I was recently lucky enough to come across this bass on craiglist. I enjoy Matsumoku basses and the price was right so purchase was a no-brainer. So many MIJ instruments of the 70's and 80's were clones of existing American instruments but Westone basses represent the exact opposite approach. They put their own designs front-and-center from the get-go. The Spectrum GT is a very good example of this.
Really this is just a very nice bass. Mine has some playwear, and a plastic ring at the input jack to cover what I assume is some finish chips. However nothing so bad as to to mar the fact that this appears to be a well-built instrument. Weight is moderate at between 8 and 9 pounds, fretwork is good, and the neck is a comfortable example in the "J" family.
Like other Westones and many other Matsumoku basses this bass features proprietary and/or unusual hardware. The Spectrum GT has Switchmaster reverse taper knobs, a heavy Magnatone bridge that has a second mounting option that goes through the bottom of the bridge (but not through the body) with a quick-release option and also a roller string tree.
Tone is good, though the pickups are extremely hot. It was necessary to plug into a buffered input to cut down on clipping. P/MM configuration for pickups is reasonably uncommon in the bass world but this bass and several other Westone models has it. Both pickups are the same dimension, large soapbar shaped pickups with angled corners and a sloped edge for resting one's thumb. The pickups are pushed a bit outward from the traditional positions of P and MM pickups, so the voicing are different, but not in a bad way. Just different.
My preferred tone was both pickups on, both tone's wide open and the volume rolled back just a touch from full-on. It's not a delicate tone, but it's a great thick sound that would be great for many genres.
A few oddities and shortcomings to note:
-The push-pull on the volume pot is a phase switch that functions when both pickups are selected and brings a nasal honking tone to the bass. Just like a T-40 and just as useless. A series/parallel or a coil split option for the MM pickup would have been a much more useful choice.
-The V/T/T is far less effective, IMHO than a V/V/T setup would be.
-The short horn makes some neck dive inevitable. I found it to be manageable, but folks who sling their instruments low will notice it quite a bit.
These 30+ year old basses become available with some regularity and even great-condition examples can be had for $400 or less which represents a fantastic value for a very-well-built Vintage MIJ instrument that truly has it's own character. Don't buy this bass to get a P, an MM or both, buy it to get a Westone!