IC Booster questions.......

[Seven64]

Ok, so I feel like a complete noob, but am very confused while trying to figure out what is going on in the circuit i just breadboarded.  I am trying to build a simple clean buffer/booster for myself, and love the booster in the magnus modulus.  I am following this schematic:



and pulled out the rest of the circuit leaving me with ic1.  I have it breadboarded up, but cannot get it to boost my signal past unity.  wired as the schematic shows it, the pot doesnt do anything at all.  when i put a fixed resistor in place of the 50k pot and put the pot on the output with pin 1 from output, pin 3 to ground, and wiper to output jack, it will take it from silent to unity with no boost.  i tried swapping different resistors to set the internal "gain" at different places from 1k to 47k, but nothing gave me the boost i am looking for.

why does this setup work with the rest of the pedal, but not isolated like this.

and my voltages are 9.6v at pin 8 and 4.6v at pin 3.

**edit**

i found something on here about putting a small polarized cap between the 4.5v and gnd, and have added that but it didnt seem to do anything with the pot setup either way.

[Keppy]

The gain of this booster relies on the ratio of resistance in the feedback loop (50k pot) to the resistance to Vb at the inverting input (10k to 100uF to JFET). Since the J201 (and the portion of the circuit acting on its gate) is connected in between the inverting input and Vb, I think that's what's messing you up. Connect the negative end of the 100uF cap straight to Vb and I think it should work.

[Seven64]

is Vb the 4.5v?

if so, it makes a horrendous ticking sound.

**edit**

put a 10k between pin 6 and the 100uf cap.  now it has boost, but sounds like a super choppy tremolo. 

[Seven64]

ok, got it.  needed the 100k resistor between the 100uf and 4.5v.  thanks for the tip!  now to try and fully understand this.......