Why the generic 1 kHz sweep and not the 20Hz I'm talking about.I'll certianly let you know the 1kHz power sweep as planned.
Why the generic 1 kHz sweep and not the 20Hz I'm talking about.I'll certianly let you know the 1kHz power sweep as planned.
Maybe I'll start doing 40Hz like Amir has recently incorporated. At any rate, I believe Alan is going to be getting you the data you need before me so either way you'll have an answer.Why the generic 1 kHz sweep and not the 20Hz I'm talking about.
Ahhh ... I see what you just did, my friend. Peace and no worriesMaybe I'll start doing 40Hz like Amir has recently incorporated. At any rate, I believe Alan is going to be getting you the data you need before me so either way you'll have an answer.
Could you please confirm if this test was conducted using the latest amplifier module provided by Purifi? There were issues with the previous version—was it a problem with the entire trial production batch, or only some individual units?Here is a quick and dirty IMD 19+20kHz measurement of the monoblocks shipping out to JA (Stereophile) on Wednesday.
That test was done with a recent batch from December.Could you please confirm if this test was conducted using the latest amplifier module provided by Purifi? There were issues with the previous version—was it a problem with the entire trial production batch, or only some individual units?
Why the generic 1 kHz sweep and not the 20Hz I'm talking about.
Nope, just the very first batch of 9040 modules back in JuneJudging from the pictures online, there are also multiple versions of their 1ET6525. Did the first batch have the same issues?
Amplifiers are generally expected to amplify the full range, aren’t they?I am guessing that you are concerned with using the amp as a subwoofer amp??
Or why the 20 Hz?
Maybe… Maybe not.Amplifiers are generally expected to amplify the full range, aren’t they?
Testing at the extremes can provide a good indication of performance across the range.
Because some class D amps have had issues playing low end notes (higher THDN and power than at mid range) due to the nature of their design...inadequate power supply capacitance creating bus pumping issues.I am guessing that you are concerned with using the amp as a subwoofer amp??
Or why the 20 Hz?
I would have thought that testing across the range of interest would provide a good indication of performance across the range of interestAmplifiers are generally expected to amplify the full range, aren’t they?
Testing at the extremes can provide a good indication of performance across the range.
Not true, unfortunately. Take tube amps for example. They perform well in the midrange but suffer from low bass extension due to transformers that step down the high voltage signals (hundreds of volts) to normal voltages. Transformers saturate quickly at low frequencies, increasing distortion and having a 'bandpass filter' for a frequency response.I would have thought that testing across the range of interest would provide a good indication of performance across the range of interest
I can understand that in terms of the power supply.Because some class D amps have had issues playing low end notes (higher THDN and power than at mid range) due to the nature of their design...inadequate power supply capacitance creating bus pumping issues.
Is that not in the range of interest?low bass extension
You are correct. I thought by 'range of interest', you meant a custom user defined range and not the 20Hz - 20kHz standard audio range.Is that not in the range of interest?
I would expect any amplifier to deliver full power across the entire human audible range.Maybe… Maybe not.
A lot of systems have subwoofers to do “the hard work”, and that makes the floorstanders not have to do it all, and reduces some of the distortion in the main speakers.
Obviously someone looking at 1.4 kW amps is likely wanting some significant bass capability as that is where lost of the power goes.
But it would not be unreasonable to have a 1.4kW amp mostly for headroom… while scraping the lower registers off and servicing them with a subwoofer.
OK I get where you are coming from.I would expect any amplifier to deliver full power across the entire human audible range.
While one might argue that full power at high frequencies isn’t always necessary, the area where full power is absolutely critical is at low frequencies. In this regard, there should be no room for compromise.
There is not a lot of compromise here… it is good performing amp by most objective standards.... In this regard, there should be no room for compromise.
My main point is about transparency.OK I get where you are coming from.
1) However playing 20Hz tones at 1400W versus 1000W is somewhat different than
2) Playing music with a peak value of 1400W, and an RMS power at whatever the crest factor ends up at.
The test says it will not do #1.
There does not seem to be a test showing that it is doing #2
And, at home, we do not usually do scenario #1…
That is my point.
That failure to do 1400W sustained is meaningless unless you have some open area and/or huge room.
In which case one is almost certainly using multiple amps and speaker boxes… often some of them being subwoofer boxes.
Maybe you are blessed with a very large room, and it is a real concern.
There is not a lot of compromise here… it is good performing amp by most objective standards.
And if one is even using the full 1400W, then they just get consider using a beefier power supply.
Otherwise it seems like pissing-n-moaning about loss of a dB or less, and a legal challenge towards not meeting spec.