I would find this more important than the blowtorch blueprints.anatech said:
Except we are at cloneaudio.com now? 😕
regards
Jürgen
Referring to the JC-80 schematic published in #1822:
It is pretty good, but it has a number of typos.
For example: The 100 ohm resistors in the middle of the page are OUTPUTS, not ground.
The 100K resistors in the middle of the page are actually 1meg ohm and are connected to ground, NOT the output.
The source degeneration resistors in the second stage are really 24 ohms.
Many of the 10K resistors that appear to go nowhere, are actually 1 meg and go to servo inputs.
Later units used the 2SK240, 2SJ75 dual fets, rather than the 146, J73. The newer devices were lower distortion in this design.
This design had a 10K volume control pot in front, so ultra low design was not as important.
It is pretty good, but it has a number of typos.
For example: The 100 ohm resistors in the middle of the page are OUTPUTS, not ground.
The 100K resistors in the middle of the page are actually 1meg ohm and are connected to ground, NOT the output.
The source degeneration resistors in the second stage are really 24 ohms.
Many of the 10K resistors that appear to go nowhere, are actually 1 meg and go to servo inputs.
Later units used the 2SK240, 2SJ75 dual fets, rather than the 146, J73. The newer devices were lower distortion in this design.
This design had a 10K volume control pot in front, so ultra low design was not as important.
Hi John,
Thank you for the details on the JC-80 schematic. What were the part numbers for the MOSFET second stage transistors? Any recommendations for subs for any of the transistors for us experimenters? Thank you again.
Graeme
Thank you for the details on the JC-80 schematic. What were the part numbers for the MOSFET second stage transistors? Any recommendations for subs for any of the transistors for us experimenters? Thank you again.
Graeme
While you are both present, wouldn't you think JC's BT preamp would be a nice match for NP's F4 power amp?
;-)
regds
RK
;-)
regds
RK
Fairchild no longer lists the IRF510/9510. They cross reference to the FQP7N10 (N-ch) and FQP5P10 (P-ch). The datasheets indicate that they are comparable parts.
Grey
Grey
Let's be nice, I respect Nelson, and I would hope that Nelson respects me. We both make good designs. The JC-3 is a very old, but pretty good design. It is low in parts count. It is very low power as well. It will mate well with virtually any solid state preamp. Vacuum tube preamps will have a problem with it.
Zen Mod likes to be contrarian in a very amiable way, so don't take him seriously. He is probably promoting his own high output preamp the Pumpkin....
OK, I saved you this time choky-now behave!
OK, I saved you this time choky-now behave!
john curl said:
I hold you both in high esteem (NP and JC), and my proposal was some kind of "best of both world" concept.
I have been the owner of two ML-2s, which as far as I understand is based on the JC-3. That was a grand machine to drive my old Quads, and also the ESL-63 later on.
Zen Mod said:
................
nope in this thread ;
...............
too late for edit......
I presume that BT , for those reading this thread known , in topology both vert. and hor. sym. jobbie ,with ~36V twice PS - must be capable to drive any sane power follower ,at least in class of F4 .
not that I think that my impression is of any significance in this thread.........
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