Why does my vinyl sound so bright?

Michell Gyro upgraded to Orbe Platter with DC motor, etc. Zeta tomearm, Sumiko Blackbird, into PS Audio GCPH. I'm not looking for a world beater rig, but boy it's kind of bright during playback. Wasn't always this way, so something must have changed, but the only thing I've changed is moving it onto a wall mounted shelf, at least that's the only thing that I've changed on purpose. Any tips on where to start troubleshooting this?

Complete vinyl imbecile here, so be gentle and talk slowly...thanks for any help!
With vinyl there is always a little feedback of the acoustic vibration to the cartridge. Low frequencies are most pronounced. Perhaps your old TT location picked up more of this feedback, and therefore gave the overall sound a fuller character. The new TT location is probably better, but you need to get used to it.
Perhaps an adjustment to your VTA, lowering the arm a bit. I'm not sure why this would be affected by the move to the wall shelf, but it's worth a try and it costs nothing.
After you're SURE the cartridge cantilever is still straight and hasn't been accidentally bent, double check your cartridge tracking force, it is easiest to knock out of whack accidentally. The Blackbird tracks at 2g. Then check your cartridge loading, you can experiment with the GCPH. Then adjust your VTA to be a little negative, that is, so that the back of the arm is slightly lower than the front when the needle rests on an average thickness record.

Eldartford has a point when he says moving to the wall shelf (an EXCELLENT idea, btw) may have changed the character significantly. The improvement here usually manifests as more space between the notes, which could come across as more lively.
Keep in mind that getting that cartridge aligned and VTA and VFT set just so will dramatically affect the sound. If you are a complete vinyl imbecile then this is likely the problem. Great sound doesn't come easily with vinyl, it's worth a lot to have a very knowledgable friend who can come and help. There are some real guru's on here and vinyl asylum that can and love to help you get things dialed in. Don't be afraid to ask.
ditto the first two posts in combo.
Get a good VTF (vertical tracking force) gauge. Start there. You can find nice digital one's on this site. I got mine from SORA Sound. Great price on the same one you'll see for anywhere from $129-$185. This one piece of gear has helped me to perfectly dial in the sound of my Benz Glider.
Wall mount TT shelf is NOT an excellent idea. The house's wall in North America are usually made of dry wall. If a TT shelf mount to the dry wall in the Hi-Fi room., the dry wall(large surface area) will act as a giant DIAGHPARM and will transit the vibration(causing by sound wave) back to your TT.

Unless the wall are solid concrete then it might not be a problem.
A wall shelf into studs is better than vibrations being trasferred directly through the floor.
Edle, have you ever used a wall shelf?
Here's my guess...the table where it is now located is not leveled the same as it was in its previous location (both on the X and Y axis). The result is the stylus is not running the same angle in the grooves as it was before. Check the level. Lower the VTA.

Or, put the table back where it was before and see if the sound changes back to what you remember.

That's my guess...and I'm a vinyl imbecile, too.
If the only thing that changed is the wall mounted shelf, then there is a very good chance that is where the issue.

I've never wall mounted a TT, but I would think it would be harder to get the leveling, isolation, and perhaps other factors right, in general. Not to say it can't be done.

IS everything level? Any damage or changes to cartridge alignment in the process?
A wall shelf should never be mounted to a drywall panel using wall anchors. Such a mount won't hold the shelf and its load for much more time than it takes to say "Shouldn'ta done that."

A wall shelf should be mounted straight into the studs behind drywall. Those studs should not be standing on a plate that sits on the floor. The plate should transfer its load to the house foundation. In most houses that means putting the shelf on an exterior wall, not an interior partition.

If a wall shelf is not an option, a well-made floor rack has to be chosen to suit the needs of the turntable. Suspended turntables used to be said to need light racks and solid-base TT, heavy ones but floors and turntables vary. A wall shelf is really the best option.
Arthursmuck, there's great advice here. Turntable levelling, VTA, tracking force can all contribute to bright sound.

If the VTA is "tipped up" at the back (a high arm post) the highs may be emphasized at the expense of the bass. If the turntable is out of level, the force exerted on the stylus may change angle and give an effect similar to high VTA. Also a reduction in tracking force (if the arm counterweight shifts) will press the stylus down less into the groove and that can change the tracking angle.

