You skating on thin ice, Michael. I can try symasym in class A. According to my experience good low distortion class A amp or error correction amp had always smoother highs and mids than any BJT class AB amplifier.
I would also like to try ClassA, but i have no adequate heatsinks right now... It will show immediately if these even harmonics have a positive or negative effect, or are even too small to have sonic effect.
???
I just said, no big benefit, not none... At least symasym can compete with DoZ. (For my taste of course)
For perfect reproduction of trebles i would always go ClassA.
Mike
PMA said:
???
I just said, no big benefit, not none... At least symasym can compete with DoZ. (For my taste of course)For perfect reproduction of trebles i would always go ClassA.
Mike
Hi MikeB,
I am going to run your symasym in Class-A with IGBT's at the output....
Lets see what is the outcome.....
K a n w a r
I am going to run your symasym in Class-A with IGBT's at the output....
Lets see what is the outcome.....
K a n w a r
IMHO IGBT is special type of thyristor with divided kathode whitch is surrounded with G electrode for fast and safe switch-off.
Well - I have set iddle current of the symasym at 500mA. So it works up to 4W in a class A, for 8 ohm load. The symasym is no exception, it sounds better with high iddle current. As said, smoother highs and mids.
MikeB said:
😀 six and half inches 😉
Just kidding, how was I supposed to answer? Like low distortion class A amplifier 😉.
Pavel
making boards
Thought I'd build this amp with home-made boards. The print I get measures ~73.5mm x 99 mm (measurements from the border of the rectangle). Does this sound right?
Thanks,
SteveA
Thought I'd build this amp with home-made boards. The print I get measures ~73.5mm x 99 mm (measurements from the border of the rectangle). Does this sound right?
Thanks,
SteveA
Hi everyone,
I ran the IGBT's at 1A idle with +-25VDC rails....The Treble heard was full of sparkle...clear & loud enough to power up my Selenium HF Horns....Fantastic transperancy....
K a n w a r
I ran the IGBT's at 1A idle with +-25VDC rails....The Treble heard was full of sparkle...clear & loud enough to power up my Selenium HF Horns....Fantastic transperancy....
K a n w a r
Hi Steve, your dimension are perfectly right !
Hi Pavel, does it A: sound sligthly better (barely audible), B: quite a difference, or C: WOW, what a difference ? 😀
Kanwar, which IGBTs did you use ?
Obviously, symasym is very sensible with it's outputstage, choice of bias and outputdevices have much impact on the sound, maybe it's time to add some EC ?
Mike
Hi Pavel, does it A: sound sligthly better (barely audible), B: quite a difference, or C: WOW, what a difference ? 😀
Kanwar, which IGBTs did you use ?
Obviously, symasym is very sensible with it's outputstage, choice of bias and outputdevices have much impact on the sound, maybe it's time to add some EC ?
Mike
MikeB said:Kanwar, which IGBTs did you use ?
Obviously, symasym is very sensible with it's outputstage, choice of bias and outputdevices have much impact on the sound, maybe it's time to add some EC ?
Mike
Hi MikeB,
I have used APT100GF60LVR in Quasi-complementary scheme........
K a n w a r
Dear Pavel...be carefull when you sit over a chair!
Six and half inches?...Universal, International size of...ahahaha!...
A Pencil!
Be carefull, as there are problems related positioning...as the chair can be inverted, or some object than may hit the chair first can be, by accident, in the opposite position...hehe
Sorry, i do not know how to read Englandisher good...is it the board size?
Hey Pavel, please, do not answer here....ahahahha!
hehe!
Carlos
Six and half inches?...Universal, International size of...ahahaha!...
A Pencil!
Be carefull, as there are problems related positioning...as the chair can be inverted, or some object than may hit the chair first can be, by accident, in the opposite position...hehe
Sorry, i do not know how to read Englandisher good...is it the board size?
Hey Pavel, please, do not answer here....ahahahha!
hehe!
Carlos
Hi UWE, Chuck and MikeB:
Since Symasym uses complimentary pair of output transistors, could it be that 1/2 of 2.236amps bias current will be sufficient to drive 20 watts in class A?
Pavel:
Do you plan to run it in class A or keep it in class AB? I am curious to know too. Of course I can always wait until I finish my unit and try it myself. All I need is a high velocity fan blowing at the heatsink. A trick I learned from my old Dynaco 410 power amp.
Since Symasym uses complimentary pair of output transistors, could it be that 1/2 of 2.236amps bias current will be sufficient to drive 20 watts in class A?
Pavel:
Do you plan to run it in class A or keep it in class AB? I am curious to know too. Of course I can always wait until I finish my unit and try it myself. All I need is a high velocity fan blowing at the heatsink. A trick I learned from my old Dynaco 410 power amp.
Hi Tim,
I can try symasym in pure class A (biasing like 1.5A or so), as my case and heatsinks are designed for true class A amplifier.
But I do not intend to operate this amplifier in a "hot stove" mode. I also do not expect great sound difference when switching bias from 0.5A to 1.5A. The reason is that even now (up to 4W class A) the amp mostly works in class A for music signal, only seldom peaks will have higher power.
Pavel
I can try symasym in pure class A (biasing like 1.5A or so), as my case and heatsinks are designed for true class A amplifier.
But I do not intend to operate this amplifier in a "hot stove" mode. I also do not expect great sound difference when switching bias from 0.5A to 1.5A. The reason is that even now (up to 4W class A) the amp mostly works in class A for music signal, only seldom peaks will have higher power.
Pavel
Good point there Pavel. At loud passages, we may not notice the difference that much anyway. Thanks for your answer.
