Original Schematic Uni-Vibe (old one)

solderboy · Post by **solderboy** » 07 Nov 2007, 18:24

Hi There,

as i grub into my saved Schematics.. i found an old Operating Manual of an old Uni-Vibe (first Version i think)
its a Scan of that Manual including a Schematic that i found some years ago somewhere on the WWW ...

is anyone interested ?

tell me

bye
Solderboy

MoreCowbell · Post by **MoreCowbell** » 07 Nov 2007, 18:49

Absolutely. I'd definitely be interested in the manual scan.

Thanks,
AC

solderboy · Post by **solderboy** » 07 Nov 2007, 18:57

....

http://mitglied.lycos.de/surftone/diverse/mp3/

grab everything with univibe*

have PHUUN

ciao
Solderboy

MoreCowbell · Post by **MoreCowbell** » 07 Nov 2007, 19:55

thanks again !

Dirk_Hendrik · Post by **Dirk_Hendrik** » 08 Nov 2007, 13:48

And while you're at it grab all the other available univox stuff too. It's all at http://www.univox.org:

http://www.univox.org/schematics.html

solderboy · Post by **solderboy** » 08 Nov 2007, 14:04

Hi,

cool Site !!!!! i think it's possible, that i found my posted Files there (but dont remember)

Greetings
Solderboy

Dirk_Hendrik · Post by **Dirk_Hendrik** » 08 Nov 2007, 18:11

MoreCowbell · Post by **MoreCowbell** » 08 Apr 2008, 15:32

Some GREAT gut shots of a Shin-Ei Univibe can be found HERE !

super velcroboy · Post by **super velcroboy** » 14 Apr 2008, 02:34

god damn $1600 for a univibe. And those photos are great

amp_surgeon · Post by **amp_surgeon** » 07 Jul 2011, 02:07

Howdy. Sorry about resurrecting a zombie thread.

My introduction post is here:

https://www.freestompboxes.org/viewtopic ... 94#p152894

I thought my first contribution to this forum ought to be something useful, so here it is: A schematic of my Shin-ei/Univox Uni-Vibe, which I traced out myself. There are a number of differences between the unit I have and the schematics originally included on the back of the Uni-Vibe manual, some of which would undoubtedly affect the tone. This is also more complete as it shows which parts are on the PCB and which are offboard. It also includes the pinout of the mini DIN used for the pedal, as well as a schematic for the pedal itself.

Note that I've indicated the bulb in the light tank is 12V, 40mA. This happens to be the rating of the bulb that was in the circuit board when I bought the pedal, but it's clear from looking at the board that the bulb had been replaced at some point, so I have no idea if this is the same or even similar to the original bulb. It does seem to work ok, though.

Anyway, this might be useful for someone wanting to build a clone of this vintage effect, presuming you can round up a suitable quad set of LDR's. I haven't got a complete set of performance charts for the LDR's yet, but I'm working on it. I've recently finished building a test box for profiling LDR's.

Enjoy!

MWichni · Post by **MWichni** » 08 Jul 2011, 16:59

It's great to see traced original unit, and have ability to see characteristics of the original LDR's used in Uni-Vibe. Thank you very much for your hard work!

yeeshkul · Post by **yeeshkul** » 08 Jul 2011, 19:10

500 ohms trimmer (the bulb adjustement) and 100k for R37 makes perfect sense (helps to equal the volume of chorus and vibrato). 10n for C13 is a huge surprise indeed.

amp_surgeon · Post by **amp_surgeon** » 08 Jul 2011, 23:29

yeeshkul wrote:500 ohms trimmer (the bulb adjustement) and 100k for R37 makes perfect sense (helps to equal the volume of chorus and vibrato). 10n for C13 is a huge surprise indeed.

There are a few other components that appear to have been swapped at some point. C24 in the power supply, for example, and a few other electrolytics, but they appear to have been swapped with original value parts, as far as I can tell. I'm fairly certain that the trimmer was original, and I really scrutinized all the caps in the phase shift chain to make sure they were originals.

Anyway, this schematic reflects what's in the box now. It doesn't much resemble what I originally bought (for a sizable pile of cash). I cut every wire on the PCB and inserted Molex connectors so that I could remove the board and examine it and still reassemble the pedal. All the LDR's are now mounted on pin sockets. I'm sure I've forever wrecked it's value as a collectible, but it was all in the name of science! I'm planning on repeating this sacrilege on another Uni-Vibe just to make sure what I've learned so far isn't unique to this one unit. At some point I'd like to build some reproductions of it.

yeeshkul · Post by **yeeshkul** » 09 Jul 2011, 06:40

Mate you have a big thank for the sacrifice.

Can you please post a sound sample when the thing is back together? Also, when you measure the LDR's (i assume you use a voltage divider to get the LDR voltages -> resistance) keep on your mind that the oscilloscope probes are about 1M ohm and you are very probably dealing with bigger resistances here. I mean don't forget to use some sort of an output buffer.

amp_surgeon · Post by **amp_surgeon** » 09 Jul 2011, 09:26

yeeshkul wrote:Mate you have a big thank for the sacrifice. Can you please post a sound sample when the thing is back together? Also, when you measure the LDR's (i assume you use a voltage divider to get the LDR voltages -> resistance) keep on your mind that the oscilloscope probes are about 1M ohm and you are very probably dealing with bigger resistances here. I mean don't forget to use some sort of an output buffer.

