passlabs x1000

[claretplace]

hi im new to this site
i have the chance to buy some last run passlabs x1000

can someone please tell me the main differences between these and the x1000.5
also can i have some opinions on these monos
i would be running these through a set of focal grande utopia be
lastly any indication on 2nd hand price would be great etc

thanks in advance

 

[Zen Mod]

just buy them , if you have good offer

1000 is mosfet FE , while 1000.5 is Jfet UGS FE

however , both good amps

for me , they both could have same fun factor , while differences can be limited to taste preferences

rest of questions ........

opinion - I'm biased , so no opinion about Papamps

price range - moi - no experience and interest in buying them , so no informations about price range

 

[Nelson Pass]

The original X1000 is only a 2 stage amp - the input differential pair drives
the output stage directly through a folded cascode. Unique enough for a
regular power amp, it is probably unheard of for 1000 watts output.

That was the very first X amp, and I chose that design to demonstrate what
you could do with such a simple X circuit.

 

[moe29]

Mr. Pass,

Did you ever bridge and parallel a couple of X1000s each just for the heck of it?

16kW peak into 4 ohms i believe 4 more for 32kW into 2 ohms?


i remember reading that in the Owner's Manual and always wondered if anyone had done it! LOL

 

[Nelson Pass]

Driving the inputs through isolation transformers, I tested four to 16 KW peak
into 4 ohms.

 

[Zero Cool]

Driving the inputs through isolation transformers, I tested four to 16 KW peak
into 4 ohms.

I want to see THAT load bank!

 

[Zen Mod]

will it drive F4 ?

 

[didiet78]

Picture will be awesome

Didiet

 

[6L6]

I tested four to 16 KW peak
into 4 ohms.

What was your load? Railway locomotive braking grids?

 

[Nelson Pass]

I said peak.

 

[6L6]

Yes, I did actually saw that, but golly gee, Professor, you still must have some interesting load widgets.

 

[Zen Mod]

wall of Feastrexes , I'm sure

 

[6L6]

Perhaps something like this --

 

[Zen Mod]

yeah

exactly same size

filled with these

An externally hosted image should be here but it was not working when we last tested it.

I know that for sure - Papa asked me to construct shunt regulator for all these field coils

 

[claretplace]

hi thanks for the replys
mr Pass did you make may sets of the original x1000?
also what are the main differences between the originals and the .5 sonically

thanks

 

[tiefbassuebertr]

The original X1000 is only a 2 stage amp - the input differential pair drives
the output stage directly through a folded cascode. Unique enough for a
regular power amp, it is probably unheard of for 1000 watts output.

That was the very first X amp, and I chose that design to demonstrate what
you could do with such a simple X circuit.

According
https://web.archive.org/web/20060502130612/http://passlabs.com/downloads/x_om.pdf
there is in use a two stage approach, i. e. one gain stage (folded cascode) and one buffer (push-pull source follower).
on page 10 of OM from X250 is to read the same - go to
https://web.archive.org/web/20041204173719/http://passlabs.com/downloads/x250_om.pdf
but in real life I note, that on the front end (UGS modul) is an approach with two gain stages and one buffer (also push-pull source follower). The serial No of those X250 is 11651.
Is it possible, that later versions have change from one of two gain stages ?

Thank you for an advice and upload of X1000 images with internal views.

 

[tiefbassuebertr]

no advice ?

 

[Nelson Pass]

I note, that on the front end (UGS modul) is an approach with two gain stages and one buffer (also push-pull source follower). The serial No of those X250 is 11651.

Is it possible, that later versions have change from one of two gain stages ?

Thank you for an advice and upload of X1000 images with internal views.

Later versions of X250 used the UGS front end. The X1000 did not.

X1000.5 used UGS front end.