If your sound is brighter but also clearer, less muddy and rumbly, that's a sign you have eliminated feedback at the low end by installing your TT on the wall shelf. If this is what's happened, the feedback in the old setup may have been masking a brightness problem.
The wall shelf is mounted directly into the studs, however it is an inside wall as an exterior wall was not an option. Regardless, the wall shelf has made a significant difference as the system is on the second floor, previously when walking across the room the TT would bounce, now it is very solid and stable.

I'll look into the mutliple things given here and report back after some experimenting. Thanks everyone, for helping this vinyl imbecile without making me feel like more of one.
Arthur, it's gotta be the move to a wall mount, it doesn't take much to change the character of a TT when changing platforms. I also have the blackbird and it is very revealing.
Okay, this is weird. I adjusted VTA a tad and validated VTF at 2.0 and now music sounds garbled and warbly coming out. I'm guessing the cartridge may have bit the dust or be biting the dust. Maybe the cantilever got damaged somehow when I moved it (although I had the arm secured and it was a pretty short and uneventful trip from rack to wall.)

Any further thoughts?
Yes -- start over and remount the cartridge. Verify ALL parameters, as each will affect the other.
"Garbled and warbly" may mean the cart is disfunctional as you say. Some damage will show up on visual inspection, if you have a clear recollection of how the cart looked when new. Inspect the cantilever to see if it is centred in the mount. Other damage--a failed suspension for example--may be invisible and not show up until you try to play a record.

Is it possible the VTF is reading wrong? That might happen if the counterweight has moved. A setting much too low or much too high might give you garbled and warbly (although warbly might be TT speed instability too, I suppose).

You could start over again, as Ncarv suggests, right back to remounting the cart and balancing the arm. Check to make sure the stylus is clean, first!

It's just a thought, but if you moved the TT to the shelf with the main platter still mounted on the bearing, the suspension could have bounced some. A lot of bounce can throw settings off or worse.
Arthur, absolutely start completely over and remount as Ncarv mentioned...good luck!
How clean is your stylus? A gooped up stylus can make things sound garbled and distorted.

As for the original problem, I'll vote with Eldartford. I think you are discovering that where ever and on what ever the table was originally sited was causing some smearing that made the presentation sound warmer. After moving the table to its new location you are hearing better attack and harmonics. Stll, it never hurts to re-check everything.
Cleaned the stylus, the mounting is visually good, and it measures properly. I'm going to take it (tonearm and all) tomorrow to a local shop to have it looked at, I'm relatively certain the stylus is damaged/significantly altered somehow. It sounds like rocks and water are running under it during playback, I don't know much, but I know this sounds like something much more than an alignment issue.

Thanks for all the help!
Shows that advice is great, good advice is better, and in the end you have to rely on your own perceptions and judgements anyway. Please let us know how it turns out, and best of luck.
Thanks Tobias, and everyone who chimed in. I actually learned quite a bit yesterday from all of your replies, so I'm a few degrees less of an imbecile (about my vinyl rig anyway) and one step closer to having it up and running.

One more quick thought, as to the wall shelf. I didn't really clarify well on that point. I moved the table in December, it has played and sounded fine many times since the move. The brightness, now rocks and water sound, was new in the last week or so.

So assuming the Blackbird might be damaged, It appears a retip on these is fairly pricey, any thoughts in the direction of the value/dependability of a retip versus spending $5-700 for a new cartridge?
If you like the Blackbird, consider having it rebuilt or retipped. I've just had two carts nicely redone by Peter Ledermann at Soundsmith. You could give them a call at (914) 739-2885 ( http://www.sound-smith.com/ for an idea of their rates ). They also sell cartridges, and would advise you.
Sounds like damage. Is the cantilever straight? If not, that would be an indication that the suspension is shot. If you have a 50x or higher scope for viewing the stylus you may find that it has been chipped. I suggest NOT playing any LPs until you figure this out.
Cantilever appears straight and I don't have 50x of higher. I'm going to take it in to a place that does tomorrow. Yeah, I am NOT playing any LP's based on how this sounds. Chipped might make some sense as it would play, just terribly...
I've got a Blackbird and it is very sensitive to VTA; however, your adjustment and the resulting unsteady sound makes me thing that something happened in the move.

Use canned air to blow out the cartridge. Don't put the nozzle too close because the parts are sensitive, but see if that doesn't help. If that's no good, then completely dismount it and inspect it with a magnifying glass. If all appears ok, then try to remount it one last time. Be careful not to overtorgue the machine bolts holding it to the arm or headshell.

Try a cheap MM cartridge in the arm to make sure that the arm is ok. There could be some binding that you don't feel, but I really doubt this possibility.