Something is wrong. It should look better than that. Compare with THD shown in the log file.
But I don't understand what Esperado is trying to say 😱
I attach the simulation file and my bjt and mosfet. So, why the spectrum isn't clean?
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So is not a concern because the harmonics are below audible levels even if it's an almost continuum spectrum of harmonics?
Not the right place to explainaudible effects of harmonic distortions.
Nothing real after 100Khz, only FFT calculation artifacts. Absolutely normal.
No distortion you can hear after 20Kz neither.
Make a measurement at low frequency if you want to know high order harmonics inside the audible bandwidth.
And do not forget, it is just simulation, not real world.
Now, you decide if the level of distortion you can read up to 20Kz meet your goals.
But 0.02% is a good value for a power amp.
Nothing real after 100Khz, only FFT calculation artifacts. Absolutely normal.
No distortion you can hear after 20Kz neither.
Make a measurement at low frequency if you want to know high order harmonics inside the audible bandwidth.
And do not forget, it is just simulation, not real world.
Now, you decide if the level of distortion you can read up to 20Kz meet your goals.
But 0.02% is a good value for a power amp.
As Paulo said "so it is not a concern?". That's how it sounded like.
Many of us don't have a problem with H2. But with such graph the total HD will be not as good.
I don't have access to LTSpice (and my computer) for a few months now. But the graph seemed to show lack of bias.
I'm not saying that the graph is bad. What I'm saying is that I'm familiar with the amp simulation and what I have seen is better than 75dB. Actually, 75dB is below my standard.
I have been biasing latfet around 120mA-150mA. So may be this one is less?
I've been listening all day long to beautifull music with my SSA. The female voices are rendered with an unbeliveble presence and realism. And the piano notes are sweet and extended. Melody Gardot, Jane Monheit, Eliane Elias, Diana Krall, among others never sound so wonderful! Today is sunday but I had other things to do besides listening to the SSA. Guess what, the day is over and I just couldn't switch off the amplifier!
I'm going to build this amp the best I know how, with nice parts, nice chassis, nice psu. I'm waiting for some parts including the fets. I ordered these from here:Mosfets I Hope they aren't fakes.
Any sugestions about how to build a nice power supply for the SSA?
I'm going to build this amp the best I know how, with nice parts, nice chassis, nice psu. I'm waiting for some parts including the fets. I ordered these from here:Mosfets I Hope they aren't fakes.
Any sugestions about how to build a nice power supply for the SSA?
An other positive review about the SSA topology:
http://www.diyaudio.com/forums/elek...cendo-power-amplifier-1982-a.html#post3316820
and , in a private message:
"Thank you very much for putting together the article on the Crescendo. I am very excited with the results I am getting. As you say it must be one of the best amplifiers in the world now!"
http://www.diyaudio.com/forums/elek...cendo-power-amplifier-1982-a.html#post3316820
and , in a private message:
"Thank you very much for putting together the article on the Crescendo. I am very excited with the results I am getting. As you say it must be one of the best amplifiers in the world now!"
Thank you 🙂
I have two questions:
Could the BDY's be replaced by a single more powerfull transistor like SC5200?
What's the role of the TL431 if the zeners are in place?
Thank you again.
Hi paulo.
The precision zeners are there to fine tune the output voltage to match the + and - supply close in value, within millivolts. 🙂
The precision zeners are there to fine tune the output voltage to match the + and - supply close in value, within millivolts. 🙂
Of course, but remember you will need, anyway, a soft start if u use big caps.
TL431 is an adjustable Zener, Nor able to go high enough in voltage, thus the need of the other zeners to add their own, that you will chose according your need.
Hi Shaan, I think you forgot to include on your SSA Impotant Links on how to do the biasing on your SSA amps. I'm for sure it will be helpful to eveyone who is attempting to build it, specially on the first power up of the amp. Just my two cents.
Fred
So, Im fairly to new amp building, have built one amp recently and a few kits many years ago. Im looking for a new project and find this to be a circuit id like to build. It looks like a lot of time and energy has gone into this, and I cant wait to start.
You don't need to bias the amp, the 2 1N4148 set the bias for the fets. You need to ajust the dc offset with the trimpots or use the servo version instead.
How much current goes trough the zeners?
How many volts should be across the transistors? (vin-Vout)
thanks
I is Set by the 380 Ohm. (V=RI) need ~ 1/100 of the requested output current.
Vin-Vout/Vin is perfect around 7%: More, you need more power dissipation for the power transistor, less, you have less margin when AC flows or high demand. Tune-it to let a little margin when full power with the amp on its charge.
If it is too complicated, just change the Zener total values to let 25/30V in the TL431, according to your V.
It is the simplest stabilization you can find, so simple that i think it need no further out of topic explanations.
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