I was hoping I'd be lucky and it would be a take on the Moen Shaky Jimi/Jimi Nova, which are based on the EasyVibe.
Here's links to the Moen Shaky Jimi and Moen Jimi Nova threads.
And I'd like to thank John Hollis for his lovely EasyVibe circuit.
What's inside then? The highlights:
1 x "ST" 064C
3 x "TI" TL062C
4 x LED/LDR pairs
It does indeed look to be generally based on the Moen/EasyVibe circuit although I haven't checked the entire circuit.
I'd expect the logos on the TI op amps to look better than is seen here, but I'm no expert. They could be real.
It's just that I can't help being suspicious in this area, due to my previous bad experience with the Mosky Plexi-m.
Regardless, they seem to be doing the job of an op amp here, with no audible crossover distortion.
So what's it sound like out-of-the-box?
I'll be kind and just say disappointing.
It does produce some phasing, but it's nothing like a Univibe.
Basically, I know what to expect for the price - this thing might have some errors.
Why does it not sound like a Univibe?
In MY pedal (YMMV), the capacitors in the phase shifting stages are not the generally accepted Univibe/EasyVibe values.
Original capacitors Phase Stage Univibe/EV Ch-Vibe Stage 1 15n C3 4n7 Stage 2 220n C4 220n Stage 3 470p C5 220p Stage 4 4n7 C6 1n
C3 (4n7) is the correct value, even though it's in Stage 1 rather than Stage 4. Not a problem.
C4 (220n) is correct.
C5 (220p) should be 470p.
C6 (1n) should be 15n (given that there's a 4n7 in Stage 1).
So I replaced:
C5 (220p) with 470p
C6 (1n) with 15n (as in Univibe/EV Stage 1)
There was no point in moving the 4n7 (C3) from Stage 1 to Stage 4.
I only had to take the bottom plate off (4 screws) to change the caps, and used 0603 size.
So the phase shifts are now all correct, just in a different order.
Ending up with this
Modified/"Fixed" capacitors Phase Stage Univibe/EV Modified Ch-Vibe Stage 1 15n C3 4n7 Stage 2 220n C4 220n Stage 3 470p C5 470p Stage 4 4n7 C6 15n
So what's it sound like now, with the capacitors changed?
Nice, and just like a Univibe should sound.
I'm hearing all the expected Hendrix/Gilmour/Trower tones out of it now.
And of course I'm talking about the "CHORUS" mode, not the "VIBE"(Vibrato) mode.
Take time to set the Drive (labelled "COLOR" here) into the sweet spot, otherwise it won't sound at its best.
A couple of other things.
I would have preferred a log pot for the Speed control to get better resolution at the slow end. All pots are linear (B10k, B10k, B5k).
And it's got one of those blindingly bright blue LEDs that I absolutely hate. Just limit the current more FFS Mosky (and others).
I think they're using a 4k7 CLR. I couldn't be bothered to change it and took the easy route and put masking tape over the LED.
You could probably go to town on this pedal in you wanted to with heatshrink over the LED/LDRs, op amp swaps, etc.
(Oh no, look out for one of these tarted up in a booteek enclosure coming your way soon!)
But I won't be doing any more mods because it sounds good enough for me (for now). I'm not that fussy.
I really don't know what's going on with Mosky.
As you can see in the photos below, they took the effort to manually put a big through-hole cap of the correct value onto SMD pads for C4.
Yet they got two other important cap values totally wrong. Is this their intended design (clone) or a mistake in production?
If a mistake, it's unlikely to be a one-off because these are not hand built pedals. They use reels of thousands of SMD caps in their pick & place machines.
Here's some photos.