Help with OpAmp Clean Boost

[Box_Stuffer]

I am trying to make a clean boost using a TL072 with a charge pump. The idea is to make 1 side a distortion and 1 side the clean boost and then blend them. I am using the charge pump in place of a voltage divider, but when I set up the gain stage it is not working as it should. When I ground the negative feedback loop through a resistor it stops working. If I have only a resistor between pin 6 and 7 it works, but I don't know how to calculate the amount of gain it is creating.

Can I use a single reference voltage for two separate inputs? I just thought the charge pump would be less messy but it seems to cause other issues.

[FiveseveN]

Please always post a schematic of exactly what you're doing, charge pump and all. And ideally clear photos of the build.

[Box_Stuffer]

This is the charge pump.





The signal goes into this splitter and comes out as separate signals.




Then I was trying to make a boost based on something like this.




When I set it up like this it does not work. If I have only R1, I get a signal.

[GGBB]

Please post a schematic of how you connected everything together and pics of the build.

[GibsonGM]

Read this, report back :https://www.diystompboxes.com/smfforum/index.php?topic=29816.0

And - take each part as separate from the others, and testable...meaning, does the charge pump circuit output the correct voltage, before connecting to anything else? 

[Box_Stuffer]

The 1 Spot power supply puts out 9.5v and the voltage inverter IC puts out -8.7v.

[Rob Strand]

When I ground the negative feedback loop through a resistor it stops working. If I have only a resistor between pin 6 and 7 it works, but I don't know how to calculate the amount of gain it is creating.

You need a cap in series with resistor, checkout the TS-9 circuit for example.   Cap chosen to taste.

The Doodoo labs Sprinkle Drive has a structure close to what you want,
https://www.oocities.org/fabricadetimbres/imagens/doodoolabsdrive.jpg
(FWIW, I think the final circuit ended up with feedback diodes, two in each direction.)

Can I use a single reference voltage for two separate inputs? I just thought the charge pump would be less messy but it seems to cause other issues. 

Often you don't need the series cap in that case.  If you have a lot of DC gain it can amplify the opamp's DC offset and cause all sort of trouble , perhaps even enough DC offset at the output to cause the diodes to clip!!

[m_charles]

you gotta be able to at least know the basics of schem reading (if you don't already) to get much help here. Those stripboard diagrams aren't much help. You can learn how to read basic schems in a day if you dig into it.

[antonis]

If I have only a resistor between pin 6 and 7 it works, but I don't know how to calculate the amount of gain it is creating.

Easily..

Just put "infinite" in Gain formula denominator..
(unity gain buffer..)

P.S.
As Rob said above, you DO need both a resistor and a capacitor to GND..
The resistor sets the gain (together with feedback one) and the capacitor ensures DC gain roll-off to unity..
(capacitor blocks DC which results into unity gain..)
Without that cap in series with gain resistor, your 800mV DC off-set [9.5 - (-8.7)] is multiplied by stage's gain on op-amp output..
(you can easily realize that for a gain greater than 10X your circuit is permanently hitting power supply rail..)