Ortofon A90 with Graham Phantom

" You now have me thinking that my SRA will be off - even level headshell the actual cartridge will be slightly back down. damm "

Brain fade gents - Doh

The back of cartridge will be slightly up - probably close to the 92% SRA that Fremer.

I say that if the cartridge doesn't fit as intended with the "bumps" positioned in the headshell, you are defeating its intended design by "making it fit". Those bumps I am sure are there for the same reason you put cones under your preamp. I would not choose that cartridge for that arm, unless it could fit properly.

05-20-10: Downunder
I have a Phantom and A90 and I know the problem you are experiencing. I also use the mint tractor. The phantom is wide but not very deep, so it is impossible for all 3 ridges to be in contact with the headshell, only the front ridge.

That's what I have found - the same was true of the Ortofon Jubilee in the Phantom (or the Graham 1.5T for that matter).

05-20-10: Downunder
Your alignment does not sound quite right. The back of the A90 should be parallel. Either both of the back ridges will be seated on the headshell or none will be. Otherwise your cartridge body will be twisted slightly left or right.
I would go through all parts of the alignment again to double check.

Not in my setup with the Phantom II armwand.
Like you say, the Phantom headshell is quite narrow from front to back (narrow oval shape) but at the left-hand rear (looking from the front) there is an asymmetrical extension that connects the headshell back to the wand.
Looking from the front of the cartridge the left rear 'ridge' of the A90 is under the headshell (the extended part that connects back to the wand) - while the right rear 'ridge' does not contact the headshell at all. The cartridge is mounted symmetrically in the headshell and aligned with the Mint protractor (though its in the same position with the Graham jig).
You can clearly see the right rear ridge outside the headshell in this photo

Despite this, the A90 is still by far the best sounding cartridge I've heard in my system. I suspect the rigidity of the cartridge/headshell interface and resonance control etc is still far superior to most other cartridge designs - due to the A90's rigid and highly damped one piece SLM body/spine.

Smoffatt,

If like Stringreen you 'worry' that the bumps are not all under the headshell there may be another option.
Assuming your Phantom has the SME base, you could slide the base a few mm rearwards and move the cartridge forward in the slots to compensate - allowing all the ridges to contact the headshell.

The only negative consequence of this would be that the Graham jig - which expects a fixed relationship - could no longer be used. Obviously any of the 3rd party alignment protractors, such as the Mint, would still work perfectly.

Unlike taking a dremel to your $4K cartridge - this could be completely reversed, should you wish to use the Graham jig in the future.

To be honest, I doubt you'd hear any sonic difference whether all the ridges are under the headshell or not (so long as alignment and azimuth is correctly adjusted for both circumstances).

Paul, that explains the difference.

Smoffat and yourself have Phantom II's. I have mark1 and the left side of the headshell is symetrical with the right, hence their being a gap on both back ridges with mine.

Nice thought re the SME mount. I have the SME mount, so I might try moving thebase back a few mm's. I can then tell you if there is any sonic difference.

I am hoping Bob Graham is reading this thread, as he may have a simple fix - I am guessing a headshell spacer - however since the Phantom headshell is so thick, it is hard to find screws long enough to fit.

cheers