Hey
I really need some help with my high THD ... i really dunno what happen to my High THD can anyone help me giving me some advise with 10hz THD is 0.0006% .. but i simulated a 73% for the Blameless power Amplifier.
I really need some help since I have stucked.
Below is the Blameless.asc and also the Diagram of the THD result .
Mind everyone for the help!
View attachment ClassB(THD8ohm).txt
I really need some help with my high THD ... i really dunno what happen to my High THD can anyone help me giving me some advise with 10hz THD is 0.0006% .. but i simulated a 73% for the Blameless power Amplifier.
I really need some help since I have stucked.
Below is the Blameless.asc and also the Diagram of the THD result .
Mind everyone for the help!
View attachment ClassB(THD8ohm).txt
Well, the output clearly shows he's simulating 10kHz, not 10Hz. That's a much more reasonable number.
Likely you're DC-operating points are completely banana.
Always distrust the computer.
Have fun, Hannes
What does it mean by DC-operating points are completely banana?
How does it know ?
add .options plotwinsize = 0 to your spice diagram. also you will have to simulate at a small timestep like 0.05u.
Post your LTSPICE .ASC file and we can help more
I have post the .txt file and you can change to .asc .
thank you
This gives sensible results:
.four 0.01kHz V(OUTPUT)
.tran 0 500m 100m 0.1m
Ya man ... the THD is lower but it should be 0.0006% in the BLameless ..
IS the input voltage frequency should be same as 0.01K for the command of
.four 0.01kHz V(OUTPUT)?
Are they the same?
How does it know ?
Any amp you want to simulate you need to know very well first. You need to understand how it works and what the DC-working points (currents, voltages) are. Otherwise you cannot be sure that the results are worth the time you needed to generate them. A simulator does not replace basic understanding of the circuit.
However, first you should read the wikipedia-article on distortion
I'm sure then it's more clear what signal to put in (1kHz) and what to analyze for (1kHz).
Have fun, Hannes
Hey.
If the longer Time Stop the make the Distortion to be more accurate?
Another question, What is the optimal Frequency if the stop time is 2000m?
Cause I use .trans 2000m 1m 0.01m as the command to operate a 10Hz of Input voltage. But i dunno does the Frequency is suitable or not?
Also what is the Suitable Step time for a suitable Frequency?
If the longer Time Stop the make the Distortion to be more accurate?
Another question, What is the optimal Frequency if the stop time is 2000m?
Cause I use .trans 2000m 1m 0.01m as the command to operate a 10Hz of Input voltage. But i dunno does the Frequency is suitable or not?
Also what is the Suitable Step time for a suitable Frequency?
there must be enough cycles...10 is enough generaly,at least in my
simulator whch is not ltspice..so set up the stop time accordingly..
a 20ns step time is enough at 10khz..
if you decrease the frequency, don t decrease the step time
colinearly, stay at 50ns for 1khz, and so on..
simulator whch is not ltspice..so set up the stop time accordingly..
a 20ns step time is enough at 10khz..
if you decrease the frequency, don t decrease the step time
colinearly, stay at 50ns for 1khz, and so on..
Interesting - why is that (with the time step)
I usually simulate 10 cycles with timestep 101n7 for 1kHz
and 10n1 for 10kHz. (no real reason for these values - they are easy to type, and they don't divide the cycletime I suppose)
You must take a look at the actual waveform that you fft. this way you can make sure it isn't heavily distorted (clipped).
Also check the bias conditions in the output devices.
In real life the BC5?7 and BC8?7 devices are rated at max 45Vce. So if you actually built that amp with these devices in the VAS it is likely to go up in smokes.
I usually simulate 10 cycles with timestep 101n7 for 1kHz
and 10n1 for 10kHz. (no real reason for these values - they are easy to type, and they don't divide the cycletime I suppose)
You must take a look at the actual waveform that you fft. this way you can make sure it isn't heavily distorted (clipped).
Also check the bias conditions in the output devices.
In real life the BC5?7 and BC8?7 devices are rated at max 45Vce. So if you actually built that amp with these devices in the VAS it is likely to go up in smokes.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- Blameless THD