I suspect that Jfets can be brought to life if the circuit architecture around them allows for their inherent characteristics and I also suspect that in the the right system the B1 would sound just fine.
However, for me it's o/p impedance of 1000R would be enough to explain why some amps may sound a bit tame when partnered with it - I would prefer 10 - 50R
I believe it's down to the designer to design the "life" into a circuit.
Also, some systems / speakers already abound with "life" & excitement while others need all the help they can get.
I don't believe Jfets have some mystical lifeless quality that forever dooms any circuit / system they are used in to sound boring but, like any other component, they do need to be implemented well in a circuit and that circuit to be partnered well in a system.
mike
However, for me it's o/p impedance of 1000R would be enough to explain why some amps may sound a bit tame when partnered with it - I would prefer 10 - 50R
I believe it's down to the designer to design the "life" into a circuit.
Also, some systems / speakers already abound with "life" & excitement while others need all the help they can get.
I don't believe Jfets have some mystical lifeless quality that forever dooms any circuit / system they are used in to sound boring but, like any other component, they do need to be implemented well in a circuit and that circuit to be partnered well in a system.
mike
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And what is your feeling about Mosfets ?
About JFETs, may-be the problem do not come from them, but the way they are used ? They love to be polarized with a lot of quiescent current (chosen for that) and kept hot.
Often, too, and because the high Z of the gate, the gate resistance to ground is sometimes set at a hight value, so the input impedance..
But more current flow in signal wires better it is and charging more the previous preamp can change a lot the way it sound ?
They are supposed to be more linear than bipolars (more like a tube), is this "liveness" just less distortion or some small signal losses ? Or their different noise factor's curve ?
I had F5 in my system for a brief, and as far as I can remember it was a much different sound to SSA with laterals.
homemodder have a new thread
http://www.diyaudio.com/forums/soli...k-simple-symmetric-amplifier.html#post2879431
moderation
http://www.diyaudio.com/forums/soli...k-simple-symmetric-amplifier.html#post2879431
moderation
PauloPT, see post #1708 and see Lazy Cat reply. I think he wants to show the finished product first before offering the group buy. I think most of us here on this thread is looking forward to build this project and wants to hear how it sounds. It might be an amp to be considered " The Very Best Amplifier I Have Ever Hear!!!"
It might be an amp to be considered " The Very Best Amplifier I Have Ever Hear!!!"
It is.
Even my awfully inefficient speakers came alive when I played SSA through them. Beforehand, only my JLH could do this, but it had a volume limit for clean listening. SSA, on the other hand, sounded more and more cleaner and ALIVE as I turned the knob clockwise. I am building it again!
a.wayne,
I built the Lateral output version with BD139/140 VAS, +-24V Supply.
Lynk-> http://www.diyaudio.com/forums/solid-state/193923-simple-symetrical-amplifier-92.html#post2724491
I built the Lateral output version with BD139/140 VAS, +-24V Supply.
Lynk-> http://www.diyaudio.com/forums/solid-state/193923-simple-symetrical-amplifier-92.html#post2724491
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Hi. New to the thread I'm finding quite a bit to take in. It's fun to see all of the great ideas and try to follow the evolution and forks of the circuit. Great work guys! Knowing that even small things can be significant, it's easy to miss the thinking behind some of the details but I'm trying. Looking at the circuit in post 916 (with both PNP and NPN current boosters for each FET): Both types of transistors seem to be doing the same thing. Was the combination of both PNP and NPN boosters used to make the upper and lower output halves more inherently matched? I can see that the .22 Ohm resistors improve the behavior of the added bipolars. I was pondering whether it might be worthwhile to have the .22 Ohm resistors towards the supplies also include the FETs in the local feedback provided (to help linearize and match FET behavior) by moving the 1K cascode load resistors to the other side of the .22's (then going directly to the power supplies)? Then any drop across those .22 resistors would slightly reduce the FET drive. I've probably missed something, but figured I'd put the idea out there before I forgot about it.
LC,
The order of my VAS transistor has arrived, 2SA1707/2SC.
http://docs-asia.electrocomponents.com/webdocs/1002/0900766b810021b5.pdf
having 150Mhz response, high Hfe, seems suitable to as VAS.
What should I improve in my circuit other than having a driver and better VAS ?
(which transistor should i use as driver ? is MJE13032/33/34/35 enough or use MJL3201 better ? or other recommendation ?)
Given that have sufficient improvement, what value should i put on feedback resistor ?
The order of my VAS transistor has arrived, 2SA1707/2SC.
http://docs-asia.electrocomponents.com/webdocs/1002/0900766b810021b5.pdf
having 150Mhz response, high Hfe, seems suitable to as VAS.
What should I improve in my circuit other than having a driver and better VAS ?
(which transistor should i use as driver ? is MJE13032/33/34/35 enough or use MJL3201 better ? or other recommendation ?)
