Scratchy sound on certain notes right side only?

What could cause a "scratchy" sound on certain notes at certain volume, be it voice, piano, but especially with saxophone, right side only? I have switched cables, no luck. Checked all connections. I know its not the speakers because if I switch l/r cables from the phone preamp out the noise comes from the left speaker. Equipment is jr michell orbe with sme iv.iv arm & clearaudio virtuoso cartridge. Tracking force etc seems to be right on. Any help would be appreciated.
You've isolated the problem as coming from the phono preamp or before. Good. Now isolate it further. Swap the L and R inputs from the tonearm to the phono stage.

Does the noise change sides?

If not, the problem's in the phono preamp. Check tubes and tube connections, etc.

If so, then the problem is one of:
- loose tonearm wire-to-phono cable connections or,
- loose cartridge clip connections or,
- the records are damaged or,
- your cartridge is mistracking.

My bet would be one of the latter two causes. If it happens on multiple records (or new ones), my bet would be insufficient antiskate force to maintaing stylus contact with the outer (R channel) groove wall. Try increasing antiskate a bit.
Thanks for the thorough answer Doug. I don't know why I didn't think of switching the input to the phono but when I did there was no change. Noise still on the right. Phono pre is the problem.
Could also be a grounding issue either within the phono pre,possible bad IC connection, or the TT connection ground.
You've got a lot of tubes in the chain. Any chance you have an intermittently noisy tube? Might try reversing the small tubes in your pre-amp and your amp - see what happens. If it reverses channels you've found your problem.
Thanks for all the replies. I know its not any of my tube equipment because there is no problem with any other source, just the table. Switching the input from the table to the phono pre did not result in the noise moving to the left side, it stayed on the right. Has to be the phono stage.
Thanks again,
Yohjo, pop the cover on the 99 and swap the tubes, R to L, but only do the input tubes. If it doesn't move to the other channel then go back and swap the gain tubes.

Also, what gain configuration are you using with the 99?
Could be a tube.
Yohjo, Agreed if no other sources produce the problem it has to be in the phono stage. Doesn't your EAR phono-pre have tubes? Are you still using that - its listed in your systems? If you are, check the tubes. :-)
Definitely it is a bad tube or tubes! either pre-amp or phono stage. Best to test all tubes in the path.
Sorry guys, I should have added what the phono pre is, the EAR is gone, I am using a ps audio gcph. It's definitely the gcph. Not the 99 as no problems on any other source. Gain on the 99 is in same position as it always has been.
Ah, so you're Magnum does not have the phono stage.