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🙂
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🙂
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
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
Last edited:
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.
😎
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.
😎
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
Did you ever bridge and parallel a couple of X1000s each just for the heck of it?
16kW peak into 4 ohms i believe

i remember reading that in the Owner's Manual and always wondered if anyone had done it! LOL
Driving the inputs through isolation transformers, I tested four to 16 KW peak
into 4 ohms.
😎
I want to see THAT load bank! 😉
I tested four to 16 KW peak
into 4 ohms.
What was your load? Railway locomotive braking grids?
Yes, I did actually saw that, but golly gee, Professor, you still must have some interesting load widgets. 😀 😀 😀
yeah
exactly same size
filled with these
I know that for sure - Papa asked me to construct shunt regulator for all these field coils

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

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
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
AccordingThe 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.
😎
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.
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.
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