I'm building the test box based on conditions described in some old Perkin Elmer app notes. I'm using a fairly large light-tight plastic NEMA enclosure with a light source that has a color temp that's pretty close to 2850 kelvin. Distance from the light source to the LDR socket is about 10X the bulb radius. The LDR socket and lamp socket leads go to binding posts on the outside of the box, so all of the test circuitry can be external to the test environment. There's also a light meter sensor next to the LDR socket so I can use an external light meter to calibrate the lamp to a known level.

The resistance range of the LDR's seems to be much larger than most "off the shelf" LDR's available today - less than 1K to over 20M. The most important characteristics are going to be the resistance graph over the range of light normally seen in the light tank, as well as the rise and fall times. I can plot the static resistance using any digital ohmmeter. For the rise and fall times I was planning on using my HP 412AR VTVM. The input impedance is 200M on ranges above 300mV, and it's got DC output on binding posts with an output impedance of about 2 ohms. This should make a really good buffer between the LDR ladder circuit and my Tektronix TDS1000B digital storage scope.

yeeshkul · Post by **yeeshkul** » 09 Jul 2011, 15:09

I was also measuring many types of LDRs. I used the Uni-Vibe LFO and had my LDRs just sticked in and connected to a voltage divider with an output buffer. So i could measure them under the exactly same conditions as they are meant to be. I used oscilloscope with a transient recorder feature to see the voltages across on the LDRs. Good luck anyway!

amp_surgeon · Post by **amp_surgeon** » 10 Jul 2011, 15:30

yeeshkul wrote:I was also measuring many types of LDRs. I used the Uni-Vibe LFO and had my LDRs just sticked in and connected to a voltage divider with an output buffer. So i could measure them under the exactly same conditions as they are meant to be. I used oscilloscope with a transient recorder feature to see the voltages across on the LDRs. Good luck anyway!

I considered that approach, and it would actually be pretty easy since I've already socketed the LDR's. The problem is that I'd need a bucket full of LDR's to compare with. What I was hoping to do was produce characteristic curves that pretty closely matched the ones they include in LDR datasheets. This would hopefully allow me to compare datasheets without actually buying any LDR's, and when I did buy an LDR I'd already have a pretty good idea how closely it was going to match the original.

The Rotagilla · Post by **The Rotagilla** » 10 Jul 2011, 21:07

So I did some comparing last night between all the Univibe schematics I have. When I compared Amp_Surgeon's to the schematic that is included with the Univibe manual that's floating around there are five parts differences -

1) C16 on AS's is a 0.006uf, on the manual schematic it's a 0.0047uf.
2) R37 on AS's is a 100K, on the manual schematic it's a 47K.
3) R45 on AS's is a 1.8K, on the manual schematic it's a 4.7K.
4) R46 on AS's is a 1.8K, on the manual schematic it's a 4.7K.
5) R47 on AS's is a 4.7K, on the manual schematic it's a 47K.

Amp_Surgeon's scheamtic vs. R.G. Keen's Neovibe -
1) C13 on AS's is a 0.01uf, on R.G.'s schematic it's a 470pf (C12).
2) C16 on AS's is a 0.006uf, on R.G.'s schematic it's a 0.0047uf (C15).
3) R5 on AS's is a 1M, on R.G.'s schematic it's a 1.2M (R7).
4) R37 on AS's is a 100K, on R.G.'s schematic it's a 47K (R37).
5) R49 on AS's is a 150r, on R.G's schematic it's a 68r (R48).

Or thereabouts.

R.G. · Post by **R.G.** » 11 Jul 2011, 02:31

Characterizing LDRs is difficult because of the light and dark adaptation of the materials, and the confounding issues of speed of response, amount of resistance change, and spectral effects of the exciting light. The materials have competing and opposing requirements for getting fast response and wide range, according to the Perkin-Elmer technical data they picked up from Clairex and may have extended. I haven't done an exhaustive search of the history.

To test an LDR you put it in the dark (doh!) and feed a calibrated light to it, then watch what happens. If you want to know its resistance changes, you can feed it a constant (and perhaps voltage limited) current and then simply read voltage as being proportional to resistance. A simple tester would do this with a DC current source, set up to not exceed the LDR's current or power/self heating limits.

Getting a calibrated light source is *hard*. These are rarer than voltage reference sources. Back when I was doing this, I picked up some green LEDs, and decided that *this one, right here* was my reference source, whatever it did. This let me test LDRs on a relative basis, as they'd be different with different LEDs. I also picked a reference LDR, so I could back-test LEDs whenever I might need to pick and calibrate a new reference.

I made up a fixture where the LDR was put in a dark cavity facing the LED, and fed the LED pulses. The LDR was driven from an active constant current source, and so its voltage was proportional to the resistance. It was *hard* to get the ranges down right, as LDRs can and do range from kohms to tens or hundreds of megohms. But the nice thing about this is that I could feed the LED a pulse of current for a very short time and see the LDR response before it had a chance to light adapt; likewise, I could light-adapt it for a while, then blip the LED off and see its reponse before it could dark-adapt. And of course, I could just turn it on or off, and see the resistance fall/rise and get the time response to a light-step, as well as seeing light and dark adaption on the LDR.

This was probably more elaborate than needed, but it let me mess with LDRs until I decided I could match them for resistance range and speed.

DrNomis · Post by **DrNomis** » 11 Jul 2011, 02:48

When I built my Univibe, I didn't even bother about matching the LDRs, I just bought 4 from Jaycar Electronics, and bunged them into their holes on the PCB I used, and they worked just fine for me, the lamp I used was a miniature 12V/60mA type, again it worked just fine for me...