MN3007 frequency

[caspercody]

Hello

I found a website that calculates the frequency of a 555 circuit. And using the formula Td=N divided by (2 times Fclock) I get different results.

Trying to figure out the frequency of the Rockman Chorus using the website 555 calculator I get 85KHZ (R1=2.7K, R2=560K, and C1=15pf).

Using the formula I get 23.5KHZ at 22 milliseconds (this 22ms is based off of page 9 on the manual). N=1024 (for MN3007 chip) 1024/(2*23500) = .02178

My question is, which HZ should I use to drive the MN3007 to get the 22ms delay time?

Yes, I have tried more then one tome to breadboard the Rockman 555/4013 section. I believe I got the circuit to work, I put a bigger cap in the C1 spot and got (2) LEDs to flash. At the 15pf value the LED's are on, but maybe flashing to fast for me to see any flashing. But when I connect to pin 2, and 6 on a MN3007 circuit I get no sound. When I use another type of frequency type circuit (4047, or MN3101) the chorus works. The 4047 circuit is noisy, and the MN3101 circuit I have different value caps from 68pf up to 680pf and the time does change (by the way anything over 470pf start to hear the high pitch of the clock).

https://www.rockman.fr/Manuals/SC.pdf

https://www.build-electronic-circuits.com/circuit-calculator-conversion/555-timer-calculator/

 

[Cybercow]

Dunno about the specific frequency, but here's a schematic of the Rockman X100 Chorus section . . . .
The LED isn't necessary as it is simply used to indicate that the power is on. (The LED flashes at a specific frequency).
Stereo is achieved simply by using dissimilar resistor values at the input to the Left and Right channels. On the Rockman X100, the Right side passes thru a 33K resistor and the Left side passes thru a 100K resistor. The main signal passes thru a 120K resistor to the Right side and goes thru a 39K resistor to the Left side.

 

[caspercody]

I finally got the chorus to work, but not the 555/4013 circuit. I think I have bad 4013 chips. I used a 40476 circuit and used the below website to come up with the R1, R2, and C1 values for a 23KHZ output to the MN3007. I see for JTEX Rockman engine he used a TC4S584F Schmitt trigger in place of the 4013. I ordered some Schmitt triggers from Tayda and will try his approach.



I also removed the input and output IC’s and followed the Stereo Chorus design. Just a 100NF into pin 3 (along with a 100K pot and 100K resistor to supply the voltage), and another 100NF after the pin 7, and 8 4.7K resistor’s connection together. I then connected into a AionFX PCB I have for Deep Blue Delay. I have the chorus connected to Pin 1 of IC1A, and Pin 3 of the Mix pot. All the PT2399 components are not installed.

74HC/HCT4046/74HCT9046A : VCO Calculator

Free Online Engineering (Javascript) Calculator to quickly estimate the Component values used for a 4046 VCO with PLL. Formulas are derived from a spreadsheet by Philips.

www.changpuak.ch

JTEX Electronics - RockEngine

“Jerry, WOW! That's all I can say! Sounds great, better than the original, and the SMD boards are artwork! We search around for every clone*, and yours was the only one that sounded genuine besides the originals.” – Chris R, New York *Jerry's note: thank you, but it's not really a clone :)

www.jtex.ca

 

[caspercody]

I did FINALLY get my version of the Rockman Chorus working with the 555/4013 chips. I believe it was my inverted for the negative voltage. I reduced the circuit down to just the negative voltage being applied to the LFO section, and the 555/4013 being powered with normal power. I made (2) inverters one with a 555 chip and the other I used a Pedal PCB board, but when I connected the LFO, 555 chip, and 4013 chip the negative voltage dropped a lot. The positive voltage was close to supplied voltage (9vdc), but the negative dropped down around -5vdc. So, I redid the 555/4013 to run off normal power.

I used a CE2 PCB I got from Aion FX for the input, output, and MN3007 portions, and used the 4013/555/LFO circuit from the Rockman circuit. I also added a 6.8K resistor for the LED of the sweep speed, replaced the 6.8K resistor for the Speed with a 2.7K and 10K pot (similar to the chorus rack mount unit), added a switch to switch between 15pf and 30pf for the 555 frequency cap, and last used 120K resistor (per updated schematic by Mark Davis) for the Depth resistor (Pin 5 of 555 going into pin 7 of LFO) instead of 330K per the original X100 Schematic.

Everything seems to work.