Pass X150

Tom B. 57

Member
2008-04-30 5:58 pm
I am expecting an X150 to be delivered Wed. or Thur.

The seller described it as being upgraded. When I asked how it was upgraded he said that the transistors have been replaced with currently used transistors. Would not other parts need to be replaced if this were the case? Current models are X150.5 and X150.8. It is my understanding that there is more than just different transistors used in these current models.

Would these currently used Transistors be compatible in the older circuit design?

Tom
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
The seller described it as being upgraded. When I asked how it was upgraded he said that the transistors have been replaced with currently used transistors. Would not other parts need to be replaced if this were the case? Current models are X150.5 and X150.8. It is my understanding that there is more than just different transistors used in these current models.

Would these currently used Transistors be compatible in the older circuit design?

Who knows? I am not aware of any upgrades, particularly ones involving
replacement of output devices. The only changes historically have been
from TO-3 cases in old models to TO-247 cases currently used.

Newer models have changes to the topologies, but again, there is no
information on what might have been done to the unit.

You can always arrange for Pass Labs to look at the unit.

:cool:
 

Tom B. 57

Member
2008-04-30 5:58 pm
Well, I've been listening to the X150 for a couple of days now and I must say it is certainly is a big step in the right direction from my Phase Linear 400 and B&K ST1400 Series II.

I am very pleased with the way this amp sounds powering my original Snell Type A speakers. I am using an Oppo 105D running through my Odyssey Candela preamp and everything seems to be happy playing together.

I no longer care if transistors have been swapped or not. I am happy with what I hear and that is pretty much all that matters.

I must say that being an entry level piece of Nelson Pass designed gear I am duly impressed. Maybe one day I will be able to afford another Pass creation.

Thank you Mr. Pass, for this amp is bringing me great pleasure.

Tom