GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Analog Playback
In the Thread: Schroder Tonearms

Post Subject: VTA VTF balancePosted by berlinta on: 2/11/2010

Hello Romy,
I should have made myself more clear about the paragraph you quoted. Typical situations:
a. The arm is installed on a deck that accomodates more than one arm. The listener, if lucky, has two(for all intents and purposes) identical cartridges and gets to listen to the front end that he's used to vs. the frontend with my arm as a substitute in his own system. A month later, I get the call...
b. An audiophile comes over to his friend who happens to have aquired one of my arms. He likes what he's hearing and a week later, he brings his own turntable for a comparison. They listen for an afternoon. Not nearly as valid a basis, but it happens all the time.
C. People attend shows and they sit down, listen for several tracks or even whole records and comment favorably about the sound, - of the system, not the arm. Whouldn't you say that it follows the principle of deductive reasoning that a stellar sounding system can't feature a mediocre component?
Yes, the arm may well be the weak link in that chain, that's why I have done(and still offer) side by side comparisons at shows.

I never said that VTF/VTA balance is critical on warped records. I said that if you're record is perfectly flat, you're unlikely to hear the difference between a neutral and a stable balance arm.
On the other hand, if one follows Pierre Lurne's logic of the ideal inertia ellipsoid being a circle, your point is overthrown. In reality, all cantilever/suspension assemblies behave in a non-linear fashion, neither is the compliance, nor the inertia constant in all directions. So the notion of producing a neutral balance arm, while getting closer to providing the cartridge with the same inertia to work "against"(making it behave more linearly) will always remain a compromise, just like vinyl playback alltogether(or life, for that matter).

Very few people understand the working principle behind the bearing in my arms. If you read the "DIY-Schroeder tonenarm" thread under:

http://www.diyaudio.com/forums/analogue-source/13372-diy-schroeder-tonearm.html

you'll find every possible misconception and my attempts to correct them, so that diyers can benefit from the principle without have to pay an insane price.

I'm not shure I got your point about "VTA/VTF lock", what do you mean by: the arm will try to "maintain VTA", despite no change in VTA(?)

And believe me, I know EXACTLY that the magnets need to be ground precisely, or else the entire exercise would be mute. This bearing option(hate the word upgrade) costs the customer 200$ extra, not exactly "substantial extra cash"(sorry Paul), when considering that it takes about 4 hours to do it. The magnets on the SQ bearings are also larger and have a higher energy "content"(N52). A big advantage of this arrangemant is that you can alter VTA to accomodate heavier pressings or records that were cut at different rake angles without having to readjust VTF. And the stability around the longitudinal axis is increased.

No, the proper curvature does not depend upon the cart compliance, but on the diameter and strength of the magnets, the dimensions of the soft iron yoke around it, the attachment point of the thread(vs. the COG of the armwand/counterweight assembly) and, last but not least, the mass distribution inside the cart. I usually go for a minimal remaining restoring force(0,05gr VTF change for 5mm VTA change).

The link to the DPS arm picture(oooold...) posted earlier is somewhat misleading, since it shows the arm with the magnets resting firmly on top of each other. That's so I could take that picture without having to mount a dummy cart.

Lastly, I can assure you that, for a long time, the choice of thread material ensures stable operation under all conditions. BTW, many years ago, I received a customer(from a city in Asia infamous for its high humidity)complaint that the arm was responsible for changes in sound. Every time he would come home, he'd turn on the AC and shure enough, it took an hour before the system sounded the way he liked it. I inquired to find out that the AC dropped the temp from typically 28°C or higher and a humidity approaching 95% to 21°C and 55% humidity. I told him that that was likely affecting his cartridge(suspension) more than anything, and shure enough, I took the arm back and the problem reappeared with another, well reputed tonearm. Only that he didn't like the sound as much once the AC had done it's job. So he did swap again and bought another cartridge that featured a damper/alignment chosen to work better(and is less succeptible to change) in his climate range.

Many high quality vinyl replay audio components are like cars. You need to feel comfortable with them. Any arm is only as good as the setup(person) allows, it's up to the individual to decide with which arm he achieves the best(constantly satisfying) results. But you can't blame a Formula 1 race car for needing a good mechanic to perform (close to)100%. There are very few people out there who really know how to get the best out of a race car, - or a turntable...

Cheers,

Frank

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