Neovibe vs Easy vibe pics and clips inside

[John Lyons]

Easyvibe vs Neovibe

A friend sent me an easyvibe perfed up and I started looking into the workings of it.
I added a 20K trim pot to replace the 10k/10k mixing resistors at the output of the circuit.
The effect seemed a little too subtle and this allowed me to dial in the balance of the phase circuit.
I still think the easyvibe is a bit weak in the depth of tone and effect. More on this below.

Member Tungngruv made the Easyvibe perfboarded here










I rehoused the esyvibe in and oak box with tweed covering

SteveB posted some clips here a while back of his Neovibe build that blew me away.
These clips were recorded with a laptop mic and although less than ideal acoustics,
they were the real univibe sound not unlike Hendrix live (Band of Gypsies)


Here is Steve's build.














I got to talking to Steve about his build and I wanted to send him the Easyvibe for comparison.
He made a few clips of  the Easyvibe and a few of the Neovibe

Here are the clips:

www.mrdwab.com/john/ez-vibe1.mp3
www.mrdwab.com/john/ez-vibe2.mp3
www.mrdwab.com/john/ez-vibe3.mp3
www.mrdwab.com/john/ez-vibe4.mp3

www.mrdwab.com/john/neo-vibe1.mp3
www.mrdwab.com/john/neo-vibe2.mp3
www.mrdwab.com/john/neo-vibe3.mp3
www.mrdwab.com/john/neo-vibe4.mp3


This last clip alternates between the two vibes.
This one is using my Screamer pedal (TS-808 with mods) , 
I kick on the Neo-Vibe, then turn it off at the beginning of the next phrase.
Then, I turn on the EZ-Vibe, turn it off & end with the Neo-Vibe.

www.mrdwab.com/john/neovibe_ezvibe.mp3

The clips were recorded like this:
71 Strat with a HB in the bridge position. The amp is a '70 Princeton Reverb with a 12" speaker.
The clean sounds were using nothing but the vibe into the amp.
The volume is on 3, treble on 5 or 6, bass on 4, reverb on 3.
I think I kept the intensity all the way up on most samples.
The Trower stuff is using a Marshall Shredmaster pedal after the vibes with the same amp setting.
For the Neo-Vibe the intesity is around 2 o'clock most of the time.
On the slower speeds, I may have gone higher with the intensity.


Sound differences between the two:
My ears tell me that The Neovibe has a bit more sweep into the lower mids giving it a deeper effect.
More vocal into that "we-yow" sound as opposed to the Easyvibe which sound more like "we-you"
( you're laughing now aren't you?)

Parts values and positions:
There are a lot of things than determine the voicing of the univibe variants:

Cap choice in the phasing stages. (both Neo and EZ use the same values)

Input caps. The Neovibe uses 1uf and the Easyvibe uses .001 !!!

LDR and bulb/LED choice and positioning. Color of LED and LDR light to dark range.

Then you get into opamp verses transistor etc etc.

Can anyone comment on the input cap differences Why would one use .001 and one use 1uf?
I wonder if that is a significant difference in why the Neovibe has more depth in the mid to low mids?


Hopefully this will give some insight into the differences between these two circuits

Thanks SteveB and tungngruv for your work on these builds.
SteveB's initial Neovibe recordings can be found at my website linked in my signature below.
(recommended)

John

[oldrocker]

That was a cool comparison of the two Vibes.  Since I never heard an actual Neovibe I never knew how close the Easyvibe sounded.  The Neovibe is stronger no doubt.  Although I love my Easyvibe I would like to try a Neovibe at some point. 
Does the Neovibe work at higher voltages?  Is that light bulb it uses still available?
I think the Easyvibe isn't an actual clone so I didn't really expect it to sound the same.  If I build the Neovibe I might redo my Easyvibe into strictly a phaser via John Hollis's instruction.

[John Lyons]

Oldrocker

Glad you got something out of the post, it took a fair bit of work... mostly by steveB and tony...

Yes, you can get the bulbs still. There are a few ones that will work. Radioshack has some as does Parts express.
I like the phase the most, I hardwired mine for phase only. In RG technology of the univibe I think it gives the specs for the bulb.
Should be an easy search if not. the Neo does use 18v I think as well.

If I can't get the Easyvibe on track with more depth of tone I'm thinking about building the Univibe clone at JC malliets site.
The layout is more "rubust" and as far as I know it follows the neovibe/univibe to the letter.

