They sell two caps, the plastic lighter one and a metal one called a 2.5-4.5 GR ADJ. RESONANCE CAP that is heavier so allowing you to push the main weight nearer the gimble, would the 2nd be better as getting the weight nearer the pivot is better for resonance? KAB Electro Acoustics http://www.kabusa.com
I’m not sure it matters. Either will stop the ringing caused by the spring. This was applicable to the original Mk2 arm. Not sure if the current models even have that issue. Kevin told me it’s better to have the counterweight closer to the pivot point, but I’m frankly not sure whether the benefits of that are outweighed by adding more weight, or if more weight on the end is even a legitimate concern.
It's basic physics. If the bulk of the weight is towards the rear, it will be less stable. With the weight closer to the pivot, the effective mass will also be lower, I believe.
Right. Though I’ve used the Technics 10g aux weight to good effect. The Concorde Pro S 40 is a bit heavy, and the aux weight brings the counterweight to a more reasonable distance from the pivot.
Not sure why the counterweight position would affect stability, but guess I'm not very clear what you mean by stability. For many situations, it is advantageous to get the counterweight closer to the pivot to reduce the inertia (and resulting effective mass). Rega even uses reversed tracking force spring pressure to allow the counterweight to move closer to the pivot when balanced, then backs off spring pressure to set tracking force. And there are many aftermarket high mass counterweights to concentrate the mass closer to the pivot. But it ultimately still depends on the cartridge compliance and where you want to position the resonance point. Sometimes we want a higher effective mass, so it may work (and sound) better with the counterweight closer to the end of the arm. Except you aren't moving all the mass closer to the pivot, you are also adding some further from the pivot that must be accounted for in the equation. It may lower effective mass, or may increase it, depends on where the counterweight is to begin with since the inertia is a product of the mass and square of the distance. If the counterweight is toward the end of the tonearm, adding the aux weight will probably lower the effective mass. But if the counterweight is closer to the pivot, adding the aux weight will increase the effective mass, even though the main counterweight moves closer to the pivot. No biggie, there has been a lot of discussion around here on this topic (and disagreements too), and even some fairly simple math examples, just pointing out there is a transition point for the effective mass with regard to the two counterweights (main and aux) at different distances from the pivot
I'm running an SL1210GR/AT0c9-XML with the following upgrades....Achromat, Rega clamp, ATLH11H headshell and KAB damper. I've read the arm is the weak link but it's able to track the +18db bias track on the HFN&RR test record with just a little minor buzz so it clearly can track well. Is it really that bad? My Roksan Nima, fitted with an AT33-PTG/II couldn't track past +15db. If I had a bigger record collection (less than 250 and it's not growing) I'd have sprung for a G but I think that's it as far as upgrades go, except for maybe the Isonoe feet. Are they are a genuine improvement over the 1210GR feet?
Where I draw the line is when the CW is not making full contact with the stub. With an ~18g cart + headshell combo, the CW on my deck was not making full contact with the stub. Using either the 10g or 15g aux weight solves this problem. It should track slightly better this way too, especially on records with any degree of warp to them. I have looked at the resonant frequency in software with no aux weight, the 15g one, and the 10g one. Practically speaking there was very little difference. You *might* be able to see a difference of 0.25-0.5Hz, if that. If you want to screw around with this, I do recommend trying more than one record for each test as there are differences with different records IME. I am guessing this is down to cutting/mastering and pressing differences.
The stock feet are pretty good. That said I think there are some situations where the Isonoe feet will offer better isolation. The Isonoe feet alone basically turns the deck into a suspended, floating suspension system and there are add ons like the sorbothane boots with glass inserts to further isolate the system. A few have found that they offered nothing extra beyond what the stock feet offer, but chances are if the deck needs more isolation from footfalls or whatever that these feet will better isolate from most issues.
Tracking ability is mainly dependent on the cartridge… but yes, I agree that these tonearms are heavily underrated. The magnesium tonearm on the 1200G in particular.
Well, not sure on that, but just didn't understand about the stability comment, not saying it isn't true. There is the case of arms like the Technics that have the pivot at the same angle as the offset to avoid azimuth changes as the arm moves vertically, which then causes the counterweight to move in an arc instead of straight up and down, that is a little unstable, and is why other designers choose to place the vertical bearing axis perpendicular to the arm tube. Tonearm designers have to weigh all the compromises while working to meet their goals, and it's of course not all dictated by physics either, so we've wound up with a lot of nice tonearms over the years that all work and (probably) sound a little different from each other, without many that are clearly better than all the others
I decided to order a pair of the Isonoe feet in silver to replace the black stock feet on the 1210GR. I like the asesthetics and I do live in apartment with suspended wood floors so hopefully may get some sonic benefit. The sorbothane boots, glass or non-glass version, seem to be impossible to get hold of from UK internet retailers at the present time, despite Isonoe being a UK company. So I've ordered some sorbothane discs from ebay to seat the feet on. I can return the Isonoe feet if they don't do anything for me so a low-risk strategy.
Just received the armboard I ordered at Ammonite Audio to mount my recently acquired SME V tonearm to the 1200G. Not a flimsy punched out plate of steel like most armboards, but a solid machined block of aluminium: Well though out design, with a ring and center plate mounted together in a way that it almost looks like one part from the top! Centerplate can be swapped out to fit other types of arms. I hope I have some time upcoming weekend to mount this one and show you the results.
Congratulations on a nice upgrade! Looking forward to your results. The Ammonite Audio mount looks to be quality stuff. The only plate mounts from steel that I’ve seen are thankfully non magnetic stainless steel ones (eBay) that have more absorbent properties compared to aluminum. With the low surface height of the Technics platter, even using a 5mm thick mat, I would like to know if the SME Series V has a useful range of height (VTA/SRA) without having to use a cartridge spacer? I appears the SME Tonearm support bracket, which holds the tonearm rest & cueing device, interferes with the top deck - something no one seems to mention with this modification.
Yes, the limited height differential between SL-1200 top plate and the bottom of the arm rest plates of SME 309/IV/V arms does dictate how low the arms can be set, whichever replacement arm board is used. But in practice this does not appear to be a real issue. SME boards are by far the most popular of the Ammonite Audio boards that I make and sell; and even though this lower arm height limitation was originally a concern to me, nobody seems to have had any problems in actual use. Accessing SME baseplate adjustment screws in the cramped center plate of my armboard was a bit of a PITA, but a kindly customer experimented and told me that a simple T10 Torx key allows all adjustments to be carried out quite easily, so I now inlcude one of those with SME SL-1200 armboards (although I forgot to include one in Oelewapper's order).
That centerplate gives hope that with the right arrangement of holes could be used on a 100C/1500c, depending of tonearm's protrusion underneath. Tonearm wires would be soldered to the phono pcb, in place of the originals.
Ah yes, that’s an interesting idea; the centerplate likely matches the diameter of the 1500 tonearm base very closely.
Yes, that does appear to perfectly mimic SME’s HTA Key for setting overhang. For what it’s worth, as long as the two SME base clamp bolts are sufficiently loose, the HTA adjustment is accessible on the opposite side of the base as well.
Well guys, I finally had the time to mount the armboard and arm. Sounds and looks great so far, but I'll have to do some more listening to come to conclusions. I'll post an update in the upcoming days, probably with a recording included. But I already know that this is definitely an upgrade I can highly recommend!
