> Might be wrong, but looks like a JC topology?
If you read the article carefully, I immediately acknowledged the similarity to the JC-80 and gave the credit to John.
We did worked out the circuit ourselves before John published the JC80 schematics.
So like Nelson has to refer the F5X topology to ProFET, we do the same to the JC-80.
But the devils are in the details. And they will follow.
To answer your question directly, I personally like to include a ground return path of the outputs.
Especially when the input is a floated X or a H, like in the schematics in the article.
You can argue it is not necessary. Straightly speaking it is not.
But this is what I like. Hence it is optional.
Patrick
If you read the article carefully, I immediately acknowledged the similarity to the JC-80 and gave the credit to John.
We did worked out the circuit ourselves before John published the JC80 schematics.
So like Nelson has to refer the F5X topology to ProFET, we do the same to the JC-80.
But the devils are in the details. And they will follow.
To answer your question directly, I personally like to include a ground return path of the outputs.
Especially when the input is a floated X or a H, like in the schematics in the article.
You can argue it is not necessary. Straightly speaking it is not.
But this is what I like. Hence it is optional.
Patrick
I would venture to guess it's from PMA's interpretation of JC's Blowtorch (official circuit not published yet) embellished with jfet cascodes and F5 feedback to set the voltage gain.
9/23/2009:
http://www.diyaudio.com/forums/anal...rch-preamplifier-part-ii-147.html#post1930881
9/23/2009:
http://www.diyaudio.com/forums/anal...rch-preamplifier-part-ii-147.html#post1930881
The circuit in the link above is a Blowtorch variant with Zeroo Global Feedback (ZGF).
One goes about the design of a ZGF circuit quite differently to that with global feedback, though the topology might look the same at first sight.
This is the post from John I referred to :
http://www.diyaudio.com/forums/anal...c-80-ebay-pcbs-power-train-4.html#post3059976
You can see even the same feedback topology of the F5.
And since the schematics is dated 1983, you may also argue that the F5 is a derivative of the JC-80.
We set out to make a F5X low power version as preamp with TO220 output devices, and landed by happy coincidence at the JC-80.
(Our simulations and PCB layout dated back to 2011, before John published his schematics.)
So again, all credit to John.
Patrick
One goes about the design of a ZGF circuit quite differently to that with global feedback, though the topology might look the same at first sight.
This is the post from John I referred to :
http://www.diyaudio.com/forums/anal...c-80-ebay-pcbs-power-train-4.html#post3059976
You can see even the same feedback topology of the F5.
And since the schematics is dated 1983, you may also argue that the F5 is a derivative of the JC-80.
We set out to make a F5X low power version as preamp with TO220 output devices, and landed by happy coincidence at the JC-80.
(Our simulations and PCB layout dated back to 2011, before John published his schematics.)
So again, all credit to John.
Patrick
Part 2 of the article this weekend.
In the meantime, enjoy the thermal design articles.
http://www.diyaudio.com/forums/pass-labs/183362-f5x-euvl-approach-16.html#post3280044
Quite a few surprises, even for me .....
Patrick
In the meantime, enjoy the thermal design articles.
http://www.diyaudio.com/forums/pass-labs/183362-f5x-euvl-approach-16.html#post3280044
Quite a few surprises, even for me .....
Patrick
I wasnt suggesting that, just that the JC80 type circuit/s have been used by many as a headphone amp, so i'm sure this will too.
i'll build the DAO circlotron if/when you release the article for that version (may try the SE before then, or is this just the standard tailored version?), I have matched up most of the parts just never got around to building it (circ version), too many projects. mainly because it will require more test gear and time than I have available to find proper values/operating points based on the specific active devices I have in my possession.
i'll build the DAO circlotron if/when you release the article for that version (may try the SE before then, or is this just the standard tailored version?), I have matched up most of the parts just never got around to building it (circ version), too many projects. mainly because it will require more test gear and time than I have available to find proper values/operating points based on the specific active devices I have in my possession.
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Patrick,
Sorry by my intrusion on the thread and you are right I did not read the introduction on the pdf, my apology for that since I only looked at the schematic that just rang the bell and reacted.
I do appreciate your professional approach to circuits and impeccable work on your amplifiers.
My best wishes,
Antonio
Sorry by my intrusion on the thread and you are right I did not read the introduction on the pdf, my apology for that since I only looked at the schematic that just rang the bell and reacted.
I do appreciate your professional approach to circuits and impeccable work on your amplifiers.
My best wishes,
Antonio