input cap blend pot?

[carboncomp]

Want to use this blend pot on a rangemaster, and just brad-boarding it up, but dint measure a change in capacitance with my DMM, so have I built it wrong or can someone explain why it would not measure?  (using a 4.7nF and 47nf cap)

[John Lyons]

The pot's resistance isn't going to let you measure the caps.
Put the caps in parallel by themselves and you can measure them.
Then use the largest then smallest cap by itself to see how they sound.
When you implement the cap blend you will not get the smallest caps
value as there is still some bleed through from the large cap though the 100k pot.
I'd make the small cap .002 or .003 and you'll have a close range to .0047 by istself.
Larger pot values will help keep the
caps more distinct (.0047 will be closer to .0047)

[carboncomp]

Thanks Mr Lyons,

So im thinking may be worth using a 100k "No load" pot if i want to keep the stock 5uf with no bleed from the larger cap?

[John Lyons]

Yeah, you could do that. But it's easier to just use a little smaller cap that you need.

[carboncomp]

Ok, I bread-boarded it up, and I certainly get a difference in in frequencies making it though, but its only in the last quarter tern on the pot?

Do I need to adjust any of the other parts of the RM? this is how I have it now. 

[runmikeyrun]

try a smaller value of pot... try 50k or 25k and see what happens.

[seedlings]

Or put a resistor across those two legs where you get the 'last quarter turn'.

CHAD

[John Lyons]

Which taper pot did you use?

[chi_boy]

Since its on the bread board, can you try copying the Easy Face setup for the input?

[amptramp]

You might want to connect the blend pot/capacitor assembly to the base of the transistor rather than the power supply.