hard to compare really. I’m more into “vintage-style” things but, yeah, Yamaha instruments are really excellent. still, a TRBX504 is hard to compare to a classic Fender design. and, still, a Jazz Bass (Squier or not) should work for slap.
if there is a gear issue here, it’s more about the amp IMO. and/or maybe a setup on the bass and better amp settings.
Yeah - really it’s apples and oranges there, true. Modern double humbucker bass vs vintage J. Good point.
So I went to the shop to buy an amp and decided to check some basses as well. Just check, not to buy - ibanez, another fender, couple others. But when I took yamaha it just felt soooo good, so I couldn’t stand it. Idk, size, shape, weight, sound - was jut so cool for me.
And now I own trbx304 (unfortunately I couldn’t find 504 anywhere in the city) and fender 100 - the lows are so much better than on 15 and 40.
Thank you guys, this is such a helpful community =)
a 304 and a Rumble 100 is a nice setup 
I find that, in the current Rumble range, the 100 and the 500 are the two really interesting amps. just my opinion of course.
Yeah that’s a nice combo, will go far with that.
Obviously I loved the feel of the 304 too, there’s just something about the TRBX necks. So good.
Having a bass that feels right makes such a difference. I played a TRBX304 and it was quite nice
Improve whatever you think is the weakest link in the chain; I have an Affinity Jazz bass and as long as it’s set up properly, it’s a very capable bass; i got mine just for slap. I wouldn’t get the 304, I’d get at least the 504.
Number of times I’ve played past the 20th fret on a bass: zero.
A rumble 15 amp would be the first think I’d get rid of! A rumble 40 is the smallest I’d go. I have one but i never use it, i prefer playing through and interface or Zoom B14 pedal and headphones. I often play late at night and i don’t play live with anyone right now.
Technique is something you’re going to always want to work on improving anyway.
Whatever you buy is up to you and your budget, better gear never hurts. There are many good reasons one might choose to buy something new, sometimes it’s just because you want to and it inspires you to play more often. I bought 5 basses in the about the first 9 or 10 months I played bass, each one had a certain purpose that i wanted it for but the majority of the time i only play 2 of them. It’s like owning a router, you might not use it often but when you need it, it’s handy to have!
That never works 
That is the feeling of the right Bass for you.
I’m glad you did not resist.
A lot of that has to do with the speaker size.
You are more than welcome. 
This is so true! It’s one of the most popular bass people gig with.