Mounting dual arms on the Gavia.

[Dan_ed]

Salectric has spent some time in pursuit of this so hopefully he will post some thoughts on this subject. He and I have traded emails in the past on this subject. It looks like I've lost those emails. I'll check the other laptop but in case I can't resurrect that conversation I thought I'd start a thread here to capture thoughts on this subject.

I do recall that Salectric had already found that there are differences in Gavia playback when the aluminum stub is mounted or not mounted in the second arm position. He also had found that there was a price to pay when a second arm is mounted. At the time I was a little slow on picking these differences up myself when I attempted to verify what Salectric was reporting. In the end, this was because I was really behind him in finding the best material to mount the Gavia on. I've since found a combination that works very well for me so it is much easier to hear the changes involved with mounting that second arm.

My own experiments have involved fabricating a second arm board from wood. The first attempt was a quick mock-up with some Baltic Birch plywood. The result was not very impressive and left the sound smeared. I've since fabricated a second arm board out of cocobollo that is much better sounding than the plywood. No real surprise here, but it is impressive how much difference the change in wood makes. Yeah, like that would be news to Chris Brady.

I'm still formulating new impressions of dual arm mounting since elevating my Gavia on Stillpoints. I see this whole dual arm mounting as an issue in vibration control. Since that is what the Stillpoints excel at, I'm expecting things to change. Whether or not the change is better, or good enough, remains to be seen.

Maybe if I can get this to work well Thom will make me an arm board from aluminum.

[Salectric]

Dan,

Sometime ago I tried a couple of different armboards for mounting a second arm. These included two armboards made of solid wood (red oak or hard maple) and one of Thom's 3/4" aluminum armboards. The arms mounted on these were a VPI JMW 10, AQ PT-6 and Moerch DP-6. What I found was that the wood armboards adversely affected the sound of the main arm (either the Moerch or Triplanar). When the second arm was on the aluminum armboard, there was significantly less effect on the sound of the main arm, but there was still some.

Perhaps more importantly for me, I found that after the novelty of having a different arm and cartridge to listen to, I tended to just return to the main arm since it sounded better anyway. In other words, I wasn't taking advantage of the second arm. On the other hand, someone with a mono cartridge or someone who is more into trying different cartridges (like Raul) might really appreciate the benefits of a second arm.

Dave

[galibier_numero_un]

Hi Dave, Dan …

You all know me to be a "one arm" guy too, but I can see where some would want an option (e.g. mono). My Dyna XV-1s is so good at making bad records sound good, that I don't know why I'd want a "bad" cartridge for bad records. It seems counterproductive to me.

In the early armboards, I provided a threaded, tapped hole on the under side of the armboard. I think you (Dave) may have had one of these armboards for the Moerch you were running at the time. The idea behind this hole was to thread a large (7/16") carriage bolt into it that would form a support by exerting a modicum of tension between the armboard and the turntable shelf - thereby stopping any residual motion in the armboard.

I wonder if I should have eliminated this option. I faced quite a few questions from customers about this bolt. You wouldn't believe how many individuals challenge me for giving them too many choices. Sometimes I weaken and give up. Deprogramming people who quote the approved publications by chapter and verse can be tiring. These rags have a very efficient spin machine and sometimes I just want to fight bigger battles. Sorry for the rant. Perhaps this forum will serve to help in this regard.

What further prompted my removing the tapped hole was my experimentations with the Graham 2.2 and Moerch DP-6 tonearms I was running at the time (pre Triplanar / Schröder). On perhaps 10% of the records I played, there was a subtle difference. As I thought about it further, I concluded that depending on the individual's top shelf implementation, this could hurt the situation as much as help it.

Perhaps I should go back to this tensioner option and the heck with people who can't deal with it.

Note, that the Stelvio armboard has a 1/4 x 20 tpi hole tapped in the under side of the damping cylinder which can be used for the same purpose. I put it there as much to allow for easy racking during anodizing as for this support functionality. I have to admit that I've never threaded a bolt into it to test out the theory on the Stelvio armboard. It may be something that's fruitful.

If you (Dan) want to mess with a support/tensioner on your Cocobolo armboard, you can combine a long bolt with a thread coupler to accomplish this - much like our Triplanar "kickstand" tweak. If you like it, you can thread a brass insert into the cocobolo (stating the obvious to you) … or not.

Cheers,
Thom