Have a look at Morgan Jones 4th Edition of Valve Amplifiers. In a balanced Phono for MC he compares the outs and ins of BJT- and Fet-Cascode,
You can have a look at amazon.
Reinhard
You can have a look at amazon.
Reinhard
V1, V2 or V3, V4 respectively form so called SRPP circuits,
the upper tube constituting plate load for the lower and at the
same time buffering.
I have the 3rd edition but i will get the 4th too. Excellent book.
So the Aloia is a BJT-Tube cascode with an SRPP on top.
So the Aloia is a BJT-Tube cascode with an SRPP on top.
http://www.amazon.de/Valve-Amplifie...=UTF8&qid=1326372976&sr=1-2#reader_0080966403
You can have a look here, page 629 ff,
Reinhard
You can have a look here, page 629 ff,
Reinhard
Well no, the preview does not show the page.
Maybe you could post the schematic here?
Fair use applies.
tnx.
_-_-bear
The only concern I have with this sort of cascode is the introduction of another power supply, and the possibility of its noise or sonic effect (some people don't believe in that...) could be an issue. I do not know that answer... I posted to JC's blog on that, but the comment/question "went away"... so again I do not know.
_-_-bear
Probably someone doing something in industry or the government... but as a front end in a phono stage mine pre-dated Arthur's by something like two years. Thorsten can speak for himself - he's on here - but iirc his design was shown to the world after Arthur's.
No doubt the idea occurred to others, as it must be fairly obvious if I came up with it!! No doubt there... 😱
Now what year it was will take some thought... it was in the early to mid 90s, in that range. But to pin it down might require some detective work and reconstructing events that related to it. Not sure it is all that important?
_-_-bear
Yes, the folded cascode does not profit from the PSU regulation of the top element much. JC Morison claims it sounds better though. On the positive side there is some independence of choice concerning the idle current in the Fets so several can be paralleled even when the tube has less idle current then required in the Fet section.
Bear, it would be good to find out. I experienced here several times that people claimed to have invented what i posted and did not given them the credit they think they deserve.
Is that important ? I do not know but i do not like to make people uncomfortable.
Is that important ? I do not know but i do not like to make people uncomfortable.
Not all pages are shown.
Jump directly to the page, otherwise the actual limit will expire.
Joachim, yeah I see it, good point you can run the JFets current up independently.
But even so the extra supply makes me nervous. I guess one has to try it and see what the real world issues turn out to be (if any). The JFets still have to sink the tube's current, unless I am going blind again, or daffy. Both are entirely possible, even likely!
_-_-bear
But even so the extra supply makes me nervous. I guess one has to try it and see what the real world issues turn out to be (if any). The JFets still have to sink the tube's current, unless I am going blind again, or daffy. Both are entirely possible, even likely!
_-_-bear
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It's ok for me.
I am satisfied to have gotten to that point before Arthur did. 🙄
My only other claim to any fame at all is that I did a SE Mosfet DC coupled before Nelson Pass did it. Yay!
He did inspire me to come up with it because of his Zen idea.
Does any of this get me a plaque somewhere?
How about my footprints and handprints in some concrete in Hollywood?
Hmmm... Silicon Valley... nah...
_-_-bear
In the end it plays a role how it sounds. That can be done with various topologies.
I going into bipolars for phono and line lately. There are no more good P-channels and correctly designed a bipolar stage can have less distortion, at least in an open loop circuit.
For low impedances bipolars also have less noise.
I have no problems to share circuits at all. Sometimes i have to be quiet though because i do NDA work. That is where i make my living from mostly at the moment.
I going into bipolars for phono and line lately. There are no more good P-channels and correctly designed a bipolar stage can have less distortion, at least in an open loop circuit.
For low impedances bipolars also have less noise.
I have no problems to share circuits at all. Sometimes i have to be quiet though because i do NDA work. That is where i make my living from mostly at the moment.
Didn't work for me - dropped it into the search right away. NG.
Maybe someone can post the page or a screen print?
_-_-bear
