Wobuliker (Lovetone Wobulator) AlanP Tremopanation

[LaceSensor]

Hi all

This is based on Alan P's excellent layout Tremopanation. The boards say 0.3 on them, but I'm sure this is 1.0. Anyway.
Its a recreation of the classic Lovetone Wobulator dual tremolo/vibrato/panner pedal.

There are 4 modes.
1 TREM - both Left and Right move up and down at the same time, but with a "cross-over" effect where Left is low pass filtered and Right is high pass filtered.
2 PAN - Left and Right move in anti-phase without a cross-over, akin to a normal "figure-of-eight" auto-panner.
3 VIB - same as TREM but in anti-phase, creating subtle phase cancellation (and therefore pitch and volume change) effects.
4 DUAL TREM - this again uses the cross-over but brings into play the second LFO. Left is now driven by LFO 1 and right by LFO 2.

1 - 3 are all driven via LFO 1 only, which I wasnt completely expecting.
And because of the various cross-over and LP/HP filtering in some cases, you need to activate both L and R footswitches to get the most out of them.
That being said, with the modes where there is filtering, you can access independantly the same rate setting on L and R, but subtly different sounds, by activating only one of the two footswitches, and sum to Mono.

4 - this is the really cool one, dual speed independant LFOs. Kinda like the Doppelgangers dual LFO mode, but trem rather than phaser. Ace!

Obviously with 2 amps its a whole other story. I have had a 10 minute play with 2 amps, and it sounds incredible.
Overall its extremely versatile with many subtle variations in sound. If you like trem, this is one to beat perhaps.
The only lacking thing is tap tempo of course.
One final item to figure out is why R has a tad more hiss in the sweep then L... Alan might have some thoughts on that.

I added the output transformers and phase switch. I didnt get any buzzing or grounding noises with 2 amps regardless of placement of the phase switch. Still, nice to have it. Quite a squeeze to get it all in a 1790ns, I had to omit the trigger input, but retained the speed expression input (so far untested, but Alan has verified it...)

This would probably make more sense in a portrait orientation; I have 2 other boards from osh so might build one that way and see
The only other thing left to do is try some other vactrols, as Alan noted it could use some more depth perhaps. Right now I just have unknown LDRs from Tayda in there so god knows (!)

aaand heres the pics:









Thanks Alan for a wonderful project. I doubt Id have ever played a Wobulator if not for this.

ps it doesnt tick. I could detect a tiny bit at first, so I added shield cable to the input and that has solved it.

[midwayfair]

One final item to figure out is why R has a tad more hiss in the sweep then L...

You said that the right is high-passed, right? So the left is cutting some of the noise with its low-pass filtering, unless the filtering disappears in other modes.

If you're running both sides in mono, does the trem mode sound "normal"? Or is there some mid scoop when they're summed?

What's the bypass scheme on this?

Overall very nice.

[LaceSensor]

One final item to figure out is why R has a tad more hiss in the sweep then L...

You said that the right is high-passed, right? So the left is cutting some of the noise with its low-pass filtering, unless the filtering disappears in other modes.

If you're running both sides in mono, does the trem mode sound "normal"? Or is there some mid scoop when they're summed?

What's the bypass scheme on this?

Overall very nice.

Ill have to check that all out again but the HP / LP filtering thing sounds like its probably the answer.
There isnt any wierdness / scooping with summing to mono. It sounds great to me.
Its buffered bypass.

[Cortexturizer]

Quite a project!!! I imagine that's a perfect execution of a Lovetone circuit.
Any chance of a sound sample?

[alanp]

Tayda LDRs are specced at 500k dark. It's worth experimenting. My trafo's are finally shipping from mouser, and I'm going to experiment with LDR's when I put them in (not energetic enough to bother till then.)

Lace, I'm always amazed by how tidy your Lovetone builds are (as well as the artwork )

[alanp]

Oh yea, and the boards are 1.0... I just forgot to edit the text on the board 

Trivia, I could have done this with two dual opamps and not three, at the moment two of the ones on the board have unused opamp sides, but figured that having isolated chips (rather than share a chip across different parts of the circuit) would help with tick isolation.

[LaceSensor]

Tayda LDRs are specced at 500k dark. It's worth experimenting. My trafo's are finally shipping from mouser, and I'm going to experiment with LDR's when I put them in (not energetic enough to bother till then.)

Lace, I'm always amazed by how tidy your Lovetone builds are (as well as the artwork )

Yeah I will have a mess around. Ive got a bunch of different ones, about 4 different Futurlec types. I just wanted to hear it working.
Thanks for the tidyness comment. I do try! This one coulda been neater, but its always tough to know the first time, and a couple wires coulda used a tad more slack to allow bundling together with cable ties. Nevermind. Its not untidy, for sure!

Oh yea, and the boards are 1.0... I just forgot to edit the text on the board 

Trivia, I could have done this with two dual opamps and not three, at the moment two of the ones on the board have unused opamp sides, but figured that having isolated chips (rather than share a chip across different parts of the circuit) would help with tick isolation.

i think for the $0.30 required to buy another TL072, you made a wise choice.

[LaceSensor]

Ok so really turning amps up, and moreso in stereo I feel, there is a tiny tick. Its in no way as bad as the low profile dopp 1.4

I'm going to add screened cables to the transformer outs.

[alanp]

Sod. Stupid tick.

Big question is, is it as bad as the stock unit's ticking?

[LaceSensor]

Don't own a real one (yet)

Ian

[LaceSensor]

good news, everyone

Tick solved. Shielded cable on the outputs to the transformers, with the shield grounded to signal GND.

Such happy. Many success.

[billstein]

Impressive build Lace. Glad you got that tick sorted. It was on the pedal not you right?

[pickdropper]

Really nice build.  I like labeling a lot: with that many knobs and dials it could get cluttered but that looks nice and neat.

[LaceSensor]

Really nice build.  I like labeling a lot: with that many knobs and dials it could get cluttered but that looks nice and neat.

cheers. I blatantly just rip off the real ones...

[LaceSensor]

Some more info, I did a lot more work on tick minimization than Ive written about so far, including adding an input buffer, shielding various / all cables
In the end it seems proximity of the rate input exp jack to the input jack was getting some cross talk. Ive got rid of it now on my build by moving stuff around etc and using different jacks to get the connections as far away from each other as possible. I will post a pic below which should seem obvious.

Long and short though is that any future builds will likely be "portrait" orientation, to allow more room to isolate the jacks at the bottom. This will likely work cool anyway, as it will allow me to place the foot-switches closer together also. I dont think the buffer is necessary in hindsight; added bonus I have a (modified) Klon buffer in here too, ha.

All told this has been a fun build and learning exercise; I didn't expect to have to try so many things but I have figured out what does and doesn't "count" with making this circuit quiet and tick-less


Final pic of the "proof of principal" study: