Experiments with VTF


I've spent the last couple of days experimenting and optimizing the VTF of my cartridge. I wanted to share my obervations. Hopefully this will provide some inspiration to newbies to experiment with this adjustment.

Initially, instead of making very small (~0.01 g) incremental changes, try making some large changes (~0.1 g) in each direction to get an appreciation for the effect VTF has on sound reproduction.

What I found when below optimum is that the sound is very airy (too much depth from the lack of bass), although lean and slightly tinnier in timbre and with lower bass response. You will notice this as you will have greater presence of midrange and highs and less bass.

When above optimum, the airiness decreases, the sound becomes richer in timbre but too thick, with improved bass but slightly less defined and resonant. You will notice this most from a thick, minimally airy (less defined depth)sound.

I would recommend approaching the optimum using 0.05 g increments from a setting that is too low. As you approach optimum, you will find bass to improve and timbre to become more correct and natural and the ariness to lessen but still be there.

When you get close, begin to make 0.01 g increments till you find the perfect balance between airiness/soundstage, dynamics, natural timbre and bass presence and definition.

It is a long and painstaking process but very rewarding. It is amazing just how much 0.01 g can make when you get close.

I would recommend a record that has female vocals, some good bass and lot's of ambience. I mainly used Norah Jones-Come away with me.

With my transfiguration Orpheus, I found the optimum to be around 1.955 - 1.960 g.

Good luck and have fun
aoliviero
Do you make adjustments to VTF independent of VTA?
Yes. I agree with everything Aoliviero and Nsgarch wrote about that. The VTF tuning we're discussing is so small there's little practical effect on VTA (SRA, actually, as NSgarch said). Nor are the sonic changes from VTF fine-tuning at all similar to those of SRA fine-tuning. These adjustments sound very different.

Do you think that the differences you note are due to the change in the force the stylus is applying to the groove or to effective changes in VTA (which must change with VTF changes)?
No and no.

IMO the diffenences are due to the pressure that VTF applies to the cantilever/suspension interface. This is why excess VTF sounds so much like excess antiskating, as I mentioned above. They both apply too much external pressure and inhibit cantilever freedom.

The more pressure on the cantilever, the less free it is to respond. Its response to groove modulations will be slower and its peak amplitudes will be physically contstrained. The sonic result is smothered HF's and smothered dynamics and a general dullness or lifelessness.

OTOH, if VTF is too low, the arm and cartridge have insufficient inertia to resist moving when really big and slow transients (aka, bass notes) come along.
If the arm moves then some of the energy that should have deflected the cantilever relative to the magnets, doesn't. Result: softer bass with lower amplitudes.

Now where did I put that cartridge warming lamp? I actually suggested we use our Littlelite for that during winter months Neil, but Paul vetoed it for some reason. Oh well, another great tweak lost forever! I'm gonna design a tonearm with a built in heating coil and a thermostat. Should sound great!

Doug,

"I'm gonna design a tonearm with a built in heating coil and a thermostat. Should sound great!"

That's exactly what I saw!! Well, it was a tiny little incandescent lamp in a little 'witch's hat' reflector on a little goosneck and it's designed to heat the cart while the arm's in the rest.

You know, come to think of it, the Littlite would be perfect! Too bad about Paul -- score one for 'intelligent design'!
for the heating bulb, you should get started right away by increasing the voltage by .1v, allowing for thermal stabilisation, I'll hope to hear from you guys in a couple of years :-)
Sorry, it was irresistable
I want to add my experiences of the last week where I can confirm that differences of .05 gm make a valid, repeatable difference. I was not able to repeat anything lighter. I checked alignment before and after the adjustment process and it was spot on. The difference from where I started and ended was .2gm lighter than recommended
in doing this I was able to lower vta to where the sra should theoretically be correct and the overall results were very satisfying.
my .02 (gm!)
For the record, it would take a 1,000W bulb to keep most cartridges warm in Ndoshi's listening room.

I presume that's why he uses a Koetsu. ;-)