Swapping Kt88 tubes on muzishare x7 for Kt150

The answer is NO. You want deeper bass correct? Reinforce the bass, move the monitors closer to the back wall. If they are on stands, beard the stands the width of the speaker from the base to the floor with just card board and watch how much the bass improves. You can make it wider or narrower but the BASS will improve. It may not go deeper but to tell the truth it's a bad idea anyway.

60-80hz is a better cut off and then the timing isn't so screwed up. Blending a sub is really easy with that type too.  LOL Sit on the sub.. The fact of a sub being a lot closer to the seated position and decoupled, might really surprise you how good it can be without backing the screws out of the sheetrock or the neighbors for that matter. 

Placement is the key first for more of what you already have. If the speaker can't reach that deep, you have to add it, simple.

The KT150 tubes will change your sound but will not enable your speakers to go any lower in HZ. 

That's a question you should be addressing with the manufacturer.

KT88's I've heard in my amp have no shortage of bass. Even EL 34's.

All about how the speakers play the room. 

Stick with the tubes your amp is designed for.

You won't get any more power. You won't extend the bass at all, and you run the risk of destroying your amp.

Filament current is higher with the KT150 over the 4 tubes it could be as much as an extra amp of current. KT150's also require either higher voltage or higher current to work properly. Anybody tells you there was an improvement likes to listen to distortion. They also require a much lower impedance drive or they could go into runaway. They also may not physically fit.

As mentioned, your amp is probably not the problem, but room, speaker placement or characteristics of the speaker itself.

No, not with your X7 I'd suspect.  Stay with KT88s.  Here is why...one other thought.  

@hvuck did you happen to notice your X7 amp designed for KT88s weighs 22.5kgs?  Now compare that to the new Muzishare X10 amp designed for KT150s, weighing in at 35kg. Wonder why there is a weight difference b7 between your X7 and the X10 model amps?  Worth researching more, this may be a sign. Bigger transformers, maybe.  

The KT150s can operate with higher plate voltage which typically requires larger and heavier transformers. Seeing this trend over the past two years with amp designers now coming out with weightier amps to run KT150s properly, in their window of optimum operation so to speak.   

RE: KT150s

My amps are designed to run KT150s, sometimes they can be so clear and transparent, and while it sounds great with a little more low end, there is more top end too - ruthlessly transparent some times. Gives the perception of less bass sometimes too. Totally neutral.  Some love this.   There are times I wanted to go back to a KT88 sound for added midrange warmth. Ended up with KT120s as my alternate set. If you must, maybe sell your X7 and buy the new X10 which runs KT150s natively if you must have KT150s.  Another angle to your question.