Rick,
You are describing the exact symptom of a bent sub chassis. Exactly what I ran into. To be sure, you need to dissassemble the table and remove the sub chassis. Then simply put a straight edge across the top of the subchassis casting will either confirm or deny this being the cause. I'll be rather surprised if this isn't the source of your problem. Have you had a look in the audioasylum.com vinyl archives yet as I suggested in my previous reply?
Happy Trails! Vince@freewheelcycle.com |
Ugh! A bent sub-chassis sounds horrible. I hope that's not the problem. Vince, is there some prescribed way to test the integrity of the sub-chassis? I don't recall it looking bent when I had the table taken apart upon purchase and initial set up, but maybe I wasn't looking hard enough.
In any case, I've recently managed to get the table to have only one spring cover that doesn't fit perfectly (platter at about 1/4 inch and even around the circumference). Sounds fine, but drives me nuts to look at it.
Jakob, I'll see if I can find someone with a scanner. Can't promise anything, though.
Best, |
Hey Rick,
I suspect your problems actually go a little deeper than the springs. Older Alexandrias had a sub-chassis made of a cast alloy which eventually sags (bends) under the platter's weight. The fix is a replacement sub-chassis made of the same much stronger machined alloy billet as used for the current Delphi. We had the same symptoms on a used Alex I recently purchased for my wife. I did a little research on the Vinyl Asylum at audioasylum.com and came across other people that had experienced the same. A very pleasant woman at Oracle HQ confirmed this was very common and arranged to ship a replacement to my favorite dealer. It wasn't terribly expensive.
Happy Trails! Vince@freewheelcycle.com |
HI out there
I have just bourt a 10 year old uesed Oracle Alexandria mkIII, and are looking for a manuel. It has not bin possibel too find one in denmark where I live. So if som one out there could bee persuede into scanning theres and mailing it I would be grateful
Jak
I now it is out of subject but I am getting desperat |
Rickk, I doubt that the "white" spring is the problem. Have you "re-threaded" the plastic ring supports? Mine end up at about 1/4" from the top of the spring, leaving only a bit of the spring exposed on the top. Do the springs look like they are elongated? I would go through the whole exercise of re-threading the the plastic ring supports and see where it ends up then. BTW, if the platter ends up too high, the belt might not align properly on the motor spindle, so not higher than 11/32" is a proper precaution. I feel that the best position is really 1/2 way of the platter's travel between hitting the top and the bottom. Bob P. |
Hi Bob,
I made sure the springs were in the proper order of strength when I set it up. However, I recall that one of the springs was color-coded white. I am going off memory, but I think I have a white spring instead of the yellow. Possibly that is the problem?
Thanks, |
Rickk, are you sure that you have the proper springs in the proper location? They are colour coded to distinguish which go where, since the load will be different in each location. The strongest spring is Green and should be on the right suspension module, a Yellow spring is slighly weaker and should be installed on the left rear and the remaining Grey spring on the left front. I just finished doing the recalibration of my Alex III with Rega 300 and had no problems with obtaining the 11/32 inch clearance. The springs (table) are about 14 years old. Salut, Bob P. |
Newbee,
I appreciate your input. It's near impossible to find anecdotal information regarding these tables. The platter was level before I adjusted the springs and after. However, it has never bobbed evenly as you describe. I believe the literature states that it should bob evenly 4 times and then stop. I have not been able to achieve anything close to that experience, but the sonics sound fine to me nonetheless. Sounds like the same thing you're experiencing, except that my table looks like crap with the spring covers sitting unevenly. I guess I'll try setting it up from scratch again and see what happens at 1/8".
Thanks again, |
My platter is also 1/4" above the plinth. I've no problem fitting the caps over the springs. Perhaps you do need new springs, however before your go that route you might try lowering the platter to 1/8th inch. So long as the platter is operating perfectly level and that space is even around the platter I don't think this height issue is that critical. Worth a try.
Regarding the tone arm. My Oracle came with the Oracle arm - nice arm but a PITA - I changed it to a MMT. I did not change the spring(s) and it has worked fine, however I've always felt, subjectively, that the spring on the arm side could have been a bit stiffer. When you press down on the platter and release it, it doesn't move up and down in a perfectly vertical motion. But in practice it didn't really make a sonic difference, to my ear anyway.
Wish I could have been of more help........ |
The bottom of the platter is just under a 1/4" from the plinth. The manual specified 3/8" but that seemed really high when I set it up that way and caused all three spring covers not to fit. I lowered it to the present distance and followed everything else as described in the manual but still have problems with two of the spring covers. It is very puzzling. What is the distance between the plinth and the platter on your set up? |
How far off of the plinth is the bottom of the TT platter? Is it the distance spec'ed out in the manual? I've never had this problem and really can't imagine how it would occur. |