John

[jonathan perez]

wow...

its...


the SWING of the univibe is in the NEOVIBE...

damn.....ok, so ill be building that hahahaha

[RaceDriver205]

ok, so ill be building that hahahaha

You should. With a clean tone, playing through the neovibe is very enjoyable to listen to.

[tcobretti]

Thank you very much for this analysis.  This very interesting, and even though I built a easyvibe, I guess I may have to build a neovibe just to compare them! 

[R.G.]

My ears tell me that The Neovibe has a bit more sweep into the lower mids giving it a deeper effect.
More vocal into that "we-yow" sound as opposed to the Easyvibe which sound more like "we-you"
( you're laughing now aren't you?)

Not in the slightest.

The human ear is very sensitive to things that sound "vocal". And the differences between the "eee-ow" and "eeee-oooo" vowel sequences are quite distinct when you describe them interms of the resonant peaks that define them in the human vocal tract.

Translated into linguistics-speak, what you said was "the Neovibe produces a set of lower resonances which closely approximate a 'we-yow' vowel/dipthong sequence as opposed to the Neovibe's 'we-you' sequence. The resonance peaks are better spaced for this vowel approximation in the Neovibe than in the Easyvibe, leading to a more vocal-seeming quality of sound."

Cap choice in the phasing stages. (both Neo and EZ use the same values)

This is a case where same values does not make for the same result. The easyvibe uses opamp phase stages which produce a more textbook allpass response. The Neovibe/Univibe is a less-than-perfect transistor stage that stamps its imperfections on the response. I suspect that you'd have to do more than tinker the caps to get them to be identical.

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.

LDR and bulb/LED choice and positioning. Color of LED and LDR light to dark range.

And this one is dead on!

Then you get into opamp verses transistor etc etc.

And this one is big, as  I noted above.

The Neovibe is the Univibe, as closely as it can be made, and cleaned up a bit in some trivial details. The Easyvibe is, well, an easy approximation of the Univibe.  It's right there in the names.   

[petemoore]

The resonance peaks are better spaced for this vowel approximation in the Neovibe than in the Easyvibe
  Perhaps somethings could be done to the Easy Vibe lessen the comparitive differences...[making it less 'EZ' but keeping the 'easier to wire up' opamps] maybe use resistors to lower the input impedances ofthe opamps, and use a larger input cap?
  Any ideas welcome...
  I've been using the SS phaser with phase stage values for 'wobblier' sound [somewhere between Univibe and SS values]..sounds good. Still not all that Vibey though..it's holding the phaser position on my PB .. for the time being.
 

[solarplexus]

and what would it change if you choose different LED colors... let's say... blue, red, amber, green ?  would that affect the sound ?  Could choosing a brighter/darker LED make it closer to the neovibe?

[SteveB]

Thanks for posting, John. Great assembly of information.

I built that one back in '96, & it has gone through some minor changes since then.
That bulb in the photo is a 12V 50mA, & I changed it to the recommended 12V 25mA a few months ago. The other bulb was still working, but I wanted to see what the sound of a bulb with a lower current rating was. I like the 25mA, but can't tell how different it actually is with doing an A-B test with the bulbs. I'd rather leave well enough alone The film canister is also lined with adhesive backed foil now. I had the LDR's lying flat, facing up for a long time, but now, they are back as the appear in the photo, perhaps even closer to the bulb.

I changed the speed pot to the one that is available from Small Bear. Much better range spread throughout the rotation of the pot.

I lowered the resistance of the 2 side by side resistors on the LFO to get the speed faster. I just piggybacked some more resistors on top of the existing 2.2k. I measured, & it is somewhere in the 1k range +/-. Yeah, I'm lazy, but it it sounds like I want it....

I have a 10k resistor in place of the 4k7 that is connected to the base of the bulb driver. 47k was too subtle, & 4k7 was too choppy for me.

Once again, great work, John!

Steve

Steve

[snoof]

nice work on this comparison!!  very informative.  i have an easyvibe, and a microvibe, and i need to do some A/B testing w/ those two.  i will eventually build the neovibe, and the voodoo vibe, i'm kinda a vibe junkie

[John Lyons]

Thanks for the input guys! I'm going to tey a couple things before I start on a Neovibe build.

Larger input cap, and more resistance to try and lower the impedance (thanks pete) Woulf that be adding resistance to ground at the input?

