Hi there,
Could you, Petter mail me?
engelholm.per@telia.com
Nice if us scandinavians keep toghether! ;-D
Could you, Petter mail me?
engelholm.per@telia.com
Nice if us scandinavians keep toghether! ;-D
Hello... This thread seems to have died out or something.
Did Petter ever get his X100 to work?
I have soon big populations of Fairchild IRFP240 and IRFP9240 here (the industry standard versions), and hopefully can then start obtaining the "lesser" parts and building an X circuit of my dreams.
What I am most afraid of is that as my room's temperature (or the amplifier's internal temperature) rises some degrees, the current sources go into a mismatch and smoke comes out from everywhere.
I think we can be quite sure that NP doesn't use "triplets" in his commercial amplifiers, or I'd be at least amazed if he did. By looking at the pictures in the Pass Labs' products section I have seen only one trimpot in a single X amplifier channel. I wonder would it be any more criminal than this thread to see if I can find a real X amplifier and see what's inside. But if there really aren't any stability problems with Petter's "triplets", I might as well be happy with them. And I don't seriously think any owner of a real X amp would appreciate me opening the case of his treasure.
BTW. Do I lose anything if I use IRF610 as the input pair and forget about JFETs?
-Kimmo Sundqvist
Did Petter ever get his X100 to work?
I have soon big populations of Fairchild IRFP240 and IRFP9240 here (the industry standard versions), and hopefully can then start obtaining the "lesser" parts and building an X circuit of my dreams.
What I am most afraid of is that as my room's temperature (or the amplifier's internal temperature) rises some degrees, the current sources go into a mismatch and smoke comes out from everywhere.
I think we can be quite sure that NP doesn't use "triplets" in his commercial amplifiers, or I'd be at least amazed if he did. By looking at the pictures in the Pass Labs' products section I have seen only one trimpot in a single X amplifier channel. I wonder would it be any more criminal than this thread to see if I can find a real X amplifier and see what's inside. But if there really aren't any stability problems with Petter's "triplets", I might as well be happy with them. And I don't seriously think any owner of a real X amp would appreciate me opening the case of his treasure.
BTW. Do I lose anything if I use IRF610 as the input pair and forget about JFETs?
-Kimmo Sundqvist
I believe the most people use doublets, i.e a fixed resistor with say a 5K paralell pot. This means that if you turn the pot towards zero, you will get zero ohms.
The triplet approach basically gives you more useful turns (less sensitivity) on the turns but is by no means necessary. You can obtain a similar effect by using fixed resistor with series low value pot (say if target is 200-250 ohms, a 200 ohm unit with a 50 ohm series pot will give you maximum usage of all turns). The "Problem" with that approach is that you get all the current through the trimpot. Probably not all that much of a problem, but still ...
I thus believe triplets will give you the best result -- low power consumption in the trimpot + fairly linear use of all turns. This again leads to better stability.
A note on JFET's: If I found a better photo of the JFET pass units, I could probably see a little more. However, through the fuzz there seems to be 4 JFETS's parallelled per side (much like a double Pearl input stage) connected as a long tailed pair?
Sorry to all those who have made this thread exciting -- I have not yet had the time to complete the unit
Petter
The triplet approach basically gives you more useful turns (less sensitivity) on the turns but is by no means necessary. You can obtain a similar effect by using fixed resistor with series low value pot (say if target is 200-250 ohms, a 200 ohm unit with a 50 ohm series pot will give you maximum usage of all turns). The "Problem" with that approach is that you get all the current through the trimpot. Probably not all that much of a problem, but still ...
I thus believe triplets will give you the best result -- low power consumption in the trimpot + fairly linear use of all turns. This again leads to better stability.
A note on JFET's: If I found a better photo of the JFET pass units, I could probably see a little more. However, through the fuzz there seems to be 4 JFETS's parallelled per side (much like a double Pearl input stage) connected as a long tailed pair?
Sorry to all those who have made this thread exciting -- I have not yet had the time to complete the unit
Petter
Circuit Simulation
Try searching for switchercad it's was created by a semiconductor company. It has IRFP240 and IRFP9240's (I think) - I am running linux now so I can't check. It is totally free and works well for me. The interface is different than Circuit Maker which I too tried, but it can be learned in about an hour. I think it even has tubes.
If anyone knows about a good simulator for linux I would like to know about it.
Darrell Harmon
Try searching for switchercad it's was created by a semiconductor company. It has IRFP240 and IRFP9240's (I think) - I am running linux now so I can't check. It is totally free and works well for me. The interface is different than Circuit Maker which I too tried, but it can be learned in about an hour. I think it even has tubes.
If anyone knows about a good simulator for linux I would like to know about it.
Darrell Harmon
Whats wrong with the pic content?
Isen't this circuit patented?
-------
Not just hobbyist read this forum.
- HarryHaller
-------
If someone would really want to copy all his boards and circuits woulden't it be easyer to buy one of his amplifier?
I sincerly don't believe that DIY'ers will be a derangement to Mr.Pass success.
-Simon
Isen't this circuit patented?
-------
Not just hobbyist read this forum.
- HarryHaller
-------
If someone would really want to copy all his boards and circuits woulden't it be easyer to buy one of his amplifier?
I sincerly don't believe that DIY'ers will be a derangement to Mr.Pass success.
-Simon
Hmmmm......
Having thought about this a bit further... (I deleted my other post)
I also agree that this picture should come down.
When Nelson decides to publish the service manual (schematic) for these amps then perhaps it might be ok... Perhaps that could be our guiding criteria...
But for now since it's still a current product, in my opinion it's not such a good idea...
I for one am extremely appreciative of the support that Mr. Pass gives the DIY community and would not want to jeopardize that in any way...
Just my thoughts,
Steve
Having thought about this a bit further... (I deleted my other post)
I also agree that this picture should come down.
When Nelson decides to publish the service manual (schematic) for these amps then perhaps it might be ok... Perhaps that could be our guiding criteria...
But for now since it's still a current product, in my opinion it's not such a good idea...
I for one am extremely appreciative of the support that Mr. Pass gives the DIY community and would not want to jeopardize that in any way...
Just my thoughts,
Steve
Can you guys stop being such a bunch of zealots?
This pic is no different from any other pic: it's just a pic!
Unless you you have 3D vision I dare anyone to come up with a schematic.
Furthermore, Nelson is a big boy that can take care of himself. If he's got a problem with this I am sure we'll hear from him soon.
This pic is no different from any other pic: it's just a pic!
Unless you you have 3D vision I dare anyone to come up with a schematic.
Furthermore, Nelson is a big boy that can take care of himself. If he's got a problem with this I am sure we'll hear from him soon.
I don't really think the picture is that big of a deal, but I would have asked NP for permission before posting any such pictures.
If you look on the passlabs webpage, you can see the underside of this board in the X150 product info:
http://www.passlabs.com/images/product/x150inside.jpg
--
Brian
gte619j@prism.gatech.edu
If you look on the passlabs webpage, you can see the underside of this board in the X150 product info:
http://www.passlabs.com/images/product/x150inside.jpg
--
Brian
gte619j@prism.gatech.edu
