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
Andrew,

Great post. Your VTF protocol is very similar to mine, as is your description of what to listen for.

Every MC I've used has responded well to this approach:

1. Set antiskating at or near zero. Excess antiskating will interfere with the VTF optimizing process.

2. Starting from a VTF that's known to be sufficient for clean tracking, reduce VTF in ~.05g increments until HF's begin to go fuzzy and/or audible mistracking "buzz" occurs on dynamic peaks. That "mistracking point" is your benchmark, and it changes with the weather.

3. From the mistracking point, increase VTF in .01-.02g increments. Listen for just the things you described, a filling in of midrange and upper bass weight without loss of HF speed, extension and "air". Go too far and you'll lose highs and microdynamics.

Most cartridges have a very narrow VTF sweet zone that balances heft vs. finesse. On my TriPlanar/UNIverse it's .02g wide or less, and never more than .04g above the mistracking point. Other cartridges have acted similarly, though not always with such precision.

4. Nudge antiskating back up in microscopic increments, using just enough to prevent R channel mistracking on very difficult passages. Excess antiskating produces sonic mud and slowness that sound quite similar to excess VTF.

Finding a cartridge's mistracking point and moving upward from there in tiny increments is a fast, repeatable and reliable method for dialing in VTF.

Best,
Doug

P.S. The VTF sweet zone can change during a session if you're playing alot of high energy music, especially if the cartridge was cold to begin with. As the suspension warms up, the optimal VTF goes down.

I've even had optimal VTF go back up during a break, since that allowed the cartridge to cool down again. This happened during Raul's visit. We stopped playing for about an hour to have dinner. When we came back the bass was weak. I replaced a thick O-ring with a thin one, adding about .02g, and everything was fine again.

Anyone for set and forget? ;-)
I do as Doug suggests: Start heavy and work towards lighter. BTW Doug, someone actually makes a "cartridge warming lamp." I assumed you already had one ;--) If I can I'll find the manufacturer for you. N.
.
Folks,

Couple more things:

1) Material with piano is very good and included in my Norah Jobnes. this seems to be a good indication of timbre.

2) There is no ultimate "perfect" setting. As you get close to optimum, you'll need to make tradeoffs between upper end extension and bass response.

Gregm,

I started with an SRA of about +1.5 degrees. A parallel tonearm with the Orpheus provides about 1.2 degree SRA.

Doug,

Good to hear about your method. I had a little difficulty trying to figure out the mistracking point. I don't know if this would be close to the minimum recommended value. Anyway, with my cartridge, I think i'm higher than 0.04 grams above mistracking. this range would probably be higher for higher compliance cartridges.

Andrew
Do you make adjustments to VTF independent of VTA? 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)?

I always thought it was the alignment of the stylus/groove wall contact that had the greastest impact on sound. FWIW.
Newbee,

In trials, I did not compensate SRA when changing VTF. It would be difficult to do this precisely. As well, I always thought that changes to VTF were more pronounced than large changes in SRA. I agree that azimuth has a big impact as well. Unfortunetly with my arm, it's difficult to make changes in azimuth in a measureable way. Do you know if the Graham offers this option?