Rockman Chorus Pedal

[Vivek]

Rob, what is the voltage at pin 3 of MN3007 in the chorus that works and the chorus that does not work ?

[caspercody]

Here are voltage readings with it bread boarded just like the schematic (Rockman X100 Rev .10). The voltage supply reads +6.04/-6.04.

IC106A - TL062
1 - 0.58
2 - 0.58
3 - 0.58
4 - -5.60
5 - 0
6 - 0
7 - 0
8 - 6.04
IC110 - MN3007
1 - 6.04
2 - 6.04
3 - 0.58
4 - -4.47
5 - -5.70
6 - -5.6
7 - 2.88
8 - 2.60

IC109 - 4013
1 - -5.60
2 - 6.05
3 - 6.03
4 - -5.6
5 - -5.6
6 - -5.6
7 - -5.6
14 - 6.04

When I remove the (-) voltage connection to the 4013 chip, my (1) voltage jumps up to -6.01. When chip 4013 is connected the (-) voltage drops to -5.60?

[caspercody]

I do believe I got it to work!!!

Thanks!!!!

[Vivek]

Congratulations Rob !

[caspercody]

I got the Rockman filters to work, but I changed the circuit to just use positive, and ground power. I removed the negative power supply. I got the circuit to work with a 4046 chip. I think I have a bad 4013.

Can anyone please show how to wire up the 4013 chip with out using the negative  voltage supply?

[ElectricDruid]

I got the Rockman filters to work, but I changed the circuit to just use positive, and ground power. I removed the negative power supply. I got the circuit to work with a 4046 chip. I think I have a bad 4013.

Can anyone please show how to wire up the 4013 chip with out using the negative  voltage supply?

Honestly, I think your time would be better spent finding out what's wrong with your negative supply rather than trying to redesign the circuit to avoid it. If the 4013 is bad and affecting the -v supply, it might be that simple.

The 4013 should work at 6V. It only uses Vdd and Vss, so connect 6V to Vdd, and Ground to Vss and off it goes. But 4000 series logic is fine up to 18V or so (IIRC) so +6/-6 works fine too (12V across the chip).

At some point you'Re going to need the full 12V because the 3007 won't run at 6V. And that means your clock signals need to be 12V too, because if the 3007 is at 12V, it'll need clocks of the same level (or some additional levl shifting - don't let's go there!)

HTH

[caspercody]

The MN3007 does not work at 6v? That might be my problem the whole time. I will remove the 6v regulator from my bi polar power supply. I left the bread board intact with the in and out filters.

When I did have the 4013 connected with the 6v bi polar power supply, I was getting 6v out of pin 1, but nothing out of pin 2/5. It was connected per the schematic, should I have the same voltage out of pin 2/5? Can anyone please provide voltage readings of IC106 A and B, MN3007, and 4013?

[ElectricDruid]

The MN3007 does not work at 6v?

No. Check the datasheet:

https://www.experimentalistsanonymous.com/diy/Datasheets/MN3007.pdf

In fact, according to the datasheet, it won't work within the given specs below 14V, but we know it does work below that (it probably just degrades some of the other figures a bit - distortion, S/N, etc).

[Vivek]

I did get the MN3207 to work with 6V though

It does perform better with higher voltages

[ElectricDruid]

I did get the MN3207 to work with 6V though

It does perform better with higher voltages

The MN3207 is a completely different story. It was specifically designed as the low voltage variant, and works fine at 5V, with the reduction in headroom that you'd expect (about 1.2Vpp, iirc). This headroom difference probably explains the slightly worse noise figures of the 3207 versus the 3007. Some people think that the 3007 is less noisy, but actually I think it'd be more accurate to say that that the signal is louder. I suppose ultimately it amounts to the same thing - that's why we have S/N as a measure.