Dennis Hui said:
The TAA Audioxpress organization is very small and has always relied on simplicity. the original mag was printed on what appeared to be cheap paper run through a photo copier. Still it was great! If they say they got your subscription you will get the mag. They just dont move to quickly. Go to Peterborough , NH sometime --you'll see why!
apassgear said:
Papa says that ordinary unregulated PSU will work fine.
And, if we need suggestion, he would suggest ZV5 or ZV3 types.
I would suggest ZV5 type based on my experience with respect
to the "soft start" and the lower "modulation at low frequency".
🙂
sandstorm33 said:
Now that just isn't true -- it wasn't slick like "Audio" or "Radio and Electronics" or the ham radio magazines like QST, CQ or Ham Radio, but it certainly wasn't produced on a mimeograph or Xerox either -- I have every issue going back to 1970 -- and you would be surprised by the folks who contributed "in their youth" -- and are on DIYAUDIO.
Peterborough NH was pretty famous for some very fine magazines "in the day".
An externally hosted image should be here but it was not working when we last tested it.
jackinnj said:
You misread my intention..The Mag was great and Peterborough was a Publishers Colony...Content was most important and the contributors were (and are) the creme dela creme.. Odd you chose the Twin Twenty issue... mine is still in use in Rhode Island.
Nelson Pass said:
Nelson, thanks for posting the F5 schematic. It was a surprise. Sure, it's much more fun to read the article, but even a schematic is highly appreciated. Now that we have F5 here being the main topic, it's worth waiting for the buffer...( As you once said,it's better to concentrate on one thing at a time)...
Best Regards,
Vix
Thanks Nelson for the schematic and everyone else for their very useful comments. Nelson is a genius - and he is now talking about tweeks for the F5!! But what generosity!! Thanks a lot again.
Balaced alternative
Conceptually, this should work, even if there is no balanced source (pre) available.
"Current Feedback" to the sources of J-Fets, as the F5. Don't know if it would count as X-ed in this case.
Anyone to comment?
Deriving the "voltage feedback" solution (as per susy patent, to the gates) will be trivial for you a-Pass-ionados.
Ciao, Tino
Conceptually, this should work, even if there is no balanced source (pre) available.
"Current Feedback" to the sources of J-Fets, as the F5. Don't know if it would count as X-ed in this case.
Anyone to comment?
Deriving the "voltage feedback" solution (as per susy patent, to the gates) will be trivial for you a-Pass-ionados.
Ciao, Tino
Attachments
Re: Balaced alternative
The cross line does not exchange any signal voltage between the
left and the right. The reason is that the cross line is an potetial
zero point which is always the centre of vertically symmery in any
case with respect to the electrical potential. Just a thinking . . .
zinsula said:
The cross line does not exchange any signal voltage between the
left and the right. The reason is that the cross line is an potetial
zero point which is always the centre of vertically symmery in any
case with respect to the electrical potential. Just a thinking . . .
Attachments
Think current!
But this isn't important to the function.
Important is the current which flows from one half to the other wîth the signal. This current will change the voltage over R7/8/13/14.
In the F5, this current flows to ground, and here it flows to the other half of the circuit.
It is a diff pair....you have to connect the sources/emitters 😉
Tino
Not exactly.... voltage will sit at zero if the Idss of all JFETs is equal, otherwise it will be anywhere close zero. So far, you are right.Babowana said:
But this isn't important to the function.
Important is the current which flows from one half to the other wîth the signal. This current will change the voltage over R7/8/13/14.
In the F5, this current flows to ground, and here it flows to the other half of the circuit.
It is a diff pair....you have to connect the sources/emitters 😉
Tino
Re: Balaced alternative
With some value adjustments, this will presumably work, but it is
not an X topology.
zinsula said:
With some value adjustments, this will presumably work, but it is
not an X topology.
F5 & PCB group buy
Mr Pass. Sorry to read you hurt yourself in weightlifting x serie. Hope you're recovering well. Thanks for the new F amp, neat design in it simplicity. Single question will FirstWatt build it or will there the opportunity for a PCB group buy ? Regards
Mr Pass. Sorry to read you hurt yourself in weightlifting x serie. Hope you're recovering well. Thanks for the new F amp, neat design in it simplicity. Single question will FirstWatt build it or will there the opportunity for a PCB group buy ? Regards
Balanced Amp
Here is a design that I have worked over a year ago, the main difference between this and a balanced F5 is the input mosfets and the biasing circuitry.
I have tried JFETs in the simulation but i can not seem to get the same gain as a mosfet (so higher distortion) and the source impedance is not as low (so lower bandwidth). But then I didn't try the 2SK370 and 2SJ108.
Cheers
Tim
Here is a design that I have worked over a year ago, the main difference between this and a balanced F5 is the input mosfets and the biasing circuitry.
I have tried JFETs in the simulation but i can not seem to get the same gain as a mosfet (so higher distortion) and the source impedance is not as low (so lower bandwidth). But then I didn't try the 2SK370 and 2SJ108.
Cheers
Tim
Attachments
As I haven't made it to the bookstore....
what is the supply voltage? Is it similar to the F4 or wildly diferent?
Thanks,
C
what is the supply voltage? Is it similar to the F4 or wildly diferent?
Thanks,
C
I was thinking it might be economical to build the PS into a seperate enclosure and tap off of it Naim Style for the various Fx amplifiers.
What do you guys think? Is a possible, relevant, and viable option? More interested in the last 2 options as most things are possible.
C
p.s. I didn't take any traffos. Old Threshold knobs though, and awesome heatsinks!
What do you guys think? Is a possible, relevant, and viable option? More interested in the last 2 options as most things are possible.
C
p.s. I didn't take any traffos. Old Threshold knobs though, and awesome heatsinks!