Re: Re: Cascode
Since Mad_K did not catch up yet, I reply to myself.
The BC550 base bias voltage divider got some additional filtering and the collector voltage had to go higher. I want to know more of Mad_K's subjective impressions about the cascode performance boost in this kind of circuit.
salas said:
Since Mad_K did not catch up yet, I reply to myself. The BC550 base bias voltage divider got some additional filtering and the collector voltage had to go higher. I want to know more of Mad_K's subjective impressions about the cascode performance boost in this kind of circuit.
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Maybe your sound stage came back as you knew it after they warmed up and played for a while? Also if you don't get very good matching for VDS on all FETs after 30mins (the stronger their Beta, the easier the variation for current), they are going to slightly mismatch the level between channels. Not good for stereo perception. Maybe you can trim for VDS matching with very little value different Rs.
ricardo:
try the site's search function.
doing so yields this link as one example:
http://www.diyaudio.com/forums/showthread.php?postid=1626063#post1626063
good luck!
mlloyd1
try the site's search function.
doing so yields this link as one example:
http://www.diyaudio.com/forums/showthread.php?postid=1626063#post1626063
good luck!
mlloyd1
RCruz said:
Ricardo: Here is a link to an article that explains in pretty basic language how the JFET works and how to measure Idss.
http://w7zoi.net/jfet101.pdf
http://w7zoi.net/jfet101.pdf
mlloyd1 said:
jazzzman said:
nicoch46 said:+9v on drain ,tester on mA beetwen
gate and source on gnd
for good match what is important is the time, more are better, 15-30minute
becouse the idss after five start to go up and down .........
Thank you very much...... As I am quite new to these subjects and considering the high tech conversations I read in this thread, I really was afraid to ask...
Now I will study the matter and report to you latter.
Regards
Ricardo
I have a couple of pretty dumb questions. Please don't kick me off the forum but:
(1) What kind of capacitors are best to use (it looks like something pretty exotic is used in Mad-K's picture (see post #2 above)); and
(2) Is there a common ground between the left and right channels?
Thanks,
Jazzzman
(1) What kind of capacitors are best to use (it looks like something pretty exotic is used in Mad-K's picture (see post #2 above)); and
(2) Is there a common ground between the left and right channels?
Thanks,
Jazzzman
same gnd as madk share ,but separate are better
gnd in-out rca/ in-pcb , connect out-pcb gnd only on pcb to avoid loop
psu are important too , good reg ,tray two minireg from ska-audio ....and optivol if you need a pot ...with this one you can remure the last 100k and caps are only 1uf ......
gnd in-out rca/ in-pcb , connect out-pcb gnd only on pcb to avoid loop
psu are important too , good reg ,tray two minireg from ska-audio ....and optivol if you need a pot ...with this one you can remure the last 100k and caps are only 1uf ......
Hinicoch46 said:+9v on drain ,tester on mA beetwen
gate and source on gnd
for good match what is important is the time, more are better, 15-30minute
becouse the idss after five start to go up and down .........
Why wait for 30 minutes... do we need the fet to heat up ?
Do fet´s become stable with temperature ?
Hegards
Ricardo