Warbling on horns, piano and vocals


Got my 401 set up with my Schröder CB-L and there's a warbling on the horns and piano and voices with multiple cartridges. I swapped arms and the sound is pure, no warbling. Any thoughts about what could be wrong with the arm or installation of the arm?

dhcod

I would think that if you could record a test record track, like the 1kHz or 3kHz ones, that might help.
Usually with an ADC (Analogue to Digital Converter.) or with the ADC built into a sound card or microphone input on a PC.

I suppose if it good with the previous/other arm, then I assume we are thinking that the platter speed is not the cause.

From memory the long arm is something 19gm effective mass, and the 9” was 13 or 14 grams. So I don’t think adding the Schroder brass spacer to increase the effective mass is going to be helping.

Does the arm have any visual oscillation ?

If that is not it, then I would have thought that any resonance would have presented as something different than a warble.

Have you reached out to Frank via email? He is pretty responsive.
And I would be interesting in knowing what is happening.

I'm thinking it could be that the turntable is on a wall shelf and it's vibrating because it's sitting on something that's not massive enough. I'll test it today sitting on the hearth.

I'm thinking it could be that the turntable is on a wall shelf and it's vibrating because it's sitting on something that's not massive enough. I'll test it today sitting on the hearth.

Only affecting one arm and not the other?

 

To understand if there is a low frequency resonance of the system:

  • If we knew whether the cartridges were high, medium, or low compliance would help.
  • And also the effective mass of the other arm, and whether the effective mass of the CB-L is correct at 19gm.

 

Some ‘reflected’ high frequency resonance in the arm:
I am unsure how one would get a low frequency warble, but some IMD of a high frequency resonance might be possible.

 

This is getting well beyond me, and hence the suggestion to reach out to Frank.

No, both arms- just in a different way.

I just put it on the hearth and the warble in one and the distortion in the other are gone. And now I've returned it to the wall shelf without the discs under the fat spikes so the spikes go right into the wood of the shelf and I lowered the spikes to their lowest level to reduce any play in the shel. It's about 60% better but still warbling and the other arm is distorting again. Or mistracking or whatever it actually is.

This table may be going away until we move in a couple years to somewhere I can fit a proper massive stand.

No, both arms- just in a different way.

ahh…

That makes much more sense now.

 

Do you have say a CD player?

If that is playing, and you lay the hands upon the hearth or shelf, can you feel it jumping to the beat?

Maybe you need a safe cracker with sand papered fingertips? 😉

I was thinking was it was AM on the cart causing the amplitude to beat up and down.
If it is the deck itself, then the thing speeding up and slowing down would cause a frequency modulation, and that would also warble.

I would still suggest a short capture of a sound file as a way to see which one it is.
Then knowing the nature of the effect, we should be able to find the causal mechanism.