I know, but the internet was even less civil back then.
The Neovibe has satisfied hundreds? Thousands? of people over the more-than-a-decade that it's been available. The ones who haven't been satisfied have mucked up the build. All of those I found out about I got running.
It ain't magic. It's a collection of parts.
- lolbou
- Old Solderhand
Thanks RG, your articles on this unit are my very Bible at the moment (and your optocoupler mod helped me a lot on a modern Vibe repair...)!
Thanks a lot for your answer RG...
So that's why I've found both online...R.G. wrote:I've measured both 250K and 100K pots in original univibes given to me to repair. Both work.
Well, it's because I computed the equivalent resistance of the 4k7+100k//220k and 4k7+250k//220k and I almost found a 50k difference in the values, so I thought it would affect the LFO frequency... Still I don't really catch how the resistors can limit both ends of the pot course (especially the lower)...R.G. wrote:The originals have both series and parallel resistors to the pot to limit what the pot does electronically. So the pot value is not hyper-critical.
I'll give it a closer look!!R.G. wrote:The Neovibe has satisfied hundreds? Thousands? of people over the more-than-a-decade that it's been available. The ones who haven't been satisfied have mucked up the build. All of those I found out about I got running.
Thanks a lot for your answer RG...
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
- lolbou
- Old Solderhand
The LFO went on breadboard this morning (with BC548s)
When pot is shorted: f= 5Hz.
When pot is 100k: f= 0.76Hz
When pot is 240k: f= 0.35Hz (I used fixed resistors)
So the value of the pot does affect the frequency (in this I'm right), but the sweeping cycle is 1.5s longer with 240k, which is not probably critical at extreme values like RG said...
By going for a 100k, you might get happy with it though...
Just my two cents (as regards to RG's billions ) here...
When pot is shorted: f= 5Hz.
When pot is 100k: f= 0.76Hz
When pot is 240k: f= 0.35Hz (I used fixed resistors)
So the value of the pot does affect the frequency (in this I'm right), but the sweeping cycle is 1.5s longer with 240k, which is not probably critical at extreme values like RG said...
By going for a 100k, you might get happy with it though...
Just my two cents (as regards to RG's billions ) here...
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
I've built 2 of 'em, one for me and one for a friend of mine and we are more than satisfied, we are happy!!!R.G. wrote:
The Neovibe has satisfied hundreds? Thousands? of people over the more-than-a-decade that it's been available.
Your "The technology of..." articles are milestones for DIYers.
With your optocoupler LFO mod now I'm building a potless pedal control for the vibe with an hall proximity sensor. I'll post results of my experiments when the thing will been tested properly.
- Kregg
- Breadboard Brother
I'm am assembling a Neovobe build and I need some guidance on how to do the following (from GGG project file https://www.generalguitargadgets.com/pd ... update.pdf ):"If you want the best performance out of your Neovibe, leave these two resistors out and use a 200K pot to adjust the mix for deepest phasing. Then measure the resistance on each side of the wiper and put the nearest 1% resistor values in for R35 and 36."
Could someone please offer a clearer explanation to someone in their rookie year?
Thanks
Could someone please offer a clearer explanation to someone in their rookie year?
Thanks
"Political correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."
The two resistors form a divider.
This is the same principle as the volume control pot used on pretty much all pedals.
So, to replace those two resistors with a pot, you'd attach the middle pin of the pot at the point where R35 and 36 meet, with pin 1 joining C18 and pin 3 connecting to R37. Or vice versa, the important one is having pin 2 at the junction of R25 and R36.
Then turn the pot until you get the sound that you like the best. Un-solder the connections (taking care that you don't nudge the pot shaft in the process) and measure resistance between pin1 and pin2. Then measure the resistance between pin2 and pin3. These 2 readings give you the values for your ideal R35 and R36.
Hope that helps/makes sense?
This is the same principle as the volume control pot used on pretty much all pedals.
So, to replace those two resistors with a pot, you'd attach the middle pin of the pot at the point where R35 and 36 meet, with pin 1 joining C18 and pin 3 connecting to R37. Or vice versa, the important one is having pin 2 at the junction of R25 and R36.
Then turn the pot until you get the sound that you like the best. Un-solder the connections (taking care that you don't nudge the pot shaft in the process) and measure resistance between pin1 and pin2. Then measure the resistance between pin2 and pin3. These 2 readings give you the values for your ideal R35 and R36.
Hope that helps/makes sense?
- Kregg
- Breadboard Brother
Excellent explanation, thank you very much!
"Political correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."
- coi2001
- Breadboard Brother
I built the forum vibe using Brad's board form Classic Amplification. Got the reverse dual audio pot, LDRs, and lamp from Small Bear and used a cough syrup dosing plastic glass lined with aluminum foil as light shield. Works great. I appreciate the usefulness of the trimpots which protect the lamp from blowing (although I managed to fry one) and allow you to dial in what sounds best to your ears. I have not made a power supply for it, and I am running it on 2 x 9V batteries (used, providing 15-16 V).
i was wondering what people do for power supplies for univibe-type projects. Has anyone tried running it on 9V power supply and using a voltage doubler and a 15 V regulator?
i was wondering what people do for power supplies for univibe-type projects. Has anyone tried running it on 9V power supply and using a voltage doubler and a 15 V regulator?
- mictester
- Old Solderhand
Information
That's a really nice build!coi2001 wrote:I was wondering what people do for power supplies for univibe-type projects. Has anyone tried running it on 9V power supply and using a voltage doubler and a 15 V regulator?
Power for it - I always mains power them, using a 15 VA 15V AC secondary transformer, a little 5A bridge rectifier, 2200µF 35V smoothing capacitor, 7815 regulator with 100nF bypass capacitors at the pins (on both input and output) and a 1000µF 25V supply filter capacitor.
You could use a voltage multiplier, but the little 7660S and so on would not really be powerful enough to drive this current-hungry pedal. You'd have to use something more sophisticated.
"Why is it humming?" "Because it doesn't know the words!"
- coi2001
- Breadboard Brother
mictester wrote:That's a really nice build!coi2001 wrote:I was wondering what people do for power supplies for univibe-type projects. Has anyone tried running it on 9V power supply and using a voltage doubler and a 15 V regulator?
Power for it - I always mains power them, using a 15 VA 15V AC secondary transformer, a little 5A bridge rectifier, 2200µF 35V smoothing capacitor, 7815 regulator with 100nF bypass capacitors at the pins (on both input and output) and a 1000µF 25V supply filter capacitor.
You could use a voltage multiplier, but the little 7660S and so on would not really be powerful enough to drive this current-hungry pedal. You'd have to use something more sophisticated.
Thank you, the power consumption of my build if 24-31 mA, depending on the speed-intensity setting, but I see you point of not messing with the voltage doubler and going for a little power supply. It's just that it's another box/adapter to carry.
Do you usually use a wall wart type of transformer and the rectification/power conditioning in the vibe box?
thanks
Costantino
PS: Attached below are photos of the light shield before I painted it black. It's held on the board by three pin connectors that wedge into the inside of the plastic cup lip and keep it firmly in place.
- Attachments
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