Add more resistance to the LED driver to get the LED dimmer to see what that does.

One thing that's fun to try is putting a pice of white paper between the LED/LDR to change what light the LDR sees. Try every other LED/LDR (thanks again Pete for that one)


The color of the LED can make a difference but I'm not sure it aplies here so much.
Cadmium sulphide Cds (most LDRs out there) are most sensitive to Green light
Cadmium selenide Cse (you can still find them if you look) most are sensitive to red light.
I would think this would be more of a case in a tremolo or stutter type device where you want a sharp on and off action with the LDR but it wil make differences here as well.

John

[John Lyons]

Yikes, typo alert!

What I meant was:
If I lower the resistance to ground would this bring the impedance down? Since the input is biased with 10M resistance would I just lower that 10M to ground and leave the other 10M , or lower both...say 100k?
I don't really understand the 9v to 10K before the bias 10Ms...

[slacker]

If you want to lower the input impedance then lower the value of the 10M that's connected to the + pin of the opamp. The other 10M, the one that goes to ground is just a pulldown resistor so you can leave that one as it is.
The 10k resistor forms a sort of voltage divider along with the diode and the 2 LEDs to ground. The diodes and the LED set the bias voltage at about 3.5 - 4 volts and the 10k limits the current through them. Doing the bias voltage like this rather than by using a normal voltage divider using 2 equal value resistors means that as the battery voltage falls the bias voltage stays the same, because the diodes/LED combo drops the same voltage. This means that the circuit and especially the LFO will operate the same as the battery voltage falls.

[John Lyons]

Good info Slacker
Thanks for that explanation.
I overlooked the two 10M resistors being on either side of the cap. Not really bias there...

John

[slacker]

No trouble, nice sound clips it's an interesting comparison. After to listening to the clips though I have to say that my easyvibe sounds a lot more like your neovibe clips. It's hard to judge purely from sound clips but it certainly sounds more univibey than your easyvibe.
I guess there's a lot of variables in a pedal like this, not least the choice of LDRs and LEDs and how you attach them together. On mine I've just taped the LDRs to the side of the LEDs, so they're not light tight and the light from the LEDs is probably more diffused than if you attach them directly to the end of the LEDs. I don't know but I wonder if this replicates the neovibe's bulb better.

[The Tone God]

I have a modified version the the Easyvibe LFO on my site that I felt had alittle more "vibe" feel as well as a few added features. It mostly called for reversing the polarities of the LED.

It would be interesting to compare.

Andrew

[John Lyons]

Slacker

So with your LDR/LED set up with the LDR reasiong the side of the LED you get a good bit less light on the LDR. This goes along with rasing the resistance to the LED/Bulb driver and reducing the amount of light that hits the LDR. I'll have to follow through with this theory when I get my easyvibe back.

Tone God
So your LFO is set up to reverse the cycle of the LED? Is that what you meant by reversing the polarity?

John

[joelap]

Wow, this thread rocks!

Ok:  my first impressions from listening were that I preferred the easyvibe over the neovibe for some reason.  I think I preferred the tone of the Floyd song on the easyvibe better.  However, it does sound to me that the neovibe has a bit more of a "yow" like Basicaudio said.  I loaded all the files into winamp, popped them on shuffle and tried to identify which were which blindly after a while of listening.  I was able to identify which song had the neo/easy on floyd.  However, when the shuffle came to the Trower song, I had thought the neo was the easyvibe.

So I guess my impressions are that they are both awesome circuits, and in a live situation or a blind test, it'd take a great pair of ears to be able to say "thats a neovibe" or thats an easyvibe.

Nice soundclips, but I wasn't able to tell too much of a difference between the two that would warrant me pulling the plug on my current easyvibe project and doing a neovibe instead.  I'll be honest.     maybe my ears arent as good as others are.

[slacker]

So with your LDR/LED set up with the LDR reasiong the side of the LED you get a good bit less light on the LDR.

Yeah it reduces the amount of light the LDR gets, which changes the range of resistances it sweeps over. The other thing is that if you look at an LED from the side as it gets brighter and darker it looks a lot more like a bulb than if you look at it from the end. I don't know if it really makes a difference but it might be worth experimenting with.

Here's a picture of my easyvibe board.

Tone God
So your LFO is set up to reverse the cycle of the LED? Is that what you meant by reversing the polarity?

The Tone God's mods are here http://www.geocities.com/thetonegod/downloads/downloads.html