HI Salas I have put a 7,22 idss without resistor , and I have 6.7 Vds ,too low ?
sound good ,but are some day that I don't play ...nexts on second stage
sound good ,but are some day that I don't play ...nexts on second stage
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.
Attachments
Thanks Salas
I have done the second stage ,all sound better 🙂 I feel a little lower sound stage but not sure ....
I have done the second stage ,all sound better 🙂 I feel a little lower sound stage but not sure ....
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.
only for 8min but 7,233 7,230 .... i thinks in the end the soundstage as same GR , but when I have a mix bl on 1stage and gr on second the speaker are totally disappeared with a touch 2HD romantic... nice.
But I 'm happy for gain and sound ,not arrived cartridge and minireg
But I 'm happy for gain and sound ,not arrived cartridge and minireg
I see that amplabs.com has 2sk170bl at 20 pieces for $20. Are 20 pieces enough to ensure that I can get 4 pieces that match? I have no idea how variable the Idss is on these things.
jazzzman said:
Hi jazzman
Could you please point me a simple way to match fets.... maybe measuring Idss ?
I am building one phono stage with the help from Salas but I am quite new to these matters.
Hope I do not bore anyone with my question
Regards
Ricardo
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
+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 .........
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 .........
mlloyd1 said:
jazzzman said:
nicoch46 said:
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
for resitor use Dale ,Prp are good too than if you want play with more exotic
caps I use vishay mkp 1837 on riaa but you can try polystyrene -mica
for serial caps 100nf and out clarity caps SA but the same you can play whit more exotic.....
caps I use vishay mkp 1837 on riaa but you can try polystyrene -mica
for serial caps 100nf and out clarity caps SA but the same you can play whit more exotic.....
Thanks, Nicoch46. How about the ground? Do you have to keep left and right channels separate, or can they share a common ground?
Jazzzman
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 ......