Ibanez - RC-99 Rotary Chorus  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Dirk_Hendrik
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Post by Dirk_Hendrik »

Like the schem. Change to TB is easy.
Sorry. Plain out of planes.

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gigelmargel
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Post by gigelmargel »

Hello Dirk,

Thank you very much for all your fabulous work in tracing pedals!!!

I've just finished a clone of RC99 using your project and it worked from the first try. And it was love at first sight, too. I think that it's the best chorus that I ever heard. And I heard over 20 famous choruses (I own 7 or 8 of them).

My only question is about the trimpots. SR2 (10k) it's clear for the biasing of MN3207. But what are the roles of the another two?
SR3(50k) seems to be for setting a maximum/minimum of the delay time, but for SR1 I have no ideea.
Do you have the alignament procedure for RC99?

Best regards,
Radu

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Dirk_Hendrik
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Post by Dirk_Hendrik »

gigelmargel wrote:Hello Dirk,

Thank you very much for all your fabulous work in tracing pedals!!!

I've just finished a clone of RC99 using your project and it worked from the first try. And it was love at first sight, too. I think that it's the best chorus that I ever heard. And I heard over 20 famous choruses (I own 7 or 8 of them).

My only question is about the trimpots. SR2 (10k) it's clear for the biasing of MN3207. But what are the roles of the another two?
SR3(50k) seems to be for setting a maximum/minimum of the delay time, but for SR1 I have no ideea.
Do you have the alignament procedure for RC99?

Best regards,
Radu
Late response, great vacation.
Thanks for the feedback. Nice to know there are people out there who use this stuff! :thumbsup
No, I do not have an alignment procedure. All I have is in this thread.
You are right on SR3. It sets the basic frequency and makes this frequency independent of component tolerances.
SR1 is a level control for the signal going to the BBD. Mine is at max.
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

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gigelmargel
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Post by gigelmargel »

Dirk_Hendrik wrote:Late response, great vacation.
Thanks for the feedback. Nice to know there are people out there who use this stuff! :thumbsup
No, I do not have an alignment procedure. All I have is in this thread.
You are right on SR3. It sets the basic frequency and makes this frequency independent of component tolerances.
SR1 is a level control for the signal going to the BBD. Mine is at max.
Thank you very much Dirk!
Glad to hear that you have a great vacantion :)
I hope to put RC99 as soon as possible in an enclosure and after I will post some pics.

By the way, I have a DCF-10 and a Session Man II. If you want, I can post some pics :)

Best regards,
Radu
Last edited by lolbou on 19 Aug 2012, 13:50, edited 1 time in total.
Reason: Quoting edited...

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Post by bucksears »

In the process of getting parts together to build this one; how do the seven pads (1-7) on PCB1 align with PCB2?

Thanks for a great project!

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Post by Dirk_Hendrik »

One on one as the schematic could have told you ;-)
Sorry. Plain out of planes.

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Post by bucksears »

Dirk_Hendrik wrote:One on one as the schematic could have told you ;-)
Yeah, it was late last night and didn't dig into it that much, but you are correct sir! I'm redoing the layout in Illustrator so I can try and squeeze everything on one PCB.
Thanks!

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rlawlor
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Post by rlawlor »

I’ve recently tried to build the Ibanez RC99 using your schematic but I can’t seem to get it to work, I’m only getting the dry signal through. If you or anyone spots any obvious mistakes in the schematics for the pcbs I’ve made that would be great PS the two boards are connected via TP1 to TP1 and TP2 to TP2
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Dirk_Hendrik
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Post by Dirk_Hendrik »

Does your BBD have output signal? Does the LFO run?
Sorry. Plain out of planes.

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Post by rlawlor »

Is there any way of checking the LFO without a scope? Maybe with a multimeter?

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Post by rlawlor »

Both chips are receiving 8V

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Post by rlawlor »

Sorry forgot to say, the BBD has no output

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Yazoo55
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Post by Yazoo55 »

Sorry to be a pain Dirk. I'm building this now. Can you confirm the potentiometer types please? Are they log or linear. The parts list and pcb layouts say they are all log. The 2007 revision schematic says the same thing but I found your 2010 revision schematic which shows all the potentiometers as linear. Lastly, is the trimpot SR3 50K or 20K?

Sorry again, I love building but I am definitely technically challenged.

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Post by Yazoo55 »

I built the chorus pedal and went for all linear pots and it is all working nicely. Initially I used a TL062 instead of the TL022 but the effect, while noticeable, was not very strong. I then put in a TL022. I also replaced the 7808 with an LDO version. I just couldn't see how this could work properly with the original 7808 which has a voltage drop of 1.7 - 2 volts, given that the input voltage is 9 volts. I measured and the 7808 gave me 7.6 volts which would have been within the range specified in the datasheet. I don't understand how it could do this.

For the SR3 trimpot, I turned the Delay Time pot to full on, then adjusted the trimpot until the effect was just "over the top", as opposed to being fully bonkers.

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