I wondered that too because JFET's are symmetrical in construction. Each side of the gate channel is the same AFAIK.
Something is wrong, possibly short circuit or burned JFET(s) in your buffer.
Check carefully (without voltage applied) wiring and check all JFETs between D and S with an Ohmmeter.
In some JFET's D and S are indeed interchangeable, but it's not true for all JFET's and under all conditions!
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J3 22R8
J4 25R2
J2A 41R6
J2B 46R2
Rs used 10R
J2A
Idss 7,54mA
Vp 0,76V
J2B
Idss 7,47mA
Vp 0,66V
J4 25R2
J2A 41R6
J2B 46R2
Rs used 10R
J2A
Idss 7,54mA
Vp 0,76V
J2B
Idss 7,47mA
Vp 0,66V
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Merlin,
do you have a CRC Filter in your PSU? During startup the buffer draws quite some current until it settles to the designed bias current. I have the same (well not that extreme) with my SMD Calvin buffers. However after a few seconds it adjusts to expected behaviour.
Just a thought...
do you have a CRC Filter in your PSU? During startup the buffer draws quite some current until it settles to the designed bias current. I have the same (well not that extreme) with my SMD Calvin buffers. However after a few seconds it adjusts to expected behaviour.
Just a thought...
I'm well aware of that.
My point being if enough people have compared the Siliconix 4391's to other brands of 4391's, then there could be some truth to it.
Care sharing a schematic of this LTP style jig?
I've searched both here and Google and couldn't find one.
Thanks...
Joshua, I really don't know. It may have been one of the headphone forums or AudioKarma where someone made the statement that the Siliconix 4391's were better than the Fairchilds.
Maybe dodo can shed some light on the differences since he made the statement the "Fairchilds are much worse than Vishay 2N4391".
Maybe dodo can shed some light on the differences since he made the statement the "Fairchilds are much worse than Vishay 2N4391".
It's ALIVE!
I finally got one channel of this buffer completed this evening.
I only built one channel initially to see if it was going to play music or go up in smoke.
Much to my surprise it does play music. I was able to get the DC offset between 0 and 1mv after adjusting the trimmer pot.🙂
I'll assemble the other channel and see how it sounds connected to my Adcom 535II amplifier.
Soldering those little SMD resistors does take some time.
I finally got one channel of this buffer completed this evening.
I only built one channel initially to see if it was going to play music or go up in smoke.
Much to my surprise it does play music. I was able to get the DC offset between 0 and 1mv after adjusting the trimmer pot.🙂
I'll assemble the other channel and see how it sounds connected to my Adcom 535II amplifier.
Soldering those little SMD resistors does take some time.
Do you still have 1.25 V between ADJ and OUT of the LM317/337?
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Hi Felipe,
Connect only 1 channel at a time and measure the current consumption of each channel.
Also, do you have R9 connected?
Saying that "A" is better than "B" without specifying in what it's better and in what application it's so, is meaningless.
I finally got one channel of this buffer completed this evening.
I only built one channel initially to see if it was going to play music or go up in smoke.
Much to my surprise it does play music. I was able to get the DC offset between 0 and 1mv after adjusting the trimmer pot.🙂
I'll assemble the other channel and see how it sounds connected to my Adcom 535II amplifier.
…
Well done.
