250k/500k Strat vol pot versus turning down the tone knob

[uOpt]

Re: 250k/500k Strat vol pot versus turning down the tone knob

Ah.

Allright, I think I know where the problem is. Unfortunately I have to run. Can you describe how you measure? What does your test pickup go into and what is the input impedance of that?

Also, you chart doesn't have the frequencies labeled on the x-axis? The whole thing is a bit weird looking since it doesn't show a resonance peak where there should be one.

 

[DreX]

Re: 250k/500k Strat vol pot versus turning down the tone knob

Ah.

Allright, I think I know where the problem is. Unfortunately I have to run. Can you describe how you measure? What does your test pickup go into and what is the input impedance of that?

Also, you chart doesn't have the frequencies labeled on the x-axis? The whole thing is a bit weird looking since it doesn't show a resonance peak where there should be one.

The test device is a CGR-101, the input impedance is 1M ohm. The test set up is a Lolar Blackface Neck, two pots of varying values (both were close in value to 250k or 500k, to within 5k) and .047 uF cap, connected with alligator clips to simulate a 1 vol/1 tone/1 pickup guitar circuit.

 

[DreX]

Re: 250k/500k Strat vol pot versus turning down the tone knob

Also, you chart doesn't have the frequencies labeled on the x-axis? The whole thing is a bit weird looking since it doesn't show a resonance peak where there should be one.

The x-axis is labeled with kHz values, it's just a bit blurry do to the layering of the test screen shots. I could have cleaned that up, but, oh well.

I'm not surprised to see a lack of peaks because we know that 250k pots attenuate high frequencies, and the peaks are high frequencies. The no-load tone pots show much less attenuation, and the peaks are still visible.

 

[DreX]

Re: 250k/500k Strat vol pot versus turning down the tone knob

When I have time I'll rig a guitar so that I can record both circuits, now that I have a recording process worked out.

 

[uOpt]

Re: 250k/500k Strat vol pot versus turning down the tone knob

No, there should be a real resonance peak, the pickup is still a second order LPF and 250k isn't enough to kill the peak, otherwise a Strat would sound totally lifeless.

But I have no idea whether it should show up when inducing sound the way you do.