Its a bit technical, if you cant look at a schematic
But you should be able to understand this: Cascoding is making a big brute transistor do the work for a smaller, more sophisticated transistor.The smaller one,gets to decide about the sound, the bigger one decides about the power, then
This is a very narrow explanation, but in most of NP's amps I guess pretty good, nonetheless. A cascode could also be made with similar J-fets to get a wider bandwith and so on. Cascode drawback is (there is always one) It eats some gain! Many people have trouble about their X-CCS-CC-BosoZ not being able to drive their poweramp to full output. PDF on its way.
Steen
I have been wondering since the early 80's about the supposedly 2 editions of the 400A. I always heard that the early 400a's were not cascoded. But all the 4000a's were! I have no clue where this story comes from, but I hope you can clear this once and for all, Nelson. If they were all the same, I am gonna kick my own butt, for letting one go, not so long ago!
Steen
barchetta,
All right, I'll take a whack at it...
Cascoding is the practice of standing a gain device (be it tube, bipolar, FET, MOSFET, or Farbleblatz from the planet Zircon) on another one's shoulders.
Draw this on a piece of paper:
For simplicity, we'll start with an N-ch JFET, since it can be made self-biasing (don't worry about what all that means--it's just a disclaimer on my part).
The incoming signal starts at the left of the piece of paper. It goes through a wire to the Gate of the JFET.
Drop a resistor from that same wire to ground.
Now, attach a resistor to the bottom element--the Source--of the JFET, and run the other end of the resistor to ground.
Got that?
Good.
Now comes the cascode.
Draw another JFET above the first one. Its Source attaches to the Drain of the bottom JFET.
The Gate of the top JFET goes to the midpoint between two resistors, one leading up to the positive rail, the other down to ground.
The Drain of the top JFET goes to a resistor. This is also where you take your signal.
The other end of that resistor goes up to the positive rail.
Assuming that you didn't get lost back at the second stoplight (remember? the one at the gas station two blocks after the left turn on Elm?), those directions will get you a drawing of a cascode. The top JFET is the cascode beastie. If you want to know why you'd do such a thing, say so--we'll leave that for another post.
If you want another (somewhat more technical) view of the subject, Nelson has a white paper on the subject somewhere in the bowels of the Pass Labs website.
(whoever wrote about wine above--it's rolled off the bottom of the reply screen),
Pouring wine anywhere other than in a glass...in my opinion, and I think I can speak for Nelson as well, is sinfully wasteful. Wine is for drinking. Or sometimes cooking. Period. Shame on anyone who feels differently.
Not to mention the fact that the parts will smell funny the first time they get hot.
steenoe,
Outrider is a good album, but uneven. I feel that the strength of the music still rests on Jimmy Page and Robert Plant (didn't Plant sing one song on that album?). I've never been entirely comfortable with the other vocals. For a somewhat more rock-ish album, try Coverdale/Page if you want post-Zeppelin Jimmy Page stuff. More consistent. In fact, it sounds pretty close to early Led Zeppelin.
Grey
All right, I'll take a whack at it...
Cascoding is the practice of standing a gain device (be it tube, bipolar, FET, MOSFET, or Farbleblatz from the planet Zircon) on another one's shoulders.
Draw this on a piece of paper:
For simplicity, we'll start with an N-ch JFET, since it can be made self-biasing (don't worry about what all that means--it's just a disclaimer on my part).
The incoming signal starts at the left of the piece of paper. It goes through a wire to the Gate of the JFET.
Drop a resistor from that same wire to ground.
Now, attach a resistor to the bottom element--the Source--of the JFET, and run the other end of the resistor to ground.
Got that?
Good.
Now comes the cascode.
Draw another JFET above the first one. Its Source attaches to the Drain of the bottom JFET.
The Gate of the top JFET goes to the midpoint between two resistors, one leading up to the positive rail, the other down to ground.
The Drain of the top JFET goes to a resistor. This is also where you take your signal.
The other end of that resistor goes up to the positive rail.
Assuming that you didn't get lost back at the second stoplight (remember? the one at the gas station two blocks after the left turn on Elm?), those directions will get you a drawing of a cascode. The top JFET is the cascode beastie. If you want to know why you'd do such a thing, say so--we'll leave that for another post.
If you want another (somewhat more technical) view of the subject, Nelson has a white paper on the subject somewhere in the bowels of the Pass Labs website.
(whoever wrote about wine above--it's rolled off the bottom of the reply screen),
Pouring wine anywhere other than in a glass...in my opinion, and I think I can speak for Nelson as well, is sinfully wasteful. Wine is for drinking. Or sometimes cooking. Period. Shame on anyone who feels differently.
Not to mention the fact that the parts will smell funny the first time they get hot.
steenoe,
Outrider is a good album, but uneven. I feel that the strength of the music still rests on Jimmy Page and Robert Plant (didn't Plant sing one song on that album?). I've never been entirely comfortable with the other vocals. For a somewhat more rock-ish album, try Coverdale/Page if you want post-Zeppelin Jimmy Page stuff. More consistent. In fact, it sounds pretty close to early Led Zeppelin.
Grey
Hey Grey, I am sure that the guy that cant read a sch. will understand now I will read your post carefully, a couple of times!
Thanks for bothering.
