Has anyone ever tore into one of these? I really like the way they sound and was wondering if anybody had traced one, and whether it could possibly make a DIY project somehow.
Thanks in advance.
RDV
I have the one called Rotovibe JH-4s..but all i can really tell you is that it is a 4 stage optical phaser. I really prefere my Easyvibe over this one though..not too happy with the speed being set by the rocker that also workes as bypass switch, its also a little bulky and heavy
Johan
Quote from: JohanI really prefere my Easyvibe over this one though..
Wish I could say the same, my Easyvibe is a pile. It just doesn't cop the Univibe feel at all. In fact I've gone back to my DIY Phase45, cause it doesn't rob so much low end.
Regards
RDV
Here's what Jim Dunlop says on their web-site;
"The Univibe that we produce has the exact circuitry of the 60's that is responsible for it's sound. The dynamics of the circuitry is complex due to the fact that it involves an incandescent lamp and cds photo cells. This character is one of the "magic" elements of the Univibe. The lamp has photo/thermal inertia, which changes the sound at different modulation speeds producing faster up than down frequency sweep and other subtle nonlinear characters within the modulation cycle. This gives it a unique sweep character. Also, the selection of frequency shift spacing is the same as the original produced in the late 60's. The Univibe is a mono effect. The Univibe operates from a 18v external power adapter.
The Rotovibe has a cost effective approach to the circuitry. This enables us to package it into a foot controller for convenience. The frequency shift spacing is slightly different than that of the Univibe and the lamp is replaced by a different scheme. This scheme doesn't possess the nonlinear character of the Univibe lamp's circuitry. The Rotovibe produces a more linear sweep through out the range of modulation speeds. The Rotovibe is a mono effect. The Rotovibe operates from a 9v external power adapter or an internal 9v battery."
Sounds like they are similar. The univibe schems are floating around. I realize that isn't much help but maybe it will at least point you in the right direction. :D
AL
Quote from: RDVQuote from: JohanI really prefere my Easyvibe over this one though..
Wish I could say the same, my Easyvibe is a pile. It just doesn't cop the Univibe feel at all. In fact I've gone back to my DIY Phase45, cause it doesn't rob so much low end.
Regards
RDV
..thats odd...do you have the proper 10M resistors and 1nF cap at the input?..if you make the resistors smaller, you have to make the cap bigger..thats really the only place wher you might be robbed of you lowend....that and the 1uF on the output..
Johan
I'd be curious if anyone had a schematic for the Rotovibe as well. I just bought a DOA Rotovibe last week and I'd like to make it do it's thang.
It's a pretty intense-looking circuit with lots of ICs and a couple of trimpots. Anyone know what these trimpots do? Mine is passing signal, but there isn't really any effect, and the leds are very dim. I thought it was a power supply thing, but it does it with battery or adapter.
For the curious, for ICs, it has 2 TL064s, a TL074, MC14013BCP, MC14016BCP, HD14070BP, and a GD4093. there are several 3904s and 3906s too.
It's a pretty red. That's about it.
Roger
A good example of what the rotovibe does do is on Live's "Lightning Crashes".
I definitely used all the specified components for my Easyvibe. It just doesn't cut it for me, I may replace the Univibe value caps and make it a standard phaser.
Regards
RDV
This subject comes up every 6 months or so. Every time it does, I open mine up and concider tracing it, but it's a BIG circuit and I always think to myself 'life is too short to trace this out'. Maybe I'll crack it open again and see what I think this time.
Mine has always sounded a little thin to my ears, not really 'warm' like a Univibe.
Ry
I have a Rotovibe. I bought it a few years before all the univibe clones came out. I did a few mods to it mainly to get more swing out of it but it never cut it for me not to mention the horrible bypass. I gutted the pedal, fabbed a piece of perf to fit inside, and made my own vibe design which I am quite happy with.
Due to my simultaneous decrease of interest and increase of laziness upon looking at the complexity the circuit and my overall destain for the sound I never traced the board. It just sits on the shelf next to the Dunlop rocker tremolo board I have.
Andrew
Quote from: ALThe lamp has photo/thermal inertia, which changes the sound at different modulation speeds producing faster up than down frequency sweep and other subtle nonlinear characters within the modulation cycle.
I love it! Photo-thermal inertia! That falls just a couple of ounces short of making sence, but will make most people say "WOW! I want some photo-thermal intertia."
At first i was like "if photons have momentum, they can have inertia..." then i was like "no"
Oh well, I guess almost every box has at least one good sound in it.
I'm quite sure that like most Dunlop boxes, 75% of the circuitry in it is for switching and buffering so they can save $.75 on the switch.
Thanks all
RDV