Given that have sufficient improvement, what value should i put on feedback resistor ?
Hi Sheldon
Quite possible but the more devices in parallel the less performance you get according to single one. Problem is very low Uce for BC550/560, gain matching selection, degeneration emitter resistors, TO-92 case not really suitable for thermall dissipation even if there are few in parallel, etc.
Better to use one of TO-126/TO-220 Sanyo/Toshiba high performace transistors.
Hi Esperado & Jay
First I have to say it's topology that matters to define the "sound" of an amplifier, than it's about the ingredients, spices used. To my opinion it is very important for an active device, to find out the most important role it's playing in certain position and than to search the most suitable device for the job. Of course this decision is of very subjective nature but nevertheless it is always worth to try different type of devices for the best end-result.
My suggestion for a power amplifier configuration would be high biased j-fet devices for the input zero voltage-gain buffer, BJT-s for the input differential gain stage and VAS, mos-fet-s for the ouput drivers and again BJT-s for the outputs.
For the future task I intent to try modern power SiC-fet devices, since I don't prefer output mos-fet-s.
Up to +/- 60 V as also specified with 63 V ELCO's voltage. But than do not use less than 4 ohm nominal speaker impedance per channel.
Hi Shaan
It is indeed an excelent amplifier as recognized by many. Have fun with new SSA project.
Regards Andrej
Maybe, it depends how many members would express sympathy for the group buy. It is matter of future discussion and the course of events in this thread.
Homemodder,
Regardless of what you think of the design, your inputs are judgmental and often offensive. You seem to subscribe to the belief that putting clever people down makes you look even smarter.
I think Andrej's work is excellent. Along with the outstanding pcbs from Alexx MM, Andrej has made the SSA very buildable and easy for DIYers. You too have contributed meaningfully before, lighten up and play the game. I find Andrej's view on devices and their relative positions very interesting, and I've been designing amps for many years and have seen most schematics. The quest for originality is mostly fatuous; nothing is new under the sun, but that is no reason to condemn golden oldies.
I know you have a good mind, you don't need to prove it, some of your comments in other threads are very constructive.
Andrej,
Swordfishy, Mikelm, Lineup and I ran a Group Buy for the FetZilla, and we have sold about 160 pcbs. There is no reason your SSA would not sell twice that, so I would encourage you to go for it....
Cheers,
Hugh
Regardless of what you think of the design, your inputs are judgmental and often offensive. You seem to subscribe to the belief that putting clever people down makes you look even smarter.
I think Andrej's work is excellent. Along with the outstanding pcbs from Alexx MM, Andrej has made the SSA very buildable and easy for DIYers. You too have contributed meaningfully before, lighten up and play the game. I find Andrej's view on devices and their relative positions very interesting, and I've been designing amps for many years and have seen most schematics. The quest for originality is mostly fatuous; nothing is new under the sun, but that is no reason to condemn golden oldies.
I know you have a good mind, you don't need to prove it, some of your comments in other threads are very constructive.
Andrej,
Swordfishy, Mikelm, Lineup and I ran a Group Buy for the FetZilla, and we have sold about 160 pcbs. There is no reason your SSA would not sell twice that, so I would encourage you to go for it....
Cheers,
Hugh
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Maybe, it depends how many members would express sympathy for the group buy. It is matter of future discussion and the course of events in this thread.
LC,
How many would you like
we are all waiting with baited breath and the SSA tree is getting very dangerously crowded... 
Andrej ---> We Are With You !!! No Mather How Many Storms may Come !!!
Dear
Andrej,
I Just Wonder To Speak Here For All The Good Will, Good Diy Spiritual Members,
Who Simply Admire Yours Great Heart - Soul - Unselfish Will . . . and Give . . .
To All Of Us Positive Sound Lovers . . . .
I truly Wish You A lot of Good Business Spirit
and Even More Nice & JoyFul Hobby Time
and Most of All,
I wish You As Much As Possible Tastefully Sound Listening Moments,
With Yours Soul & Spirit Inspired Designs, For Which Most Of Us We Are
Truly Thankful To Yours Genius Gifts Giving to the All
Audio Community
World-Wide
A. G.
Very efficiently spent time recently, regarding business and hobby
Some jerks will never learn their lesson, morons up to their ends.
Dear
Andrej, I Just Wonder To Speak Here For All The Good Will, Good Diy Spiritual Members,
Who Simply Admire Yours Great Heart - Soul - Unselfish Will . . . and Give . . .
To All Of Us Positive Sound Lovers . . . .
I truly Wish You A lot of Good Business Spirit
and Even More Nice & JoyFul Hobby Time
and Most of All,
I wish You As Much As Possible Tastefully Sound Listening Moments,
With Yours Soul & Spirit Inspired Designs, For Which Most Of Us We Are
Truly Thankful To Yours Genius Gifts Giving to the All
Audio Community
World-Wide A. G.
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