Jump to content

Pass Labs x150 and x150.5 - Quicky

Recommended Posts


I do indeed like my Pass Labs amps.


Nothing much here, just a quick comparison of my old x150 vs my (New to me) newer x150.5

Both bought through SNA.



Old x150 front and internal side shot.

Built 2002 - First sold in 2003 in Hong Kong - Outputs on one side replaced 2006 (supplied by PL) - I bought it in 2012

I then cleaned up the previous repair and did a recap while I was at it. Later ended up replacing the noisy transformer - Possibly damaged when the first owner blew the snot out of it with his idiot 8amp primary fuse - Meant to be 2.5amp.

I still have it today, and sorry, No it's not for sale. It's been inhaled by dad. :)






Newer x150.5 front and internal side shot.

Built 2012 - First sold in Australia 2012 - No other history - Purchased by me 2016







I know the .5 series have had two maybe three revisions through its life.

Mine being one of last ones has the full 20 outputs per side (first ones had 12).

Also has more and larger filter caps totaling 180,000uF (no idea what early ones had).

Early ones had UGS4 modules, mine has UGS5. (input section modules).


Big suprise is the size of the transformer.

I thought the old one was big, new one is massive. Three times the physical size of the old one.


Sound wise.

Papa Pass says "Same sonic signature, but more of it".

He's not wrong.

More extended bass and treble, and far cleaner and smoother. Something I didn't think possible.


Now leave me alone so I can enjoy it properly :D



  • Like 4
Link to comment
Share on other sites

Thanks Green Wagon - saves me taking the lid off my XA30.5 just to see what's inside. :)   If I understand correctly, they are basically the same amp but one is biased differently to class A.


I love the understated description on Passlabs website for the X150.5:


"offers a nice basic stereo power amplifier. Quite musical it fits well into multi use systems, shared between music and films."


Refreshingly different from the hype other manufacturers indulge in. :thumb:

Link to comment
Share on other sites

No worries Tony :)


BUT, yours being a xa might be somewhat different.

Cause it's all up in ya face class A and all that ;)

Google it, should find images pretty damn easy.


And if you see a pic of the master, you'll understand his laid back position.

Have a look at some of his posts on diyaudio.

The master of smooth.

Hes had to put one or two in their place. And boy, he does it so well. Gets all the info then lays it all out for all to see. No one has dared try a come back after that :D


EDIT. last write up I saw on an xa30.5, when they did the power test it was able to thump out 120wrms................ from whats supposed to be a 30wrms amp..


EDIT TWO. Just had a quick look, and yup, the xa30.5 is exacary the same inside on a quick look......

Edited by Green Wagon
Link to comment
Share on other sites
  • 4 years later...

Thanks for posting this description and photos of your X150.5 


I think I have an earlier model, guessing it uses 31000uf caps x 4.

Now curious to open up, as it may be time for recap and rebias etc

Link to comment
Share on other sites


  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Create New...
To Top