About the album "Outrider" the strenght is only Jimmy'boy Yep The Plant man did sing one on "Outrider" Which was pretty good too. But thats not too hard to comprehend, considering that everyone must be convinced that Mr. Plant has the greates voice in: Well you name it All the other songs on "Outrider" were done by other singers. Well, the singers are not the point, the Guitar is I dont think you will find much around, to better that performance!! Well except maybe, Muddy Waters, Hmmmm and Son House and of course Robert Johnson, the one and only! But they are all history now. Playing the guitar, expressing your soul and feelings, to my knowledge only the old Bluesmasters could do that with so much power!! Comming out from the Missisipi Delta, those Black musicians had the hardship loaded on their shoulders to sing the true Blues! A few White guys in Europe could do it too. Jimmy Page was one of them! On Led Zeppelin's first album, several of the tracks were written by the old black Bluesmasters That also goes for The Rolling Stones first album!
Who do you think wrote "I just want to make love to you"?? Stones first hit I like this talk, indeed!
Steen
I will read your post carefully, a couple of times!Thanks for bothering.
About the album "Outrider" the strenght is only Jimmy'boy
Yep The Plant man did sing one on "Outrider" Which was pretty good too. But thats not too hard to comprehend, considering that everyone must be convinced that Mr. Plant has the greates voice in: Well you name it All the other songs on "Outrider" were done by other singers. Well, the singers are not the point, the Guitar is I dont think you will find much around, to better that performance!! Well except maybe, Muddy Waters, Hmmmm and Son House and of course Robert Johnson, the one and only! But they are all history now. Playing the guitar, expressing your soul and feelings, to my knowledge only the old Bluesmasters could do that with so much power!! Comming out from the Missisipi Delta, those Black musicians had the hardship loaded on their shoulders to sing the true Blues! A few White guys in Europe could do it too. Jimmy Page was one of them! On Led Zeppelin's first album, several of the tracks were written by the old black Bluesmasters That also goes for The Rolling Stones first album!Who do you think wrote "I just want to make love to you"?? Stones first hit
I like this talk, indeed!Steen
About Jimmy Page...
I saw Led Zeppelin several times. Once in the mid-70's Robert Plant happened to remark between songs that Page had had a door slammed on his hand, breaking a finger. I'd noticed that Page was hitting a bottle of Jack Daniels pretty hard, but hadn't thought much about it--just put it down to a rock star's lifestyle. Plant saying that Page was drinking to deaden the pain put things in a different perspective. I and a friend spent the rest of the night trying to determine which finger had been broken. We never did figure it out. The man never missed a note.
Grey
EDIT: If he intends to fix a bad channel, he needs to learn to read a schematic. It's not impossible to fix something without that skill, but it definitely makes things more difficult. No time like the present to start learning.
I saw Led Zeppelin several times. Once in the mid-70's Robert Plant happened to remark between songs that Page had had a door slammed on his hand, breaking a finger. I'd noticed that Page was hitting a bottle of Jack Daniels pretty hard, but hadn't thought much about it--just put it down to a rock star's lifestyle. Plant saying that Page was drinking to deaden the pain put things in a different perspective. I and a friend spent the rest of the night trying to determine which finger had been broken. We never did figure it out. The man never missed a note.
Grey
EDIT: If he intends to fix a bad channel, he needs to learn to read a schematic. It's not impossible to fix something without that skill, but it definitely makes things more difficult. No time like the present to start learning.
Nope! Coverdale/Page were never anything but schoolgirls rock! If you listen to early Led Zep, you will find very serious Blues. I would call it "Acid Blues" but I dont know if the danish words does it? Take a listen to "Dazed and confused" and you will know what I mean
Happens to be one of my absolute greatest favourite songs ever. Led Zep did give a greatlive version of the song on "How the west was won" I cant help thinking what great luck it was, that Jimmy Page stumbled over those tapes. One of the best performances ever seen, by any rate. I have loads more to come
Steen
Man, I wish I did. I did see some of the other old stars though. Talking about the Blues, I did see John Mayall several times
I wont drag this around, but it was ofcourse, Muddy Waters homeboy, Bassplayer Willie Dixon!
Who else could have written a song like that?? Dixon wrote a lot of Muddy's hits! He had the Urban sound that really hit, those days!.
I feel like pointing out one more song, Namely "You shook me" Written by the incredible pair; Willie Dixon and J.B. Lenoir, it turned out to be one of the greatest songs ever made! J.B. Lenoir unfortunately died in early years! I am certain that he would have made a great impact on the music scene. His songs does live on though. Especially "You shook me" interpreted by Led Zeppelin, on Led Zep 1. Listen to it, and be amazed!
Steen
Naah, I am gonna find a newer shining specimen for myself Wasnt that a bit southern sounding? I am just practising!
It seems that all my friends likes Threshold, one has Stasis 2, one has S150, one has S200, one has 400A (the one I am looking to put my hands on) He...he....
Bluesman, my middle name. I have a "Hellhound on my trail"
Steen
Wasnt that a bit southern sounding? I am just practising!It seems that all my friends likes Threshold, one has Stasis 2, one has S150, one has S200, one has 400A (the one I am looking to put my hands on) He...he....
Bluesman, my middle name. I have a "Hellhound on my trail"
Steen
And there I was thinking that it was the Hound of the Baskervilles.
I have a love/hate...strike that...love/distrust thing about cascodes. I will freely grant that there are times when they're necessary, such as Nelson's 'wasting of volts' or reduction of capacitance. But I still prefer not to use them if I don't have to. Note that three out of the six circuits that I'm working on at the moment use cascodes, but that doesn't mean that I don't grumble under my breath every time I look at the schematics.
Grey
I have a love/hate...strike that...love/distrust thing about cascodes. I will freely grant that there are times when they're necessary, such as Nelson's 'wasting of volts' or reduction of capacitance. But I still prefer not to use them if I don't have to. Note that three out of the six circuits that I'm working on at the moment use cascodes, but that doesn't mean that I don't grumble under my breath every time I look at the schematics.
Grey
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.