TechDAS Airforce V arrived :-)

[BillK]

Fair point. I know that Thom Mackris, who makes the Galibier tables, doesn't like the cantilevered armboard approach. He's said this to me over email, and I don't think he'd mind me sharing his stance. Anyway, I just thought I'd express that I've heard at least a couple different philosophies on how to best mount an arm. I'm no expert, certainly!

Likewise Harry Weisfield has stated several times that he doesn't like the idea of vacuum hold down, which is why VPI sells their periphery ring.

Graham Engineering and VPI differ on the best way to do a unipivot.

SME, Rega and Linn differ on how to mount an arm to an arm board.

Ayre believes in no negative feedback in their circuits, ever. Boulder and Pass use negative feedback as they feel fit.

…and so on.

Each company does their own thing and usually has a reason why other companies are doing it wrong.

 

[hvbias]

For sure. And I think that the best we can do, as consumers, is go out and audition and gather the impressions of other end users. I keep an open mind on everything.

I agree with this. For instance I have never heard any turntable have the sheer close to "nothing-ness" of noise floor like AF1 and Basis Inspiration, approaching that of a Studer A80, which makes me think that vacuum hold down done properly is what I would consider a must have on an end game turntable. No periphery ring clamp from VPI or that one other manufacturer that made a heavier one came remotely close.

 

[mtemur]

Likewise Harry Weisfield has stated several times that he doesn't like the idea of vacuum hold down, which is why VPI sells their periphery ring.

I wonder if he come up with a logical explanation why. Considering he’s gotten rid of anti-skating on his tonearms I start to believe the necessity of vacuum hold down more.

 

[djsina2]

I wonder if he come up with a logical explanation why. Considering he’s gotten rid of anti-skating on his tonearms I start to believe the necessity of vacuum hold down more.

Audio Tekne also told me don’t use AS or vacuum.

 

[mtemur]

Audio Tekne also told me don’t use AS or vacuum.

Well nobody can convince me not to use anti-skating on a pivoted tonearm but I wonder why he said don’t use vacuum since all lacquers are cut on the lathes using vacuum hold down. Additionally I couldn’t get a perfect flat record surface on any turntable other than vacuum hold down ones. Perfect flat record surface is a must for perfect azimuth. I measured azimuth on many tables. Even the flattest looking records are not flat. You adjust azimuth using a test record but if you use another test record you will get not only different numbers but a different balance between channels which requires another azimuth setting. I only achieved same results for different test records with a vacuum hold down turntable. Unfortunately my turntable does not have a vacuum hold down feature. Maybe mats with 1 degree tilted surface can solve this problem.

 

[Gregadd]

Although I never saw any evidence it was rumored excessive amounts of vhd pressure caused Micr- fractures in vinyl records. I used the SOTA system for years and never heard any evidence.
The VPI clamp and outer ring was a much simpler solution. Morever SOTA also required a clamp.

 

[BillK]

HW believes that no vacuum system is perfect and of course no vacuum is perfect, so it creates a constantly oscillating column of air modulated by the vacuum pump between the LP and platter.

The ring accomplishes much the same flattening as vacuum with no mechanical oscillations.

 

[thekong]

If there is indeed oscillation created by modulation of the vacuum pump, I wonder if some sort of buffer tank and regulator could smooth out the modulation! Audiophiles have been using these methods to smooth out air supply to airbearing arms, albeit the air flows in the opposite direction in this case. Maybe I should try it to see if there is any improvement !

While the ring may achieves similar result, I find it cumbersome to use, especially with some airbearing arms where the armtubes are so close to the platter in the resting position.

 

[BillK]

There's no perfect solution here, just alternatives.

The ring definitely has its awkward moments and I've had some with it where it didn't sit quite right.

There are times when vacuum hold down systems also fail, plus it's a lot more mechanical complexity, that can also fail, to achieve the same end.

Finally there are those who feel a vacuum hold down makes the LP too inert, who feel the resonance of the vinyl itself as the stylus tracks it adds a warmth they miss when using a turntable with vacuum hold down.

Thats part of what makes audio so interesting.

It's sort of like the ongoing feud between subjectivists and objectivists, both stating theirs is the way to audio “truth.”

You have to find the approach that works best for you and sounds the best with downsides you can live with.

 

[Gregadd]

I think there was some reservoir tanks.

 

[BillK]

There are in the TechDAS design, but no reservoir tank is perfect, there will always be some variation.

Now is it audible? That’s a whole different question.

 

[hvbias]

I'd opt for the much simpler answer, VPI don't know how to engineer a good vacuum hold down system. The company has always struck me as a DIY type company, their turntables are very basic.

 

[PeterA]

VPI certainly offers a lot of options: rim drive, direct drive, and belt drive and also uni pivot and gimbal.

TechDAS is high mass belt drive with air suspension as you move up. I always thought the Air Force two was cool but I’ve never seen one on the used market.

 

[lscangus]

I have a bit of issue with the vacuum hold down on TechDas. I found out that some disc are sucked down less strong than the others. Any one can share their experiences and tips?

 

[djsina2]

I have a bit of issue with the vacuum hold down on TechDas. I found out that some disc are sucked down less strong than the others. Any one can share their experiences and tips?

How would you know this?

 

[lscangus]

How would you know this?

u can try lifting the disc up and see if it is sucked down properly or firmly.