Neovibe vs Easy vibe pics and clips inside

[snoof]

From what I understand, they shape the LFO waveform as you suggested.  I assume that they change the waveform from triangle to a more sine shape.  As a mod on mine, i wired up two diff pieces of perf, one w/ 2 diodes, one w/ all 4, and put a switch to toggle between them.  neat mod I think.  The 2 diode version has a mellower vibe to it.  I should try an asymmetrical setup to see what that sounds like...

[soggybag]

The biasing is done like that so that the bias voltage stays constant as the battery voltage falls, if you did it using a voltage divider the bias voltage would fall as the battery voltage fell. I think this is so the performance of the LFO remains the same at different voltages.

This makes sense.

I built one a few years ago and after some debugging I found that it would not work if the two LEDs setting the bias were not the same type as the other four paired with the LDRs. I've never understood why this is.

[krhnyc]

Small Bear has the LDR's you need, and in the descriptions of the LDR's on his website he recommends which ones to use for which crkt.

Thanks for the reply. Steve @ Smallbear says that the Clairex p/n he used to stock for this project went the way of the dodo. He does have LDRs listed (for Neo Vibe) and says they may work but he cannot guarantee it. Any experience here using those for the EZ? Any other p/n's or sources? Any and all help is appreciated.

Thanks,

Kristopher

[Solidhex]

Uh oh

  If anyone knows where to source that part let me know... after listening to these samples I have to get a Neovibe going.


--Brad

[krhnyc]

Uh oh

  If anyone knows where to source that part let me know... after listening to these samples I have to get a Neovibe going.


--Brad

The LDR's that Small Bear sells are for the NEO vibe... you can get them there. I am looking for the Easy Vibe photocells.

[jaytee]

Just a thought, maybe an LDR would respond better to a white LED like it would from a lamp. Also, I don't see the need for 4 LED's. One LED could be used and arranged like a univibe.

[RedHouse]

Interesting pic from Fulltone's website. This is said to be a picture of the LDR's and Bulb under the light shield on a real vintage univibe, which BTW is covered by a shiny reflective tin cover (not quite a black film canister):



If true, this kinda suggests to me that the real vibe functioned a bit more from the bounced ambient light within the shield and perhaps less from the direct light from the bulb.

I'll have to try it myself, I've mostly used the typical arrangement we all use, LDR's facing Bulb (sometimes at slightly off-angle).

EDIT: whoops, I meant to post this in the other thread: http://www.diystompboxes.com/smfforum/index.php?topic=61005.0

[HeIsAll]

Yes, the LDR/LED combo looks the same in the pic above as it does now. Same position...just has black tape around a drinking straw slid over them and a cap piece over the top. (tony came up with the drinking staw light shield while on a date with his wife...)
who says romance is dead?

John

How would you secure a straw to the board?  Nice idea - just trying to picture it in my head.

[John Lyons]

The electrical tape covered straw (light shield) doesn't connect to the board.
The LED/LDR combo fits into the straw snug enough to stay put.
The straw slides over the combo, if you wanted to you could glue it all together by filling the straw top with glue, no need to though.

john

[DougH]

Just a thought, maybe an LDR would respond better to a white LED like it would from a lamp. Also, I don't see the need for 4 LED's. One LED could be used and arranged like a univibe.

Sorry to revive such an old thread, but I was thinking the same thing. Why not use one clear super-brite LED with the 4 LDR's arranged around it like in a univibe. Cover the whole thing too.

[John Lyons]

One thing to keep in mind is that an LED has a specific "viewing angle" where as an incandescent bulb emits light from all angles.
If you sand an LED's case with 400/600 grit sandpaper you might be able to get enough viewing angle for LDRs placed around it
but the main viewing angle is with it pointing straight on.
With a reflective light shield and the sanded or bought as frosted LED you would get the best result I'd say.

John

[R.G.]

N.B.
A cavity which is mirrored entirely on the inside effectively mixes light to a uniform level everywhere inside. That's why the original used a shiny cap and up-pointed LDRs - the light was uniform-ized by the shield, if imperfectly because one side was not mirrored.

[DougH]

You're right, John. The "super-brites" especially, are only "super bright" if you are looking at them dead-on, perpendicular to the base. But if the inside of the light box is reflective, as R.G. mentioned, it may not matter that much what angle the LDR/LED are oriented to each other.

I think it's time for me to get busy playing with this and build one. I've had the PCB for years. Time to order parts... Thanks!

[nico13]

I recently read that the Danelectro Chicken Salad is fitted with surface mount RC4558 opamps.

Did anybody already use them in an Easyvibe build? Would swapping the TL062 opamps of the Easyvibe stock version with RC4558 affect the tone a lot?

[alex frias]

As I posted earlier at this same topic I did it on the first and the last IC's. I did other small mod's and liked the results. I would sayI perceived a small but positive change in the overall sound.

[nico13]

Thanks Alex,

It's been a long time since I didn't read the whole thread.

Does the easyvibe sound more analog (warmer) with 4558?

[alex frias]

I think so, but just a bit more.
It is not exactly like an Univibe, not so "vocal", as someone posted here, but very good anyway.

[nico13]

There's something i just noticed on Tungngruv's easyvibe (the top picture on the previous page): the LEDs used are 5mm (instead of the 3mm ones suggested by John Hollis).
Does this use of 5mm LEDs give a good improvement to the sound? Did anybody ever compare changing the LEDs size?

[John Lyons]

There should not be any difference really.
The 5mm LEd would be easier and more efficiently
light up the LDR though I would think.
The 5mm LED matches the size of the LDR more closely...

john

[nico13]

Input caps. The Neovibe uses 1uf and the Easyvibe uses .001 !!!
... Can anyone comment on the input cap differences Why would one use .001 and one use 1uf?

One uses high impedance opamp input buffers, one uses a much lower impedance transistor input stage.


I increased the input cap to 0.1µF and find the sound fuller. I think (as Alex Frias did) it's worth a try to increase this value again: the input cap in the Danelectro Chicken Salad is 2.2µF and it has a really good wobble.