widowmaker said:
from personal experience,I know that NP don't make difference between mail addys,domains ,are you known on DIY or not.....
just a thought-he recently changed ISP,mebbe some sort of spam filter was in action (it happens all the time);
or-if you examine his post again (and that is often needed with NP
) I have impression that his mail to you is maybe bounced...dunno for sure.....
I don't currently employ a spam filter, each piece of mail is
actually glanced at, and since Network Solutions is now the
host, I don't expect future difficulties.
actually glanced at, and since Network Solutions is now the
host, I don't expect future difficulties.
Nelson Pass said:
woa! (blue car!) 😉
so-even I can send you personal e-mail ,with another one brilliant idea
nah....
forum is good enough 😉
Nelson Pass said:
We talking about SE JFET amp -
I had (and still have) a few ideas (not only for jfet amp) ...
but...
It doesn't matter anymore...
F3
After the Ver 8 Zen light, I started on a Ver 9 and before I could finish, the Firstwatt JFET F3 amp was released so i thought I would wait until Mr. Pass published the schematic. Here are some tips that might be useful to others building the F3. I used the Ver 9 PD boards for this project and modified them for the F3.
The JFETs were measured as per the Ver 9 article. The JFETS I used measured 1.02 volts across the 1 ohm source resistor. I adjusted P1 to get half the supply at the output and 2.5 volts Drain to Source on the JFET. Then I hooked up the distortion meter and adjusted the source resistor for the minimum distortion. The source resistor turned out to be about 1 ohm. When I tried to adjust for half the supply voltage at the output I couldn't get there. I was short a couple of volts. I changed R12, 10K to 15K and put in a 10K pot. at P1. Now I could make the adjustment.
After adjusments on P1 and the Aleph CCS P2, I measured .0126% at 1 watt @1KHz. I ended up with 1.5 VDS on the JFET. At .1 watt the distortion was .003% just what Mr. Pass had published.
Listening comes after I get the other board changed to the new values. Oh who am I kidding, I will have to listen to just one channel. I can't wait for the other channel!
Thanks Nelson for the great articles. With out them I would not have built so many amps.
First Pass DIY amp built in 1990.
BDP
After the Ver 8 Zen light, I started on a Ver 9 and before I could finish, the Firstwatt JFET F3 amp was released so i thought I would wait until Mr. Pass published the schematic. Here are some tips that might be useful to others building the F3. I used the Ver 9 PD boards for this project and modified them for the F3.
The JFETs were measured as per the Ver 9 article. The JFETS I used measured 1.02 volts across the 1 ohm source resistor. I adjusted P1 to get half the supply at the output and 2.5 volts Drain to Source on the JFET. Then I hooked up the distortion meter and adjusted the source resistor for the minimum distortion. The source resistor turned out to be about 1 ohm. When I tried to adjust for half the supply voltage at the output I couldn't get there. I was short a couple of volts. I changed R12, 10K to 15K and put in a 10K pot. at P1. Now I could make the adjustment.
After adjusments on P1 and the Aleph CCS P2, I measured .0126% at 1 watt @1KHz. I ended up with 1.5 VDS on the JFET. At .1 watt the distortion was .003% just what Mr. Pass had published.
Listening comes after I get the other board changed to the new values. Oh who am I kidding, I will have to listen to just one channel. I can't wait for the other channel!
Thanks Nelson for the great articles. With out them I would not have built so many amps.
First Pass DIY amp built in 1990.
BDP
Re F3
I took a distortion measurement with a source resistor selected from the graph Mr Pass had for Vgs vs source resistance. The JFETS that measured 1.02 volts in the test setup would require a slightly less than 1.5 ohm source resistor for R5, (R3 for Ver 9). I used a 1.5 ohm. When the output voltage was adjusted for half the supply the VDS of the JFET was 2.46 volts and the 1 watt distortion measured .037%, not too bad.
Anyone else building the F3? Besides Mr Pass!
I took a distortion measurement with a source resistor selected from the graph Mr Pass had for Vgs vs source resistance. The JFETS that measured 1.02 volts in the test setup would require a slightly less than 1.5 ohm source resistor for R5, (R3 for Ver 9). I used a 1.5 ohm. When the output voltage was adjusted for half the supply the VDS of the JFET was 2.46 volts and the 1 watt distortion measured .037%, not too bad.
Anyone else building the F3? Besides Mr Pass!
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