pinnocchio,
the backend-PSU that you are using does not differ much (does it at all?) from the "PSU" that I have done a layout for on the FC-100 PCB.
Keep in mind: you do not need a regulated power-supply, nor does the PSU need to be "silent" and accurate!
What you need is: current, immediately, when it is and how much is demanded.
The demand for current shall not be delayed by filters or whatsoever.
The frontend power-supply should be very stable, accurate and silent though.
Best regards - Rudi
the backend-PSU that you are using does not differ much (does it at all?) from the "PSU" that I have done a layout for on the FC-100 PCB.
Keep in mind: you do not need a regulated power-supply, nor does the PSU need to be "silent" and accurate!
What you need is: current, immediately, when it is and how much is demanded.
The demand for current shall not be delayed by filters or whatsoever.
The frontend power-supply should be very stable, accurate and silent though.
Best regards - Rudi
Yes! Rudi, you are a absolutely right!
I don't even think that your design are not the best decision for FC-100.
Main reason that I liked separated PCB from Project16, are possibility to use big
4pole capacitors and eventualy CRC...
This give me a idea to use in CRC filter KMH (or even SMH) Nichicon series for primary capacitors and Mundorf M-lityc (for example) after resistors...
But in your design Rudi, I like excellent ground topology, directly straight to the Output stage and speed...
Will try both to experiment.
@Telstar:
read all pages This power amp. design deserve this!
I don't even think that your design are not the best decision for FC-100.
Main reason that I liked separated PCB from Project16, are possibility to use big
4pole capacitors and eventualy CRC...
This give me a idea to use in CRC filter KMH (or even SMH) Nichicon series for primary capacitors and Mundorf M-lityc (for example) after resistors...
But in your design Rudi, I like excellent ground topology, directly straight to the Output stage and speed...
Will try both to experiment.
@Telstar:
read all pages This power amp. design deserve this!
Hm I'm afrad it is not only to read.OK, it’s only 30 pages after all
This is mandatory if you want to understand amplifier:
RMI-FC100, a single stage audio power amplifier by author Roender! 133pages only, but precious...
and Rudi's "Roender's FC-100 prototype and builder's thread" not more than 101p. and essential!
and even small "GB For RMI-FC100 Parts"
and interesting for your fun: "RMI-FC100 MKII, single ended folded cascode VAS"
So you have a lot for serious reading
Anyway, for possibly balanced input to FC-100:
Input transformer? Or other solution? Anyone with that experience?
Because for preamp I'm planing to orient to some good balanced tube design.
In my preliminary research and emotional predilection are for Allen Wright's RTP (FTP5 are good contender to)
or some transformer coupled... parafeed may be.
Do not thinking for preamp with essential gain stage. 6dB is enough may be for FC-100.
Just trying to have best from "two worlds" if this is possible ever...
Thanks for the compliments!
For balanced input, you can use transformers from Lundahl, Jensen, etc...
There's also the electronic way using something like this :
THAT Receiver: Differential line receiver / preamp
The α24 fully-differential line amplifier
Hope this helps!
Do
It seemed too easyHm I'm afrad it is not only to read.
This is mandatory if you want to understand amplifier:
RMI-FC100, a single stage audio power amplifier by author Roender! 133pages only, but precious...
and Rudi's "Roender's FC-100 prototype and builder's thread" not more than 101p. and essential!
and even small "GB For RMI-FC100 Parts"
and interesting for your fun: "RMI-FC100 MKII, single ended folded cascode VAS"
So you have a lot for serious reading
Now I know what to do during Easter holidays, while listening to music.
Thanks Do,Thanks for the compliments!
For balanced input, you can use transformers from Lundahl, Jensen, etc...
I know well Lundahl's, even now I have in "closet" LL1674A and LL1544A lying around.
I just asked if someone have real trials with FC-100 and transformer coupling...
And yes, it's very dependable from preamp output impedance, reflected Z and etc. Not so easy "universe"...
By now I will reject semiconductor way
@jmmartins, please use 2SK170BL with IDSS > 9mA.
Refer to post #96 in Mihai's thread:
www.diyaudio.com/forums/solid-state/111756-rmi-fc100-single-stage-audio-power-amplifier-10.html
Regards - Rudi_Ratlos
Refer to post #96 in Mihai's thread:
www.diyaudio.com/forums/solid-state/111756-rmi-fc100-single-stage-audio-power-amplifier-10.html
Regards - Rudi_Ratlos
I'm happy almost like you!Love this amplifier!
Did you change anything from original?
Excluding some different from BOM parts (Takman resistors and GPD series capacitor in shunt regulator) and back-end PSU arangement?
Did you change anything from original?
Excluding some different from BOM parts (Takman resistors and GPD series capacitor in shunt regulator) and back-end PSU arangement?
In the shunt PCB, I believe there was an error on the traces for one of the MKP capacitors that was not connecting anywhere for one of the pads. I'm not too sure if it was on this shunt but it rings a bell. Please double check this.
I kept all the same values for everything but partly used some of the parts I like to use in most of my builds. You noticed the more important ones. I'm thinking of changing the input cap (which is a Panasonic) to a Jantzen Supreme or Jantzen Silver. I have them in stock so I will try. The only thing to watch with these is the possible pickup of RFI due to them being much larger and away from the PCB ground plane. I usually put some copper tape around them and solder a cable on the tape and link it to a star ground on the amp PCB.
All the best!
Do
I'm not happy. Because I have to build it yet lol
Then you really must!
You can ask author of development Rudi_Ratlos. Very helpful guy, or look in original roender's theme for FC-100.Are source files publicly available somewhere in this thread?
Good luck in this nice FC-100 journey!
Kiril
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