Even halogen sticks (1500 w each/ 220 v though) look very nice 🙂
http://www.diyaudio.com/forums/pass-labs/91168-diy-f2-clone-15.html#post1145315
http://www.diyaudio.com/forums/pass-labs/91168-diy-f2-clone-15.html#post1145315
I received yesterday the R085 depletion JFet , thank you again Tea-Bag .
Today I insert them in the circuit with the CCS , needed a negative voltage on the gate ( about 3 volt ) , set the current at about 1,8 amps , rail voltage 30 volt .
And it works succesfully .
Today I insert them in the circuit with the CCS , needed a negative voltage on the gate ( about 3 volt ) , set the current at about 1,8 amps , rail voltage 30 volt .
And it works succesfully .
Yes , of course , probably tomorrow . I am just going to vary the value of the CCS power resistor , and also would like to try a source resistor for the JFet of 1.2 ohm instead of 1 . The gain with the new device , is slightly greater than the Dmosfet version .
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OK the schematic in this post represent the simple modifications to the previous circuit , which was working with depletion Mosfet , now with the Depletion JFet R085 .
As built . And , of course , the schematic doesn't show it , but an input capacitor is needed in this circuit .
As built . And , of course , the schematic doesn't show it , but an input capacitor is needed in this circuit .
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with an external power supply I have ; stabilized and variable ... its like a laboratory box .
Thanks,
One for both channels?
This is starting to look more like the ArchNemesis.
Presumably you will be driving this with a capacitively coupled source, since
the negative voltage will appear at the input.
😎
the negative voltage will appear at the input.
😎
I didn't had much time to listen to it , but from the beginning I would say " different " and " against the noise " are the words that came to my mind .
As you know I did enjoy a lot the D mosfet De lite itself ; will see, I might be tempted to try back the light bulbs with the Jfet .
🙂
By the way this is how my JFET amp prototype looks like , this time with the light bulb .
The light bulb I believe is about 18 ohm or so .
It sound very good , probably better in my taste than the CCS version , don't know really .
The voltage now is 30 volts , and I am wondering how high it can be set .
thanks
The light bulb I believe is about 18 ohm or so .
It sound very good , probably better in my taste than the CCS version , don't know really .
The voltage now is 30 volts , and I am wondering how high it can be set .
thanks
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Thanks Stefano. This is valuable information for me at the moment. Interesting, that you prefer the bulbs to the CCS. IMO generally less distortion is just the second step to enjoyable sound. The first step would be a "composition" of the involved amounts of particular non-linear distortion which generates a sound, that the brain is going to interpret as "approximately natural" or at least as "mostly charming". In other words: A composition, where the emergence of listening fatigue is mostly deferred.
So, why you shouldn't get "better" results with just the bulbs? The ear wants what the ear wants.
So, why you shouldn't get "better" results with just the bulbs? The ear wants what the ear wants.
r085 question
after testing last evening the attached s circuit some questions
in this setup the r085 produces only 1,5W before clipping tried with lab supply different settings and a symmetric clipping was around 24V supply and 1,5Amps giving a output at 8 Ohms with 25Vss making some 8W
a first mono test sounded not so nice ( a lot of distortions when asking for higher levels without distortions maybe 0,5 W was possible)because the source was a emu dac with transformer output and with too high output impedance.
question-did anyone build the fig 7 in the delite articel-cant´t believe that this works with the 1Ohm source resistor-maybe papa can explain-any ideas to lower input capacitance?
the same setup but with a LL2733 in the source and drain to +24V gave no gain but my dac could drive it easily and it sounded very sweet on my altec 605
after testing last evening the attached s circuit some questions
in this setup the r085 produces only 1,5W before clipping tried with lab supply different settings and a symmetric clipping was around 24V supply and 1,5Amps giving a output at 8 Ohms with 25Vss making some 8W
a first mono test sounded not so nice ( a lot of distortions when asking for higher levels without distortions maybe 0,5 W was possible)because the source was a emu dac with transformer output and with too high output impedance.
question-did anyone build the fig 7 in the delite articel-cant´t believe that this works with the 1Ohm source resistor-maybe papa can explain-any ideas to lower input capacitance?
the same setup but with a LL2733 in the source and drain to +24V gave no gain but my dac could drive it easily and it sounded very sweet on my altec 605
