I found one of my amplifier distorted in short of time after high energy low frequency gone in the music. How do you measure that phenomena?
My priority when I design an amplifier are: 1. slew rate. 2. low THD at 20kHz. 3. Monotonic harmonic profile. 4. Good clipping (better it have soft clip). 5. High PSRR.
My priority when I design an amplifier are: 1. slew rate. 2. low THD at 20kHz. 3. Monotonic harmonic profile. 4. Good clipping (better it have soft clip). 5. High PSRR.
It's good that you wrote something about the magnitude response, but I think the deviations you allow are too large, they may even be audible in a direct comparison. You didn't write anything about clipping indicators.
Anyway, happy New Year!
Considering AFOM objective:
How would an amplifier earning 5 points for rated power but losing 5 points on THD+N, IMD and response into complex load be equal to low power amp that excels all other criteria?
There could be a separate list for features, price, rated power and other criteria.
Happy New Year to all and may your DIY projects be very successful.
useful features should not make it to the list. How would speaker’s protection and clipping indicator show on DBT or measurements? Even price and rated power are dubious criteria.
How would an amplifier earning 5 points for rated power but losing 5 points on THD+N, IMD and response into complex load be equal to low power amp that excels all other criteria?
There could be a separate list for features, price, rated power and other criteria.
Happy New Year to all and may your DIY projects be very successful.
(No class D!) A SMPS Power supply is the same as a linear one except it is a rectifed 50-150Khz output instead of 50-60Hz. Can be highly regulated
by (PWM)feedback - varying the duty time at the trafo. Rectifed 100Khz supplies have 0 ripple in the audio band !
They have been using 500-1KW SMPS's on the Wolverine. No mains , just (small)>50Khz ripple. Amp PSRR >20K is the metric to be looked at here.
With most SMPS , amp overcurrent can also trip the PS at overload.
OS
You might be surprised, some of us do such tests
. The results are of course unpopular, FR deviations are really the only important point, distortion is pointless unless it reaches enormous values. It is unpopular for audiophiles and DIYers as well. The test must be level matched, with no clipping of course.
Ostripper, I guess this must be for a regulated SMPSU? An unreg SMPSU will still have ripple components since the incoming mains is FWBR before it goes to the switching stage I believe, so the only way to get rid of the LF ripple components is to reg them out. It is cheaper and easier to regulate an SMPSU rather than a linear PSU as you know. I think the way to deal with this is to just ensure the PSU noise is measured in wideband (80 kHz)- regulated SMPSU will show lower mains ripple, but we should catch any HF noise.
It has been proposed that rather than a single number, a graph showing the amplifier's performance in each category accompanies the overall score.Considering AFOM objective:
useful features should not make it to the list. How would speaker’s protection and clipping indicator show on DBT or measurements? Even price and rated power are dubious criteria.
How would an amplifier earning 5 points for rated power but losing 5 points on THD+N, IMD and response into complex load be equal to low power amp that excels all other criteria?
There could be a separate list for features, price, rated power and other criteria.
Happy New Year to all and may your DIY projects be very successful.
You won't 'hear' protection features in a DBT, but it's one of those aspects that must be included IMV. There was a Trio amplifier from many years ago that had no output protection. If you shorted the output, the amp OP devices blew. OTOH, on my low power class A amps, because the OP devices are hugely overrated if you short the output, the amp module fuses pop but the amp is ok. In the case of the sx and kx2 amps, they would score 2 points for overcurrent protection, but get 0 for DC offset and 0 for thermal protection.
Most of the ones made for class AB amps are highly regulated. They even regulate the line side of the switcher to get the power factor right (PFC).
Good ones will have an advanced PFC stage and - https://www.monolithicpower.com/understanding-llc-operation-part-i-power-switches-and-resonant-tank
an advanced LLC resonant converter IC. Absolutely outperforms a linear in every way.
OS