Continuing with my Sagan Delay themed pedals:
https://www.madbeanpedals.com/forum/index.php?topic=32079.msg308259#msg308259 (https://www.madbeanpedals.com/forum/index.php?topic=32079.msg308259#msg308259)
https://www.madbeanpedals.com/forum/index.php?topic=32333.0 (https://www.madbeanpedals.com/forum/index.php?topic=32333.0)
This is my Space Chorus. It's a Pedal PCB Caesar, which is a copy of the Walrus Audio Julia. It's super cool. The build docs don't have a schematic. I'm curious to see how the delay lag (Space control) is implemented. I think it would be cool to mod some other chorus circuits with this, like the Small Clone. Biasing the 3207 looked weird on the scope (no position on the trimmer gives anything close to a symmetric waveform on the output), but it sounds great. That's been messing with me, maybe an artifact of the delay pot?
Enclosure is no film on polished metal with a 10 mm LED. The transfer came out a bit rougher than the other two, but it looks fine in real life ;D I have a NE5532 in there, which I think sounds better.
(https://imagizer.imageshack.com/img923/3783/G3PW5E.jpg)
(https://imagizer.imageshack.com/img924/5805/TVvb08.jpg)
(https://imagizer.imageshack.com/img922/4465/QAeKX7.jpg)
(https://imagizer.imageshack.com/img924/2628/zllOyw.jpg)
The soft touch really did not want to go in there! It took flipping some caps to the back and angling in the PCB. The pins on the blend pot are barely poking through.
(https://imagizer.imageshack.com/img924/8966/R6hDgZ.jpg)
Well played, that looks fantastic! Killer trio.
Man this trio is killer! I love how clean this build is, nice work.
Damn John, you should do all your builds like this, looks so good! How does it sound co.pared to a regular CE-2? It's just a modded ce-2 I believe. Awesome build.
Style in spades! Most excellent! 8)
Nice; very nice indeed.
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Once again, excellent work!
I figure the lag control connects one lug to the LFO output, and the other lug connects to basically a 5V source. The wiper leads to the clock chip. It's probably similar to a Manual control you see on a flanger that sets how wacky the wooshing can get. On a PT2399 type of circuit, I'd imagine it is something like the Animate control on EQD's Sea Chorus/Madbean's Gravity Wave.
...I think the LAG control is the 220K resistor between the depth control and Q4 (CE2 schematic)...the Caesar chorus substituted a 250K potentiometer as the LAG control..if i'm not mistaken.
Quote from: artstomp on February 01, 2021, 12:20:51 AM
...I think the LAG control is the 220K resistor between the depth control and Q4 (CE2 schematic)...the Caesar chorus substituted a 250K potentiometer as the LAG control..if i'm not mistaken.
I would agree with that. I have the same control on my Replicant series chorus pedals (even though they are Small clone based, same principle). It works the same as changing the timing capacitors (like on the VFE Choral Reef).
Thanks everyone! 8)
Thanks for the info on the Lag. It adds another dimension to this thing. I'm surprised it's not on more common.
Super cool man, you're going to have a pretty sharp looking pedal board pretty soon.
Those all look absolutely amazing!
I love how this looks like a mashup between vintaxe EHX and Boss aesthetics! I was also really curious about that lag control. Makes sense I'd say.
Outstanding job.
What I found mysterious was when you said your scope wasn't happening when biasing the BBD. Similar happened to me once when I did the Blueshift. It worked first try, trims tuned in by ear, all good, but the scope wasn't able to do it's thing on that particular build as far as optional fine tuning is concerned. Fortunately it was a minor non critical thing, whatever caused it. So, as it sounded great as is, I left it as is, because it was just an optional troubleshooting job (potentially very time consuming) for an unnecessary optional fine tuning option.
Thanks Guys! 8)
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Quote from: Thewintersoldier on January 31, 2021, 08:38:43 PM
How does it sound co.pared to a regular CE-2? It's just a modded ce-2 I believe. Awesome build.
I wanted to spend some more time playing with this before a gave a full endorsement, but now I'm sure. This thing sounds incredible.
Quote from: RDL68 on February 01, 2021, 06:56:44 PM
What I found mysterious was when you said your scope wasn't happening when biasing the BBD. Similar happened to me once when I did the Blueshift. It worked first try, trims tuned in by ear, all good, but the scope wasn't able to do it's thing on that particular build as far as optional fine tuning is concerned. Fortunately it was a minor non critical thing, whatever caused it. So, as it sounded great as is, I left it as is, because it was just an optional troubleshooting job (potentially very time consuming) for an unnecessary optional fine tuning option.
I've built a lot of BBD pedals and the scope biasing has been very reliable for me. This one was weird. The bias point (by ear) is towards the middle of the trimmer and there's only a narrow range that will produce chorusing. But the output from the BBD looks like more like an EKG than what I normally see. Because it is chorusing in the middle of the trim, I don't think adjusting resistors values would resolve the issue. I've had other BBDs that biased at the end of the trim rotation and those needed a resistor change. Anyway, it works real good ;D So, maybe I'll let this this one slide.
"I've built a lot of BBD pedals and the scope biasing has been very reliable for me. This one was weird. The bias point (by ear) is towards the middle of the trimmer and there's only a narrow range that will produce chorusing. But the output from the BBD looks like more like an EKG than what I normally see. Because it is chorusing in the middle of the trim, I don't think adjusting resistors values would resolve the issue. I've had other BBDs that biased at the end of the trim rotation and those needed a resistor change. Anyway, it works real good ;D So, maybe I'll let this this one slide."
Exactly, many builds & I've never seen this mystery surface before. Mine was just for myself so I let it go. If it was built to be sold I'm sure it would give me niggling thoughts, so I'd investigate until I nailed it & if that wasn't possible I'd rebuild the whole thing first (if it happened a 2nd time, gawd help me, hehe). These 2 builds of ours that it happened to are different circuits too, so it puzzles me whether it was something identical causing it (like something common wired off the pcb itself for eg) or 2 completely different things causing it. Mysteries without answers... :)