Hi, first time posting her, hope anyone can help me…
I’ve been playing for about 5 months, and today this happened -
I’ve got my bass hooked up to darkglass vintage deluxe and from there into a fender rumble 40 amp, in the middle of me playing an increasing whoosh sound started filling the room until it stopped and then my bass didn’t make any sound.
it’s not the battery (active bass)
it’s not the cable - checked
it’s not the amp - checked
Anyone got Ideas?
Thanks!
Did you try a fresh battery even if you think this one is ok?
Yep, almost certainly the battery 
yes, that’s the first thing I did, I replaced the battery with a brand new one…
I also connected with the same cable my E-Drums to the amp and it’s not the amp.
could it be the built in pre-amp?
I’d take the Darkglass out of the equation for now. Turn on the amp, plug in your instrument cable. If you touch the end of the cable that plugs into your bass you should get some noise (I’m assuming you don’t have another electric instrument to test it).
So the amp makes noise and the cable is OK. Plug in the Bass and touch the circular metal part of the pickups with something metallic i.e a screwdriver or a spoon it doesn’t matter what. You can even press down the string to touch the pickup pole piece. If there’s no clicking sound then you’ll have to logically trace the fault out from the bass output jack to the pickup (I don’t know your current skill / competence level taking stuff apart and using an Avo.)
You can bypass the Yamaha preamp by using a long piece of wire to go straight from the output jack to the pickup. It’s a quick hillbilly way to chase down electrical faults on vehicles. It works, it’s just not elegant.
You might be ‘lucky’ and it’s the Darkglass. Though I just googled the price 
Thanks for the suggestion, I’ve got no experience taking a bass apart, but I think I’ll give a try.
I’ve got E-Drums, maybe I can hook them up to the darkglass pedal, and see what happens…
Hooked up E-Drums to the darkglass, works fine
so by elimination is it the trbx304 internal pre amp?
It’s quite possible. Generally somewhat rare for something completely solid state like that to straight up fail under normal operation though, so it could also be some other electronics connection inside the bass that failed.
Yamaha generally has excellent warranty service. Is it still under warranty?
Is there a switch to bypass the active EQ part and just run the pickups passive? I think you still need the 9v battery to get a signal from the pickups?
Think so, bought it in December.
no such switch
The bass came back to life for about 25 min
and then died in the same manner, a rising swoosh sound and then silence
I’d try and get a warranty repair at this point.
For that you need to step up to the TRBX504 which has an Active/Passive switch and a huge upgrade in Pickups and Electronics. Well worth the extra investment. I own both the 304 and 504.
You do not need a battery in the Passive mode on the 504. 
MY TRB5Pii makes a very annoying sound when the battery is about to die, which is why I would have bet money on your problem being the same. But, it seems something more inside the bass is not as it should be; perhaps a soldered connection that moves and disconnects (or expands and shrinks, even though there shouldn’t be any big temperature changes inside your bass…)
Anyway, Howard’s suggestion is certainly the best way forward for you now. Best of luck!
@boltaxa2 Earlier it was suggested just running the 304 directly into the amp by itself ie nothing else in the signal chain. Have you tried that yet?
Tried that. The same, it works for 10-15 min then makes that sound and dies
And there is no noise when touching the metal part of the pickups with something metallic.
The symptoms sound to me like they might indicate a capacitor that is failing. But that’s just a guess. Contacting the seller saying you need warranty work is probably the best bet.
You could always take your Bass into a Music store and try one of their amps with their cables. That would eliminate everything except the Bass.
One thing not mentioned is some form of electrical or RF interference.
Try plugging your Bass into the amp outside. Just a thought.
Other than that I think @howard has the right idea.