# Circulator (Grand Orbiter) Build with boneyard mods



## Raspymcnasty (Nov 13, 2021)

I just boxed up the Circulator (Grand orbiter) with some of @Chuck D. Bones mods. I’ll list them below.

This pedal sounds pretty good, goes deep and wide.

From this Thread
“1. Increased R2 & R3 to 2.2M because I like my pedals to have a 1Meg input impedance. C1 was reduced to 47nF because it could be. 
3. Replaced C8 with 390pF, cuts the high end above 40KHz. 
4. Inserted 10K resistors (R103-R106) in series with pins 1 & 16 on IC1 & IC2. Pins 1 & 16 program the operating current and gain of each amplifier. The way EQD connected them all in parallel, there is no guarantee that they will share current equally. Putting those resistors in forces them to share. Should make for smoother phase sweep.
5. Changed the SWEEP pot to C100K, reduced R33 to 2.2K (to compensate for the 10K resistors I added in item 4) and reduced R34 to 10K. Gives the SWEEP pot more range and at the very bottom of the range, SWEEP acts like a Manual control.  
7. Changed the RATE pot to C500K. Some not-so-good things happen when the RATE pot is above 500K. The sweep becomes asymmetric. There is a tendency for the LFO to stall or fail to start up. 
8. Added a 3.3Meg resistor (R109) from pin 3 of the RATE pot to IC1 pin 3 (Vref). Along with item 9, ensures that the LFO will always start and never stall.
9. Added a 22K resistor (R107) from IC3 pin 8 to IC3 pin 6. Along with item 8, ensures that the LFO will always start and never stall. 8 & 9 must be done together.
10. Changed the RES (Resonance) pot to C100K and R23 to 33K. Makes for a much smoother adjustment. 
11. Increased R27 to 33K. In the original design, the Circulator will break into oscillation when RES is dimed. “


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## fig (Nov 13, 2021)

Very cool build! #s 8 & 9 are a fantastic addition!


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## finebyfine (Nov 15, 2021)

Gorgeous build!!


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## Paradox916 (Nov 15, 2021)

Wow. Great job. I would love to hear it!


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## Preverb (Nov 16, 2021)

Cool.  With the mods, I wonder if this would cover the same ground as my old PT909 did (think they have the same # of stages).  
Did you use one of the pre-drilled enclosures from Tayda?  

This is one I would like to do in my second round of pedals.  It is looking like 6-8 weeks for PCBs to get to Aus though...


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## finebyfine (Nov 16, 2021)

Preverb said:


> Did you use one of the pre-drilled enclosures from Tayda?



I used a tayda predrilled 6 knob for my circulator build and just made sure ti have larger washers on hand for the toggles


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## Preverb (Nov 16, 2021)

I think one of the mods was to remove the phaser/vibrato toggle.  Do you find that you use the vibrato side at all?


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## Barry (Nov 16, 2021)

Looks great!


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## giovanni (Nov 16, 2021)

Love the graphics! Nice build!


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## Raspymcnasty (Nov 18, 2021)

Preverb said:


> I think one of the mods was to remove the phaser/vibrato toggle.  Do you find that you use the vibrato side at all?


I don’t but i haven’t played it enough


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## Chuck D. Bones (Dec 3, 2021)

Looks great!

Buuuuuuut...
You have the 3.3M resistor connected to IC1-4 in the pic, should have been IC1-3.  It will still work, but it's not the way I intended it.


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## Coda (Dec 4, 2021)

Chuck D. Bones said:


> Looks great!
> 
> Buuuuuuut...
> You have the 3.3M resistor connected to IC1-4 in the pic, should have been IC1-3.  It will still work, but it's not the way I intended it.


Maybe he works for JHS?…


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