CE(FJ)-1 Chorus

[Scruffie]

The Close enough for jazz, Chorus!

Forum folk seemed to be constantly wanting to and struggling to build CE-1 clones due to its split supply and rare BBD so I cooked this up.
I didn't have an original to compare it to so it's mainly based on simulation, assumption, notes from the original schematic and breadboard tweaking. With the original LFO & Filters, hopefully it will scratch that itch without breaking the bank.

[duck_arse]

The Close enough for jazz, Chorus!

Forum folk seemed to be constantly wanting to and struggling to build CE-1 clones due to its split supply and rare BBD so I cooked this up.
I didn't have an original to compare it to so it's mainly based on simulation, assumption, notes from the original schematic and breadboard tweaking. With the original LFO & Filters, hopefully it will scratch that itch without breaking the bank.

Code Select Expand

[quote]Access to www.madbeanpedals.com was denied[/quote]
something amiss w/ yer link/image.

[Scruffie]

I wondered if that would catch me out, I was too lazy to upload it twice so linked to an external attachment.

[Mark Hammer]

Wot?  No noise gate? 

[Scruffie]

Wot?  No noise gate? 

No need! The MN3007 has far superior S/N specs, doesn't have to overcome 8dB+ signal loss and is running at twice the sampling rate of the MN3002. It's not dead silent but as good as any other chorus.

[njkmonty]

 Finally finished! Looks great Scruffie

[Mark Hammer]

Wot?  No noise gate? 

No need! The MN3007 has far superior S/N specs, doesn't have to overcome 8dB+ signal loss and is running at twice the sampling rate of the MN3002. It's not dead silent but as good as any other chorus.

I figured as much.  Just yankin' yer chain a little. 
I still maintain that the only thing that was really special about the original CE-1 was that it employed a different LFO waveform for chorus than it did for vibrato.  One can turn pretty much any chorus pedal into a vibrato unit, simply by lifting the dry signal.  But you're still stuck with that triangle LFO.  The CE-1 used the right LFO for the job.  Glad to see you retained it.

[Scruffie]

Wot?  No noise gate? 

No need! The MN3007 has far superior S/N specs, doesn't have to overcome 8dB+ signal loss and is running at twice the sampling rate of the MN3002. It's not dead silent but as good as any other chorus.

I figured as much.  Just yankin' yer chain a little. 
I still maintain that the only thing that was really special about the original CE-1 was that it employed a different LFO waveform for chorus than it did for vibrato.  One can turn pretty much any chorus pedal into a vibrato unit, simply by lifting the dry signal.  But you're still stuck with that triangle LFO.  The CE-1 used the right LFO for the job.  Glad to see you retained it.

I don't think I could have claimed it had much in common without! Although the 'vibrato' on the original doesn't remove the dry signal stock as far as I'm aware... I made it a 3 position toggle to provide that as an option.

It does have a couple of things setting it apart besides the LFO (which is clipped a little on the bottom on the triangle setting for a little of your favourite hyper shaping) the wet signal isn't just low passed, it ends up with a little bit of a boost in the mids too, that and the delay time is shorter than the usual chorus... rides that chorus/flanger middle ground.

I wouldn't say I'm a big convert to the CE-1 but I can see now why people prefer it over a CE-2 et al.

[POTL]

The original circuit uses 4 transistors to drive the BBD, they act as a clock and a driver. This is a multivibrator circuit or something like that.
You replaced it with CD4011, why did you decide to do this?

[POTL]

I wondered if that would catch me out, I was too lazy to upload it twice so linked to an external attachment.

The original circuit uses 4 transistors to drive the BBD, they act as a clock and a driver. This is a multivibrator circuit or something like that.
You replaced it with CD4011, why did you decide to do this?

[Scruffie]

Simpler, faster, better, cheaper? and does the same job.

[skyled]

What changes would be needed to use the MN3207 instead?

[Fender3D]

Poor Scruffie...
He did a thoroughly work to replicate the correct power supply, so you can obtain the same control voltage and waveform, and you would toss it all away to use another BBD? 

BBD supplies aside, you should add a voltage converter to adapt VCO output to MN32xx clock inputs, at least...

[Scruffie]

Poor Scruffie...

What changes would be needed to use the MN3207 instead?

I really don't think it's suited to the MN3207... that sounds like a whole new design. But as Fender3D said, using a voltage converter for the clock pulses and then you'd almost certainly want to reduce the input gain (@R40).

Xvive produce the MN3007 again now, so it shouldn't be too hard to source.

[skyled]

Poor Scruffie...

What changes would be needed to use the MN3207 instead?

I really don't think it's suited to the MN3207... that sounds like a whole new design. But as Fender3D said, using a voltage converter for the clock pulses and then you'd almost certainly want to reduce the input gain (@R40).

Xvive produce the MN3007 again now, so it shouldn't be too hard to source.

Oh I didn't know they started making the big boy again 

[Kipper4]

Thanks for sharing Scruffie.

[Ben N]

I love this trend (if trend it be) of re-creating/re-imagining classic circuits of yore with obtainable parts and modern performance (e.g. Thomeque's and others' Electric Mistress work, Ripthorn's PT2399 based Echorec emulation, etc.). I'm not prepared to go down the rabbit hole of faithful reproduction of those circuits, and sure as heck wouldn't shell out for an original, but the idea of a workable near approximation is thoroughly appealing. Nice work, Scruffie, and thanks for sharing!

[box]

Thanks for sharing Scruffie and we are waiting for pcb :
Regards,
box

[POTL]

Poor Scruffie...

What changes would be needed to use the MN3207 instead?

I really don't think it's suited to the MN3207... that sounds like a whole new design. But as Fender3D said, using a voltage converter for the clock pulses and then you'd almost certainly want to reduce the input gain (@R40).

Xvive produce the MN3007 again now, so it shouldn't be too hard to source.

The XVIVE website says that there are no more chips, the dealership price is about $ 10 for one.
Many suppliers do not have them or they are running out.
Are you sure XVIVE is re-releasing again? If you look at the guts of boutique pedals, then everyone has Cool Audio, crop manufacturers like MXR and BOSS also have Cool Audio, maybe only EHX uses MN3007 / 3008/3005, but only puts them in the most expensive projects, in other pedals it's 3207 / 3208/3205.

[Scruffie]

The XVIVE website says that there are no more chips.

Where? I can't see that on the site?

I see them for sale on Smallbear, Banzai, Cabintech and even Reverb... and if you can find an MN3002 for $10 I'd like to know where

Thanks for sharing Scruffie and we are waiting for pcb :
Regards,
box

Yeah, where is that Scruffie guy anyway!?